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Project Specific Discussions => Filters/Equalizers => Topic started by: audiox on June 26, 2008, 03:09:54 AM

Title: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on June 26, 2008, 03:09:54 AM
(http://audioxxx.googlepages.com/W492_face_1.jpg)

(http://audioxxx.googlepages.com/W492_pcb_1.jpg)

(http://audioxxx.googlepages.com/W492_pic1.jpg)


I have designed a new (more DIY friendly) PCB for Neumann W492. It is a good sounding equalizer that I selected to be part of my mixer project. I will publish all the documentation here when it is ready.


Electronics:

Schematic  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVMDkyMmRlNjEtZmQwMS00OTgwLWJkYzMtNWRmNGYyZTE1NTRm&hl=en
Parts list  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVNWUxZjBhNjYtYjI0Ny00YzYwLWFlZmYtMTZjZTU4ZjhlZmE4&hl=en
Wiring  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVN2QwNmY2MTEtM2ZjYS00MDM5LTk5YzItNmFjZDIzNGM0YWUw&hl=en
Component designations top  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVNTZjNmUzYmMtYWJhYS00YTAwLWEwZDQtYjVlZThlMDlkZmQ5&hl=en
Components values top  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVMDEzYmEzNzAtNDI2ZC00NjllLTlkNTctZjlmNzRiMGRmNzJh&hl=en
Component designations bottom  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVMWE5ZjQ3MWMtNjZmOS00NzJjLTgzYTgtOTQzYWQ5MTljYjEw&hl=en
Components values bottom  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVYjMwMTU3MzctNWEwMi00NTVhLTlhNTgtMjU3ZDUyYjZiMjgy&hl=en
Trimmer adjustment  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVM2YzYTFlZmMtYjY0OS00NDkyLTlhOWYtNjVlYmNmZTkwNGM0&hl=en

PCB (Sfernice potentiometers):

Copper top  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVMGVlYmQxNzEtOTJkOS00YmIxLTg3ODEtMjQyN2UzNTdhZDE5&hl=en
Copper bottom  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVN2UwNDMzMmYtZjAzNi00MWQ4LTgzYjEtZWJiMWNlZDYxYWE4&hl=en

PCB (Omeg potentiometers):

Copper top  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVYzFhZjc5ZmEtNTFhNS00MDE1LWIxMDMtODEyMGNhZDQ3Njgw&hl=en
Copper bottom  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVNGY3YjhiMzQtMDE2Yi00MjFmLThjZTgtMmJlM2UyNWJlMjM1&hl=en

Curves:

Filter 1  http://docs.google.com/fileview?id=0B_XBYPfmG8pVYWZjOGU4N2QtODE2YS00ZTgyLTkwMDEtMzIzN2Y4YWE0YjQx&hl=en
Filter 2  http://docs.google.com/fileview?id=0B_XBYPfmG8pVOTBkNTg5MDMtODZlMC00Mjc3LWE2ZGUtM2Y4NDIyZmJlMmEx&hl=en
Filter 3  http://docs.google.com/fileview?id=0B_XBYPfmG8pVYmZkYjhkZDQtOTQ1Mi00ODcyLTk1ZWItYmRjZjMxYmI4MmQ2&hl=en
Filter 4  http://docs.google.com/fileview?id=0B_XBYPfmG8pVMWI3Y2E3NTQtMDU0MS00Y2RlLThjMmUtN2ZiZGY5N2EwNDQy&hl=en

Mechanical:

Potentiometer assembly  
http://docs.google.com/fileview?id=0B_XBYPfmG8pVMTg4OTRiYWItYWY5ZS00OGRjLWFkMzEtYjM4MWE0OTM3YmMz&hl=en


Some details:
- low shelving filter +/-15dB, 50-400 Hz
- presence/absence filter +/-15dB, 0,063-1 kHz
- presence/absence filter +/-15dB, 1-16 kHz
- high shelving filter +/-15dB, 3-10 kHz
- all filters can be switched individually in/out
- balanced input and output


Boards are available here:

http://www.groupdiy.com/index.php?topic=10776.0


Potentiometers and knobs:

http://www.audiomaintenance.com/acatalog/potentiometers_conductive_plastic.html
http://www.groupdiy.com/index.php?topic=345488#345488

If you have other sources of potentiometers and/or knobs, please let me know. I will add them here.

http://www.vishay.com/docs/51031/p11.pdf (P11 datasheet)

**********

My other projects:

Studer 169 EQ
http://www.groupdiy.com/index.php?topic=33996.0

Neumann OA10 discrete op-amp
http://www.groupdiy.com/index.php?topic=34105.0

Balanced 12 input summing amplifier
http://www.groupdiy.com/index.php?topic=29082.0

Balancing/unbalancing amplifier
http://www.groupdiy.com/index.php?topic=29333.0
Title: Neumann W492 equalizer DIY project
Post by: Junction on June 26, 2008, 03:44:06 AM
I would be interested in 4 x PCB's for this, assuming you are going to manufacture PCB's.

You mention the pots are hard to get, is there an alternative pots that are easy to get that you could design it with?

How long do you think it will take to get to PCB stage? Great project, best of luck with this.

Michael
Title: Neumann W492 equalizer DIY project
Post by: matta on June 26, 2008, 04:00:06 AM
Great looking layout/design!

I own a pair of the smaller W491's. If I"m not mistaken they are transformer coupled on the output or inputs, I assume these W491's are transformerless?

Also I assume for the frequencies you are using rotary switches? I know on my W491's both the freq's and the Gain are both on stepped switches, in your design are they constantly variable, or are the freq's on switches and the gains on pots?

It does indeed look like a very cool project and funds permitting and depending on costs I'd be in for a few boards.

Cheers

Matt

P.S "A post like this should probably be in the "Black Market" section of the forum"
Title: Neumann W492 equalizer DIY project
Post by: audiox on June 26, 2008, 04:16:14 AM
I am going to order my boards from Olimex. That is why I have selected the size so that two boards fit side by side in their proto Euro card. It costs 30 euros so the price will be 15 euros for one board. I will prepare Gerber files for Olimex if someone else also likes to order from them. I will also prepare normal Gerber files (only one board) for ordering from other manufacturers. I am not going to start selling these PCBs. This is not a business to me. I am just sharing my design with you. If someone manufactures these PCBs and sells them to others, that is ok to me.

The W492 is DC coupled (no blocking capacitors) so potentiometers must be conductive plastic. Normal carbon pots will start to scratch quite fast. As I told I will order Sfernice P11 for my own use. I can order some extra if someone else needs them too.

Frequency selection is continuosly adjustable (potentiometer). All potentiometers are mounted on PCB. Only in/out switches are wired.
Title: Neumann W492 equalizer DIY project
Post by: livingnote on June 26, 2008, 04:22:41 AM
Oh, I like it! Nice and organized layout...

Did you get the pictures alright?

Btw, for us home etching nuts over here, is there any chance you could post a layout so that I can give that thing the scanner treatment? I could run a little comparison with the console when I get around to building it.

This gets me thinking...how about something along the lines of a stereo version? Neumann never built any of those. I guess it should be simple enough with 2 board, stereo pots and some component matching if necessary.
Title: Neumann W492 equalizer DIY project
Post by: Tubemooley on June 26, 2008, 05:09:36 AM
Yo - This is great. Your design looks very good. Posting your design as Gerbers is great. I understand completely if you don't want to go into the business of selling PCB's. But doing all this work and posting it for us is more than admirable. One note - Purchasing Sfernice P11 pots is very difficult. I have tried. They are not in stock hardly anywhere. You can place an order for some minimum quantity (like maybe 50 pieces) and then wait 3 months to receive them. They are Cadillac pots. But they are not easy to just get. I have seen one or two places which stock some of the singles. Whether or not they have the desired value is the question. And dual's or triples..... forget it. DW.
Title: Neumann W492 equalizer DIY project
Post by: jensenmann on June 26, 2008, 07:26:27 AM
Audiox, that´s a friggin´cool project. Thanks for sharing.

In your place I would not post the gerbers in the public. There are so many lurkers around here waiting for a opportunity to make a fast buck. I´m pretty sure that it won´t take long from posting gerbers to the day when the first "german broadcast eq clone" is sold by a "professional" company with your work burried inside. This happened here before - several times. The day you realize this will be the day that it´s too late and maybe the day you get angry. I would definitely not give anybody the opportunity to profit this way from my work.

I think it´s cool to post the pdfs for home etchers plus the component placement. If you want to share the gerbers send them to Gustav or some of the other boardmakers here and let them distribute the finished boards. Don´t send gerbers to anybody else. That way nobody will be able to simply edit your files a little and then have a finished piece of proaudio-gear.

just my 2 cent
Title: Neumann W492 equalizer DIY project
Post by: audiox on June 26, 2008, 08:27:30 AM
I think I will publish the Gerbers when I have finished them (despite all the warnings). I don't want money or glory from my designs. I am happy if someone builds them. If some other misuses them it his shame.

Sfernice P11 is not so difficult to get. A friend of mine works in a company that stocks the type I have used in this design. He gave samples for the prototype. And there are several distributors for Sfernice too. I am going to make 10 channels first, so I need at least 80 potentiometers. I am going to order some extra, so please feel free to contact me if you need them. I was told that delivery time from Sfernice is only few weeks (in Europe).
Title: Neumann W492 equalizer DIY project
Post by: bernbrue on June 26, 2008, 09:14:32 AM
Hi Audiox,
very interesting project. Top quality DIY EQ are quite rare here, so for my part, I would like to build this one. Keep us informed especially concerning pcbs and pots. You shouldn´t publish the gerbers here, as Jens mentioned, contact some of the pcb sellers here (e.g. Gustav), who would be glad to provide you and all others here with pcbs for a reasonable price.
regards
Bernd
Title: Neumann W492 equalizer DIY project
Post by: clintrubber on June 26, 2008, 09:20:15 AM
Quote from: "audiox"
I think I will publish the Gerbers when I have finished them (despite all the warnings). I don't want money or glory from my designs. I am happy if someone builds them. If some other misuses them it his shame.

People like you and me and many others here would indeed not enjoy the money they might have made this way.

Various others don't care at all about that though, money is money. I would hate to see something like that happen based on the info you provided.

I'd suggest to reconsider your distribution-plans; before you know it we have for instance yet another PCBs available, but only with cases-deal in The Black Market.

Add at least a clear disclaimer to the documentation and artwork: anyone who uses the provided files isn't allowed to do so for profit (both for PCBs as for 'derived' items).


Best regards,

  Peter
Title: Neumann W492 equalizer DIY project
Post by: okgb on June 26, 2008, 09:59:15 AM
Agree with above

there are some in the community here with a proven record
for honest & fair distribution
Title: Neumann W492 equalizer DIY project
Post by: audiox on June 26, 2008, 10:02:25 AM
OK. I will wait with the Gerbers. I have contacted Gustav, maybe he is interested in manufacturing the boards.
Title: Neumann W492 equalizer DIY project
Post by: cannikin on June 26, 2008, 10:10:15 AM
Very Cool project... I want boards!  great work. :thumb:  :thumb:
Title: Neumann W492 equalizer DIY project
Post by: jensenmann on June 26, 2008, 12:17:07 PM
Quote from: "audiox"
OK. I will wait with the Gerbers. I have contacted Gustav, maybe he is interested in manufacturing the boards.


Good move  :thumb:
I´m sure most people here will appreciate when PCBs are availble, not only the files.

thanks and down a :guinness:
Title: Neumann W492 equalizer DIY project
Post by: bernbrue on June 26, 2008, 01:27:28 PM
Audiox,
very good decision. Gustav is a very loyal man. Looking forward to the boards
regards
Bernd
Title: Neumann W492 equalizer DIY project
Post by: synthi on June 26, 2008, 02:29:42 PM
Great project, thanks for sharing!

Synthi
Title: self etching
Post by: kato on June 26, 2008, 03:35:53 PM
Can you share just the copper layer for those of us to self-etch a couple boards?  Thanks,  Kato
Title: Neumann W492 equalizer DIY project
Post by: livingnote on June 26, 2008, 05:35:59 PM
Yah speaking of Neumann, I was thinking sometime of possibly doing a rebuild of the W495 STB, I wonder if that's been done here before somewhere...
Title: Neumann W492 equalizer DIY project
Post by: audiox on June 27, 2008, 01:46:24 AM
Lets wait for Gustavs answer. I send him e-mail yesterday. After that I make a decision about publishing (or not) Gerbers and copper layer pdfs.

I think that publishing pdf is practically same as publishing Gerbers. I can do pdf to Gerber conversion in 15 minutes, so I guess others can do it too.
Title: Neumann W492 equalizer DIY project
Post by: audiox on June 27, 2008, 02:09:10 AM
To Livingnote:

Have you noticed that the W495(ST)B uses 741 op-amps. So I wouldn't use it in original form in any demanding applications. The circuit is quite simple, so DIY version is not impossible but I would change the op-amps and the balanced output circuitry. However using the original switches makes it very very expensive. It is cheaper to buy a used one than to build a new.  

And by the way thanks for the pictures you send me some days ago.
Title: Neumann W492 equalizer DIY project
Post by: Brizco on June 27, 2008, 05:57:42 AM
thanks for all the documentation!

cant wait to build some :)
Title: Neumann W492 equalizer DIY project
Post by: audiox on June 30, 2008, 07:24:39 AM
I contacted Gustav 4 days ago by e-mail. No answer so far. Maybe spending his holiday?
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on June 30, 2008, 09:50:35 AM
very nice project , can't wait for pcbs!!want them!!
thx. :thumb:
Title: Neumann W492 equalizer DIY project
Post by: okailla on June 30, 2008, 11:21:20 AM
Great Project! I need 2 PCBs and two sets of these potentiometers.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 01, 2008, 04:19:08 AM
Gustav manufactures the boards. More info soon!
Title: Neumann W492 equalizer DIY project
Post by: jensenmann on July 01, 2008, 04:24:11 AM
:green:  :thumb:  :thumb:  :thumb:
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on July 01, 2008, 05:03:47 AM
:thumb:  :thumb:
 :green:
Title: Neumann W492 equalizer DIY project
Post by: Gregory Pecary on July 01, 2008, 05:06:31 PM
Guess what ?

For many many years it was nearly impossible in Paris to get other pots
than P11.
You only had the choice between realy crapy Radiohom and the Sfernice P11.
Nowdays,the choice remains the same.Radiohom or P11.
It means that the p11 is still overstocked in Paris.
Even in crazy values like quad 100k or dual log /rev log.

Ok for the story.

Here are few links to see what i am talking about.


SAINT QUENTIN RADIO


linear range single

http://www.stquentin-radio.com/index.php?page=categorie&color=2&cat=2&sous_cat1=25&sous_cat2=81&sous_cat3=0&code=0&desig=0&vignette=1&id=0&act=0

log range dual

http://www.stquentin-radio.com/index.php?page=categorie&color=2&cat=2&sous_cat1=25&sous_cat2=82&sous_cat3=0&code=0&desig=0&vignette=1&id=0&act=0

Lin range dual

http://www.stquentin-radio.com/index.php?page=categorie&color=2&cat=2&sous_cat1=25&sous_cat2=83&sous_cat3=0&code=0&desig=0&vignette=1&id=0&act=0

log range dual

http://www.stquentin-radio.com/index.php?page=categorie&color=2&cat=2&sous_cat1=25&sous_cat2=84&sous_cat3=0&code=0&desig=0&vignette=1&id=0&act=0

SELECTRONIC

http://www.selectronic.fr/recherche_produit.asp

And search '' P11''

I can of course help any non french speaker to place an order if interested.

Cheers

Greg :cool:
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 02, 2008, 02:11:20 AM
If I understood right from the web site this French distributor stocks only cermet, not conductive plastic...
Title: Neumann W492 equalizer DIY project
Post by: Gregory Pecary on July 02, 2008, 02:27:11 AM
Yes.
Does it make a difference ?
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 02, 2008, 04:18:42 AM
I would use conductive plastic because the circuit is DC coupled.  

There is also a mechanical problem because these pots have 6mm spindle and the original has 4mm. So 10mm knobs doesn't fit. The smallest knob size for 6mm spindle is 15mm and that can be a problem in front panel design (there is not much space between the knobs for markings).
Title: Neumann W492 equalizer DIY project
Post by: signalflow on July 03, 2008, 10:47:19 AM
audiox,

Where are you getting your P11's from, how much are they?  I maybe interested in getting in on that order.

-Casey
Title: Neumann W492 equalizer DIY project
Post by: stitch-o on July 03, 2008, 11:16:24 AM
Quote from: "jensenmann"
I´m sure most people here will appreciate when PCBs are availble, not only the files.


I am one of them.
I JUST sold some studio eqs and now realize what I did...
about an hour later, I saw your thread.

I am happy again...thanks!

cheers!
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 03, 2008, 01:07:09 PM
Boards are available. Many thanks to Gustav. See the first message in this thread. I also added some info of my source of conductive plastic potentiometers.
Title: Neumann W492 equalizer DIY project
Post by: cannikin on July 03, 2008, 05:37:17 PM
If you get paypal happening ... i'll take 16 P11 from you
Title: Neumann W492 equalizer DIY project
Post by: hitchhiker on July 03, 2008, 07:53:55 PM
Like David, If Paypal OK then I'd like 4 of the P11,

Thanks for the cool project. I have 2 of the 495stb here and they are sweet, BTW the chips are not the poor early v 471 (they are a later upgrade v) just as PRR clearly pointed out years ago. Don't be afraid of picking these up folks.
 My one complaint would be the 2 db gain steps are too big. 1 db steps would be so much better IMO.
Title: Neumann W492 equalizer DIY project
Post by: MartyMart on July 03, 2008, 09:14:53 PM
I'm speaking with these guys tomorrow :

http://www.nobelelectronics.co.uk/vsfernice.htm

If there's a decent interest in pots for Europe then I may do a group buy
when I get a good quantity break/discount for perhaps 200 units.

Will let you all know tomorrow, payment would have to be up front as there's
16 pots needed for a pair !!

Will keep you all posted,

Marty.
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 04, 2008, 01:08:18 AM
Nice work on this project. Looks pretty straightforward even for a noob like me.

I have 2 questions...

what is everyone doing for power?

And 2, about pots.. Audiox, can you confirm the lead spacing for the pots? Is it 2.54 or 5mm? I've found a few pots that would work (I think) but they are all 2.54 spacing and I can't tell which P11 you are using from the part list. Can you tell me if this one would work?

http://www.alliedelec.com/Search/ProductDetail.aspx?SKU=7532292&MPN=590SX1N56S103SP&R=7532292&SEARCH=7532292&DESC=590SX1N56S103SP

Thanks!
Title: Neumann W492 equalizer DIY project
Post by: Grand Master Audio on July 04, 2008, 01:36:06 AM
Hi all,

what is it about the vishay sfernice p11a that is so unique?

is it a physical difference or and electronic difference?

just curios to see why you would not use a normal pot here.

Best
Pete
Title: Neumann W492 equalizer DIY project
Post by: mad.ax on July 04, 2008, 04:54:58 AM
About pots...

AFAIK Sfernice P11 are 5.08 spaced. Too bad cause most of the alternatives are 2.54...
Probably too late to change the board design and include a dual footprint...


According to the part list, we need 8 X 10KLIN PA11QXF
and looking at the drawings all pots footprints look the same.
But from the schematic, P4 and P6 should be dual pots, no?

Axel
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 04, 2008, 06:10:49 AM
All potentiometers are dual 10K linear. Only two of them needs to be duals, but the dual type is used in all positions because it is mechanically more stable than single and buying only one type is cheaper than buying two types. Pin spacing is 5.08mm.

to sinestaraudio:
Conductive plastic pots must be used because the circuit is DC coupled. Normal pots start to scratch quite soon.
Title: Neumann W492 equalizer DIY project
Post by: MartyMart on July 04, 2008, 06:13:20 AM
EDIT _ Sorry Audiox , we crossed posts there !

I almost have the full 18 digit code down but just need the spacing between
the two sets of pin connections, front to back on the board.

Is it also 5.08mm  or 7.62mm or 10.16mm

Many thanks,
Marty.






Yes there's two pots in the schem that seem to be "dual" and the image of
the pots are all the same, It looks like 8 dual pots required, judging by the
front to back pot image size in the project doc's ( compared to data sheet images )

I'm trying to get a group buy together and have PM'd about the details.
I can get  a decent price break @ 250 units.

The Sfernice data sheet needs an 18 digit SAP code for an accurate order,
so the PA11QXF is not enough detail.

Lets see when Audiox gets back about the pots.

Cheers,
Marty.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 04, 2008, 09:17:30 AM
Length between the two rows of pins is 5 mm. Please note that standard tracking between the elements is quite poor in this potentiometer. So you must order the pots with interlinearity option. I think that option is mentioned somewhere in the datasheet.
Title: Neumann W492 equalizer DIY project
Post by: dustbro on July 04, 2008, 11:44:02 AM
Quote from: "audiox"
I have about 100 knobs more than I need because of the minimum order quantity. I am going to make them available too.

 :thumb:
I would definitely go for the knobs and pots
Title: Neumann W492 equalizer DIY project
Post by: cannikin on July 04, 2008, 12:13:21 PM
Quote from: "dustbro"
Quote from: "audiox"
I have about 100 knobs more than I need because of the minimum order quantity. I am going to make them available too.

 :thumb:
I would definitely go for the knobs and pots


ME too
Title: Neumann W492 equalizer DIY project
Post by: king-rb on July 04, 2008, 01:53:23 PM
...
Title: Neumann W492 equalizer DIY project
Post by: MartyMart on July 04, 2008, 02:12:07 PM
Here's the exact 18 digit code for ordering the correct pots, though I find out
on monday about a group buy price for over 250 pots !!

P11A2Q0EJSX00103K  that's 17 digits and the final 18th is the special request
for interlinearity, which doesn't have a "number".

Marty.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 05, 2008, 01:55:50 AM
Potentiometers and knobs available:

http://www.groupdiy.com/index.php?topic=28431
Title: Neumann W492 equalizer DIY project
Post by: lofi on July 05, 2008, 06:18:21 AM
think a gb might be preferable though, with 8 pots a board its going to get quite expensive, plus your freind only has 250 before restocking or 31 boards worth.

its the exclusivity of these pots thats making me hold back from joining in the fun

love and kisses

Iain
Title: Neumann W492 equalizer DIY project
Post by: MartyMart on July 05, 2008, 10:15:43 AM
Iain, let me see what the suplier says on monday, but audiox price is about
right to be fair.

If there's interest in over 250 pieces and the price is under 8 euros then I'll
put up a feeler thread.
I can't possibly fund that kind of number, so payment would be up-front of
the order, which will take approx 4-6 weeks.

The other option , if you are going to put 2 boards in a 1u rack, is to use off
board pots, there's some others with conductive plastic and similar spec for
around £3.50 each ..... I'm still searching !!
( that's a lot of off-board wiring though ! )

Marty.
Title: Neumann W492 equalizer DIY project
Post by: lofi on July 05, 2008, 12:38:40 PM
i have no doubt that the price is about right sir, it was the small supply available that worried me.

i am also looking to make a summing/mixer box for my DAW so thinking about 24 EQ's. i am tossing between this and the ts80 available and cost/performance would be a factor.

Iain
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 09, 2008, 12:14:13 AM
Hey Marty,

It looks as if there is a huge interest in pots in the BM.. In case Audiox runs out... did you get an answer from your distributor?


EDIT:
ALSO,  is the only reason to use these pots cuz of DC? Do they "sound" better? Could I put some type of blocking caps, and then use regular carbon pots? Ok, maybe stupid question... but I am a total noob here. and cheap.

thanks
Title: Neumann W492 equalizer DIY project
Post by: cannikin on July 10, 2008, 12:22:05 PM
Hey Audiox

Can you post some pictures of your unit?  trying to figure out the layout of parts on the chassis.
Title: Neumann W492 equalizer DIY project
Post by: MartyMart on July 10, 2008, 12:57:21 PM
They are still thinking about it !
He came back to me on tuesday just to check the final "correct" pot details
and I've heard nothing more.
I asked for a quote for 250 and 500  !!!!

I'll chase them up.

MM.
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 10, 2008, 08:21:03 PM
Thanks Marty!

I also thought of the off-board pots, been looking like crazy at all the distributors.  Makes the front panel easier to do in my opinion... No worry about the wires, no one is going to see it but me!

What do you guys think about the DC blocking caps to be able to use carbon pots? Stupid idea??
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 12, 2008, 03:01:09 AM
To mitsos:
Carbon pots and DC blocking caps doesn't work because potentiometers provide also DC path for the op-amp inputs.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 12, 2008, 03:01:46 AM
I added a new drawing about potentiometer assembly and front panel drilling:

http://audioxxx.googlepages.com/potentiometer_assembly.pdf
Title: Neumann W492 equalizer DIY project
Post by: cannikin on July 12, 2008, 03:16:47 AM
Thanks Audiox

Now I can visualize how this thing lays out on the front panel ... thanks very cool very excited.
Title: Neumann W492 equalizer DIY project
Post by: Purusha on July 12, 2008, 07:12:10 AM
I have two questions.

1. What kind of PSU can we use with these?
Will there be any PSU boards available?

2. What kind of miniature toggles can we use here?
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 12, 2008, 08:15:10 AM
Any psu type giving +/- 12 to 18V will do the job. I guess there are number of designs available that have been succesfully used with other diy projects.

There are generally two types of small toggle switches: miniature and subminiature. Most common is the miniature like C&K 7101 (the standard toggle switch). Subminiature has smaller body (for example Farnell 957-5715. For those living in Northern Europe Elfa 35-355-31 is much cheaper).

If you want that the switches are in the same line with the potentiometers, it is better use the subminiature because there is not much space. If you mount the switch so that the lever moves horizontally, them miniature switch fits too. But it is better looking when it moves vertically. See the face drawing in the first message of this thread.
Title: Neumann W492 equalizer DIY project
Post by: Purusha on July 12, 2008, 09:25:40 AM
Thanks for the info.

I will post my design today. Almost done  :thumb:
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 14, 2008, 04:01:03 AM
Here is information about Neumann W492 knobs. As far as I know these are the order codes for the type used in the original equalizer. Codes are from Ritel catalogue, but is a good idea to check them from the distributor before ordering anything.

Knob 10mm, standard finish, with line, black, 4mm shaft
order code: 2110403

Cap 10mm, standard finish, with line, red
order code: 3010014

Cap 10mm, standard finish, with line, yellow
order code: 3010016

Cap 10mm, standard finish, with line, green
order code: 3010017

Cap 10mm, standard finish, with line, blue
order code: 3010015

www.ritel.ch


Marty: If you are planning groupbuy, Ritel has distributor in UK:

Bulgin Components PLC
Spilsby Road
Romford
Essex
RM3 8SB UK
Great Britain
 
Phone:    +44 (0)1708 343 800
Fax:    +44 (0)1708 376 544
e-mail:    [email protected]
web:    www.buglin.co.uk
Title: Neumann W492 equalizer DIY project
Post by: Purusha on July 14, 2008, 04:05:50 AM
If anyone organizes this GB I am in for 4 sets  :wink:
Title: Neumann W492 equalizer DIY project
Post by: [silent:arts] on July 14, 2008, 04:14:37 AM
Quote from: "audiox"
Here is information about Neumann W492 knobs. As far as I know these are the order codes for the type used in the original equalizer. Codes are from Ritel catalogue, but is a good idea to check them from the distributor before ordering anything

all knobs I have on my (original) Neumann gear are from Elma ...
(but Ritel looks very similar on their homepage)
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 14, 2008, 04:27:56 AM
I have seen some (older) Neumann units with Elma knobs too. But W492 equalizers that I have seen had Ritel knobs. Also in W492 brochure there are Ritel knobs.
Title: Neumann W492 equalizer DIY project
Post by: [silent:arts] on July 14, 2008, 04:33:21 AM
never mind, they look very similar.
take whatever is cheaper.
Elma is availabe in single orders from Farnell and Schuricht, but they are expensive there :roll:
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 19, 2008, 11:03:54 AM
12 units built & tested. All work fine! (Actually I have one more than I need so it is possible that i sell it.)

Some measurements (all filters off):
THD: 0,002% @ 1 kHz
Noise: -95 dBu (BW=20 kHz)
Frequency response: -0,1 dB (20 Hz - 20 kHz)

I will soon write some intructions how to adjust the 4 trimmer resistors.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 20, 2008, 02:21:41 AM
New document added about adjusting the trimmer resistors:

http://audioxxx.googlepages.com/W492_trimmer_adjustment.pdf
Title: Neumann W492 equalizer DIY project
Post by: fantomas on July 20, 2008, 03:27:17 PM
any chance to put the PCB image to etch my own boards¿
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 21, 2008, 01:04:21 AM
Talked before.

Boards are double sided with plated holes, so it is practically impossible to make them at home.
Title: Neumann W492 equalizer DIY project
Post by: kazper on July 23, 2008, 02:47:18 AM
Any chance we could go through Omeg on the pots. ECO line?
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 23, 2008, 03:23:14 AM
You can use any conductive plastic potentiometer. Manual wiring is of cource needed with those types that don't fit mechanically on the pcb. Carbon potentiometers are not recommended. They start to scratch quite soon because the circuit is dc coupled.
Title: Neumann W492 equalizer DIY project
Post by: Purusha on July 24, 2008, 07:55:18 AM
What kind of toroid do I need for this project?
Title: Neumann W492 equalizer DIY project
Post by: Purusha on July 24, 2008, 04:05:31 PM
What toggles we need for this project SPDT or DPDT?
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 25, 2008, 02:57:32 AM
Transformer can be quite small. Current consumption of the eq is about 70 mA per channel.

Switches are SPDT (simple one pole on/off switches). See the wiring diagram.
Title: Neumann W492 equalizer DIY project
Post by: king-rb on July 25, 2008, 04:03:49 AM
"conductive plastic potentiomenters" where can i get some in germany=? its okay if they dont fit on the pcb..
Title: Neumann W492 equalizer DIY project
Post by: Michael Tibes on July 25, 2008, 04:15:34 AM
RS components should have them, I think most of their range is conductive plastic. Don't know if they're the cheapest though.

Michael
Title: Neumann W492 equalizer DIY project
Post by: Fredrik on July 26, 2008, 02:39:38 PM
Does someone know of a company that stocks and sells the sfernice p11 with the special request for inter liniarity?
Title: Neumann W492 equalizer DIY project
Post by: kazper on July 26, 2008, 03:51:59 PM
Any one look into Omeg for the pots?

Conductive plastic track giving a life of 20x103 cycles (or over twice the life of carbon tracks) I think they will work.

http://www.omeg.co.uk/pce16brc.htm

(http://www.omeg.co.uk/images/1ecopot5.gif)

http://www.omeg.co.uk/e2ge16bc.htm

(http://www.omeg.co.uk/images/2geco.gif)

Kevin
Title: Neumann W492 equalizer DIY project
Post by: Rossi on July 26, 2008, 04:20:40 PM
Would wire wound pots do? Reichelt has 10k 4W wire pots @ € 2.50 apiece. No duals, though.
Title: Neumann W492 equalizer DIY project
Post by: tommypiper on July 28, 2008, 11:50:30 PM
Seems wire pots should work, even since there is coupled DC...

Where's Audiox on the subject?

Do you have a part number?

Which pots need to be double, and which are single?
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 29, 2008, 01:54:48 AM
If Omegs work maybe we can convince audiomaintenance to stock them?  Colin is going to do kits for the S800 eq... maybe he'd do this one too?  

TommyP, IIRC, only two pots need to be doubles... looks like P4 and P6. Audiox said he made them all doubles for mechanical stability.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 29, 2008, 02:16:02 AM
Did some internet searching and found this:

http://www.audiomaintenance.com/acatalog/potentiometers_conductive_plastic.html
SF-01-009 - 11mm - 2 gang 10k linear

Looks the same type that I used in my design.
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 29, 2008, 10:21:40 AM
Audiox, I did see those.  With all the options with SF I wasn't sure.

Can you or anyone else confirm,  if you think the Omegs would work?  They are much cheaper (I just got a quote from Omeg... only 0.71 GBP each if you buy 100!) , so I can't imagine they'd be of the same quality, but if they would work, it would make this project much more affordable.  

here is the data on it:
http://www.omeg.co.uk/e16data1.htm

thanks!
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 29, 2008, 11:33:34 AM
Is it conductive plastic (or just a potentiometer with plastic enclosure)? I didn't find any info about the resistance track material.

You should use conductive plastic potentiometers because of the dc coupling. Potentiometers with carbon track start to scratch quite soon.
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 29, 2008, 02:20:22 PM
I wasn't sure either... I assumed Kazper had checked...

Anyway, from Omeg's home page: (Third line of opening paragraph)

Quote

"We use conductive plastic elements in our potentiometer range to give over twice the life of carbon."


http://www.omeg.co.uk/index.htm

Does this mean it's ok then?
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 29, 2008, 03:06:32 PM
Send them e-mail and ask if they use conductive plastic element in that specific model.
Title: Neumann W492 equalizer DIY project
Post by: tommypiper on July 29, 2008, 04:55:16 PM
Quote from: "Rossi"
Would wire wound pots do? Reichelt has 10k 4W wire pots @ € 2.50 apiece.


Rossi, what's the part number, please?
Title: Neumann W492 equalizer DIY project
Post by: Rossi on July 29, 2008, 05:41:05 PM
The Reichelt number is P4W-LIN 10K.

There is a link to the datasheet on the product page; according to that it is manufactured by AB ELECTRONIC SACHSEN

http://www.reichelt.de/?;ACTION=3;LA=4;GROUP=B26;GROUPID=3138;ARTICLE=54296

Andybody know if wire pots are okay with DC? I have no experience with wire pots so far.
Title: Neumann W492 equalizer DIY project
Post by: wolfgang on July 30, 2008, 03:45:32 AM
@MartyMart:

Do have any news from nobeleelctronics?

In the meanwhile i am also contacting an Czech Electronics Supplier, maybe they want to sell something!

Is that Code you postet for the pots correct?

Regards,
Wolfgang
Title: Neumann W492 equalizer DIY project
Post by: MartyMart on July 30, 2008, 06:18:51 AM
Wolfgang, I have news but it was not great.

there's 20 weeks lead time for an order !!
Plus they have three weeks in August off for holiday.

200 + pieces are £6.51 each, may be slightly better for 500 pieces.

My work schedule means that the group buy/ organization could be a problem and I would need all orders paid up-front.

I'm seeking an alternative for the dual pots and have all the single 10k's I
need for 2 complete stereo boards.
You only need 2 duals per project and not 8.

Marty.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 30, 2008, 06:29:57 AM
Marty check this:

http://www.audiomaintenance.com/acatalog/potentiometers_conductive_plastic.html
SF-01-009 - 11mm - 2 gang 10k linear
Title: Neumann W492 equalizer DIY project
Post by: MartyMart on July 30, 2008, 07:27:29 AM
Audiox, thanks for the link, hey could you tell me the specific pots that have to be a
dual on the layout and it it the front or back pin connection that does the job
on the single 10k's ? ( one row of pins against two )

I have Bourns conductive plastic for those .... pin spacing needs some bending though
as it's 2.54mm !

Marty.
Title: Neumann W492 equalizer DIY project
Post by: audiox on July 30, 2008, 08:46:48 AM
P4 and P6 are duals. Front connections are used on singles.
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 30, 2008, 11:06:16 AM
I just got an email from Omeg about their pots. They are conductive polymer.
If you order 100, the dual gang cost 1.11 GBP each + shipping. 4 weeks lead time, but  they don't have 4mm shafts in stock. She didn't say if/when they would get more, but they have 6mm and 6.35(1/4"?)... round. Colin said they won't be stocking pots for this EQ.  Is there a reason to choose the PA11 over these?  I`d be willing to try it with these, if it doesn't work properly, we're out 10 GBP per channel.  

I can't organize a GB because of where I live... anyone else (prob best in UK)?
Title: Neumann W492 equalizer DIY project
Post by: Fredrik on July 31, 2008, 12:45:57 PM
Rapid online stock omeg pots for around 1 euro a pop. The duals are about twice that price, not bad.
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 31, 2008, 01:29:41 PM
That's cool, so we can buy smaller quantities. I just checked shipping with 2 channels' worth of pots and it came to 40 Pounds!   :shock:  :shock:

wow. I sent an email to the US rep to see if there's any there..
Title: Neumann W492 equalizer DIY project
Post by: mitsos on July 31, 2008, 01:38:02 PM
That's cool, so we can buy smaller quantities. I just checked shipping with 2 channels' worth of pots and it came to 40 Pounds!   :shock:  :shock:

wow. I sent an email to the US rep to see if there's any there..
Title: ?
Post by: shabtek on August 29, 2008, 01:17:49 AM
started getting this together and noticed there is no value given for c8, c10.

anybody know why?-- is this part of a symmetric layout style or only to facilitate tweakery? according to the schemo, these are parallel to other caps so it will work without them, but will the corner frequency be as it should?
Title: Neumann W492 equalizer DIY project
Post by: audiox on August 29, 2008, 07:26:50 AM
C8 and C10 are not installed. They are included in the layout because it makes it easier to change the frequency range (if you need a cap value that is not standard).
Title: Neumann W492 equalizer DIY project
Post by: mitsos on September 08, 2008, 09:56:00 AM
If anyone is looking for alternate pots for this project, Laura at TAW has offered to order the Omeg ECO pots. 10K linear singles and duals.  I placed a feeler in the BM to get some idea of quantities so she does not get stuck with a bunch of pots, and we're looking at about 50 channels... I think the pricing will be about $18 per channel..

The only caveat is that the duals have 7.5mm spacing between the two rows of leads and the pcb is 5mm, but it's not a problem for me.  

Check the feeler for more info. This is not a group buy, the pots will be sold by TAW.
Title: Neumann W492 equalizer DIY project
Post by: kazper on September 08, 2008, 03:31:11 PM
I checked out the omeg's that I have left over from my Calrec purchase and they will fit nicely provided you don't buy real boxy caps. As Mitsos said, there well be some bendage to get the duals in there.

Cool if this goes through as I need some caps from TAW and been holding out.

Kaz
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on September 11, 2008, 01:42:10 PM
Hi there , sorry for the noob request , but has someone done a bom??I'm working on mine , and , as always...I'm lost in the forest of ceramic / film capacitors... :oops:  :oops:
Thx...
Title: Neumann W492 equalizer DIY project
Post by: mitsos on September 11, 2008, 01:57:48 PM
I could send you mine.. but there are no part numbers.. Just a bit more info than audiox's part list (lead spacing etc). Don't know if it will help you much, I just send it to Laura at TAW with a request for polypro caps where possible, and she sent the stuff to me. Except the pots/trimmers/swtches/ICs.  pm me your email if you want me to send it to you.
Title: Neumann W492 equalizer DIY project
Post by: cannikin on September 11, 2008, 02:54:52 PM
you can try this, part numbers are from Mouser:

(http://idisk.mac.com/cannikin-Public/W492_parts_list.jpg)

you can handle the resistors - metal film mouser #
271-THE_VALUE_OF_THE_RESISTOR-RC  Example (271-1K-RC = 1K)

This is where I'm going with it but use at your own risk.... :cool:
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on September 11, 2008, 04:18:00 PM
Ok Mitsos , thx!!!
With F*rnell , I've several problem to find all poly in the w*ma brand...

Here is mine :
http://www.keepandshare.com/doc/view.php?id=798030&da=y

EDIT: thx Cannikin too!! :thumb:
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on September 11, 2008, 04:22:34 PM
It's easier for me to have all from F*rnell , but if every poly (wima) are avaible at TAW , I'll order them here...
what about CK7101??No suitable parts at F*rnell??
what about Phoenix resistors 0,6w??Good brand??
thx guys , really helpfull !!
Title: Neumann W492 equalizer DIY project
Post by: mitsos on September 11, 2008, 04:41:38 PM
the CK7101 is the switch? I think any switch will work, no?  Someone pls verify this?

.6W resistors seem like a lot..You may have issues with things not fitting the board. It's pretty tight.  On the BOM I sent you I put the max width and/or length of the caps so I wouldn't get something too big.  You may have cosmetic probs with two of these resistors next to each other, or next to a cap. Things may not fit flush... Cannikin's suggestion above brings up 1/4 W.

I ordered all 1/8 W resistors. I hope that's not too little?  Audiox or anyone else care to comment?
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on September 11, 2008, 04:47:16 PM
In fact , I do not find a CK7101 at F*rnell...and I've no idea if it must be on/on or something else...We'll see!!
 :green:  :oops:  :green:
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on September 11, 2008, 04:54:56 PM
regarding .6W resistors , I've tried with some I'd laying around .It s ok.
What about the brand??Is it a good brand??
Title: Neumann W492 equalizer DIY project
Post by: buschfsu on October 03, 2008, 02:00:43 PM
cannikin, your bom has polyesters and ceramics mixed in.  i though polypropelyne/styrene  was the best way to go for eq? any concerns with these?
Title: Neumann W492 equalizer DIY project
Post by: bernbrue on October 03, 2008, 02:26:13 PM
Hi,
I thought of using Lorlins (1x12 and 2x6) instead of the pots. Ok, I would have to wire them, but are there any other obstacles I didn´t think of?

My questions:
- would it make sense to use switches instead of pots (was thinking of using it as mastering EQ)
- are the most relevant frequency covered with Lorlins?
- are 12 positions (6 for the dual pot) enough for mastering purpose?

Would like to hear your suggestions/opinions
regards
Bernd
Title: Neumann W492 equalizer DIY project
Post by: craptical on October 11, 2008, 06:41:22 PM
Hi Bernbrue!

From a mastering perspective I would feel a bit limited with so few(6) frequencies in the midrange. I would go pots for frq (Maybe even one set of frq controls for both channels, where possible (4-gang pots!)) and rotaries for amount, in +/- .5 dB steps. This gives you a range of +/- 3 dBs if you skip the "zero" position in the middle (and use the in/out switch). I rarely find myself going outside the +/- 2 dB range when mastering. Maybe a .5/1/1.5/2/3/4 scale could be useful if greater range is needed.

I was also thinking about this project as a possible mastering tool, so I too welcome any additional thoughts on the subject.

 :guinness:

/Dave
Title: Neumann W492 equalizer DIY project
Post by: Gold on October 12, 2008, 10:04:04 AM
I am building a couple of EQ's for mastering. I have these boards but I don't plan on building them anytime soon.

I'm using 12 position switches for gain and frequency. Gain is +/- .5/1/1.5/2/3.
I think having more choices for frequency is good. It's more important to work in the right place. I wouldn't use pots unless the the frequency range was small. I like good left/right channel matching.
Title: Neumann W492 equalizer DIY project
Post by: craptical on October 12, 2008, 11:59:35 AM
Thanks Gold, good point about channel matching. And also, repeatability gets lost with pots.
Title: Neumann W492 equalizer DIY project
Post by: bluezplaya on October 12, 2008, 01:21:20 PM
How do these EQ's sound?
Title: Neumann W492 equalizer DIY project
Post by: cannikin on October 12, 2008, 02:00:56 PM
Anyone have a correct part number (US) for the trimmers.  I bought a set from from Digikey and they are the wrong ones... hate when that happens
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on October 12, 2008, 07:26:36 PM
Hi Cannikin...
I bought those : 9607927 and 9607978 @ Farnell...(Vishay)
Hope that helps...
Cheers.
Title: Neumann W492 equalizer DIY project
Post by: cannikin on October 12, 2008, 09:47:38 PM
Thanks RD

heres the mouser numbers for USA

594-63P103
594-63P201
Title: Neumann W492 equalizer DIY project
Post by: cannikin on October 16, 2008, 11:22:49 PM
Ok I thought there was a post about this but I can't find it

Value of C10 and C8?  

NEVERMIND.... They are not needed unless you want to change the Freq.

its in there
Title: Neumann W492 equalizer DIY project
Post by: cannikin on October 17, 2008, 01:15:39 AM
Anyone want to buy some OPA2604AP with me to replace the 5532?

Newark gives a 40 cent price break over 25? so with 2 stereo channels thats 32 which means $5 off the price without shipping.
Title: Neumann W492 equalizer DIY project
Post by: RedNoise on October 17, 2008, 02:16:21 AM
Hi Cannikin! 2604 or 2134 ????I'm in , dependin on price !
Email me if you want !
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on November 15, 2008, 05:19:43 PM
Hi folks. I need a little help troubleshooting my W492s. I built two of them and all tested well at first. But now I can't figure out what is wrong.

I'm using a SSL9K PSU board fitted with 7815/7915 (left out components of the 48v rail). PowerTX is a 50VA,2x15V toroid. I've used this board for my Fetboys and my 312s which all work great.

Well, strange thing on this unit is that sometimes my 7815 output voltage is 0.8V. Seems totally random, sometimes when I power up the EQs I get the correct voltages and all is fine, the next time it's dead. Then when 0.8V at the output of the reg, there's still fine voltages both the negative rail and before regulation on the positive rail.. I've never seen the 0.8V output without load though..

I've tried swapping out the 7815 - no luck.
Changed the ceramic (100n) on the +15V output rail - no luck.
I've tried powering only one of the EQ boards - same thing, both channels...

Clue anyone?

EDIT:
The unit was in the "dead state" just now, and I accidentally shorted the input of the 7815 to ground with my probe - and suddenly the unit came alive  :o What's going on? Next power up - WORKS - then WORKS again - then DEAD...  aaarghhh  :)


J
Title: Re: Neumann W492 equalizer DIY project
Post by: cannikin on November 15, 2008, 08:08:36 PM
Can't really help you but I have a power related intermittency issue on one channel.  which is really strange.  the EQ will go on-off-on-off
Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on November 15, 2008, 10:33:35 PM
I can't say if this is happening with you guys, but I recently had this problem with a pair of home-etched 312s running on a working Fabio PSU. Everything was working fine for about a week, and the day I take it over to a buddy's studio to show him, it craps out! Talk about embarrassing, at least the singer he was recording that day had already left.  I don't remember the details but I somehow had two ground references (case and power) and ended up with 0V on phantom and the thing didn't work. When I put all the 0V references together it came to life! Probably not related to your issues, but throwing it out there anyway.  Is AudioX around to shine a light maybe?

Cannikin, what PSU are you using out of curiosity?  Did you build with 2604 or 5532?  If still interested try seller AudioTek168 on ebay. They sell them for 6.99 a pair with free shipping from Taiwan. If ordering that many, they'll probably cut you a better deal.

Have you guys gotten to testing them (soundwise) at all? I am ordering my pots from TAW this week and I think I have everything else, so looking forward to getting these done!

Good luck with getting it solved!  Keep us posted!
 
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on November 16, 2008, 01:45:41 PM
Mine has 5532, and it's my first EQ project. Not calibrated - and no "soundwise" test yet..

Well, what I think I'll do next is to redo my AC IN->Toroid->PSU wiring. I've read some posts about the isolation on toroid leads causing some trouble. Could it still be faulty wiring, even if my voltage readings are correct (before regulation)? What will happen if one of the leads I use as CT isn't connected ,or has a bad connection, to GROUND??

Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on November 16, 2008, 03:39:15 PM
Quote
What will happen if one of the leads I use as CT isn't connected ,or has a bad connection, to GROUND??
It sounds like you have a suspicion? I am no expert, but it makes sense that if you disconnect the 0V of one secondary that part of the circuit has no 0 reference. Kind of like the problem I had except mine was after regulation. Either way though, that part of the circuit had no 0V and I read 0V on phantom. So, yeah, I'd check that for sure... Let us know what you find.
Title: Re: Neumann W492 equalizer DIY project
Post by: rhodes54 on November 25, 2008, 05:00:10 AM
Hi all,

I'm about to start building the 492W EQ and need to order the pots. I have a question about the OMEG pots:
- Do they work ok as they are lot cheaper than vishays.
- Do the OMEGs fit in the PCB or do they need to be wired?

Thanks!

Title: Re: Neumann W492 equalizer DIY project
Post by: Harpo on November 25, 2008, 05:34:04 AM
The unit was in the "dead state" just now, and I accidentally shorted the input of the 7815 to ground with my probe - and suddenly the unit came alive  :o What's going on? Next power up - WORKS - then WORKS again - then DEAD...  aaarghhh  :)
What specific voltage regulators do you use ? Never had trouble with LM78xx/uA78xx/LM79xx/uA79xx, but some, like TS7815 / TS7915, seem to be famous for hanging at power up.
Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on November 25, 2008, 08:51:23 AM
I have a question about the OMEG pots:
- Do they work ok as they are lot cheaper than vishays.
- Do the OMEGs fit in the PCB or do they need to be wired?
It's funny since I put the order together, but I haven't gotten mine yet. Need to get my act together and place my order. The pots should "work" just fine. They are conductive plastic just like the vishays, which is a requirement for this circuit.

About fit, the single gang ones should fit perfectly, as they have the same lead spacing. The dual gang, on the other hand, will require a slight bending of the leads. The spacing between gangs on the Omeg IIRC is 7.5mm and the Vishays are 5mm. The difference is 2.5mm, so 1.25mm bend inwards in each set of legs should do it. Shouldn't have a problem, just don't go crazy with the bending.
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on November 27, 2008, 05:11:10 PM
I use LM7815/LM7915.. Tried to swap the reg of the positive rail, but that didn't change things..
My second son was born a week ago, so I haven't been able to look at this much.
But now I had a little time to redo the connections between the toroid and the PSU board. Cut the secondary leads and scraped off all the insulation, but sadly that didn't help either. At first I thought I'd fixed it as the unit work on about 10 power ups in a row, but no. Still dead at random power ups.

EDIT: Also did the AC in -> toroid connection again - no luck.. Aarrghh

Title: Re: Neumann W492 equalizer DIY project
Post by: chrissugar on November 28, 2008, 04:10:12 AM
I read the first page of this thread, and became interested to build one channel of this EQ just to test it if it's suitable for my needs, just to discover later that there are no PDFs for self etching.
OK, I can understand that based on some previous negative experiencees people are not happy to post their PCB files, but this is an old, not anymore manufactured product for more than 20 years. And the most hilarious thing is that a complete original W492 on ebay is around 250euros which is just a little bit more than the price of the components for the DIY version. Maybe I'm a bit stupid but I can't understand how someone would build this thing and make profit by selling a clone on ebay. Or maybe it is a bit to much paranoia.

The sad thing is that this place is becoming more and more like the forums (forums I don't like) where you can try a project only if you buy the boards. This is so sad.
Most of the people from this group developed their skils by building/trying some of the projects available for free from some of the generous people, and now many of them are advocating for not publishing this info for free. :(

Anyway, I'm not afected by this because I design/redesign all the PCBs for all of my  projects, but sometimes it is great to have some PDF for self etching just to try if a projects suits your needs.

Sorry for this post but I'm so disapointed by this state of things.

chrissugar
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on November 28, 2008, 06:12:46 AM
Chris:
Have you tried contacting audiox? Based on the discussion prior to the PCB production, I think audiox might be able to help you out.
Personally I just love the PCB services provided here, and I don't really understand your frustration. The PCBs are fairly priced, and if the build doesn't suit your needs, then sell it over at the black market.

As for my unit, I gave up  ;) Changed the PSU to a Mnats I had laying around. And now I think it's finally cured !!!
Pictures coming up shortly..
Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on November 28, 2008, 09:01:32 AM
Sorry for this post but I'm so disapointed by this state of things.
chrissugar
I would also say to contact Audiox. Once you add up the costs with the vishay pots, it doesn't make much sense at all. I too would have liked self etch boards (they are double sided though, a bit more of a PITA)....

Anyway, if you decide to do this, call Laura at TAW for some Omeg ECO cond plastic pots for this.. She ordered them for this project, they should work fine and cost about $18 a channel...
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on November 28, 2008, 07:00:46 PM
Here's my finished unit.
Thanks to AudioX & Gustav
(http://www.jarlemari.com/diy/W492.jpg)
Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on November 28, 2008, 07:34:49 PM
nice! how's she sound?  Did you do that front panel yourself? Would you mind sharing the graphics?
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on November 29, 2008, 01:38:42 AM
nice! how's she sound?  Did you do that front panel yourself? Would you mind sharing the graphics?
Haven't given her a too much of a "sound test" yet, but seems pretty nice so far.
Yes, the graphics are made with InkScape and stored in SVG. I have them on a memory stick that I can't find right now, but I'll upload the graphics when I do.
Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on November 29, 2008, 05:37:00 AM
Cool, appreciate it. One less step to keep me from finishing.. If it sound as good as it looks, it'll be amazing!
Title: Re: Neumann W492 equalizer DIY project
Post by: inputoutput on November 29, 2008, 08:48:18 AM
KNALL!!!!   (great work)
Title: Re: Neumann W492 equalizer DIY project
Post by: RedNoise on November 29, 2008, 11:27:25 AM
Jarlehal : Nice Job!!!!!
Title: Re: Neumann W492 equalizer DIY project
Post by: 3nity on November 29, 2008, 11:41:30 AM
i dont see anything??
how does it comes?
Title: Re: Neumann W492 equalizer DIY project
Post by: RedNoise on November 29, 2008, 11:44:26 AM
hey 3nity , see attached file in Jarlehal post(the one saying : Here's my finished unit.
Thanks to AudioX & Gustav)
----->New Prodigy forum , new functions!
Cheers!
Title: Re: Neumann W492 equalizer DIY project
Post by: 3nity on November 29, 2008, 11:47:57 AM
wow beautiful!!
Nice front panel!
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on November 29, 2008, 02:45:45 PM
i dont see anything??
how does it comes?

It's a little difficult to spot - I added an image tag to the post..

Thanks for nice comments folks.
Title: Re: Neumann W492 equalizer DIY project
Post by: jarlehal on December 13, 2008, 04:54:18 PM
I'm so sorry folks. I promised you my w492 front panel files, but I've lost my memory stick. Argh, lost a few other things aswell..
Again, sorry folks. From now on I'll backup and backup the backup.

JH
Title: Re: Neumann W492 equalizer DIY project
Post by: Purusha on December 19, 2008, 04:26:25 PM
I am shopping for parts now... are Panasonic Polypropylene Film Capacitors, P-Series an overkill here?

What kind of caps do you recommend?
Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on December 19, 2008, 05:16:38 PM
I got all wima films (have to check which ones) and panasonic lytics from TAW.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on December 20, 2008, 06:50:54 AM
Despite warnings I have decided to publish the PCB manufacturing documents of the W492 equalizer. I hope that it helps those who want to make their own boards. Documents are allowed to use only for DIY purposes.

http://audioxxx.googlepages.com/W492_copper_top_mirror.pdf
http://audioxxx.googlepages.com/W492_copper_bottom_mirror.pdf
http://audioxxx.googlepages.com/W492_GERBER.zip
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on December 20, 2008, 07:13:04 AM
Thx for sharing those Audiox :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Ptownkid on December 20, 2008, 04:33:02 PM
I spoke to audiox about this, and you will soon be able to get a parts kit for this project.

Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Purusha on December 20, 2008, 04:50:17 PM
Nice!

What caps do you plan to offer in the KIT?  ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: craptical on December 20, 2008, 04:51:01 PM
I spoke to audiox about this, and you will soon be able to get a parts kit for this project.

Sounds great! Will it include the pots?

/Dave
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on December 20, 2008, 05:52:09 PM
Ptown, if you do the kits with the Omegs, Laura at TAW has them. They are $18 a channel IIRC. Maybe you could cut a deal with her to take what she's got left over off her hands. Thanks for doing this by the way.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on December 21, 2008, 03:02:11 AM
KIts???Wowwwww , nice!!!
Some W492 in 500 series??? 8)
At first sight should be doable , isn't it ??
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on December 21, 2008, 03:03:34 AM
Ptown, if you do the kits with the Omegs, Laura at TAW has them. They are $18 a channel IIRC. Maybe you could cut a deal with her to take what she's got left over off her hands. Thanks for doing this by the way.

IIRC Laura also have all the wima caps needed in here!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on December 23, 2008, 12:16:36 PM
yes i was going to order to sets from laura but if you do the kits ill support.  ptown with this be on your site?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: discobloud on January 04, 2009, 02:16:41 PM
Any news on the kits?  Going to hit the buy button for 4 kits.  Thanks.  Mark
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on January 12, 2009, 05:25:31 AM
If I have understood right quite many are making their W492 with Omeg pots because of the lower cost than Sfernice. The problem is however that the section spacing of Omeg is 7.5mm (Sfernice has 5mm). Potentiometer pins can be bended but it is not very elegant solution...

It is not a big job to make an "Omeg" version of the pcb with 7.5mm spacing. If you are interested, please let me know.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 12, 2009, 08:42:01 AM
It is not a big job to make an "Omeg" version of the pcb with 7.5mm spacing. If you are interested, please let me know.
I would still love to see this done since I'll probably end up etching a couple more of these. Thanks!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on January 12, 2009, 09:02:04 AM
W492 with Omeg potentiometers:

http://audioxxx.googlepages.com/W492_omeg_copper_top_mirror.pdf
http://audioxxx.googlepages.com/W492_omeg_copper_bottom_mirror.pdf
http://audioxxx.googlepages.com/W492_GERBER_OMEG.zip
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 12, 2009, 12:17:58 PM
Thank you very much!!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on January 12, 2009, 04:59:13 PM
You rock Audiox , thx !!!   ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: marcfrom on February 25, 2009, 01:42:49 PM
Does someone can tell me what fuse value to use whith 110V or 220V for W492 Clone EQ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on February 26, 2009, 06:47:19 PM
On the trafo/fuse note.. The 5532 docs say 8-16mA per chip, x 8 = 64-128 mA per channel... SOOO, for two channels 128-256mA total?
 If I use a 15V trafo, that would mean 15V*.256A= 3.84VA... If I use a PSU such as the SSL9K, and a trafo with dual secondaries, would I double this (3.84VA per secondary)? If so, less than 8VA max is needed, which means a 10VA should be plenty (assuming no LEDs)...

Is this right?

For a 10VA trafo doing 2x15V, would the proper fuse value be 10VA/15V or 10VA/30V?
Plus some extra "headroom" of course.

Thanks!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: needlz on March 22, 2009, 01:08:29 PM
In case anyone is using the Omeg pots & Tats case with this project - It looks like the Omegs stand taller than the originally spec'd pots. They do not come close to lining up with the holes. I am going to try keeping the top row on the PCB and wire the bottom row off board. As as side note, bending the leads to get the double ganged Omeg pots to fit in the PCB is really easy - just be careful.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: signalflow on May 12, 2009, 08:55:16 PM
I'm wanting to run this eq un-bal.  Will just runnung the + rail only work or do I just need to tap into pin 1 of U1a and not populate R1-4 and C 1 and 2?  Also how do I come out un-bal as well?  Should I just take the + out and call it a day?

-Casey
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on May 13, 2009, 01:02:37 AM
Unbalanced operation:

Input to the (-) pin. Change R1 to 10 kohm. Do not connect/ground the (+) pin.

Output from the (-) pin. Do not connect/ground the (+) pin.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: canidoit on May 13, 2009, 01:26:39 AM
How does this unit sound? Any comparison to other units?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: signalflow on May 13, 2009, 02:16:43 AM
Unbalanced operation:

Input to the (-) pin. Change R1 to 10 kohm. Do not connect/ground the (+) pin.

Output from the (-) pin. Do not connect/ground the (+) pin.

Thanks for that.

-Casey
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ryansteele on May 15, 2009, 12:36:17 PM
are the boards gustav offers spaced for sfernice or omeg? just ordered some boards, need to get going on the pots.

thanks.

EDIT: i'm guessing by the timeline of the discussion that gustavs boards are the original with the 5.08 spacing. the 7.5mm board gerbers seem to have been posted later on. but, please correct me if i am wrong.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on May 15, 2009, 12:49:39 PM
hello everybody, i've question perhaps stupid.

I've built 2 unit of dual w492 work fine but when use this  units i lose 6db .
i use a psu 2x15v 15va
And don't don't what about this lost .
Someone could give me help please.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: signalflow on May 15, 2009, 02:28:43 PM
Are you inserting the Eq's un-ballanced or balanced?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on May 15, 2009, 03:09:30 PM
if these are wired up balanced, will they still work ok if pin 3 is tied to ground? i have a mix of unbalanced and balanced gear i will be using mine with both. i have my patchbay setup so it shorts pin 3 to ground for unbalanced ins/outs.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: solderspongebob on May 15, 2009, 05:33:29 PM
Quote
are the boards gustav offers spaced for sfernice or omeg? just ordered some boards, need to get going on the pots.

Funny you mention that - I e-mailed Gustav the exact same question only yesterday, but his reply was that he honestly doesn't know.

I would guess they are the original boards for Vishay-Sfernice pots, but apparently the Omegs fit with a little pin bending.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on May 15, 2009, 05:45:47 PM
Quote
Are you inserting the Eq's un-ballanced or balanced?

Balanced
for the input i 've linked + to the 2 of xlr and - to the 3 of xlr and 1 of xlr to the ground of rack,
for the output: + to the 2, - to the 3 and ground of pcb to the 1 of xlr.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on May 15, 2009, 05:49:28 PM
solderspongebob, if it's aigain the same like a few month the pcb is for the p11 but you can put on the omeg green if you  fold the pin.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kazper on May 15, 2009, 09:42:36 PM
Looks Like Taw has 5 sets left of the omeg pots $18 A set..

Kaz
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ryansteele on May 26, 2009, 05:33:45 PM
i actually just grabbed those 5 sets. i needed 8 sets, was worried that TAW wouldnt have them.

laura said she could help me out, and had all i needed in stock. excellent. have a 4 space chassis on the way from RP Electronics to go with it. i'm psyched.

moral of the story is: laura is great, everyone should deal with her.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: delaymix on May 26, 2009, 06:46:09 PM
Days ago that I'm thinking of adding an high pass filter to the equalizer, with selection of three different cuts. To what extent might this be interesting? Any idea which would be the best way to add this feature to this project? What do you think?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gold on May 26, 2009, 08:07:50 PM
I have the schematic for the Neumann HT75 HPF/LPF. It would appropriate. They are two channel ganged units and use 6 pole 5 position switches for frequency select and soft bypass.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Michael Tibes on May 27, 2009, 06:52:09 AM
I'd love to see these. I have been wanting to have some hi/locuts...

Michael
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gold on May 27, 2009, 07:19:46 AM
I'm graphically challenged ;) I could scan it and send it to you. It folds out and would have to be scanned in a few pieces.

They are 18 dB/oct. I use them every day and find them very useful and very good sounding. I would be very enthusiastic to see boards done. The switches have an odd form factor and would be difficult to replace. It would be nice to remake them with currently available parts.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: zayance on May 27, 2009, 10:04:52 AM
Is there any way of getting PCB for this project?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: signalflow on May 28, 2009, 12:06:56 AM
Is there any way of getting PCB for this project?

Read this thread

http://www.groupdiy.com/index.php?topic=10776.0 (http://www.groupdiy.com/index.php?topic=10776.0)

-Casey
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: zayance on May 28, 2009, 08:18:47 AM
 :-[ i missed that one, thanks.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: skal1 on May 28, 2009, 08:02:08 PM
Hi


did you get the chance to  scan that schematic of HT75 HPF/LPF ,i would like to build a dedicated HPF/LPF thingy

 Bless

skal1
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on May 30, 2009, 03:32:13 PM
Hi


did you get the chance to  scan that schematic of HT75 HPF/LPF ,i would like to build a dedicated HPF/LPF thingy

 Bless

skal1
highly interested in this as well. i have a friend who was asking about building some hpf/lpf's for him. i'd love to have some as well. if someone made a pcb, i'd buy quite a few.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on May 30, 2009, 03:39:30 PM
also, not sure if TAW still has the pots in stock, but i did an order with all the resistors and caps from TAW. if anyone is building the w492, you can get everything expect the trim pots and opamps from TAW.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gold on May 30, 2009, 06:26:11 PM
I can scan it and send it to someone who can stitch the pieces back together and post it. Any volunteers?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: filterstein on May 30, 2009, 07:49:15 PM
Not a graphic wonder, but i'll give it a try.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gold on May 31, 2009, 02:41:54 PM
I'll scan in on Monday. Send me your email address and I'll send it to you.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: filterstein on June 01, 2009, 11:00:06 AM
Your inbox is full, but the email link in my profile should work.
You can send it there.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jarlehal on July 20, 2009, 07:25:47 PM
Folks. I promised you my front panel (sticker) files a while ago. But then I couldn't find my memory stick.
Now, guess what!?! It turned up here the other day.

So here I give you my modest artwork. I used an app called InkScape. A great open source project.

http://www.jarlemari.com/diy/w492.svg

If there's interest, I have made some for my other projects aswell. I could host them on my web page.
I used the Sfernice pots btw.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iangomes on July 29, 2009, 01:53:14 PM
are the boards gustav offers spaced for sfernice or omeg? just ordered some boards, need to get going on the pots.

thanks.

EDIT: i'm guessing by the timeline of the discussion that gustavs boards are the original with the 5.08 spacing. the 7.5mm board gerbers seem to have been posted later on. but, please correct me if i am wrong.

Same question...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on July 29, 2009, 02:53:48 PM
the gustav pcb isspaced for P11 vishay like sernife.
you can put it the omeg also but you need to twist the pin
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iangomes on July 29, 2009, 02:55:21 PM
the gustav pcb isspaced for P11 vishay like sernife.
you can put it the omeg also but you need to twist the pin

Thank you my good man!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: daggertX on August 02, 2009, 09:10:16 PM
does it matter if the p11 pots are log vs linear? 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on August 02, 2009, 10:10:29 PM
10KLIN PA11QXF
it is in tha bom.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AndersB on August 07, 2009, 11:47:33 AM
So I've finished this very nice project (Neuman W492 ;) ) but i have some trouble with the first filter. when i turn the P1 clockwise I get some very ugly pops. on the scope it looks like maybe some DC  or some very powerful distortion.
When i back it of a little is disapearing. I useing a tune for testing so its every time the bassdrum get's hit.

I sounds like the filter is ok, cause I can hear the "sweep"

The other three filters is ok - and sounds very good.

I'm using an unbalanced test signal from my soundcard ( pin1 + 3 to ground) is that a problem?

I have regulated the PT1 to 100 ohms before soldering.

I've checked for soldering bulbs, chacked the resistors (i used 619 ohm isted of 620 ohm - should be ok)
I've changed the NE5532.

I'm running out of ideas here.

TIA

Anders B
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on August 07, 2009, 01:57:32 PM
hello which potentiometer do you use for , perhaps you could see on this side
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AndersB on August 07, 2009, 04:42:27 PM
Well i use Conductive plastic pots (Omeg from Rapid)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Moses on August 07, 2009, 05:07:27 PM
Hey guys..

Just putting together a BOM for myself on this.. Does anyone know if Ptownkid ever did do a kit for this project?

Im *trying* to spec Wima caps, should I be looking which range should I be looking at, there seem to be a few options out there!!

Thanks for your patience guys!!

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on August 07, 2009, 07:38:15 PM
if it's the green pot plastic from omeg try to turn the pin, i had a problem one time and finaly i have turned the pined on the double gang to have a good contact
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on August 08, 2009, 02:04:37 AM
when i turn the P1 clockwise I get some very ugly pops. on the scope it looks like maybe some DC  or some very powerful distortion.
When i back it of a little is disapearing. I useing a tune for testing so its every time the bassdrum get's hit.

Sounds like a faulty potentiometer that is losing wiper contact. The U2B voltage follower gets its bias through the wiper of P1. That is why we use conductive plastic pots.

Try connecting a 100k resistor from P1A pin 2 (the middle pin) to ground. If that solves the problem (or most of it, there can still be rapid level changes during the adjustment), then you most likely have a faulty potentiometer. The resistor affects the gain adjustment scale, so it is only for trouble shooting.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AndersB on August 08, 2009, 02:52:40 AM
ok thanks :) I'll try that.

I have  tryed to adjust the other filters. and its working fine. but it's not posible to get  it near the +15 dB. I'm using my scope and it can go from almost infinity to almost 8 v p-p. But when I listen to it it sounds fine, so it's more a queation about proper adjustment.

I've checked resistors and soldering and it looks fine.

Could I change the values of the trimmers to eg. 1K and 50k ?

/Anders
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on August 08, 2009, 03:45:43 AM
but it's not posible to get  it near the +15 dB.

http://audioxxx.googlepages.com/W492_trimmer_adjustment.pdf

If you don't have a level meter, use your oscilloscope:

http://www.sengpielaudio.com/calculator-db-volt.htm
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AndersB on August 08, 2009, 07:09:20 AM
Well I'm using my oscilloscope and i shows aprox. 8 volt p-p but according to www.sengpielaudio.com +15 dB should be aprox 12,3 V p-p. I've read the trimmer_adjustment page 'bout 20 times, and I have done excactly what it says.

Is there something wrong in my dB to voltage calculation? I'm not a pro in diy electronics, so please have a little patience with me :-)

/ Anders
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on August 08, 2009, 09:20:28 AM
Most of the oscilloscopes are not precision instruments, so you can't expect very high accurary. Best alternative is to use your soundcard and some freeware sine generator and level meter software. Since the measuremet is relative you get accurary of something like 0.1dB easily.

If you running the the eq unbalanced the output level is 6 dB lower than in balanced mode. That is probably your source of error. You can find the instructions to compensate that level drop earlier in this thread (in case you are going to use the eq permanently unbalanced).

With unbalanced connection (and without the modification) you should do the adjustment so that the maximum gain is +9dB (not +15dB).
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on August 08, 2009, 09:53:19 AM
on my side i've calibrated this Eq with vu inspector on protools ,
i put a signal generator with just the good frenquency ( 15hz for the first shelve for exmple and i turn the trimmer to have +15)
and i have +15 on all bands.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AndersB on August 08, 2009, 11:01:47 AM
Quote
If you running the the eq unbalanced the output level is 6 dB lower than in balanced mode. That is probably your source of error.

Well I think you're absolutly right :) when the trimmers are adjusted before soldering I'll get somthing like 6 V p-p so that make sense.

I'll try to measure it i unbalanced mode later.

Thanks for your help audiox :) I'm greatful :)

/Anders
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: _casio on August 11, 2009, 10:40:40 PM
jarlemari -

Thank you! I've been following this thread/slowly putting together this project for months, and just happened to pull open the thread after a rather long hiatus.

An open question to everyone - for those of us who have boards with the original pin layouts and used omeg pots: has anyone put together a front panel layout to accommodate the slightly different spacing as a result of bending the pins? Or does anyone have an idea of the best way to go about creating and/or modifying one for a more accurate fit?

I'm hitting the home stretch on my console build and, having built two 492's and the ssl, I'm just down to panel layouts.



-drew 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Ptownkid on August 12, 2009, 12:13:20 AM
Hey guys..

Just putting together a BOM for myself on this.. Does anyone know if Ptownkid ever did do a kit for this project?

Im *trying* to spec Wima caps, should I be looking which range should I be looking at, there seem to be a few options out there!!

Thanks for your patience guys!!

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Ptownkid on August 12, 2009, 12:15:08 AM
Hey guys..

Just putting together a BOM for myself on this.. Does anyone know if Ptownkid ever did do a kit for this project?

Im *trying* to spec Wima caps, should I be looking which range should I be looking at, there seem to be a few options out there!!

Thanks for your patience guys!!

Mo

No i didn't get around to it. Money got a little tight around here for a while. It is in the works still. As for your cap question, don't get too bent out of shape about getting the most amazing (or expensive) caps out there. It's been shown time and time again that it makes very little difference.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kazper on August 12, 2009, 01:36:23 AM
jarlemari -

Thank you! I've been following this thread/slowly putting together this project for months, and just happened to pull open the thread after a rather long hiatus.

An open question to everyone - for those of us who have boards with the original pin layouts and used omeg pots: has anyone put together a front panel layout to accommodate the slightly different spacing as a result of bending the pins? Or does anyone have an idea of the best way to go about creating and/or modifying one for a more accurate fit?

I'm hitting the home stretch on my console build and, having built two 492's and the ssl, I'm just down to panel layouts.



-drew  

One issue is that they are not going to fit in a 1 U space in a par metal case... but I'm right there with you, home stretch with the Omeg's

I would think it would be as simple as moving the Hole's and legends slightly more out (what ever the difference of the pots is)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kazper on August 12, 2009, 02:02:33 AM
The omegs measure about 45mm (1.74") from top to bottom. I measured about 25.5mm from center to center, but we should verify that value to the data sheet. Bad part is I have the knobs for the stock pots, which may not look right with the extra cm between the pots.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AndersB on August 12, 2009, 03:15:06 AM
Well I made a frontpanel just by measureing, a it came out ok. But for the next W492 (the right side) I'll place the pots first and the solder them. It was a little tight, but it works. so my advice is mount in frontplate first and then solder.

/Anders
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: a2d on August 24, 2009, 08:01:56 PM
I think Ptownkid should hurry up and get that done,,, lol right after the 1176's and the La2s   


Hey guys..

Just putting together a BOM for myself on this.. Does anyone know if Ptownkid ever did do a kit for this project?

Im *trying* to spec Wima caps, should I be looking which range should I be looking at, there seem to be a few options out there!!

Thanks for your patience guys!!

Mo

No i didn't get around to it. Money got a little tight around here for a while. It is in the works still. As for your cap question, don't get too bent out of shape about getting the most amazing (or expensive) caps out there. It's been shown time and time again that it makes very little difference.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Moses on August 29, 2009, 04:49:18 PM
Hey a2d thanks for the dig, I consider myself slapped down!! I was asking purely because there had been talk of it!!

@Ptownkid, I guess everybodys got it a bit rough just now, eh? Sorry to hear you are suffering though. Thanks for the advice on the capacitor front! I was looking at the boards and it looks like (from the layout, to a noob like myself!!) the caps have to be axial, and  'boxes' rather than 'tubular' in order to fit the allocated real estate?!? Further to this, (assuming for now that Im 'stuck' with Wimas..) which range of Wimas should I be looking at, and what is the difference between, say MKS4 and FKP2 of the same value?

Thanks for your help so far!!

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on August 30, 2009, 12:14:28 AM
if you are looking for parts for this, check with laura at taw electronics. i ordered all my parts from her, including the pots. only thing she didn't have was trim pots and 5532's!

does anyone have a 2 in a 1U front panel for this that fits the green omeg pots? seems like a few people would be interested in this if there is one.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kazper on August 30, 2009, 01:04:37 AM
The omegs I believe will not fit inside a standard 1U case.... with out some strange modifications. You can get about 4 in a 3U..... or 2 in a 2U and I know that is something you may not want to hear...

I've thought about ordering another 4 PCB's and buying the correct type of pot so I can do them in a 1U.... maybe next Gman order...


I said the omegs would work for the application but the size is off from the beginning.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Moses on August 30, 2009, 06:29:06 PM
Does anyone fancy a group buy on the pots for these? Im looking at the sfernice from Audio Maintenance. Personally, I would like centre idents for the gain, but not the frequency!

As Im building 2 (for now!) I need 8 of each type already. If there is a requirement for 7 more sets of these, we get the pots for around £5-6 each, instead of £7-8!!

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on August 30, 2009, 09:59:04 PM
Hi,
  I'd be interested, I purchased two sets of PCbs from Gustav about 6 months ago and am just finishing up another G9 and a Dual GSSL, would like this to be my next project. Maybe the price break would be enough to cover shipping cost to U.S.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: diyfanatic on August 31, 2009, 06:54:45 AM
Sfernice are way too much expensive.
I've got the pcb but this project will never see the light...

instead I'm lurking on the studer eq also by audiox...waiting for Gustav...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on September 02, 2009, 10:12:59 AM
get the omegs from TAW.  they are 18$ for the 8 pots needed per channel.

ask for Laura she knows the W492 www.tawelectronics.com (http://www.tawelectronics.com)

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Moses on September 02, 2009, 08:04:06 PM
Alas Im in the UK, so I fear I shall be ordering the bits and bobs elsewhere, as shipping will probably scupper the deal... Im sure I can find the Omegs over here though!!

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: MartyMart on September 02, 2009, 08:17:23 PM
Mo, I got my pots from TAW and the price and shipping was great !
I could not better it from a UK supplier
Highly recommended

Marty.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Moses on September 03, 2009, 06:19:57 AM
Cool!! Nothing like good ol' fashioned customer service! Seems to have died a death in the uk tho... I've dropped her an email, so we shall see!!

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: MartyMart on September 03, 2009, 07:53:54 AM
Mo, she may even do a capacitor set for it as well IIRC

MM.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on September 03, 2009, 08:30:14 AM
yep wimas ceramics and electros.  all at a great price.  my 10uf wimas for my PM660 were significanly less than mouser.


also the pots were 4mm vs 6.  selco here in the us has collet knobs 4mm with different color caps cheap.  
-updated omegs aren't 3mm they are 4mm posts.

http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1 (http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: adrian on September 03, 2009, 05:46:24 PM
hi!
i'm building some W492! i bought pots from Taw, Laura is really cool!
i'd like to know if someone did a front panel with Laura pots? because it's not the same dimension as sfernice ones...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on September 04, 2009, 02:08:37 AM
http://www.groupdiy.com/index.php?topic=34576.0

Hi Adrian , scroll down , you'll find all the dimensions I used with mine.This is not a front pannel but only the dimensions...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: adrian on September 04, 2009, 04:18:27 AM
thank you!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iangomes on September 09, 2009, 01:40:59 PM
regarding changing the range of frequencies, how are those frequency values derived? Looking at the low shelf, for example, has a lower frequency range of 50 hz. On the curves graph, 50 hz seems to be at the -6db point of the peak of the curve. Is this how it is measured? I'm interested in extending the range of the frequency bands and using them in a stepped configuration. Any ideas?
Thanks
Ian
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on September 09, 2009, 04:40:22 PM
Search "turnover frequency".

Equations for those circuits can be found in any filter book. If you dont' like math, simulate.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iangomes on September 09, 2009, 04:42:34 PM
awesome, thanks. Don't worry, I like math :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on September 09, 2009, 07:53:25 PM
also the pots were 3mm vs 6.
Just so no one gets the wrong knobs:  The Omegs have 4mm spindles, same as the Vishays.

There are a couple of dimension differences between these and the Vishays. One is pin spacing, and the other IIRC is spindle height (from PCB). The first is a small issue if that and the second is a non issue if you design your own faceplate.  Just do as Audiox suggests and mount the pots to the faceplate before you solder them to the boards, to avoid unnecessary stress.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: goldvasser on September 25, 2009, 12:50:06 PM
Hi there !

I'm planning to build the eq's in a 2RU high box. Do I MUST solder the 10k pots on the pcb or can I wire them with twisted cables to fit on my special "big version" of the project ?

Thanks for your comments & suggestions...




Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on September 25, 2009, 12:52:43 PM
hello i've build two 1 unit with wire twisted and work realy fine ; can do like you want.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: goldvasser on September 25, 2009, 01:11:44 PM
hello i've build two 1 unit with wire twisted and work realy fine ; can do like you want.

Thanks for your prompt answer !!!
Merci !!!
B.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on October 02, 2009, 08:27:31 AM
anyone have the current draw for two channels? im trying to find out if i can use some smallish torroids i have laying around.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: MartyMart on October 02, 2009, 08:46:43 AM
anyone have the current draw for two channels? im trying to find out if i can use some smallish torroids i have laying around.

I can't remember where the post was but I'm 99% sure that a 7.5VA traffo will do 2 channels no problem.

MM.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on October 02, 2009, 09:11:17 AM
i've build 4 dual for me and i used 15v 15va with the 9k psu, and work fine  you could add a CRCRC before this 9 psu to have a very good signal.
Title: Re: Neumann W492 equalizer DIY project
Post by: mitsos on October 02, 2009, 10:11:46 AM
quite a while ago:
Transformer can be quite small. Current consumption of the eq is about 70 mA per channel.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iangomes on October 02, 2009, 02:35:52 PM
so I took a walk around the internet, and I haven't been able to find any explanation as to how these filter curves/frequencies are set up. Everywhere I look it says the -3db point is the turnover frequency, but if that were true, the frequency's for the low filter, for example, would be 130 hz to 3k. The points which are specified are at -15 db, not -3... can anyone help me out with this?? what am I missing? ??? ???
Title: Neumann W492 equalizer DIY project / Potentiometers
Post by: sirzodiac on October 08, 2009, 08:07:06 AM
Hi folks,

i wanna share what i learned messing around quite a while with the potentiometer issue.
First of all: both pot brands are easily available, at least here in europe.
And: the price came down to exactly the same, because of high freight cost and toll taxes for shipping from england. I know because I ordered finally both (by mistake).
I first ordered all Omegs for a total of eight channels (2-gangs only where they are needed). Later on i decided to put four channels standing in a 4U rack, with space for four more & PSU, kinda my own lunch box. So i have a total widht of 4cm (1.55") per channel, which would just fit with the Omegs, but with a pretty silly design, because the pots are closer to the neighbour channel's pots than within it's own channel.
My buddy who's gonna build the other four channels bought cases from DIY-racked, which have a horizontal spacing between the two pot rows from 15.5mm, this is only to fit with the Vishay Sfernice ones.
So i had to look for the Vishay pots. On their website there are the sales contacts per region, or, even better, you browse through the product range to your desired pot meter (P11A in our case) and look unter the "i" icon ("Product Support") for "Sales contacts". This filters just the distributors who DO sell this product. So, for little Switzerland, i had a list of eleven distributors. I choosed three bigger ones out of all them, asked for an offer, and the next day i had three quotations, two with a MOQ of 50 and one with 25, lead time between 7 and 13 weeks, price between 6.5 and 7$ each (as suggested by Audiox, i only asked for the 2-gang type, to reach the MOQ).
By the way: the SAP Order Code from Marty Mart is absolutely correct, I went through again, never trust a stranger...  ;D
Thanx, Marty!

So, in short:
- Omegs have a much bigger horizontal distance than Vishay Sfernice (26.5mm for Omegs, 15.2mm for Vishay Sfernice)
- Both are easily available (at least in Western Europe)
- The price of the Omegs can become the same than for the Vishays (in Western Europe) because of shipping and toll taxes.
- If someone is looking for Omegs, I have. PM me.

I hope this can help.
May the DIY force destroy your budget and free time as well, we all know how much fun this is!...  ;)

cheers,
benu
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: goldvasser on October 08, 2009, 12:31:43 PM
Hi !

A noob question : I have 10k A double gang Vishay pots with an indent position on center . My issue is when I am mesuring the values of the two gangs set on the indent, I have some differences between them (i.e. :track.1 : poles1-2 :4.75k, poles2-3: 4.58k - Track2:pole1-2: 4.82k poles2-3: 5K)
Is there a way, trick or something to have a balanced value (5K on center) corresponding with this indent marker ?

Any suggestions really welcome !

thanks !
Bruno.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on October 08, 2009, 12:43:36 PM
I think it's normal, i don't how to say this in english, entre la marge d'erreur du multi mettre et la marge d'erreur du pot

aLOT of 2 gang pot don't have the same value exactly.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on October 08, 2009, 03:20:49 PM
10% de tolérance tes pots Vishay ??
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: aprendiz on October 08, 2009, 06:00:04 PM
Hi,

Looks perfect for my live rack. I have half rack space for an eq.

Boards still around?

Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Whoops on October 09, 2009, 12:43:27 AM
Hi,

Looks perfect for my live rack. I have half rack space for an eq.

Boards still around?

Thanks

you will find the boards here:

http://www.groupdiy.com/index.php?topic=10776.0;topicseen
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Whoops on October 09, 2009, 12:46:57 AM
I would like to build a unit using the SSL 9K preamp and this EQ.

Could I run an unbalanced out of the SSL 9K board and bypass somehow the balanced input of the W492?
going unbalanced from one board to unbalanced in the other


also,
if the NE5532 IC's are capable, could I use this circuit with + an - 18V instead of +-15v ?

thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on October 09, 2009, 02:59:11 AM
Could I run an unbalanced out of the SSL 9K board and bypass somehow the balanced input of the W492? going unbalanced from one board to unbalanced in the other

Use the inverting input pin. No modifications required (but remember that the polarity of the balanced output changes).

if the NE5532 IC's are capable, could I use this circuit with + an - 18V instead of +-15v ?

Yes
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sirzodiac on October 09, 2009, 03:45:05 AM
@ Rednoise:

yes, even worse, it's 20%.
According Vishay's datasheet there is 20% standard (M as last letter of the SAP ordering code), and 10% and 5% only available for cermet (not for lead plastic), letters K and J...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on October 09, 2009, 04:57:53 AM
@ Rednoise:

yes, even worse, it's 20%.
According Vishay's datasheet there is 20% standard (M as last letter of the SAP ordering code), and 10% and 5% only available for cermet (not for lead plastic), letters K and J...

So goldvasser mesures seem to be correct regarding the tolerance...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Whoops on October 09, 2009, 02:03:20 PM
Could I run an unbalanced out of the SSL 9K board and bypass somehow the balanced input of the W492? going unbalanced from one board to unbalanced in the other

Use the inverting input pin. No modifications required (but remember that the polarity of the balanced output changes).


What I would like is to have the balanced input parts removed and connect the unbalanced out of the SSL9k right after them
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: gemini86 on October 10, 2009, 02:51:53 PM
Just a passing thought:

Has anyone looked into ordering a bunch of custom dual concentric pots from Omeg for this build? I was going to send in a quote request, but I feel silly doing that knowing there's no chance of me buying them. If they could be made for like 10-12 bucks a piece would that be worth it to anyone? That might make this project 51x-able?

http://omeg.com/p2c2bub2.htm (http://omeg.com/p2c2bub2.htm)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kazper on October 10, 2009, 03:09:03 PM
Just a passing thought:

Has anyone looked into ordering a bunch of custom dual concentric pots from Omeg for this build? I was going to send in a quote request, but I feel silly doing that knowing there's no chance of me buying them. If they could be made for like 10-12 bucks a piece would that be worth it to anyone? That might make this project 51x-able?

http://omeg.com/p2c2bub2.htm (http://omeg.com/p2c2bub2.htm)

Why not buy the ones that Colin is stocking at audiomaintenace?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Harpo on October 10, 2009, 03:15:18 PM
Could I run an unbalanced out of the SSL 9K board and bypass somehow the balanced input of the W492? going unbalanced from one board to unbalanced in the other

Use the inverting input pin. No modifications required (but remember that the polarity of the balanced output changes).


What I would like is to have the balanced input parts removed and connect the unbalanced out of the SSL9k right after them

Not that easy to get a single op-amp stage dremeled away from a dual op-amp without destroying the chip. ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: gemini86 on October 10, 2009, 03:35:54 PM
Just a passing thought:

Has anyone looked into ordering a bunch of custom dual concentric pots from Omeg for this build? I was going to send in a quote request, but I feel silly doing that knowing there's no chance of me buying them. If they could be made for like 10-12 bucks a piece would that be worth it to anyone? That might make this project 51x-able?

http://omeg.com/p2c2bub2.htm (http://omeg.com/p2c2bub2.htm)

Why not buy the ones that Colin is stocking at audiomaintenace?

Simply because I didn't know he sold them... :-[
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: goldvasser on October 11, 2009, 09:38:20 AM
@ Rednoise:

yes, even worse, it's 20%.
According Vishay's datasheet there is 20% standard (M as last letter of the SAP ordering code), and 10% and 5% only available for cermet (not for lead plastic), letters K and J...

So goldvasser mesures seem to be correct regarding the tolerance...

Yep, They're 20%... Is there a way to correct the value mesured to match them when the axis is on the indent ?

Thx !!! :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on October 11, 2009, 10:41:28 AM
Just a passing thought:

Has anyone looked into ordering a bunch of custom dual concentric pots from Omeg for this build? I was going to send in a quote request, but I feel silly doing that knowing there's no chance of me buying them. If they could be made for like 10-12 bucks a piece would that be worth it to anyone? That might make this project 51x-able?

http://omeg.com/p2c2bub2.htm (http://omeg.com/p2c2bub2.htm)

Why not buy the ones that Colin is stocking at audiomaintenace?

Simply because I didn't know he sold them... :-[
I don't think he does. He does sell the Vishay Sfernice pots that were the ones Audiox originally designed this board around, but they are individual pots. You want dual concentric to be able to do freq/gain on one pot, right?  That'd be pretty cool, but you'd need a couple of 3-gang pots and two duals. If you got them made, and this board fits in the space of a 500 module (I don't have dimensions in front of me), you'd just need one of those mini 500 adapter boards like geoff in this post (where do you get those anyway?):
http://www.groupdiy.com/index.php?topic=11320.msg414991#msg414991
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: [email protected] on October 17, 2009, 02:59:31 PM
where can i get the board for this eq? the link that saids it, saids its invalid.
anything? thanks.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: [email protected] on October 17, 2009, 03:00:33 PM
where can i get the board for this project?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on October 17, 2009, 03:17:47 PM
gustav sells them in the white market.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Deyo on October 19, 2009, 08:26:45 PM
Sorry to bother but I just finished the 492 units and they are hitting me with 12 DB extra . Anyone have any ideas ?   thanks   D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on October 20, 2009, 07:18:25 AM
Pehaps balance , unbalanced
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on October 20, 2009, 08:27:31 AM
Sorry to bother but I just finished the 492 units and they are hitting me with 12 DB extra . Anyone have any ideas ?   thanks   D

Do you mean that the overall gain is 12dB when all filter switches are off? In that case there must be some mistake in your component assembly. A wrong value resistor most likely. If you have a level meter, troubleshooting is easy. Feed 1kHz sine to the balanced input. The level at the output of the following op-amps should be 6dB lower than at the balanced input: U1A, U1B, U3B, U5B, U7B and U7A. If not, you have located the fault.

If the overall gain is ok but some of the filters boosts or cuts too much, try to adjust the trimmers. There are instructions how to do that. If it doesn't help, check the component values.

Pehaps balance , unbalanced

12dB of extra gain is too much to be caused by that.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: stereokillah on October 20, 2009, 12:43:12 PM
yes should be 6 bd sorry but i don't know wich db does he talking, and i had this problem with my first w492 i used unbalanced plug.
Title: The 12DB over.
Post by: Deyo on October 20, 2009, 12:53:55 PM
Audiox,
  Yes it is 12 DB over when all is shut off.   I will do what you said to do today. I will leave the result later tonight.  Thank you for the help   D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Deyo on October 20, 2009, 07:31:46 PM
Well no chance today. I will try to get back to it on Fri. Not enough time in the day.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on November 19, 2009, 12:29:45 PM
Hey man, just finished my first one today and got a chance to bench test it. Everything worked right away, which is nice for a change. This thing has insane amounts of gain, everything feel really nice, it's crazy how much you can cut and boost with this. The lowend extension goes all the way down too. I'm looking forward to finishing my other ones up and getting these in the rack.

Thanks for all your work.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Moses on December 01, 2009, 01:25:41 PM
Hey, I've just finished building 2 channels of these with Sfernice knobs, and am trying to fit them into Perusha boxes. Im a little stuck though, because tat includes a false from to mount the knobs on, which I did. However, the shafts aren't long enough to reach through the front panel and the holes aren't big enough to just mount the pots on the front panel.

Has anyone else had this problem, or got a solution?

Thanks,

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: MartyMart on December 02, 2009, 04:57:42 AM
Hey, I've just finished building 2 channels of these with Sfernice knobs, and am trying to fit them into Perusha boxes. Im a little stuck though, because tat includes a false from to mount the knobs on, which I did. However, the shafts aren't long enough to reach through the front panel and the holes aren't big enough to just mount the pots on the front panel.

Has anyone else had this problem, or got a solution?

Thanks,

Mo

I have the same problem, sfernice pots were too short so I sold 'em and got a set from Laura @ TAW
These DON'T fit the boards/ case like the sfernice though so you have to wire them "off board"

Perhaps the better option is to get longer spindle version of the sfernice ! but at £8 a pop this was too
rich for me

MM/
Title: Re: Neumann W492 equalizer DIY project
Post by: ahstarr on December 02, 2009, 06:58:05 AM
Marty check this:

http://www.audiomaintenance.com/acatalog/potentiometers_conductive_plastic.html
SF-01-009 - 11mm - 2 gang 10k linear

I can only see the SF-01-007??????
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on December 02, 2009, 07:23:01 AM
Has anyone else had this problem, or got a solution?

I have never seen that enclosure and I know practically nothing about its construction. I hope that someone else in this forum is able to help you. I guess Purusha forgot that Sfernice potentiometers are available in variety of shaft lengths. Those sold by catalogue distributors are usually with long shaft and the ones meant for mixing console spare parts have shortest possible shaft.

I can only see the SF-01-007

Maybe Colin has discontinued the 2x10kLIN without center detent. It was available when I made the layout...

EDIT: If he is reading this, maybe he could tell us if it is just temporarily unavailable or permanantly discontinued.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iangomes on December 02, 2009, 08:21:23 AM
the SF-01-009 were there yesterday... looks like i got one of the last (if not the last) set.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ahstarr on December 04, 2009, 04:14:06 AM
the SF-01-009 were there yesterday... looks like i got one of the last (if not the last) set.

apparently they will be back in the store (depending on demands) in 14 weeks....:(

Does anyone know other places to get these???

/andreas
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sirzodiac on January 03, 2010, 05:44:15 PM
Hey, I've just finished building 2 channels of these with Sfernice knobs, and am trying to fit them into Perusha boxes. Im a little stuck though, because tat includes a false from to mount the knobs on, which I did. However, the shafts aren't long enough to reach through the front panel and the holes aren't big enough to just mount the pots on the front panel.

Has anyone else had this problem, or got a solution?

Thanks,

Mo

hey folks,

just finished a dual channel with purusha's case and the vishay sfernice pots reference marty mart posted earlier and i did as well in another post.
everything works fine, the pots DO fit the board and the shaft DOES fit perfect for purusha's cases.
what probably should be said is that the shafts are not going through the front panel, the pots are mounted on the mounting plate and the plate is mounted with a fixed distance (through the L-bendings on each side) to the front panel, so only the axes are passing the holes. as the axes are 4mm a 4.5 or 5mm hole does the job.

and it looks great, and it SOUNDS great, YAW!!!

good luck everybody,
b.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on January 07, 2010, 03:13:27 PM
has anyone built the w492 with a purusha case and the green omeg pots? will this work if they are not mounted on the PCB and are hardwired?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on January 07, 2010, 04:19:19 PM
i have the purusha case and the green omegs.  ill be building this month and let you know.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 07, 2010, 04:28:42 PM
They will work without being mounted, it'll be a bit ugly but they'll work. I have a layout that 'should' work for omeg pots, haven't finished nor tested it yet but going by my measurements and datasheets it should be good.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sirzodiac on January 07, 2010, 05:32:20 PM
They will work without being mounted, it'll be a bit ugly but they'll work. I have a layout that 'should' work for omeg pots, haven't finished nor tested it yet but going by my measurements and datasheets it should be good.

don't forget the first post of this thread: audiox also posted gerbers for a omeg version. just not working in purusha's case, every layout won't work there, because of the (omeg) pot's geometry...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 08, 2010, 01:09:39 PM
They will work without being mounted, it'll be a bit ugly but they'll work. I have a layout that 'should' work for omeg pots, haven't finished nor tested it yet but going by my measurements and datasheets it should be good.
Does it involve bending the leads over the top/bottom of the board to get the pots more compact? I thought to try this, but no time yet..
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Moses on January 09, 2010, 11:35:37 AM
Almost got the first of 2 of these boxes working... (Waiting on power supply!)...  ;D

I ended up using tat's case with the Vishay pots, It's ended up being a bit of a bodge: Drilled out front panel cut outs to 7mm, and attached the mounting plate using only the pot/switch nuts as spacers. This works fine, and Elma knobs will hide the front panel bodge nicely!!

Mo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on January 09, 2010, 01:58:49 PM
Just wondering:
has anybody here done this EQ with stepped swithes instead of pots?
I want to build mine with 12 steps lorlins or maybe even 24 steps to use it for mastering but i'm not sure how to do it.
The gain is no problem, i just need 0.5db steps up and down and last steps at 1db but what about frequencies? I don't need an overlap in the mid frequencies so the ranges can be a bit more cut down.
Anyone?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 11, 2010, 09:13:53 PM
Hey guys, I've got my design for the omeg pots pretty finalized. I still don't have the chassis for this yet so I did a cardboard mount to test it out. I'll post a few photos and the layout. I'm making a 4 channel in 3U design for myself, I can give anyone that wants the illustrator file it if they want.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 11, 2010, 09:14:40 PM
another pic
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 11, 2010, 09:15:00 PM
last pic
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on January 12, 2010, 10:38:20 AM
hey, that looks great. would you be able to send me that file in illustrator and jpeg?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 12, 2010, 11:49:07 AM
hey Ben,

there is a "share your front panel thread" here:

http://www.groupdiy.com/index.php?topic=33888.0

cheers,
d
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 12, 2010, 12:43:50 PM
UPDATE: I fixed up my front panel, accidently did 270 degress instead of 300
Here's the illustrator file. http://benlindell.com/diy/W492%20to%20Laser2.ai (http://benlindell.com/diy/W492%20to%20Laser2.ai)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on January 12, 2010, 08:06:20 PM
great ben, thanks so much!

does the case you are using have the 2nd front panel for mounting the pots to or are you just using a normal rack case with the single front panel.

what knobs are you planning to use for the omegs?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 12, 2010, 08:11:42 PM
I'm no frills and just mounting them on the single front panel.

I bought a bunch of knobs from mouser, couldn't find any good 4mm knobs so I'm just wrapping some metal around the shaft and mounting them. mouser part #s 450-2040, 450-2050, 450-2060, 450-2070
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: outoftune on January 12, 2010, 09:21:48 PM
great stuff.

when you say "wrapping some metal" around them...what exactly are you using?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 12, 2010, 09:26:11 PM
Haven't done that part yet, planing on getting the thinest sheet of metal I can find and cutting it into small strips.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 12, 2010, 09:59:47 PM
You could order knobs direct from Sifam for not too much money, and get all the little colored caps and all.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: glazer56 on January 21, 2010, 04:13:28 AM
Greetings! noob question, but...
Can anyone point me to the math for calculating cap values to change the frequency? Scratching my head a little trying to analyze the schematic.

Cheers!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on January 21, 2010, 11:09:51 AM
Can anyone point me to the math for calculating cap values to change the frequency?

Google "State Variable Filter" or "State Variable Filter equations".
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: glazer56 on January 21, 2010, 04:04:44 PM
Ahh! Thanks!

Here's some info I found if anyone would like some additional info on the filter design.

www.compeng.dit.ie/staff/ptobin/3chapt08.pdf

http://www.answers.com/topic/state-variable-filter

http://www.maxim-ic.com/app-notes/index.mvp/id/1762

http://www.circuitstoday.com/state-variable-filters
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on January 24, 2010, 10:02:33 PM
guys i need some help...

i have a pair of these eqs ready for the purusha case i bought.  problem is these omeg pots are not going to work with this case.  i need the sfernice pots.  so the omegs are for sale and i need the others.  audiomaintenance has them but they come out to 240$$$ usd...ouch.  anyone know of a better price on these in the us?

thanks

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on January 24, 2010, 10:06:14 PM

  x2
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kazper on January 25, 2010, 12:12:44 AM
guys i need some help...

i have a pair of these eqs ready for the purusha case i bought.  problem is these omeg pots are not going to work with this case.  i need the sfernice pots.  so the omegs are for sale and i need the others.  audiomaintenance has them but they come out to 240$$$ usd...ouch.  anyone know of a better price on these in the us?

thanks



Non Tat case maybe?

I'm in the same boat... The omeg's were priced right, but in the end it's the downfall if you want them in a 1U.  I think it's best to suck it up and pay Collin or drop the case.

I'm eventually am going to just pay Collin once I get around to having some extra money, plus I already have the correct knobage...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 25, 2010, 08:54:28 AM
I was thinking of doing some chiclets for this exact reason.  I don't have a purusha case, but I want this in a 1U and the original faceplate layout Audiox posted is very nice and symmetric.  Anyway, you can see an example of what I mean below (except I don't want to wire them, I want to make longer chiclets extending (above or below) the EQ PCB so they connect to the original solder pads with solidcore wire or leftover pieces of thicker leads).

http://www.wavemakers-synth.com/motm/chiclets.html

Haven't done any measurements yet, but think this might work?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kazper on January 25, 2010, 09:31:37 AM
Those Chicklets are very cool and relatively cheap fix to a common problem
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 25, 2010, 09:40:54 AM
That's what I thought too.  I thought to do them iso-routed somewhere locally instead of etching (I only need 2-4 channels), but if there was interest we could just get them done at a fabhouse for pretty cheap. Or send out to oen of those ebay PCB houses.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on January 25, 2010, 10:12:36 AM
i just picked up 25 of these http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110453237964&ssPageName=STRK:MEWNX:IT (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110453237964&ssPageName=STRK:MEWNX:IT)

they are 3mm dia shafts instead of 4 but i have knobs that will work.

this takes care of the singles, now i can get the duals from colin.

btw ill have an extra 12 singles (at 4$) good for 2 channels.  you need 4 duals and your good to go.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on January 25, 2010, 11:21:39 AM
good find busch. here are the adapter boards I was thinking about. I actually had thought of doing it iso-routed since there is a business that could do that for me, and it would save me cutting up a boatload of boards. Ideally they'd be FR4 but I don't want to inhale fiberglass dust, so phenolic is more likely.  The only real problem with iso routing is doing the panelizing in Corel or something in a way that it doesn't take the router an hour to do, (longer continuous horizontal runs, less up/down movement...).

For now, I need to print and check that the thing fits.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on January 25, 2010, 12:09:55 PM
Thanks.  Nice work on the chicklets I may use the omegs next!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on January 25, 2010, 06:33:27 PM
Hi All,
        buschfsu - I was looking at those on ebay, but I wasnt sure if they could be used - still too much of a noob  ::)

  But I also ran in to this today - http://www.groupdiy.com/index.php?topic=35422.new;topicseen#new 

    I've had the PCBs from gustav for a year now, just getting around to gathering up parts
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 28, 2010, 11:12:06 AM
Hey guys. I sent of my front panels to be engraved yesterday and was double checking my front panel numbers so I did sweeps of one of my channels. They are on exactly with the curves that audiox published, if nothing else this is a very clean looking eq.

I posted them on my blog:
http://blog.benlindell.com/?p=102

Also anyone that may be using my front panel design with the OMEG pots, I just updated it, the scale was off by 30 degrees, I misread the omeg datasheet. I have the updated AI file here:

http://benlindell.com/diy/W492%20to%20Laser2.ai (http://benlindell.com/diy/W492%20to%20Laser2.ai)
Picture: (http://benlindell.com/diy/W492-to-Laser2.jpg)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on January 28, 2010, 12:32:46 PM
I did sweeps of one of my channels. They are on exactly with the curves that audiox published, if nothing else this is a very clean looking eq.

What is the analyzer software that you are have used for the plots? Freeware?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: wolfgang on January 28, 2010, 12:42:24 PM
Looks like fuzzmeasure!!

Isn´t it?

wolfgang
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on January 28, 2010, 02:13:05 PM
Yea I used Fuzzmeasure. Works great for this stuff, lets use the 96k sampling rate and sweep upto 40khz.

I'm working on a quick tutorial on how to use it for testing gear, their manual doesn't really explicitly say how to use it this way.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: south2577 on February 01, 2010, 07:46:02 PM
Hi guys

Bit of a newb question, but what are people using as a ready to go power supply for a pair of the W492's?

thanks in advance. :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on February 02, 2010, 04:46:31 AM
Keith 9k psu works great for me ... Is it what you call a "ready to go" ???
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: south2577 on February 07, 2010, 06:04:29 PM
Keith 9k psu works great for me ... Is it what you call a "ready to go" ???

Is this the same 9K PSU board available from Gustav? Can I use one PSU board to run 2 x W492's?
Sorry I'm either blind or can't find any info directly relating to PSU information for the units. Please help. :)

Does anyone have a spare stuffed PSU for hooking up a couple of these? cheers :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: south2577 on February 08, 2010, 12:10:46 AM
Found it! I must be blind.

:)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on February 08, 2010, 04:15:39 AM
thumb up icon !  ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on February 08, 2010, 06:20:42 PM
im using the mnats psu board.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on March 06, 2010, 04:13:52 PM
Finished!!!
Finished up the wiring this afternoon, this thing sounds soooo nice
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on March 06, 2010, 04:15:28 PM
One more photo of the messy guts
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on March 06, 2010, 05:09:36 PM
neat !! congrats Ben' ! I'd love to see mine so pretty ! :P
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on March 10, 2010, 10:54:38 AM
the purusha pot saga continues.

this is crazy.
now i have ...
2 sets of omegs - dont fit purusha case
2 sets of colins - shafts aren't long enough
2 sets of single deck sfernice - would work fine but no dual decks and no center detent.

ive spent way too much on pots and this case..  Anyone know where to get P11A2Q0EJSX00103K
i assume these are the dual deck with longer shafts?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on March 10, 2010, 11:46:53 AM
I've been pretty lazy on those adapter PCBs for the Omegs, but then, I'm having a hard time getting cases done, so... one thing drags down the other.... Anyway, can you just make a new faceplate for the purusha case that would fit colin's pots? I've never seen Purusha's case, if he has a second faceplate maybe you could get rid of it and bolt the pots directly to the front faceplate? just a thought
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on March 10, 2010, 12:59:06 PM
yeah id have to drill out the front panel cause its only wide enough for the shafts of the pots and switches.  argh.  wont look as nice but im ready to rack this thing and forget my pot woes.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on March 10, 2010, 09:08:19 PM
Drilled it, can't use the back panel so I'd doesn't look as cool but it works with Colins sfernice pots. Thanks for the help all
(http://farm3.static.flickr.com/2752/4423990258_de5aea8d76.jpg)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: envelope on March 11, 2010, 10:15:14 AM
2 sets of omegs - dont fit purusha case
Hello, if you would like to off load one  set of the omeg's, I am looking to populate a pair ofW492 channels.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on March 11, 2010, 10:31:02 AM
sure.  i emailed you the details
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: envelope on March 11, 2010, 12:03:45 PM
Thank you
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on March 13, 2010, 08:58:50 PM
Hello,
        Newb here  ;D   from the AudioX parts list, could someone tel me what PT1, PT4 - 10k 63p is ? and PT2 PT3 - 10k 63p is ? - they look like trimmers to me, but have never seen this 63p designation before.

  Thanks,
               chip
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on March 14, 2010, 03:56:34 AM
they look like trimmers to me, but have never seen this 63p designation before.

Spectrol 63P. You can use practically any trimmer type but 63P (or mechanically equivalent) fits the layout best.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on March 14, 2010, 08:22:18 AM
     
 ... I'm sure I'll have more questions 

         Thanks so much AudioX  :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Brizco on March 21, 2010, 06:03:08 AM
finally finished mine!

thanks audiox!!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on March 21, 2010, 10:29:11 PM
Hi,
    another newb question, I used these - http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-7040-5-ND - in my GSSLs, but got them from Newark, Newark has replaced them with these - http://www.newark.com/jsp/search/productdetail.jsp?id=58K2024&whydiditmatch=rel_1&matchedProduct=08F2505&Ntt=08F2505 - would anyone know if the Fairchild brand would be better or worse in performance ?

   Thanks,
             Chip

 BTW.. looks awesome Brizco , nice work !
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: zayance on March 21, 2010, 10:42:54 PM
Quote
Hi,
    another newb question, I used these - http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-7040-5-ND - in my GSSLs, but got them from Newark, Newark has replaced them with these - http://www.newark.com/jsp/search/productdetail.jsp?id=58K2024&whydiditmatch=rel_1&matchedProduct=08F2505&Ntt=08F2505 - would anyone know if the Fairchild brand would be better or worse in performance ?

   Thanks,
             Chip

Well i'm not a pro, but if you need precise numbers you could still make a comparison of datasheet, but for me it's still a 5532, that needs a Power supply of max +/-22V, in DIP8 with same pin outs, same same...;
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on March 24, 2010, 01:48:36 PM

     buschfsu - nice work, I see you are in the U.S- may I ask were you purchased the knobs ? I am using the Omeg pots with 4mm shaft dia.

  thanks,
            Chip


  btw, I ordered the WIMAs and pots from Laura at TAW - very reasonable pricing, fast shipping and great experience.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: buschfsu on March 24, 2010, 02:01:31 PM
yes selco has them and they take small quantity orders.  check back in the thread i posted a link

http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1 (http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on March 24, 2010, 02:15:57 PM
 
   Thanks !
             ...... I saw the prior link, but needed to navigate deeper in to the page    :-[
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on April 01, 2010, 04:48:31 PM
Hello again.. ;D

   I just need to verify PT requirements, its been stated in this thread that each of these units draws about 70mA, I am putting four units in one case, = 280mA, I have a 15va PT - .500mA in series - is this enough or am I pushing the limit ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on April 04, 2010, 03:35:01 PM
I had the boards laying around here for some time and thought to myself.. what the heck, let's do the w492 and so i started of
But now i'm thinking about the pots (noooo, not again! you must think now), which ones have the longest shafts and will fit a 1u case? i have the small panels to fit on a standard 19 inch panbel fromn Dan and so it's a bit thicker then standard. The omeg pots looks like a really small shafts and i'm afraid it won't fit.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on April 05, 2010, 04:28:27 AM
Will these pots be okay? they have quite a long shaft (which i need)and are conductive plastic.
RS stocknummer 504-2661
vishay P9A1RFISX1BB2103MLE3

(http://img-europe.electrocomponents.com/largeimages/R504248-01.jpg)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on April 05, 2010, 04:00:08 PM
no one?  ???
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on April 05, 2010, 04:02:58 PM
sorry dagoose , I've used the Omegs  ..
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on April 05, 2010, 06:33:48 PM
 
.. O.K.... another question....I was planning on using a DPDT toggle for the " Bypass " in/out, and just noticed the three through holes marked " Out , GND , In "  under the rotary switch for bypass...

   Could someone shed a little light on this ?  

    Thanks,
              Chip
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mitsos on April 06, 2010, 10:18:45 AM
Will these pots be okay? they have quite a long shaft (which i need)and are conductive plastic.
RS stocknummer 504-2661
vishay P9A1RFISX1BB2103MLE3

(http://img-europe.electrocomponents.com/largeimages/R504248-01.jpg)

No, those are LOG taper, you need linear. RS has them in linear as well, but check the datasheet to see if they will physically fit the board.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on April 06, 2010, 11:27:17 AM
hmm... your'e right... it needs lin's..   :-X
504-2627 is the pn for the lin version, will check the specs/measures tonight and if ok i will just order some to see if they will do the job.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on April 06, 2010, 01:53:29 PM
to bad... they have 2.5mm pin spacing and we need 5mm for the w492.  :(
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: envelope on April 06, 2010, 02:14:45 PM
.. O.K.... another question....I was planning on using a DPDT toggle for the " Bypass " in/out, and just noticed the three through holes marked " Out , GND , In "  under the rotary switch for bypass...Could someone shed a little light on this ?  
Thanks,Chip

Hi I'd love to help, but looking at the PCB in the first post, I cannot tell what you are referring to. Can you clarify at all. Attached is the W492 wiring guide. Is there another board for this build?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on April 06, 2010, 03:07:51 PM
   
   envelope , thanks for the reply - I feel like such and idiot, I got my threads mixed up,  I'm building two types of EQs at the same time, W492 and the G-pultec, that question was for the G-Pultec  :-[

  sorry for the inconvenience  ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Cosmonaut on April 07, 2010, 08:39:13 AM
Hey I'm trying to do a front panel, but I would like to make it for a vertical version.
 What difference should I take in account in the pots??Mainly in the gain pots with the zero/center marked.

Is there any way to mount another pot version, or something like that?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on April 08, 2010, 04:11:59 PM
Will these pots be okay?

I ordered a sample a few years ago. That was one of the worst potentiometers that I have ever seen. It is likely that they have improved the design but I still would be carefull. (Plus they don't fit the PCB and 6mm shaft / 10mm knob is not an easy combination.)

Hey I'm trying to do a front panel, but I would like to make it for a vertical version. What difference should I take in account in the pots??Mainly in the gain pots with the zero/center marked.

Collet knobs can be assembled in any position...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: JBVries on April 15, 2010, 02:27:55 PM
I'm kinda getting to my wits end here looking or pots for this project. Does ANYONE have a link to pots tht can be easily purchased that will work for this project?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on April 15, 2010, 02:49:00 PM
Jbvries, if you can stand to use the omeg pots, TAW has them set up as a set at you can order, they won't fit in purusha's case though, they work well and were really easy to order.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: JBVries on April 15, 2010, 05:59:58 PM
Unfortunately if you go to TAW and you get to the page that has the w492 eq set the availability is 0. I haven't contacted them yet but what are the other all be it more expensive pots people have used?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on April 15, 2010, 08:01:52 PM
Yea as far as I know it's always said 0 but if you call they have them
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: JBVries on April 15, 2010, 08:14:02 PM
Thanks Ben.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fallout on April 22, 2010, 10:58:18 AM
This what Laura from TAW responded back to me:

NEUMANN W492EQ SET -
6 - PC16ECO 10KA SPINDLE F21 L40 (SINGLES)
2 - PC2G16ECO 10KA X 10KA SPINDLE F21 L40 (DUAL)

I thought all the pots were dual? Are these part #'s correct?

Thanks!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on April 22, 2010, 11:02:25 AM
Nope they don't all need to be dual, just 2 of them, search the thread and there's a post about which ones need to be dual, audiox laid them out as all dual cause that's what he had one hand and for more mechanical security.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fallout on April 22, 2010, 11:04:42 AM
Cool.. Thanks Ben. I wish those Sfernice pots were easier to get! Doesnt look like audiomaintenence stocks them anymore..

-jay
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: RedNoise on April 22, 2010, 01:23:12 PM
I think "saint quentin radio" got them , in France ...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on April 26, 2010, 01:29:38 PM
Wondering.. why is it so hard to get the pots? I never had so much trouble finding parts for a project.  ???
I contacted Laura and got an email back the next day but since then i didn't hear anything from her and audiomaintenance is out of stock etc etc..

so... hmm.. basically.. does anyone have pots or now where to REALLY buy it?  ::)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on April 26, 2010, 01:46:32 PM
  what did laura's email say ? - I got 4x  omeg pots and Wima caps for this about a month ago from her, and all is good...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: wolfgang on April 26, 2010, 04:05:45 PM
To dagoose:
How many pots do you need?
I have a pot-kit for a stereo EQ left over. They are omegs from TAW.

If ou are interested pm me!

wolfgang,
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on April 27, 2010, 03:57:47 PM
To dagoose:
How many pots do you need?
I have a pot-kit for a stereo EQ left over. They are omegs from TAW.

If ou are interested pm me!

wolfgang,


That would be great! PM'ed you :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: wolfgang on April 28, 2010, 07:29:59 AM
PM´d back!

Wolfgang
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fallout on April 28, 2010, 08:16:14 AM
They (TAW) still have the pots at $24 a set.. I just ordered some today.

-jay
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fallout on April 29, 2010, 10:51:16 AM
Ben your front panel looks great.. What company do you use to do you laser engraving? Thanks!

-jay

Finished!!!
Finished up the wiring this afternoon, this thing sounds soooo nice
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: lovelyworldsound on May 02, 2010, 01:55:58 PM
Hi,

Great project, this one!!!
I have just ordered PCBs from Gustav, and will begin building a unit with two of these soon.
I just have one question:

I assume that I will need something in addition, to get some ballanced audio to/from this board - and that I will need a PSU of some kind, for feeding the +-15v traces on each of the EQ´s.

I am a (nearly) total newbie, I have only build 2 GSSL klones so far :)
Anyone knows what I will need to complete? (I´m on europe 230v)
 ;D
Thanks

Anders Bau
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on May 02, 2010, 09:41:23 PM
Thanks man, i found this guy in Vermont that does laser engraving, it was the first time he had done this kind of stuff but he did a great job and had the best prices i found. Google vermont laser engraving, I believe the name of the company was BPN.

Ben your front panel looks great.. What company do you use to do you laser engraving? Thanks!

-jay

Finished!!!
Finished up the wiring this afternoon, this thing sounds soooo nice
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on May 02, 2010, 09:43:30 PM
Yes and no. You do not need another for audio balancing. You do need a psu for the +/- 15 volts. Any kind should work, I used an extra one from mnats' 1176 project.

Hi,

Great project, this one!!!
I have just ordered PCBs from Gustav, and will begin building a unit with two of these soon.
I just have one question:

I assume that I will need something in addition, to get some ballanced audio to/from this board - and that I will need a PSU of some kind, for feeding the +-15v traces on each of the EQ´s.

I am a (nearly) total newbie, I have only build 2 GSSL klones so far :)
Anyone knows what I will need to complete? (I´m on europe 230v)
 ;D
Thanks

Anders Bau
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: lovelyworldsound on May 04, 2010, 02:56:59 AM
Thanks Ben  :)

/Anders
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fallout on May 07, 2010, 08:08:21 AM
Good thing i didn't go too nuts looking for the Sfernice pots and went with the Omeg's from TAW.. Apparently, the PCBs Gustav is selling is for the Omeg's! Can't wait to get these fired up..

-jay
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: lovelyworldsound on May 12, 2010, 03:13:11 AM
Hi Ben,

Sorry to bother you, but do you have the calculated values to use for the resistors for mnats board, for getting +-15v out of the PSU?
That would be a great help :)

/Anders Bau
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on May 12, 2010, 08:01:06 AM
Yesterday my omeg pots arrived and so i could finish my w492.
There was only one problem, the omeg pots didn't fit the frontpanel (dan) and so i had to solder them with wires which took a bit longer but worked out great!
It worked at first fire-up which is nice for a chance but it's such a simple project that it was hard to screw up. ;D
The eq is dead quiet and sound pretty good though a bit rough but i think that is what i like about it.

The frontpanel is white, i spraypainted it myself and because it was a bit cold when i did it it looks a bit like powdercoated.
Anyway.. pics!! (and yes, the led in the white frontpanel is pink)
(http://www.dagoosemusic.nl/temp/neu1.jpg)
(http://www.dagoosemusic.nl/temp/neu2.jpg)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on May 12, 2010, 09:27:12 AM
Nice work. But where is the mains fuse?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on May 12, 2010, 09:37:57 AM
Nice work. But where is the mains fuse?

Good you notice that! :)
I actually build that in after i took the pics..
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on May 12, 2010, 10:29:56 AM
Nice work dagoose !
 
  I am just finishing up four channels in a 2u rack case, I used nylon rails to support the PCBs, was curious how you secured yours, cant see how you attched them from the pix.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dagoose on May 12, 2010, 11:17:46 AM
Nice work dagoose !
 
  I am just finishing up four channels in a 2u rack case, I used nylon rails to support the PCBs, was curious how you secured yours, cant see how you attched them from the pix.

Thanks! :)

I drilled 2 holes in the pcb and used plastic rings to keep the ground loose from the screw to avoid groundloops since the the top part of the pcb is ground and the 'real ground' is on the XLR's.
Works like a charm but you don't have much place for drilling holes since there are a lot of traces going on on both sides, but it's do-able.  ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on May 12, 2010, 11:27:37 AM
Thanks! :)

I drilled 2 holes in the pcb and used plastic rings to keep the ground loose from the screw to avoid groundloops since the the top part of the pcb is ground and the 'real ground' is on the XLR's.
Works like a charm but you don't have much place for drilling holes since there are a lot of traces going on on both sides, but it's do-able.  ;D

  Aahhhh...nice clean work ! I stared at it for awhile, and couldnt figure out where to drill holes,I didn't want to drill through something and mess it up, that's why I went with nylon rails...  ;D

 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fallout on May 12, 2010, 09:37:08 PM
What size knobs are you guys using with the Omeg pots? I had a few Tyco 1/8" knobs laying around that seem to be a bit too small for the Omeg pots.

Thanks..

-jay
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on May 12, 2010, 09:46:29 PM
yes selco has them and they take small quantity orders.  check back in the thread i posted a link

http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1 (http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1)

  I got these, haven't tried them yet, I can mount a couple tomorrow and post back...but they look real nice  ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Minotaurus on May 18, 2010, 09:25:17 PM
Hi,

is there a part list for Germany (Reichelt) ?? The Links on the First Page dont work for me, and i didnt read the whole thread yet, so if anyone has one, it would be nice to have.

thx.

Klaus
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on May 24, 2010, 08:34:45 PM
I mounted the Selco knobs and they fit nice, first time using collet knobs.   
  Question.. this is only the second project I've done with Opamps, the first being the GSSL, was wondering if I should fire it up the first time without the Opamps in ?  test voltages, as with the GSSL.
  Thanks 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on May 30, 2010, 07:19:49 PM

  Question.. this is only the second project I've done with Opamps, the first being the GSSL, was wondering if I should fire it up the first time without the Opamps in ?  test voltages, as with the GSSL.
  Thanks  

  I ask because i dont know if it will damage anything else if I leave them out to check voltages.
getting close to the power up  :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on May 31, 2010, 03:40:53 AM
was wondering if I should fire it up the first time without the Opamps in ?  test voltages, as with the GSSL.

That is a good idea. Also check the op-amp output voltages after inserting the chips (a few millivolts or few tens of millivolts when working properly).

I ask because i dont know if it will damage anything else if I leave them out to check voltages.

It could be possible in a circuit where the op-amp outputs are used to bias the surrounding active circuitry. I have seen a few examples, mostly in power electronics. But in this case, no reason to worry.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on May 31, 2010, 08:32:43 AM
Thanks audiox !   ;)   

   if everything goes well, I should be powering up four channels by the end of the week.


Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: conleycd on June 04, 2010, 10:46:52 PM
Could be a flaw on my computer but it seems the Google links to the documents are not up any more.  The documents are listed as 0kb? 

Any thoughts?

CC
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Spendor on June 06, 2010, 01:48:59 AM
Hi All - just back from touring and want to start this project. I've got the pots and boards, but can't download the schematic or BOM from the start of this thread - can anyone help out here?
Cheers!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on June 06, 2010, 03:59:20 AM
it seems the Google links to the documents are not up any more.

I checked that all the documents are still in Google docs and "shared to everyone".

A few weeks ago some of the files disappeared the same way but returned next day.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: envelope on June 06, 2010, 10:19:39 AM
yes selco has them and they take small quantity orders.  check back in the thread i posted a link
http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1 (http://catalog.selcoproducts.com/viewitems/collet-knobs/basic-collet-knob?&forward=1)
  I got these, haven't tried them yet, I can mount a couple tomorrow and post back...but they look real nice  ;D

Hi Audiophreak, how have these knobs worked out for you cosmetically and quality wise? I am searching for 32 4mm shaft 11mm diameter collets.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on June 08, 2010, 04:21:43 AM
Hi envelope,
                 I got a burst of work recently, so haven't gotten back to this project in a week or so. I have the panels from " Dans front panels ", mounted the pots and have put a couple of these knobs on to see how it fit and how it looked, and both are good, they fit fine, quality seems good and they feel and look good too IMO.
                I'm building four of these in a 2U rack case, its been challenging, but I think I've got it. Will post pix as soon as possible.

  Hope this helps.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: envelope on June 13, 2010, 11:45:33 AM
Thank You, I just got a great quote from Selco, so I'm going to try them. The HWBP relay array (will install in the blank area in front of XLR's, on the substrate panel). finding the 4mm collet knobs and final wiring/assembly/shielding are all I have left to do.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on June 13, 2010, 10:39:45 PM
Looks great, clean work !

 I'm very much a Newb, what is - (HWBP Relay array will be installed in the blank space area in front of the XLR's.)

  and why not WIMA's ?  I thought most people here preferred them ?

I should have mine up and running in a week or so, wil post pix soon.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: envelope on June 14, 2010, 08:53:41 AM
what is - (HWBP Relay array will be installed in the blank space area in front of the XLR's.)
and why not WIMA's ?  I thought most people here preferred them ?
I should have mine up and running in a week or so, wil post pix soon.

Hi, HWPB is hard wire bypass, using relays. The boards are made by [silent:arts]

I should (I now have) retract the negative WIMA comment. They are fine, and can be exceptional. (if the right series in used). My reasons are based on the lack of a well stocked WIMA suppliers that is located and ships from within  Canada. 'regards

EDIT: will try TAW for Wima capacitors, they seem like good folk. 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: conleycd on June 14, 2010, 10:03:30 AM
Hey there,

Here is a good WIMA supplier http://www.tawelectronics.com/ (http://www.tawelectronics.com/) - I've always found them to be very helpful and I think they might offer a Prodigy-pro.com/diy discount.

Now... I have a question wondering if someone can answer.  I am planning to use this as the last stop in a channel strip in a rack.  I have some EA 2623-1 output transformers from classicapi.com and I was planning to strap one onto the 'end of line' to the output of the W492 eq.

Now, the primary is rated at 75 ohms secondary at 75ohm or 300ohm if in 1:2 ratio.  Do the NE5532s have enough juice to drive this transformer?  Would I just strap + to + and - to -?

In front of the eq I'll have a microphone preamp (discrete opamp), compressor (with a discrete opamp for output makeup), and then the eq.

Thanks.

CC
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on June 15, 2010, 10:33:42 PM

  Well .... I just fired up four channels in a 2U case.. no smoke and and everything seems to be working.. However ... I  wired the pots off board and soldered all the  jumpers from the top of the PCBs , so when I connected the pots, all the pots that would have been on the bottom of the PCBs are wired backwards .. DUH.. ::)

  Could I have damaged anything by this Newb mistake ?

  Over the next couple days I will correct the wiring try and calibrate, and post some pix

 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on June 16, 2010, 03:13:22 AM
all the pots that would have been on the bottom of the PCBs are wired backwards .. DUH.. ::)

Could I have damaged anything by this Newb mistake ?

Check the rotating direction of the planet Earth. If it has changed, please correct your wiring as soon as possible.

The circuit itself is not damaged, no reason to worry.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on June 16, 2010, 10:32:04 AM
Thanks audiox  :)

   after I powered it up and was just messin with the controls, I noticed that a few of the frequency sweeps seemed " backwards " after thinking on it for a few min. realized what I had done, so just have to swap the outer pin leads on the pots that would have been mounted upside down / on the bottom of the PCB.   ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on June 16, 2010, 08:27:01 PM
Hello again  ;D

   OK, I have the pot wiring straitened out. Now that I've had the unit on for a while and testing each channel, I got to the 4th channel and " pop "  audio went out, checked voltages and the pos dropped to 14.1vdc from 14.91vdc when I turned it on   :'(

  The PT is .500 amp at 30v and I am powering an LED in the mains switch from the NEG side - with no load the NEG side was -15.3vdc and POS side was 14.97vdc, with all four channels on I get +14.91vdc and -14.97vdc. The heat sinks dont seem to get too hot, so I dont think its thermal shut down, but after I let it sit for 15min. channel four was up and good, POS was +14.43vdc and NEG was -14.98vdc

   anyone have an idea whats happening ?  PT too weak ?  maybe thermal shut down ? 

  Thanks in advance   ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on June 17, 2010, 07:22:11 PM
Hello,
        Well, I fired this unit up and left my meter on it and checked it every 5-10 min. and everything seams O.K. now - POS voltage starts at +14.97 and after 10-15 min. slowly drops to +14.84 , NEG starts out at -15.03 and slowly drops to -14.78, both stabilized there for 2 1/2 hours. 
 
      Should I be concerned about this ?

  I Have an Mnats PSU with trimmers, would that be better, then I could set it right at 15v or 15.5

Here is a link to pix, only used it on my own voice so far, but sounds good and think it will be very useful.

https://goo.gl/photos/rdyaKt2qo9feE95k6

I cant say enough about TAW electronics for the WIMAs, I got them from TAW for this project and SSL 9k and G-Pultec, they have great customer service, great prices, and shipping is reasonable. also the Selco knobs for the same reasons.

  Thanks audiox and everyone for your invaluable help and knowledge, I am very pleased with this project.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on June 30, 2010, 05:36:30 PM

 .... what I do...fart   ;D

   after spending a little more time with these I like how they sound especially the upper mid section and am going to install a bigger PT. It seems to be working fine but want the rails closer to specs.

  Thanks again to audiox and everyone who contributed, without this forum and the people in it I would not have found this wonderful hobby

btw  -  envelope - how are you doing with this project ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on July 01, 2010, 04:21:18 PM
  Thanks !
               I'm glad you like the knobs, and that's awesome customer service, I'm happy it all worked out for you ( I'll bet it took a little bit of the " Sting " from those Sfernice P11A's )  sounds like you have a good proses.

   Keep us informed of your progress and parts selections.  ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: JBVries on July 02, 2010, 04:10:56 PM
Can someone tell me what kind of power these thugs take and a potential adequate PSU as I can't seem to find that info anywhere and my 492s are pretty much finished. Cheers and thanks in advance.

-JB
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on July 02, 2010, 04:57:34 PM
   envelope - That looks awesome !  is the case painted or powder coated ?  I like the contrast with the dark case, brushed aluminum Dans panels, black knobs with white caps. very cool  :)   and of course the N.. badge     ...  any inside pix ?

  JBVries - I used part # 70053 - from Digikey, its 500mA  CT secondaries in series for 4 units and I think I pushed it to the limit, am going to replace it with a #70063 that is 842mA in the same config. , but the 70053 should be fine for 2 units , although I dont know if it will fit in a 1U case or not .

  EDIT - the #62053 will fit in a 1U case, I'm using this one for a quad of SSL9K's - hope this helps
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mikefatom on July 05, 2010, 12:55:25 PM
Stuart, that's a beauty! Really nice wiring work and layout!

Are those 0.1% vishay resistors throughout that I see?

Sweet!  8)

edit: nevermind, I just saw your post mentioning the 1% Dale resistors. :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on July 05, 2010, 04:00:36 PM
Stuart, that's a beauty! Really nice wiring work and layout!


Sweet!  8)


  X2 ...  Thats some beautiful work !   gotta figure out how to get my wiring that nice  ;D

btw ,  what opamps  did you end up using ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on July 07, 2010, 11:19:23 PM

Ha Ha !!  I'll have to try that  ;D

   What models of Analog Design OpAmps are compatible ? if they're not too expensive I wouldn't mind getting a set and A/B with one of the other channels.

  On another note, I got a hold of a signal generator and went to calibrate the  W492s. I found that the trimmers had very little effect on the level - like only 1.5db . but they were all very close and was able to get them +- 0.5db -  were yours similar ?

I perf boarded a tube heater supply for a G9, and got the legs on the trimmer wrong and experienced a similar result, but wouldn't  the pin config on the PCB prohibit that ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on July 08, 2010, 06:40:14 PM
are these the ones ?

http://www.newark.com/analog-devices/op275gpz/ic-audio-op-amp-9mhz-dip-8/dp/19M1029
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: drummerjoe31761 on July 25, 2010, 07:50:49 PM
I have a complete Behringer P/S from one of their tube comps? I vandalized, Do you think I could adapt it for this project, I've looked for the Schemo's but haven't found the yet
Thanks
Joe
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: adrian on July 27, 2010, 08:06:43 AM
 i built 14 of these eq for a project and i like them very much!!! thank you audiox!
I 'd like to add a variable HPF to these (maybe 2 positions 100hz and 180 hz), so i'm looking for a good schematic!
i looked on the forum and on the internet but i don't know how i could add something like that to these eq, do i need a symetrical HPF schematic or could i take an asymmetrical signal somewhere in the signal path, send it to the hpf and then re-send it to the eq?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Morelius21 on November 09, 2010, 07:39:15 AM
Hi people,

I want make 2 eq but I have a question. In Gustav set is incluided de psu pbc? or  I must make mine?  can you tell me where to look the informantion?
I'm new and I'm still learning to move around here  :D

Thanks 
Morelius
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: adrian on November 09, 2010, 12:01:56 PM

as i know gustav doesn't sell power supply with these project,
but you can find some very good power supply on jlm audio website,

i think you could also use the ssl9K power supply,


Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: deneme on December 12, 2010, 05:02:22 AM
Potentiometers should be? Single or double?
What characteristics could you help what should I take?


I use it?
(http://3.bp.blogspot.com/_44kmc-nVHWQ/RqYyt8yvS8I/AAAAAAAAAX8/-D1XUskmrnM/s320/10.JPG)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on December 12, 2010, 10:51:29 AM
read the first pages of this thread.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: JBVries on December 14, 2010, 11:27:30 PM
Finally finished mine. Love it!!!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on December 15, 2010, 12:19:51 AM
Im in the process of racking mine too.
The only problem im encountering its nice and affordable knobs for the Omeg pots.
Shaft diameter is 4mm.

yes they sound great too.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: JBVries on December 15, 2010, 12:35:19 AM
Im in the process of racking mine too.
The only problem im encountering its nice and affordable knobs for the Omeg pots.
Shaft diameter is 4mm.

yes they sound great too.

I found these based on my EQN build......

Go to digikey and type in Kilo in the search. Then select 3.18mm shaft. If they will work on the 4mm Sfernice pots on the EQN I don't see why they wouldn't work here. Maybe not authentic but it's something to check out. Otherwise it'll be about $65 for a 4mm collet set with colored inserts from Canford. Cheers!

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: zayance on December 15, 2010, 05:04:35 AM
Quote
If they will work on the 4mm Sfernice pots on the EQN I don't see why they wouldn't work here

The Sfernice type knobs that Peter proposed for the EQN have 3.18mm Shaft not 4mm, but maybe it fitted yours nicely? I'd like to know, because could make the pots turn not very centered...
http://uk.farnell.com/vishay-sfernice/prv6saabjyb25103ka/potentiometer-10k/dp/8795711?Ntt=8795711
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: JBVries on December 15, 2010, 04:26:09 PM
Yeah I might have to redact that. I have not tried this and thought that the shafts might be similar enough for this. My mistake.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: marcfrom on February 03, 2011, 05:07:42 AM
I have build 3 W492 units, with SSL9k PSU.
When the machines are cold and i turn on i have no signal out(audio), the +15V is missing (on the PSU). I have to  turn off and on, and the +15V come and everything work ok.

I tried to deconnect the W492 PCB, and the +15V on the PSU board is ok, no need to turn off and on. It same on 3 unit.
My transformer is 25VA, my EQ with true bypass consume less than 200mA, so it's more than enough

Does anyone had the same problems?  :-[
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on February 03, 2011, 09:52:35 AM
I have build 3 W492 units, with SSL9k PSU.
When the machines are cold and i turn on i have no signal out(audio), the +15V is missing (on the PSU). I have to  turn off and on, and the +15V come and everything work ok.

I tried to deconnect the W492 PCB, and the +15V on the PSU board is ok, no need to turn off and on. It same on 3 unit.
Hi Marc,

I had some issues with LM78xx and LM79xx regs a while ago.Have you tried to exchange it to a new one?
Mine tended to do the same as yours,and after  I used better regs (just a little more expensive-no no-names!) the issues were gone.
Personally I do not use those regs when ever possible and go the LM317 and 337 route.....just a thought.

[/quote]My transformer is 25VA, my EQ with true bypass consume less than 200mA, so it's more than enough

Does anyone had the same problems?  :-[
[/quote]

Current consuption of about 200mas seems a bit high to me,as far as I can remember there are 8 pieces of NE5532 on the board,right?
If so then look at the data:8 x 6mAs (typical current)=48mAs,max. is 8 x 16mAs(max.supply current)=128 mAs.
I am not sure if there are other active/current-eating parts on board...... ???
Maybe I am wrong with this but it seems pretty high for this circuit (did you mean a single board?).....


Anyway-try to swap the 7815 to a well-known brand because it is just some cents of your money.

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: marcfrom on February 03, 2011, 11:06:21 AM
My units have two channel+ 4 relais for true bypass over a second PSU.

I already test to deconnect second PSU with true bypass and one channel, but it's the same

I seen Jarlehal in this thread had same problem, actualy +0.8V out on the 7815.

When i changed the 9K PSU insted a Mnats PSU, the problem was gone.

Does he use a better quality Regulators??  ::) I don't know.

But i will try it.

Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: diezel_addict on February 07, 2011, 05:06:03 AM
Hi All

Has anyone got any comments with regards to sound of these EQ's?  Anyone used them on a project yet?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Kevin on April 25, 2011, 02:40:30 PM
i'm thinking about this pots
http://www.musikding.de/product_info.php/info/p2299_CTR-Poti-16mm-Stereo-10k-lin.html
they fitting perfect on the board... having two laying around but not sure about sound quality
is it real that many pots scratching after a while

and other question is there any difference between the green omegs and just normal omegs?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on April 25, 2011, 04:45:12 PM
i'm thinking about this pots
http://www.musikding.de/product_info.php/info/p2299_CTR-Poti-16mm-Stereo-10k-lin.html
they fitting perfect on the board... having two laying around but not sure about sound quality
is it real that many pots scratching after a while

and other question is there any difference between the green omegs and just normal omegs?

Hi Kevin,

here´s the quote of audiox (reply#40 in this thread):
Conductive plastic pots must be used because the circuit is DC coupled. Normal pots start to scratch quite soon.

Best,

Udo.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: marcfrom on April 25, 2011, 04:54:30 PM
I want to build a Stereo W492.
Does anyone know where i can find a Quad 10K lin pots with 6mm shaft?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Danny1107 on May 14, 2011, 03:56:12 AM
Hi,

are the PCB's from Gustav for the Sfernice potentiometers or the Omeg potentiometers?
I need the 7,5mm Spaces for the dual pots...

Cheers Danny
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on May 16, 2011, 05:06:23 PM
are the PCB's from Gustav for the Sfernice potentiometers or the Omeg potentiometers?

As far as I know the boards manufactured by Gustav are for Sfernice.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on May 30, 2011, 11:41:35 AM
Hi guys.
Can any of you comment on the calibration??

i cant i have an ossciloscope but not a real meter...

i tried using PT 9.7 meters to read the dbs but i cant get the right values.

Please give me some advice.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on May 30, 2011, 02:51:49 PM
Hi guys.
Can any of you comment on the calibration??

i cant i have an ossciloscope but not a real meter...

i tried using PT 9.7 meters to read the dbs but i cant get the right values.

Please give me some advice.

Hello 3nity,

in case of doubt you can simply do it like specified following the link of the 1st page here:

NO TEST EQUIPMENT ?

If you don't have generator & level meter, adjust PT1 & PT4 to 100 ohms and
PT2 & PT3 to 5 kohms before soldering.


I didn´t get if you have a scope or not (i cant i have an ossciloscope but not a real meter...).

If yes then you can do it as follows:

Generate the specified sine waves with your ProTools (internal sig.-generator).
With all switches at the w492 set to off hook up the scope to the eq output and trim the generator level until you read 0 dBu on the scope.
This should be 0,775 volts eff. or 2,19 volts peak to peak.
Proceed as in the "Pot-Trimming-Guide",the +15 dBu must read 4.36 volts eff. or arround 12 volts peak to peak on the scope.
That´s it.

If you´re unsure about how to read it or want to calculate dB things then I recommend this very useful site (originally in german but has an english version too):
http://www.sengpielaudio.com/calculator-db-volt.htm

Best regards,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on May 30, 2011, 05:22:44 PM
oops sorry i have a scope and a signal generator but i need a vu meter or something to read dbs??
unfortunately i solder everything before reading the calibration stuff!

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Neily on June 01, 2011, 05:00:38 AM
oops sorry i have a scope and a signal generator but i need a vu meter or something to read dbs??
unfortunately i solder everything before reading the calibration stuff!



Hey dude...Just curious... What did you end up using for pots? The expensive pots are the only thing keeping me from doing this project...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on June 01, 2011, 10:58:34 AM
i used omegs from TAW electronics.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 01, 2011, 01:23:36 PM
oops sorry i have a scope and a signal generator but i need a vu meter or something to read dbs??
unfortunately i solder everything before reading the calibration stuff!



Hi, well-you can´t make the measuring stuff when the pcb isn´t stuffed ;D
So-no,you don´t need something other to read the dBs-you can read levels in volts (e.g. peak to peak for sine waves) on the scope.
Just take 0 dBU for reference which is 2,19 volts peak to peak on the scope (equals 0,775 v eff.).

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on June 21, 2011, 01:22:28 AM
I have another problem or its maybe the cables that are not properly wired.
it doesnt sound good unless i run it unbalanced...balanced it sounds like some bad low resolution audio.
Any hint please?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 22, 2011, 04:11:57 PM
I have another problem or its maybe the cables that are not properly wired.
it doesnt sound good unless i run it unbalanced...balanced it sounds like some bad low resolution audio.
Any hint please?
On a first sight at the schematics it looks like an issue on wether the input de-balancing amp (U1) or the output balancing (U7).
If you have another board or even some NE5532 left you can simply drop new ones in,one after the other and see if it disappears.These are just parts for arround 30 cents (here) so no biggie.

Anyway I would check the cabling first,then swapping op-amps.If this all fails the signal must be traced trough the circuit,and the surrounding parts at U1&U7 should be checked.

hope to have helped,

good luck,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AUDIO-ON on August 02, 2011, 08:15:09 AM
Hi there,
After more than one year with two pcb's for this project in my room I finally ordered pots, resistors and caps for this cool project from TAW.
I'm very newbie in this so I have a stupid question: how can I implement input and output gain for the EQ's? Shall I only add dual gang pots at the balanced input and output?

Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: AUDIO-ON on August 05, 2011, 06:21:48 AM
Any ideas about input and output gain for this project?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: craigmorris74 on September 26, 2011, 05:17:53 PM
I'm interested in adding transformer inputs to my channels, similar to the originals.  What would be the best way to accomplish this?

Thanks,
Craig
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: benlindell on November 20, 2011, 06:18:45 PM
I don't have a front panel in fpd but I do in Adobe Illustrator, http://benlindell.com/diy/W492%20to%20Laser2.ai (http://benlindell.com/diy/W492%20to%20Laser2.ai) if that's any help
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: backstreets on December 06, 2011, 12:13:04 PM
Hi,

I have two W492 equalizers that I use for as an M-S EQ setup in my mastering chain. I've been thinking about the idea of modding them from +-15 dB gain range to +- 7.5 dB.

I would also like to change the low cut from being 80, 20, 140 Hz to 80, 20, 40 Hz. As the 140 Hz is too high and I could use a 40Hz cut in-between 20 and 80.

I talked with Mazz (www.vintagecity.de) and he suggested that I'd check with you guys who have DIYed the W492 and see if you could help me out. From what he wrote to me I understand that I would need to change both pot's and resistors as well as caps and resistors in the Rc low-cut section.

It would be super if you could help me out on what I need to do and what to change to what to pull this off!

I attached the original W492 schematic as well.

Thanks in advance,
L
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Harpo on December 06, 2011, 06:51:04 PM
.. I've been thinking about the idea of modding them from +-15 dB gain range to +- 7.5 dB.
I would also like to change the low cut from being 80, 20, 140 Hz to 80, 20, 40 Hz. As the 140 Hz is too high and I could use a 40Hz cut in-between 20 and 80.
Different from DIY-project, but for HPF 40Hz instead of 140Hz I'd try R6=28K, R10=182K, R13=36K5.
For your reduced boost/cut range I'd increase R19+R68 to 1K91 2K43 and R42+R61 to 2K2 3K01 to get this voltage divider level down.
Good luck


edit: prev.values missing dB2AV-conversion.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: backstreets on December 07, 2011, 04:06:31 AM
Very nice, thanks a lot!

Would getting the voltage divider down be sufficient to reduce boost/cut range, no need for new pots? (That would be fantastic  ;) )

/L
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: backstreets on December 07, 2011, 08:17:01 AM
.. I've been thinking about the idea of modding them from +-15 dB gain range to +- 7.5 dB.
I would also like to change the low cut from being 80, 20, 140 Hz to 80, 20, 40 Hz. As the 140 Hz is too high and I could use a 40Hz cut in-between 20 and 80.
Different from DIY-project, but for HPF 40Hz instead of 140Hz I'd try R6=28K, R10=182K, R13=36K5.
For your reduced boost/cut range I'd increase R19+R68 to 1K91 2K43 and R42+R61 to 2K2 3K01 to get this voltage divider level down.
Good luck


edit: prev.values missing dB2AV-conversion.

Thanks for the corrections! Will go to the local component store now, then the soldering will being. I'll report back on how it goes!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: superslaukey on January 01, 2012, 10:28:22 AM
Hi,

I`m not sure if this was already addressed here: i`m thinking of having stepped frequencys for band 2 and 3. as a first approach for calculating resistor values and frequencys i did the following. since linar pots are used here, I made a graph in open office using 0 - 10000 R and 60 hz to 1000 hz (band 2). The resulting linear function can give any frequenzy from 60 to 1000 hz and the corresponding resister values by interpolation. I know, it`s not the most sophisticated approach. But is it WRONG to do it that way?

Thanks in advance and a happy new year.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: colonelmot on January 05, 2012, 05:51:18 AM
Interested in building this eq but a bit confused by the pot situation.....

Which pots (vishay or omeg) fit both Gyrafs PCBS and Dan Frontpanels?
Is there a an affordable source for the vishay pots listed in the BOM?

Thanks

Tom
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: spase on January 14, 2012, 11:48:27 PM
you can get those pots from TAWElectonics.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: SKJGProject on January 15, 2012, 04:11:34 PM
i bought an almost finished kit from outoftune some time ago, but i just realized after checking all my unfinished stuff,
that i have the sfernice pot pcb version but omeg pots...can i use them together?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 15, 2012, 05:08:13 PM
i bought an almost finished kit from outoftune some time ago, but i just realized after checking all my unfinished stuff,
that i have the sfernice pot pcb version but omeg pots...can i use them together?
Hi,
there is only the sfernice version pcb existing.It was never made for omegs so they won´t fit directly.You can mount them off-board with some short wires.
The sfernice pots are very hard to source and very expensive.
So use what you have,the omegs are o.k. for this.Check them for right values and remember that they must be conductive plastic types!As far as I remember you need 6 single and 2 duals per channel.

Hope to have helped,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: signalflow on January 15, 2012, 05:09:43 PM
i bought an almost finished kit from outoftune some time ago, but i just realized after checking all my unfinished stuff,
that i have the sfernice pot pcb version but omeg pots...can i use them together?

From what i remember people just bent the back pins of the pot into place on the PCB for the omegs.

-Casey
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dekelm8 on May 08, 2012, 10:00:06 PM
Hi Everyone.
I built this eq, but it not working... :(
I need check it that all is work good...
So my question is:
i can check the circuit band by band (connect only the first section and check if it's working) or i must soldering all the components?
The circuits (splits by pages on the pdf) can working alone or for get any response i must all the circuit togther???
Please Help ASAP
Thanks All
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on May 23, 2012, 05:50:23 PM
So my question is:
i can check the circuit band by band (connect only the first section and check if it's working) or i must soldering all the

You can build and test one section at a time if you want.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on June 17, 2012, 10:12:45 PM
I'd like to build a pair of these using stepped switches. For the gain switches, I'd like to limit them to +/-5dB in 1 dB increments using 11-position rotaries. Since the circuit calls for a 10k lin. pot, I plan on making up some series-type stepped attenuators using 340r resistors (x10) for a total resistance of 3.4K. I'll then add a 3.3K resistor on either side of the switch for a total resistance of 10K. Can someone tell me if this will work? Or is there an easier/better way to do it?

Thanks!

Ralph
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on June 21, 2012, 05:20:19 PM
Can someone tell me if this will work? Or is there an easier/better way to do it?

That is probably the easiest way because you can leave the rest of the circuit as it is.

Circuit simulator will help you with the resistor values.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on July 18, 2012, 07:23:19 PM
Great. In that case, do I connect my 3.3K resistors to the outside terminals of the rotary switch (pins 1 and 12) and leave the wiper connection as is? Sorry for the newbie questions - still struggling to understand how this works  :).

When it comes time to adjusting the trim pots, can I simply follow the same procedure outlined in the build docs, substituting 5dB for the regular 15dB range? Also, how would one recalculate the trimmer values for the alternate method using no test equipment?

Thanks!

Ralph
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dryman on August 16, 2012, 08:02:45 AM
i finished my new W492. I have to do some tricks, to connect the OMEG-Pots(https://www.buerklin.com/default.asp?event=ShowArtikel%2875E730%29&l=e&jump=ArtNr_75E730&ch=59533 (https://www.buerklin.com/default.asp?event=ShowArtikel%2875E730%29&l=e&jump=ArtNr_75E730&ch=59533), that i use. They are a little bit bigger, so i can't mount them on the PCB.
The construction is very solid and the PCBs don't need to be mounted on the case. Sounds nice.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dryman on August 16, 2012, 08:06:43 AM
Another Picture
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on January 17, 2013, 02:24:12 PM
I know this is an old thread, but figured I'd ask since I only recently picked up some boards from the BM.
The original had a HPF  of like 20-80-140 i think (but were out of order if memory serves) has anyone built a little HPF to go along with this.  I've been playing with some simulations, but nothing is really getting me close to the desired result.  Would be quite helpful for mixdown.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: wolfgang on January 19, 2013, 08:16:35 AM
I am selling 2 fully assembled PCB´s!
If some one is interested check out this:

http://www.groupdiy.com/index.php?topic=51135.0 (http://www.groupdiy.com/index.php?topic=51135.0)


regards,
Wolfgang
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: firfe on January 29, 2013, 02:43:55 PM
hi everybody
i've finished my W492.
but i've a problem with the P1 and P2 ( bass potentiometre)
there no action with this 2 pots.
and the P1 cut all the sound of the machine when i 'm around the middle position (zero-)
there 's sound before 0 and no after (0 to 15) and no action.
and P2 do nothing when i turn it.
i've changed the 2 potentiometre and the NE5532 ut nothing change.

all looks good and the pcb came from pcbgrinder.
the other pots work  good

i'm completly lost...

maybe someone have an idea to help me.

hope you can understand my beautiful english (sorry about that)
best

JF

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ramshackles on February 22, 2013, 08:45:58 AM
Hi
I'll be building 2 of these and am currently scouting for the potentiometers.

Audio Maintenance doesn't seem to have the exact ones as shown in the docs/pics (they have a 10K one, but it seems to have 3 sections...the ones in the pics seem to have 2)

They have them at mouser but with a lead time of 18 weeks !!!

Wondering if these would be a suitable alternative? :
http://www.vishay.com/docs/51047/p9.pdf

another possibilty:
http://www.bitechnologies.com/pdfs/p08x.pdf
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ramshackles on February 26, 2013, 06:33:58 AM
anyone?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pyjaman on February 26, 2013, 07:06:35 AM
The ones from audiomaintenance (the conductive plastic ones) are 2 gangs . the first "gang"you see in the pic ( closest from the shaft) is the center detent section. So they fit.
Laurent.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: noviygera on February 28, 2013, 12:28:30 AM
Hello,

is the Neumann W492 eq board available to purchase? I could not get the link to work for me.

Thanks,
Herman
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ramshackles on February 28, 2013, 03:06:09 AM
it is from pcbgrinder.com
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: noviygera on March 01, 2013, 12:41:59 AM
Is there a 3 band EQ version of the Neumann W492?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: EmptyMusicBox1 on March 26, 2013, 05:13:16 PM
 i find that on Mouser i think it's good no ? it's not a dual...

http://fr.mouser.com/ProductDetail/Vishay-Sfernice/P11A1T0AASY00103MA/?qs=sGAEpiMZZMtC25l1F4XBU6ciXKENQBPm5PykJhV1Bp4%3d

alternative ? dual

http://fr.mouser.com/ProductDetail/Vishay-Sfernice/P11L2V0FLSY00103KA/?qs=sGAEpiMZZMtC25l1F4XBUw4DjM6TNESxG%252bAn9O9U%2ffA%3d
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: portix on May 02, 2013, 07:16:48 AM
Hello,

Is this pot could work?
http://be.farnell.com/jsp/search/productdetail.jsp?sku=9357670

Is ther a cheaper alternative in euro zone?

Thanks,

Marc
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: adrian on May 02, 2013, 08:19:08 AM
interested to....
for now I have sfernice for the gain (from collin)  (with center dent) that are very good quality,
and OMEG (green ones from TAW)  for frequency because I don't want center dent on frequency pots,

the problem with omeg is they are cheap quality and in 3 years I had to change 4 times dual pots! >:(

i didn't found alternative pots, so i'm very curious about these ones! :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ramshackles on May 02, 2013, 08:34:05 AM
The model 51 you have linked to won't fit the pcb foot print (which is 5mm in both directions I believe). model 51 has 2.54 mm spacing side to side and about 7mm spacing front to back. Might not be a problem if the leads are long enough to bend, but from the datasheet there doesn't seem to be too much to work with.

If model 52 is available, this has slightly better lead spacing (5mm side to side, same as 51 front to back)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: adrian on May 02, 2013, 10:31:06 AM

in fact in my case pots are wired so pin spacing dosen't matter but I need small shaft (arround 3 or 4 mm)  (i already have button)
any body seem to stock pots like that (exept AML wich have center dent)

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: portix on May 02, 2013, 10:47:07 AM
I hope that for the next version of the PCB Audiox will think about a multi size system.
For now the cheapest quality pot seems to be the one from AML. (+/-150£ / 2 channel :( )
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: berkleystudios on May 17, 2013, 01:09:21 AM
trying to source parts before i get the boards... will these pots work....

http://www.audiomaintenance.com/acatalog/om-01-033_extended_info.html   
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: berkleystudios on May 17, 2013, 01:10:52 AM
.... dont really want center indent for my frequency selection but im okay with it for my gain pots
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ramshackles on May 17, 2013, 03:29:21 AM
trying to source parts before i get the boards... will these pots work....

http://www.audiomaintenance.com/acatalog/om-01-033_extended_info.html

you need conductive plastic ones
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: king-rb on June 03, 2013, 07:11:11 AM
hi there! just got a nice stereo build of this project from a friend. is there a way to change the min/max gain to 4 maybe 5 or 6 db instead of this crazy 15 db?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: portix on June 03, 2013, 07:46:59 AM
Use the trim pot (see calibration procedure)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: berkleystudios on July 03, 2013, 01:25:31 AM
http://www.mouser.com/ProductDetail/Bourns/91A2A-B28-B15-B15L/?qs=sGAEpiMZZMtC25l1F4XBU0lMC8qKAKdNb%2fFsrRH3ibQ%3d

still hunting down pots... will these bourns work? 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on July 03, 2013, 09:56:42 AM
Sure but you're still paying almost the same as getting the intended pots from TAW.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Siegfried Meier on July 16, 2013, 08:38:44 PM
Hey guys,

I bought parts for this quite some time ago and only now getting to it.  Seems Laura at TAW sent me enough pots for 4 channels, which I didn't need.  I'm confused though as to where the 2 dual gang pots per channel go?  There appears to be 6 single and 2 dual per channel.  Anyone?

Thanks!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on July 16, 2013, 10:32:29 PM
2nd bottom and 3rd bottom if i remember correctly, its the mid bands freq adjust, i think... i have 4 that im still putting together.  If i ever get a night off.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Siegfried Meier on July 16, 2013, 11:36:22 PM
Just found a pic online that confirms your post.  Thanks so much!

Too bad these omeg pots need to be wired off board with the Purusha case...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on July 17, 2013, 11:23:12 AM
There IS a way to do it with them connected to the board, but it's a LOT of work
If you're interested i can explain.
I just decided to wire them now, as this is the 3rd time im re-doing this project.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on July 17, 2013, 11:24:49 AM
(http://sphotos-b.ak.fbcdn.net/hphotos-ak-frc1/580595_10200366811595993_1183381528_n.jpg)

Actually, here i have a pic of how to do it using leads i cut from diodes and caps n stuff.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Siegfried Meier on July 17, 2013, 11:38:58 PM
Oh lookit you fancy pants!

Thanks, very cool idea.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on July 19, 2013, 03:27:44 AM
Actually, here i have a pic of how to do it using leads i cut from diodes and caps n stuff.
That's excellent!

Udo ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on August 10, 2013, 11:07:10 PM
Having an issue with my pair of 492s.  On both 3 of the 4 filters work fine.  Filter 3 doesnt seem to turn on or function on both channels. Im seeing 14v on the switch which im thinking isnt correct. There are no voltages on the schematic which is making things a little more difficult for my nubbliness. :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on September 12, 2013, 08:35:17 AM
Hello everybody,

started this project early 2011,then it went to the shelf,now I did it finally ;D

Nothing special,but a lot of work.....and now fully working,hahaha......
Panel is from NRG Recording,4RU,engraved(,thanks Frank!),pcbs from Gustav.
Pots (Omeg from Laura at TAW) and switches are held on a mounting plate,pcbs are attached by solid core bus wires (partly),holds up easy.
Knobs are SIFAM.
Case is from Modushop,Italy (as always).
PSU is a JLM AC/DC,modded to 12vdc on the former phantom power rail for the LEDs (low current types,2mA).
Made some grounding stuff to have the choice of connecting pin 1(XLRs) to chassis,psu/audio ground or leave it open.Was highly influenced by the 51x racks,I really can recommend it to do.Easy job,just some perfboard stripes,headers and jumpers,done.
Have these options on all i/os,great,it´s running in AES/EBU configuration now and dead quiet.
Transformer is from Schuro Elektronik,Germany,fully sealed with extra shield going to chassis ground.

Thanks to AUDIOX of course for making it possible!

Thought I should show some pics of it,here we go:

(http://imageshack.us/scaled/thumb/266/1iza.jpg) (http://imageshack.us/photo/my-images/266/1iza.jpg/)
(http://imageshack.us/scaled/thumb/42/l4uy.jpg) (http://imageshack.us/photo/my-images/42/l4uy.jpg/)
(http://imageshack.us/scaled/thumb/841/4cxh.jpg) (http://imageshack.us/photo/my-images/841/4cxh.jpg/)
(http://imageshack.us/scaled/thumb/42/79ua.jpg) (http://imageshack.us/photo/my-images/42/79ua.jpg/)

PSU & Distribution:

(http://imageshack.us/scaled/thumb/203/gjy5.jpg) (http://imageshack.us/photo/my-images/203/gjy5.jpg/)
(http://imageshack.us/scaled/thumb/407/lwcm.jpg) (http://imageshack.us/photo/my-images/407/lwcm.jpg/)

Audio wiring:

(http://imageshack.us/scaled/thumb/21/tu8v.jpg) (http://imageshack.us/photo/my-images/21/tu8v.jpg/)

Grounding/Jumpers:

(http://imageshack.us/scaled/thumb/850/2qet.jpg) (http://imageshack.us/photo/my-images/850/2qet.jpg/)

Inside pics:

(http://imageshack.us/scaled/thumb/801/cucc.jpg) (http://imageshack.us/photo/my-images/801/cucc.jpg/)
(http://imageshack.us/scaled/thumb/836/hntv.jpg) (http://imageshack.us/photo/my-images/836/hntv.jpg/)


Thanks for watching,

best regards,

Udo.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kosty on September 12, 2013, 10:06:04 AM
http://www.mouser.com/ProductDetail/Bourns/91A2A-B28-B15-B15L/?qs=sGAEpiMZZMtC25l1F4XBU0lMC8qKAKdNb%2fFsrRH3ibQ%3d

still hunting down pots... will these bourns work?

Has anyone tried these pots ?

edit: I just noticed that some users mentioned Omegs being available at rapidonline for us Europeans !
Dual pots are 65-1442 and singles are 65-1404.

@Udo : Your build looks amazing ! You just convinced me to build 8 channels :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on September 12, 2013, 01:40:32 PM
@Udo : Your build looks amazing ! You just convinced me to build 8 channels :)
Thank you for the kind words.
As said a lot of work to do,especially when mounting the pots off-board,but doable.
I made the pot connections with 1mm bus wire on the most outward pins on the lower row (gain pots) and adjusted the boards,then proceeded with thinner bus wires for the inner connections.Also one solid wire per pot on the opposite side made the construction very sturdy,absolutely no need to mount the boards anywhere else.
The easiest and fastest part was populating the boards,the big part is thinking about the project and designing the frontpanel.
The grounding options are working perfect.

Didn't want to convince you,hahaha ;),but the result is a really nice eq,a very good expansion to my existing EQs,so why not?
I like the mid bands btw.

Happy designing and building of course,

Pfüati,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on September 12, 2013, 02:54:07 PM
Udo, thats beautiful... wish i could get mine working. lol.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on September 12, 2013, 03:30:25 PM
Udo, thats beautiful... wish i could get mine working. lol.
Thank you very much.
About your issue,looks like a series build error.
Do the gain pots work on the faulty bands?
You can compare the schematics of the mid bands,they're identical concerning topology,just some values are different.Do you have the same reading on the switch on the working mid band?
ICs all in correct orientation?Lytic too?
Band three,that's the high mid band,right?
I would check all parts around the area at ic5 as a starting point.
Maybe a good picture of it might help.

Good luck,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on September 12, 2013, 04:32:44 PM
Ill get a pic thanks.  The funny thing is it was working fine, calibrated fine.  I re-wired it to fit into a 1u instead of a 2u and all hell broke loose only on that upper mid band (on both channels... so maybe i just did the same thing wrong on both...  thanks, and you mentioned sifam knobs.  Got a link to those?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on September 12, 2013, 04:54:48 PM
Hi,

I sourced the knobs here in germany:
http://www.sibalco.de/produkte/drehknoepfe/spannzangenknoepfe.html
Don't know who sells them in the usa,have only seen them at canford,uk.
I would google it.
But be aware that they are quite expensive.

About your issue,what was changed when you say you rewired them?
Still looks like a series build error to me,and if you say they worked and calibrated fine before rewirering it should be something simple.

Cheers,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on September 12, 2013, 05:58:43 PM
I had the pots connected directly to the board previously.  Now they are wired.  Thanks for the link, the part number will be quite helpful.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on September 12, 2013, 06:18:54 PM
I had the pots connected directly to the board previously.  Now they are wired.  Thanks for the link, the part number will be quite helpful.
Wires swapped?Wires for boost/gain in the correct position (1st row)?

Anyway,it's 2,5 years ago when I ordered the Sifams.
I think they are these:

Typ SP- 11mm - niedere Bauform / low profile (13,5mm high)   Serie: K010005 ,grey no line,4mm shaft

You'll need coloured caps too.
I'll look for the bill if you want.

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on September 12, 2013, 07:16:38 PM
Naa thats cool.  Thank you I can find em from there, i just wanted to see what you did about the shaft size and find a model that actually FITS lol.  I wound up having to put little collets on each pot to make em 1/4".
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on September 12, 2013, 09:55:24 PM
some VERY nice work there Udo  ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on September 13, 2013, 01:11:24 AM
Naa thats cool.  Thank you I can find em from there, i just wanted to see what you did about the shaft size and find a model that actually FITS lol.  I wound up having to put little collets on each pot to make em 1/4".
My Omegs were 4mm,Sifam has nearly all sizes both metric and imperial.
Pot sizes from 10 to 13mm diameter are for 2/3/4 mm and 1/8" shafts,the bigger ones go to 6mm and 1/4".

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on October 26, 2013, 08:44:27 PM
Potentiometers: I just found these very cheap ones:

http://www.voelkner.de/products/288619/Leitplastikpotentiometer-9mm-P092s-10-Kr-20-Lin.html

Well...they won't fit into the PCB... and they are 6mm. But the are 2Gang 10k linear conductive plastic.... for Eur 2.82 only.

Should I try them ?  ;-)


...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on October 27, 2013, 02:43:26 AM
Welcome to the forum Markus.

The pot seems to have a switch.Personally I would not like it to have a mechanical click when ccw first.Technically they would work of course.
Pricewise the sets from Laura at TAW were way cheaper,at least 3 years ago.
For german buyers you might want to ask for Omegs at PS-Potentiomerters (Alphastat) too.

Best regards and tschüss,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on November 08, 2013, 07:24:25 PM
What is the best way to make a global bypass for the W492 (bypassing all 4 bands at once) ?
- A Kind of "Masterswitch" (e.g. Lorlin)  for the 4 "single" switches ?
- Hardwired bypass (XLR in to XLR out) with relay or switch ?
- any other ideas ?

Thank you...

...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 08, 2013, 07:40:52 PM
What is the best way to make a global bypass for the W492 (bypassing all 4 bands at once) ?
- A Kind of "Masterswitch" (e.g. Lorlin)  for the 4 "single" switches ?
- Hardwired bypass (XLR in to XLR out) with relay or switch ?
- any other ideas ?

Thank you...

...markus :-)
Moin Markus,

I'd prefer relais since you can mount them very close to the i/o connectors ("shortest way").
But both options will work of course.
With your 4 switches Lorlin version you mean them attached to the pcb switch points,right?
If so your eq will go into bypass,but the signal still runs through the input and output stages( debalance/balancing).
Relais on the physical i/o will give you a "true" bypass.Dont forget the fallback diodes then("Click").
Whatever you prefer.....

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on November 08, 2013, 08:06:29 PM
Thank you, Udo :-)

Yes, I'd prefer the relays (with mandatory fallback diode of course !), too.
But I'm not sure if I will hear a switching noise in the audio path ?

...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 08, 2013, 08:25:20 PM
Thank you, Udo :-)

Yes, I'd prefer the relays (with mandatory fallback diode of course !), too.
But I'm not sure if I will hear a switching noise in the audio path ?

...markus :-)
Well,you can do a test setup for one channel,it's not too expensive (I normally use Omron subminiature relais).
Switching noise is more likely to come back into the audio path when the supply voltage is directly derived from the existing audio psu rails that feed the audio.A third rail helps,also running the dc wires for switching properly and a bit off from (unbalanced) audiolines supports it.
In my builds I often create a third "dirty" rail by modifying the phantom to 12vdc on JLM psus.
If you want to go super-save you can put in an additional extra psu (small waalwart is o.k.) for just relais,led stuff etc.This way the psus don't even share a ground connection-total isolation!

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on November 08, 2013, 08:42:37 PM
What do you think about an additional small switching powersupply built in (e.g. meanwell) for relay power (and in my case I additionally will have a lot of lights, too).

Is it a big sin to use a switching powersupply (not in the audio path, but inside the housing) ?

...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 08, 2013, 08:50:22 PM
What do you think about an additional small switching powersupply built in (e.g. meanwell) for relay power (and in my case I additionally will have a lot of lights, too).

Is it a big sin to use a switching powersupply (not in the audio path, but inside the housing) ?

...markus :-)
Depends on how far it is away from sensitive parts and how much hf noise they cause.
I'd take a cheap standard linear type.
With a smps type a good shielding might be necessary.

Udo.

Edited:Typo (I meant smps,not sms ;D)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pucho812 on November 16, 2013, 08:30:27 PM
been reading on this for a while. Wondering the possibility of adding in bell/shelf switch on the LF and HF bands. 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ramshackles on November 17, 2013, 04:34:16 AM
I've got a couple of these boards for sale on the black market. Nice looking project, but I'm concentrating on other things now..
Title: Re: Neumann W492 equalizer DIY project
Post by: Markus_Krippner on November 19, 2013, 03:35:57 AM
The unit was in the "dead state" just now, and I accidentally shorted the input of the 7815 to ground with my probe - and suddenly the unit came alive  :o What's going on? Next power up - WORKS - then WORKS again - then DEAD...  aaarghhh  :)
What specific voltage regulators do you use ? Never had trouble with LM78xx/uA78xx/LM79xx/uA79xx, but some, like TS7815 / TS7915, seem to be famous for hanging at power up.

Had the same problem (+15V from 7815 sometimes working  - sometimes not),  too.
I used L7815CV from ST Microelectronics - I thought thats a good brand name.
Well ... I replaced the L7815CV to a 7815 from an defective Behringer device (sorry... I don't know the brand name of that 7815)... now it's working properly.

---> If your 7815 is not working - try another brand.

...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: xazrules on November 27, 2013, 09:22:54 AM
Hi, can i use a trex kit from jlm audio for the PSU?

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on November 27, 2013, 10:16:25 AM
here you need +15V, 0V, -15V.

Trex or Trex2 will only provide you with +24V and 48V wich is perfect for Neve or something else.

Remember you need a bipolar psu.

Good luck!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: xazrules on November 27, 2013, 12:04:43 PM
thank you 3nity, what psu do you suggest for this project?
to keep the costs low somehow.  :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 3nity on November 27, 2013, 12:11:12 PM
It depends on where are you located.
for a simple +/- supply id go with this one: https://pcbgrinder.com/index.php?route=product/product&path=59_93&product_id=97 (https://pcbgrinder.com/index.php?route=product/product&path=59_93&product_id=97)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on January 07, 2014, 02:05:13 PM
Here's my version of the W492 :

(http://img5.fotos-hochladen.net/uploads/cimg2594yqdeu7fp35.jpg)

(http://img5.fotos-hochladen.net/uploads/cimg2597ha5c64zmv8.jpg)

(http://img5.fotos-hochladen.net/uploads/cimg258742a5kjptuz.jpg)

...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iprovlek on January 07, 2014, 02:21:22 PM
Great unit Markus!

UNIQUE...

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ding on January 07, 2014, 02:53:12 PM
I really like the way you mounted the boards. Where did you get those mounting brackets? Are they plastic? Beautiful job!!!!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on January 07, 2014, 02:59:06 PM
I really like the way you mounted the boards. Where did you get those mounting brackets? Are they plastic? Beautiful job!!!!

Yes, its plastic. It's called POM (Delrin).
Everything you see is homemade...   but well, ok... I've got a CNC, a Laser Engraver and an Anodizing Setup on my own  ;-)

...markus :-)

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ding on January 07, 2014, 03:09:32 PM
Beautiful craftsmanship!!!  :) If you ever decide to make those pcb brackets again would you consider making me a pair. I have been wanting to do the exact same thing and have been trying to figure out a way to make them at home. I imagine a CNC would help  ;D Great job!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on January 07, 2014, 03:29:00 PM
You can do something like that on your own without a CNC, but you have to make 2 parts instead of 1:

(http://img5.fotos-hochladen.net/uploads/abcrfapgsoiv5.jpg)

Make these 2 parts (e.g. 2mm plastic or wood... or pertinax from a PCB...) and screw or glue them together like a sandwich...


...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 07, 2014, 03:44:47 PM
Beautiful craftsmanship!!!  :) If you ever decide to make those pcb brackets again would you consider making me a pair. I have been wanting to do the exact same thing and have been trying to figure out a way to make them at home. I imagine a CNC would help  ;D Great job!
You might consider some of these,just cut to needed length:
http://www.reichelt.de/Distanzhuelsen-etc-/KARTENHALTER/3/index.html?&ACTION=3&LA=446&ARTICLE=9190&GROUPID=3365&artnr=KARTENHALTER&SEARCH=Kartenhalter

@Markus:Very neat work indeed (...but I told you that in the other forum already ;D...).

Best regards,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ding on January 07, 2014, 04:29:04 PM
You can do something like that on your own without a CNC, but you have to make 2 parts instead of 1:

(http://img5.fotos-hochladen.net/uploads/abcrfapgsoiv5.jpg)

Make these 2 parts (e.g. 2mm plastic or wood... or pertinax from a PCB...) and screw or glue them together like a sandwich...


...markus :-)

Great idea!!!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on January 07, 2014, 06:43:15 PM
Markus_Krippner    WOW  !!!     That's Gorgeous !!!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: avieira on January 07, 2014, 11:47:23 PM
Does anyone know where I can find some knobs similar to the ones in this pic? 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 08, 2014, 12:40:42 AM
Does anyone know where I can find some knobs similar to the ones in this pic?
Welcome to the forum.
I used Sifam knobs on mine (please see reply #487).Although mine are grey you can have them in black too.Same for the coloured inlets,you have a very big choice there.Available in nearly any usual size and any shaft diameter.
Don't know where you are located,here in germany I sourced them from Sibalco.

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on January 08, 2014, 12:43:17 AM
@ Markus... WOW!!! Bin ein bisschen neidisch... ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on January 08, 2014, 10:08:36 AM
Does anyone know where I can find some knobs similar to the ones in this pic?

  I used these , the color caps are separate pieces - http://catalog.selcoproducts.com/category/collet-knobs
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kogstudio on January 26, 2014, 01:37:00 AM
hey there,

What's a rough costing in parts for a stereo set of these?
As in how much to shell out over the total project [boards/components/case etc] so I can work out my budgets
Any rough figures/ideas much appreciated :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Bonsaimaster on January 30, 2014, 09:36:05 PM
Ok sorry for the same question. What are the best pots for this build. I want to build an 8 channel version so I need a lot of pots. They will be off board. I would like to have center indent and possible switched for the frequencies. Also for an 8 channel version can someone suggest a PSU? I am going to do a DB25 input and output. A knob suggestion would be welcomed also.

Daniel
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 31, 2014, 01:13:15 AM
Ok sorry for the same question. What are the best pots for this build. I want to build an 8 channel version so I need a lot of pots. They will be off board. I would like to have center indent and possible switched for the frequencies. Also for an 8 channel version can someone suggest a PSU? I am going to do a DB25 input and output. A knob suggestion would be welcomed also.

Daniel
I have answered all of these questions except of center indent pots (this is new) because you asked me for them via PM,even sent pics from my build at starting point.
Didn't you read them?
Also the knob suggestion is just three replies back.....

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Bonsaimaster on January 31, 2014, 09:13:34 AM
I guess I was asking the knob question in relation to a potentiometer question. I live in the US but it seems the omeg pots are hard to find. Just looking for a good combination. I did take the information you sent me. Just looking for different options.

Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Bonsaimaster on January 31, 2014, 12:14:54 PM
Will these pots work?

http://sensing.honeywell.com/index.php?ci_id=3108&la_id=1&pr_id=27657


You can use any conductive plastic potentiometer. Manual wiring is of cource needed with those types that don't fit mechanically on the pcb. Carbon potentiometers are not recommended. They start to scratch quite soon because the circuit is dc coupled.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 31, 2014, 12:39:56 PM
Will these pots work?

http://sensing.honeywell.com/index.php?ci_id=3108&la_id=1&pr_id=27657


You can use any conductive plastic potentiometer. Manual wiring is of cource needed with those types that don't fit mechanically on the pcb. Carbon potentiometers are not recommended. They start to scratch quite soon because the circuit is dc coupled.
So you have the answer already,it says "carbon element" in the description.So better not use them.

And about your center indent idea:It could be done best with a stepped pot or building a switch in as suggested.The idea behind it is that standard center indent pots do have tolerances which sadly means that the mechanical center position will not exactly match the half of the resistance.It will be slightly off and then cause a little change of the sound when one thinks it is flat.
Of course there will be a marginal infuence even with built-in switches because the audio still runs through the i/o stages.

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ArnoldLayne on February 01, 2014, 11:01:48 PM
I found these as an alternative to the expensive P11 pots. Would they be better than Omegs ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on February 02, 2014, 05:56:29 AM
I found these as an alternative to the expensive P11 pots. Would they be better than Omegs ?
Which ones does your question refer to?

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Bonsaimaster on February 10, 2014, 02:51:55 PM
Ok found this pot on Mouser website. Anyone know if one could make a dual gang pot from this? This is a great pot with 11 dents (positions) but is only 1 gang. Anyone know if you could modify it to have 2 gangs? Like adding the stacks and resealing the pot.

http://www.mouser.com/Search/ProductDetail.aspx?R=P081N-271F2CBR10Kvirtualkey57700000virtualkey858-P081N271F2CBR10K
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Andreas Pfeiffer on February 11, 2014, 03:23:13 AM
What is the best spot for an attenuator in this EQ?
Should be easy to implant in a ready build EQ.
Maybe the best at the first OP amp output?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ArnoldLayne on February 11, 2014, 03:01:30 PM
I found these as an alternative to the expensive P11 pots. Would they be better than Omegs ?
Which ones does your question refer to?

Udo.

Oh no, I forgot the link  :o
Now I don't even know what I was talking about...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: avieira on February 14, 2014, 05:45:56 PM
Could anyone kindly tell me if these toggle switches will work?  From the schematic they look like they will...but then again, I'm not very experienced at this. 

http://www.mouser.com/ProductDetail/Mountain-Switch/108-0008-EVX/?qs=sGAEpiMZZMvudeGI7i40XMpvUgTXR703%252bxnZru9LEbg%3d

Thanks!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on February 14, 2014, 06:49:06 PM
Could anyone kindly tell me if these toggle switches will work?  From the schematic they look like they will...but then again, I'm not very experienced at this. 

http://www.mouser.com/ProductDetail/Mountain-Switch/108-0008-EVX/?qs=sGAEpiMZZMvudeGI7i40XMpvUgTXR703%252bxnZru9LEbg%3d

Thanks!
You mean for switching the bands on & off,right?
So yes,they'll work fine.

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Andreas Pfeiffer on February 15, 2014, 02:41:58 AM
What is the best spot for an attenuator in this EQ?
Should be easy to implant in a ready build EQ.
Maybe the best at the first OP amp output?

Somebody has an idea, please ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ArnoldLayne on February 19, 2014, 09:42:12 PM
Ok, I think it was these:

http://tbaudiogear.com/?product=bi-10k-linear
http://tbaudiogear.com/?product=bi-2x-10k-linear

They're conductive plastic, have 10% tolerance, an way cheaper than P11's.
I saw that there is also a version with one, 11 or 21 detents... (http://bitechnologies.com/pdfs/p260.pdf)
Could this be an easy way of having some repeatability, without going into mastering requirements ?

I found these as an alternative to the expensive P11 pots. Would they be better than Omegs ?
Which ones does your question refer to?

Udo.

Oh no, I forgot the link  :o
Now I don't even know what I was talking about...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: late on February 28, 2014, 08:46:22 AM
What kind power transformer i need if i use mnats psu board. Is 2x15V and 30VA good?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kosty on March 03, 2014, 07:18:30 PM
Ok, I think it was these:

http://tbaudiogear.com/?product=bi-10k-linear
http://tbaudiogear.com/?product=bi-2x-10k-linear

They're conductive plastic, have 10% tolerance, an way cheaper than P11's.
I saw that there is also a version with one, 11 or 21 detents... (http://bitechnologies.com/pdfs/p260.pdf)
Could this be an easy way of having some repeatability, without going into mastering requirements ?


Did anyone try these ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: horvitz on March 06, 2014, 07:55:57 AM
Hey, noticed you guys swinging by looking for pots.  Anything I can do to help out?

Looking at the the copper files, I think they might fit the Omeg version using those outside holes.  The spacing between decks is 7.6mm and the pins 2.5mm LS.  The Sfernice is only 5mm between decks so no go there.  I didn't get past the first post though, so I am probably missing something.

I think your front panel might change a little, too.  The centerline of the pot is 6.95mm over the PCB and it's a 1/4" bushing. 

  Brian
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ArnoldLayne on March 07, 2014, 08:41:08 PM
Hi Brian,

I was planning on wiring them off-board personally, on Dan's (ddt) panels. The Omegs fit on them, and your pots are smaller so it works.
I'll definetely try them, but I'm also planning for a TBDD rack  ;) Also intrigued by the TBFX platform...
Nice projects !
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: horvitz on March 08, 2014, 11:01:09 AM
I was planning on wiring them off-board personally, on Dan's (ddt) panels. The Omegs fit on them, and your pots are smaller so it works.
I'll definetely try them, but I'm also planning for a TBDD rack  ;) Also intrigued by the TBFX platform...
Nice projects !

Thanks!  They are PC pins, so off-board  wiring will be a bit of work, but you should be able to make it work.  Bending a small hook at the end of the pin should help.

I've actually added a discount for you guys doing this project.  It's not published on the site but if you add 8 to your cart, it will automatically apply a 10% discount.

Brian
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kosty on March 08, 2014, 03:55:26 PM
I was planning on wiring them off-board personally, on Dan's (ddt) panels. The Omegs fit on them, and your pots are smaller so it works.
I'll definetely try them, but I'm also planning for a TBDD rack  ;) Also intrigued by the TBFX platform...
Nice projects !

Thanks!  They are PC pins, so off-board  wiring will be a bit of work, but you should be able to make it work.  Bending a small hook at the end of the pin should help.

I've actually added a discount for you guys doing this project.  It's not published on the site but if you add 8 to your cart, it will automatically apply a 10% discount.

Brian

This is a very nice gesture from you ! Thank you very much.
Regarding the spacing between decks, I think that it wouldn't be a big problem since the pots needed per board are 6x single decks and 2x dual decks.
For the 2 duals you can bend the pins from the rear deck and connect it with wires.
I was wondering if would also consider offering a discount for the single deck 10k pots ;)
I guess this would be the perfect opportunity to finally order the TBDD rack kit :)
Thanks !
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: horvitz on March 10, 2014, 01:31:30 PM
OK.  I was misunderstanding the layout.  The PCB footprints all look like dual decks.  I can make a package for 6x single deck and 2x dual.  I'll post back when that's up.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: horvitz on March 10, 2014, 01:39:07 PM
OK, package is up here:
http://tbaudiogear.com/?product=neumann-w492-eq-diy-pot-package (http://tbaudiogear.com/?product=neumann-w492-eq-diy-pot-package)

That's 2x  P260P-D2AS3CB10K and 6x P260P-D1AS2AB10K.  Price is $31.95, which is 10% off buying them all individually.

  Brian
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kosty on March 11, 2014, 06:52:59 AM
This is awesome !
The footprint is for dual decks to allow better stability, since the PCB doesn't have any mounting holes. But there are no traces to the pins on the second gang.

Will order soon :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: noiseattitude on March 17, 2014, 02:17:22 PM
Guys,
noob here :)
I have 3 question, I hope somebody could reply me.

1) For this project i have to use only SPDT Switches or fit also SPST ?

2) About the capacitors, i have to use (for 1 channel):
4 elcos, 4 ceramic and the rest is all poliester caps (like as wima) ?

3) A toroidal trafos 230v - 15v x 2 - 15VA  I think is good, can you confirm ?

Thanks in advance,

giovanni.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: horvitz on March 20, 2014, 03:15:12 PM
So sorta good news and bad news.  Well it's the same news, just depends upon if it's for you or me.  You guys totally wiped me out on the single deck pots quickly!  I've ordered more but unfortunately, BI is a very long lead so it'll be 10-12 weeks before they are back in stock.  Thanks for your orders and sorry for those of you who didn't get any.

  Brian
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: horvitz on March 20, 2014, 03:35:29 PM
It's worth pointing out though that I have loads of the dual deck pots still in stock so if you want to use 8 of those for a unit, the 10% discount still applies.  That would make a mono unit $46.80 rather than $31.95, which is still not bad.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kogstudio on April 06, 2014, 07:18:19 AM
Does anyone have any links to history of the w492,
e.g. what years it was in production, desks used in, major uses etc?

For some reason my usually good research skills have eluded me on this one...

anything useful appreciated  :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mtw on April 19, 2014, 10:31:58 PM
I bought these boards around 5 years ago  :o and am finally ready to start building them.

I took a 3 year break from doing DIY stuff, but I'm ready to get back into it.  So as a new newbie I could use some help the BoM.  I've put together this BoM from Mouser - what I'm mostly concerned about are the caps.  If someone could just give this a once over and make sure I did the right thing I'd greatly appreciate it.

https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=8b0570daba

It looks like you need electrolytics for C5,C6,C11,C18 and ceramic for C19,C20,C21,C22. The rest I went with WIMA film caps.  I chose 100V (at random) or 63V if 100V wasn't available.

Anyway just a sanity check on this list would be greatly appreciated.

Cheers!

-mtw
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Emalot on May 05, 2014, 09:44:59 AM
The link to buy some W492 boards, page 1, doesn't work.
Someone knows where i can buy these boards pleae?
Thank you
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: haebbe58 on May 05, 2014, 10:28:45 AM
Hi,

here you are:

https://pcbgrinder.com/index.php?route=product/product&path=59_70&product_id=62

Regards
Herbie
Title: PSU problem with W492 project
Post by: pvision on May 08, 2014, 05:42:00 PM
I am just finishing a stereo W492 with Gustav's boards and Dan's front panels and have run into an unexpected problem.  After 60 seconds or so the psu shuts down and the negative rail drops to around 0.7 volts

The power supply is one of Gustav's PCB1518 psu boards with 7815 and 7915 regulators.  I did a bit of web searching, read the data sheets and modified the circuit to have a 10uF cap across each regulator output plus the original 100 nF decoupling caps.  This hasn't stopped the problem

I have two of these power supplies, built with the same components, and they exhibit the same symptoms.

The regulators are ON SEMICONDUCTOR MC7815CTG and MC7915CTG and they're fed from a 25-0-25 transformer

I'll try adding diodes as per the data sheet but wonder if I am missing something obvious? 

A couple of things I should mention: the psu ground is not connected to the chassis, just to the PCBs.  The mains incoming earth is not earthed to the chassis yet either

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: haebbe58 on May 08, 2014, 06:05:17 PM
with your transformer, you get about 35 or more volts DC after rectifying at the inputs of the regulators. But they cannot stand more than 30 volts DC at their input, some have their maximum at 35 volts, but tzhat is the absolute limit So maybe you have blown them or their safety mechnism does act and they shut down.

for that application you have to choose a transformer that doesn't deliver more than 30 volts dc after rectifying which means not more than appr 20-0-20 AC. E.g. a 15-0-15 or a 18-0-18 would be the best.

Regards
Herbert
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on May 08, 2014, 06:15:56 PM
Makes sense.  When I ordered the transformers a few months ago I wasn't thinking about the voltage post-rectifier, just about the rated voltage

I'll look for some different regulators to see if I can still use these trafos

Thanks!
Title: Re: PSU problem with W492 project
Post by: kante1603 on May 08, 2014, 11:37:07 PM
The mains incoming earth is not earthed to the chassis yet either

Nick Froome
Just as a side note:This is the SAFETY GROUND!Please never ever run your unit without having it connected.It will save your life one day!

Udo.
Title: Re: PSU problem with W492 project
Post by: pvision on May 09, 2014, 02:45:40 PM
The mains incoming earth is not earthed to the chassis yet either

Nick Froome
Just as a side note:This is the SAFETY GROUND!Please never ever run your unit without having it connected.It will save your life one day!

Udo.
Point taken!

Title: Re: PSU problem with W492 project
Post by: kante1603 on May 09, 2014, 03:59:46 PM
 :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on May 09, 2014, 04:57:52 PM
Next question…
 
The first channel worked first time.  The second is being more intractable.  It doesn't pass audio.  Using a test lead connected to an amp I've tracked the signal as far as the second gain pot where everything is OK.  The third gain pot just gives a low hum and no signal

The schematic suggests the boost / cut pots (P1, 3, 5 & 7) are wired in series. P1 and P3 are, and P5 and P7 are, but there appears to be no continuity on the board between P3 and P5 and it's round there that I lose the signal

The pots in my version are OMEGs and are wired off-board

The schematic I have is dated 23.6.2008 - have there been revisions since then?

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on May 09, 2014, 05:25:38 PM
Hello Nick,

I have seen broken green Omegs sometimes.A quick check is to measure its' resistance on the outer pins which should show you roughly the max. resistance as well as the wiper is working.Best done when out of circuit,just lift the wiper and one of the outer wires.
Otherwise why not compare to the healthy eq and trace it (feed the same signal to both eqs at the same time).Might be a faulty part/op amp too.

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project - notes for first-time builders
Post by: pvision on May 11, 2014, 06:36:36 PM
A few notes that may be of use to first-timers like me and to W492 builders in general

* there is no provision for mounting the board so if you're using off-board pots you'll have to make up a mount
* off-board pots double the build time & quadruple the hassle of the project
* if you're wiring off-board it's easy to get the pots reversed, generating yet more hassle & rewiring
* OMEG pots don't fit the board as supplied - the pins are too thick
* the pot mounting holes are through-plated so if you drill them out to mount pots you are likely to lose links between the top & bottom of the board
* C8 and C20 are left unstuffed (let me check those two part numbers)
* NE5532 chips pull about 15 mA max each, there are 8 per board so the current draw is only about 60 mA average, 120 mA max / board, across two voltage rails so the demand on the PSU is miniscule
* of the 8 pots, only #4 and #6 require twin gang pots
* Dan DDT's front panels make life easy and the back panels for mounting the pots & switches are a really good idea
* the unit is balanced in & out
* there is no provision made on the PCB for gain trim or for transformers
* there is no provision made on the PCB for a per-channel bypass switch
* the plated-through holes & small diameter holes make desoldering incredibly difficult - take lots of care before stuffing

When fault-finding you should have signal on each end of every boost/cut pot.  I think you'll find all faults are the result of operator error - it's a very easy board to stuff & build, pots notwithstanding. 

Dan's panels ideally need knobs of about 10 mm diameter - 14.5 mm knobs cramp the lettering slightly.  The OMEG pots have a 6 mm shafts and most knobs for 6 mm shafts are 14.5 mm or larger

Overall it's a very good-sounding EQ, particularly at the low end.  I haven't trimmed it yet, or run any sweeps, but it's warm at the bottom end and, for me, the boost is a little bit narrow at the mid & high end.  I'll report back after some calibration

This might be a good eq to build with switched boost & cut and possibly switched frequencies

Thanks to Audiox, Gustav & Dan for the ideas & parts & to Udo & others on the forum for help along the way

The link below has some interesting reading for those wishing to change the Q of the equaliser
http://sound.westhost.com/articles/state-variable.htm


Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on May 24, 2014, 01:30:58 PM
Just read Ben Lindell's very useful blog post on using Fuzzmeasure for sweeps. These are the results for the second MF band of channel 1 of my newly-completed W492 EQ

These sweeps are with the band bypassed then + & - 5, 10 & 15 dB at an indicated 2K

The "out of band" effects are considerable. All the bands seem to affect the low end as well as the selected boost / cut frequency. Are other people seeing this?

(http://groupdiy.com/index.php?action=dlattach;topic=28332.0;attach=27716)

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on May 26, 2014, 04:03:33 PM
A quick snap of my first project. I just need a little Neumann badge for the front panel...

(http://groupdiy.com/index.php?action=dlattach;topic=28332.0;attach=27750)

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: darkus on May 27, 2014, 04:33:44 AM
Hey guys idk if you are still sourcing for correct pots. I was, and then i found these
http://www.elektronicaonderdelen.nl/passive-components/rotary-potentiometers/conductive-plastic-omeg.html

I ordered pots for 4 channels in total, cost was 75 euros with shipping. Lets see if these guys work out properly, atleast they were alot cheaper than the other pots ive seen around here.

Im not sure about the roster in those pots but if they dont fit my pcd i just wire them.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on May 29, 2014, 04:50:51 PM
OK, new sweeps after a bit of rethinking my test setup. I knew something was up, just wasn't sure what. I think I had the output feeding the input. My new sweeps look more sensible

Interestingly channel 2 drops about a dB when mid 1 is switched in - you can see it in the graphs. The rest of the sweeps are as smooth (with 1/3rd Octave smoothing) and they were done at 44.1 kHz. As I'm using the Fireface I'll try some at a higher sample rate

Channel 1
(http://groupdiy.com/index.php?action=dlattach;topic=28332.0;attach=27836)

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on May 29, 2014, 04:51:50 PM
Channel 2
(http://groupdiy.com/index.php?action=dlattach;topic=28332.0;attach=27838)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 09, 2014, 10:55:29 AM
Hey so im finishing up my taw and mouser orders and noticed most people used bourns more affordable 200r and 10k trim pots, so they fit fine?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 10, 2014, 03:14:48 AM
Hey so im finishing up my taw and mouser orders and noticed most people used bourns more affordable 200r and 10k trim pots, so they fit fine?

You can always bend the legs.

I would use a resistor and adjust as needed, if I wanted to save a little.

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on June 10, 2014, 05:11:34 AM
Does someone know, where to get the Pots from?
10KLIN PA11QXF???
Mouser?
THX
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Majestic12 on June 10, 2014, 09:48:54 AM
Does someone know, where to get the Pots from?
10KLIN PA11QXF???
Mouser?
THX

Here we go:

http://tbaudiogear.com/?product=neumann-w492-eq-diy-pot-package
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on June 10, 2014, 10:52:51 AM
 ;)
thx
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 10, 2014, 10:55:02 AM
IThanks Gustav. I went for the 3/8 and 1/4 figuring at worst I would have to bend one. As far as pots goes almost half this thread is about finding the right (and affordable) pots. Tb is out of stock.  Laura at Taw might have some ill let you all know she is supposed to get back to me today. I'll ask how many sets she has left.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 10, 2014, 05:29:17 PM
So I just got off the phone with Laura from TAW and I couldn't agree more with everyone regarding how awesome she is.  Very nice person.  As far as whether or not TAW carries the Omeg pots needed for this the answer is; Yes they have the Omeg pots for this as well as the Wima caps.  As a matter of fact she is thinking she might even put together a little kit for this. 

Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on June 10, 2014, 11:36:10 PM
So I just got off the phone with Laura from TAW and I couldn't agree more with the sentiment that everyone else who has dealt with her regarding how awesome she is.  And the answer is; Yes they have the Omeg pots for this as well as the wima caps.  As a matter of fact she is thinking she might even put together a little kit for this. 

Cheers
fine Mate
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 11, 2014, 11:50:54 AM
So as far as the toggle switches go its a 5a spdt toggle that has to be on-non-on?  Does it have to be 5a?  Does it have to be on-non-on or can it be on-off-on?
C and K aren't cheap so I am just checking out my alternatives.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: horvitz on June 12, 2014, 03:41:51 PM
I know that a whole bunch of you are waiting for me to get the BI 10K lin pots back in stock.  It is still going to be quite a while.  I thought I'd point out though that Digi-Key has the exact same part in stock.  Their part number is 987-1665-ND.  You could buy six of those and two of the 2x10K pots from me and that would give you a complete kit.  A little more money, but no waiting.

Brian
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on June 12, 2014, 03:51:32 PM
Thx Brian,

Greg
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 14, 2014, 11:39:10 AM
After some research (yeah a total of 20 minutes and sorry for wasting space) I have come to the startling and incredibly remarkable conclusion that on non on is the same damn thing as on off on.  So I guess companies just word it differently? I'm still very green. So pretty much just any ol sub-miniture spdt will do.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 14, 2014, 12:32:30 PM
Hello,

any spst will work.Look at the schemo or just at the pcb,only two points to solder.
If you have a toggle switch with an "on,off or anything else" in the middle then there's one position too much,not useful and also not used.
Just get a standard spst or spdt (one outer pin not used),so two positions for toggling,done.
Don't buy the cheapest types,they should work for some years,no? ;D
Also remember they will carry your audio.Well- known brands are the way to go.

Best regards,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 14, 2014, 08:57:24 PM
Thanks Udo. That helped clear a few things up for me actually. Overthinking and obsessing. I'm cursed.
Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 15, 2014, 12:15:49 AM
You're welcome.

I have also seen your previous posts.
About current,no,5 Ampere are not needed,hahaha.....it is just that most toggle switches are capable to handle "high" currents.
It doesn't hurt.
In my 8-ch. version I have Miyama toggles that can handle 3A.......
Btw.,given current values are always different for dc than ac by nature.
As said all of them will work because current doesn't matter here.
"None" means that there is no middle position,so it is not the same as "off"!
You can see this clearly at the c&k data sheets when you do a search at mouser.
Compare a "none"-type for position 2 (middle) to the connected terminals,it says "N/A".
Here's a sheet from c&k,look at page 2 and you will see what I mean:
http://www.ck-components.com/14430/7000toggle_19jan12.pdf/
A lot of switches on the mouser page are indicated as "(on)" or "(off)" in several positions.
The brackets mean they act momentary,not latching/permanent.

Have fun,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 15, 2014, 11:27:33 AM
Ha. Again Udo thanks for clarifying these switches even further.  Yep I still got lots to learn. I had actually read the 7101 specs and tried to compare them to other switches but I guess the differences alluded me and eventually thought the "non-off" was just semantics.  And was wrong. I had tried searching via Google variations of "spdt on non or off on" but to no real avail. I got it now thanks.  I was planning on building a monitor controller in the near future, imitating other people's projects and I'm sure this will all become useful as well then.

Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on June 15, 2014, 10:52:44 PM
I have a real strange one for this project... I have a PS with a +15v reg and -15v regulator (not a universal adjustable type which i probably should have gotten).  but when I turn the unit on, i get nothing (no audio through)  if i turn it off, and immediately back on again, it works fine.   :o  I did notice that on that initial power up, when i turned it OFF, for a split second there was audio as the unit powered down (literally a split second).  Any thoughts on this?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 16, 2014, 12:12:36 AM
I have a real strange one for this project... I have a PS with a +15v reg and -15v regulator (not a universal adjustable type which i probably should have gotten).

Should make no difference.

but when I turn the unit on, i get nothing (no audio through)  if i turn it off, and immediately back on again, it works fine.   :o  I did notice that on that initial power up, when i turned it OFF, for a split second there was audio as the unit powered down (literally a split second).  Any thoughts on this?

Sounds really strange. Are you seeing your supply voltages on the board?

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on June 16, 2014, 12:22:35 AM
Voltages are good on the board. On both power ons.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 16, 2014, 02:44:05 AM
Voltages are good on the board. On both power ons.

Did you connect the switches?

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on June 16, 2014, 06:32:14 PM
Yes, unit works perfectly after the second power on.  Makes NO sense to me at all. 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 17, 2014, 01:13:19 AM
Yes, unit works perfectly after the second power on.  Makes NO sense to me at all.
Hello,

so you mean it behaves correct after every second power up?
This would lead me to look for a faulty capacitor because it seems to be time- dependent.
If it is more a random thing then I'd still look for the regs if they are 7815 & 7915 types because some of them are known to latch up from time to time,especiallythe cheap ones.
Is it a stereo unit sharing one psu?If so try to connect/power them as single units,one after the other to see if the issue remains the same.This way you could see if it is psu or eq- related.

Just my thoughts,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on June 17, 2014, 11:41:38 AM
Thanks udo. I think im going to swap out the big caps in the ps and the VRs.   Just really strange that the voltages are good on both power attempts but just fail the first time. The cap thing makes some sense, perhaps the chips dont like that
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 17, 2014, 11:58:28 AM
Yes,i think that's the way to go.As it is time-depndent it might be a lythic or so doesn't charge enough when powered the first time.
Do you have 7815 & 7915 in your psu?
Personally I prefer other types,years back I had several latchup issues,especially with the negative ones.The cheap ones of course.It became a bit better when I bought more expensive types but was never really satisfied.
All gone when I went the 317/337 etc. route.

Cheers,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on June 17, 2014, 07:23:59 PM
Yes i have the 7800's in there :(  Perhaps i should just grab one of Ptowns universal PS's and call it a day lol.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 17, 2014, 08:52:11 PM
Yes i have the 7800's in there :(  Perhaps i should just grab one of Ptowns universal PS's and call it a day lol.
Sounds like a plan.I have Joe's (JLM) AC/DC and Powerstations in most of my  non-51x/500 builds.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on June 17, 2014, 09:51:17 PM
I've used joes stuff on all my neve builds as well as a few others.  Good stuff, just takes a long time to get in from AU.  Whistlerock makes a nice one as well... just dont need the 48v rail on any of em.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 17, 2014, 10:02:09 PM
I've used joes stuff on all my neve builds as well as a few others.  Good stuff, just takes a long time to get in from AU.  Whistlerock makes a nice one as well... just dont need the 48v rail on any of em.
Same here,that's why I once ordered a stock of them,just the pcbs.Parts are standard stuff and you can leave the 48v parts out (or modify to anpther voltage to drive leds and relais).

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Lasselakken on June 19, 2014, 11:50:51 AM
Just wanted to share a few pictures of my finished project. I managed to squeeze two channels into 1U. Omeg pots are from Rapid Online (UK) and I used some green/red LEDs to show if filters are in or out. The front is made with letraset and all drilling is hand held, so absolutely nothing lines up, but I kind of like it that way.
I drilled three 3mm holes in each pcb which enabled me to mount them on adhesive plastic stands.

https://www.dropbox.com/sc/31hak3r6m673pwi/AADsQao3RyE0nvIyI-ixrmWOa#/ (https://www.dropbox.com/sc/31hak3r6m673pwi/AADsQao3RyE0nvIyI-ixrmWOa#/)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 19, 2014, 01:50:15 PM
Finished two channels today (managed to fit them in a 2RU box).

I dont understand how switching the resistor in and out works as bypass for the individual bands. I can't figure out what the significance of that single resistor is, no matter how long I stare at it. If someone could/would explain, I would be very grateful, and quite possibly grow a little smarter.

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Lasselakken on June 19, 2014, 03:15:07 PM
The Danes are on a roll  :P
I have a couple of Lundal LL 1540 input transformers lying around. Would it make sense to use them as input transformers instead of first half of the first NE5532?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Lasselakken on June 19, 2014, 03:16:23 PM
And here's part of the LL1540 data sheet...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on June 23, 2014, 08:01:06 AM
I dont understand how switching the resistor in and out works as bypass for the individual bands. I can't figure out what the significance of that single resistor is, no matter how long I stare at it. If someone could/would explain, I would be very grateful, and quite possibly grow a little smarter.

The resistor is there just to avoid switching noise (to keep the switch poles in the same DC potential). When the switch is open, the 330k forms a voltage divider with the low value resistors connected to the non-inverting op-amp input and attenuates the audio signal almost 50dB. Which is enough to give a "flat" response.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on June 23, 2014, 08:03:43 AM
I have a couple of Lundal LL 1540 input transformers lying around. Would it make sense to use them as input transformers instead of first half of the first NE5532?

Makes more sense to use WITH the op-amp U1A which provides low source impedance for the following circuitry.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 24, 2014, 03:58:55 AM
I dont understand how switching the resistor in and out works as bypass for the individual bands. I can't figure out what the significance of that single resistor is, no matter how long I stare at it. If someone could/would explain, I would be very grateful, and quite possibly grow a little smarter.

The resistor is there just to avoid switching noise (to keep the switch poles in the same DC potential). When the switch is open, the 330k forms a voltage divider with the low value resistors connected to the non-inverting op-amp input and attenuates the audio signal almost 50dB. Which is enough to give a "flat" response.

Thanks!

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 27, 2014, 10:37:48 AM
So I am getting real close to hooking up the 2 x 15v 50va Triad toroidal through the 1518 psu via PCB Grinder and testing these guys but as I was rereading the thread (for the umpteenth time)  I realized my xfmr's current seems much higher than many others.  I guess my math was way off.  I got this from Digikey:

http://www.digikey.com/product-search/en?WT.z_header=search_go&lang=en&site=us&keywords=237-1333-ND&x=0&y=0&formaction=on (http://www.digikey.com/product-search/en?WT.z_header=search_go&lang=en&site=us&keywords=237-1333-ND&x=0&y=0&formaction=on)

Specs say this toroidal current is 3.34 amps of current.
A little look-see from one of you fine gents (or ladies) would be just the bees-knees.  I really don't feel like blowing this up but I feel like that might be too high of a current.  Thanks.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on June 27, 2014, 12:32:46 PM
So long as the current rating is high enough the rating doesn't matter.  The trafo just delivers what is required

The current draw of the equaliser is tiny - see my earlier post for details.  You could use a much smaller transformer

Your transformer will give about ± 21 volts DC after the regulators

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 27, 2014, 01:46:54 PM


Your transformer will give about ± 21 volts DC after the regulators


Its probably a typo, but the the transformer will give you about 21 volts after rectification, the regulators will regulate that back down to their nominal values (15V for the  7915/7815), which is all by the book.

Just to avoid a "But I only need 15V!" scare...

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 27, 2014, 01:56:36 PM
Nick, Udo; thank you.
I picked up the "nicer" 7915's after reading enough posts about them failing so hopefully they'll be alright. I probably should have gone the 337 route since that's what I did with the 1176 I'm finishing as well as the ml12 PSU I just finished.
Thanks again for replying so fast. I'm just two 5.1k r short (which USPS should have here today) from finishing since i misplaced them somewhere which is pretty silly and frustrating. Not a ton of a variety of knobs for the omeg pots either. 4mm is a peculiar size apparently.  The hunt continues.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on June 27, 2014, 03:36:48 PM
Yes sorry, typo.  I meant rectifiers

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 27, 2014, 11:20:35 PM
4mm is a peculiar size apparently.  The hunt continues.

http://www.musikding.de/Adaptor-4mm-6mm

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on June 28, 2014, 10:37:46 AM
Thank you Gustav.  Not so coincidentally I just found that after following a post on here regarding the same thing.  Those will do perfectly thank you.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on June 29, 2014, 03:26:04 AM
DOES someone have the Matchcode for the 2 Missing Pots? (Digikey e.g.)
For us Europeans, it makes no sense to by in US. It's too expensive Brian

I know that a whole bunch of you are waiting for me to get the BI 10K lin pots back in stock.  It is still going to be quite a while.  I thought I'd point out though that Digi-Key has the exact same part in stock.  Their part number is 987-1665-ND.  You could buy six of those and two of the 2x10K pots from me and that would give you a complete kit.  A little more money, but no waiting.

Brian
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 30, 2014, 04:19:45 PM
Thank you Gustav.  Not so coincidentally I just found that after following a post on here regarding the same thing.  Those will do perfectly thank you.

I have to admit, that I have found the plastic types to be better, but I can't seem to find them anymore :(

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on June 30, 2014, 04:24:29 PM
DOES someone have the Matchcode for the 2 Missing Pots? (Digikey e.g.)
For us Europeans, it makes no sense to by in US. It's too expensive Brian

I know that a whole bunch of you are waiting for me to get the BI 10K lin pots back in stock.  It is still going to be quite a while.  I thought I'd point out though that Digi-Key has the exact same part in stock.  Their part number is 987-1665-ND.  You could buy six of those and two of the 2x10K pots from me and that would give you a complete kit.  A little more money, but no waiting.

Brian

http://www.banzaimusic.com/Alpha-16mm-stereo-10k-lin.html

Not conductive plastic, I know...

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 30, 2014, 04:31:00 PM
Hi Gustav,

excuse me chiming in,but since this circuit is dc coupled it is absolutely necessary to use conductive plastic pots (see reply #3 on the first page).

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on June 30, 2014, 05:08:08 PM
thx G 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 30, 2014, 05:23:52 PM
If you're looking for the Omegs here's a link you can check (for german/european buyers):

http://www.alphastat.de/products/omeg/omeg.html

Send an inquiry to Mr. Kirchhoff,he is very helpfull and has managed to get some "exotic" pots for me a while back.

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kml23956 on July 03, 2014, 10:41:09 PM
US buyers need pots too. Where on earth can I get these things?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on July 03, 2014, 11:55:55 PM
US buyers need pots too. Where on earth can I get these things?
Those days I bought mine from TAW in the us,a very helpfull lady named Laura offered complete sets for us diy guys.Maybe ut's still possible?

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kml23956 on July 05, 2014, 11:46:20 PM
Thanks for the hint I will give Laura a shout.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on July 06, 2014, 02:47:01 AM
It's definitely still possible as I ordered two sets only 3 weeks ago and the incredibly helpful Laura said she still had a bunch left.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: weiss on July 11, 2014, 08:41:08 PM
my new project. fits neumann pcb :)

weiss
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on July 11, 2014, 09:38:46 PM
Nice layout......and a lot of real estate inside,no?
Maybe add an M/S-matrix and/or a "true" bypass ;)

Best and have fun building it,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: weiss on July 12, 2014, 06:55:09 AM
Nice layout......and a lot of real estate inside,no?
Maybe add an M/S-matrix and/or a "true" bypass ;)

Best and have fun building it,

Udo.

good idea, will check this out.

weiss
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: late on July 19, 2014, 11:07:42 PM
Have finished two w492 eq's. The output is not fine, it drops about -6db. 0.775v to eq input gives 0.385v output (all switches off). Checked everything but i can't find what do this. First opamp gives wrong output but there is right resistors and everything.

Edit:
Or it should drop. There is first 20k and then 10k with 5532 opamp. Why?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiox on July 30, 2014, 10:45:04 AM
The output is not fine, it drops about -6db.

Input stage -6dB, output stage +6dB balanced = 0dB total gain.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on August 08, 2014, 09:33:11 AM
my two 492 are doing their Job well.

I'd like to test some Out Transformer,

Does some one tried this before?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: digistu on August 13, 2014, 08:34:56 AM
Hi,

I'm just about to embark on two channels of W492 and wondered if anyone who's mounted the pots off board (I'm using the Omegs) has any thoughts about mounting the PCB?

I've seen Markus's elegant solution, and am wondering about fashioning something similar out of wood, but if there's a better off the shelf solution I'd love to hear it.  I'm a bit nervous about actually drilling the PCB as it doesn't look like there's a lot of room for error.

Thanks,

Chris
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on August 13, 2014, 09:18:45 AM
Hardwire the pots to the pcb,

those Alphas cost 1,60 Eur or so..

otherwise you will get a lot of troubles, trust me.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on August 13, 2014, 11:09:36 AM
Hi,

I'm just about to embark on two channels of W492 and wondered if anyone who's mounted the pots off board (I'm using the Omegs) has any thoughts about mounting the PCB?

I've seen Markus's elegant solution, and am wondering about fashioning something similar out of wood, but if there's a better off the shelf solution I'd love to hear it.  I'm a bit nervous about actually drilling the PCB as it doesn't look like there's a lot of room for error.

Thanks,

Chris
Hello Chris,

easy to wire them off board by using bus wire,the pcb will easily stay in place because it's has a very low weight.I did it on my version (reply #487) using 1mm bus wire.
Here's a nice pic from our member sr1200,just bend them to your needs (he used cut off diode legs):

http://groupdiy.com/index.php?topic=28332.msg676926#msg676926

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on August 13, 2014, 11:18:52 AM
Hardwire the pots to the pcb,

those Alphas cost 1,60 Eur or so..

otherwise you will get a lot of troubles, trust me.
Chris is talking about Omegs,not Alphas.
From a few pages ago you seem to swap Alpha pots and Alphastat (which is a supplier for Omeg pots here in germany).
Again,don't use them because this circuit is dc coupled.

Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: digistu on August 14, 2014, 10:06:34 AM
Thanks Udo!  Yours was one of the builds I was scrutinising photos of in order to try and work out a solution, so great to make sense of how you actually did it.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on August 14, 2014, 01:18:19 PM
Thanks Udo!  Yours was one of the builds I was scrutinising photos of in order to try and work out a solution, so great to make sense of how you actually did it.
You're welcome Chris,

in detail I did this as follows:

First attach bus wires to the pcb so they line up horizontally to its' surface.

Then attach the pots to the front panel and line them up.

Now you can solder the two most outward wires to the most outward pots.

Bend the pcb perpendicular to the front panel.

Then solder the rest,it's really easy.

Remember not to apply excessive heat for a long time to the Omegs,they don't like it.
Pre-tinning is the key.
You'll experience that the more wires you solder to the pcb the more stability the construction gets.

For servicing parts just remove the pot nuts and tear the whole thing out-that's it.

Attached another (blurry) pic to give you an idea.

Have fun soldering,

best,

Udo. ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on August 14, 2014, 05:00:46 PM
Silver Micas instaed of Kerkos, hmm,

have to replace my ones! THX Udo,

Really nice Job
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on August 14, 2014, 05:22:08 PM
Silver Micas instaed of Kerkos, hmm,

have to replace my ones! THX Udo,

Really nice Job
Thank you,but where do you see micas?
You don't mean the blue caps,do you?If so these are just xr7 or xicon or something I had here,definetely no silver micas.That would make no sense because they are just for decoupling,so any cheap ceramic will do the job.
The rest is lytics and Wimas.

Best,

Udo.

Edit:Found it,they are indeed xr7 from Murata,4 cents each when bought as singles at Reichelt.Look:

http://www.reichelt.de/Vielschicht-bedrahtet-X7R-10-/X7R-2-5-100N/3/index.html?&ACTION=3&LA=2&ARTICLE=22853&GROUPID=3162&artnr=X7R-2%2C5+100N

or these:

http://www.reichelt.de/Vielschicht-bedrahtet-X7R-10-/X7R-5-100N/3/index.html?&ACTION=3&LA=2&ARTICLE=22865&GROUPID=3162&artnr=X7R-5+100N&SEARCH=Vielschicht%2C+bedrahtet%2C+X7R+10%25

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on August 17, 2014, 03:39:04 PM
Ahh... Calibration is about finished (although I really need a decent osciliscope and wave generator which is on the top of my list) and I must say I am really liking this EQ.  What a great project.  I learned a ton.  Thank you AudioX for the incredibly awesome project and thank you Udo (again) for all your suggestions and of course thanks Gustav for your giant contributions in making it possible. Oh and thanks Frank for doing the bad ass front panel.  Always worth the wait for you sir.
I am currently awaiting another case and some more knobs that will match the top better so it isn't quite finished yet but damn it is close.  ;)

(http://i.imgur.com/CgdhK3Ul.jpg) (http://imgur.com/CgdhK3U)

I 'stole' some ideas for the front panel from Ben Lindell (thanks dude) as well as used Gustav's hole markings (which work with Omeg pots just fine) to make sure mine were correct (they were).

(http://i.imgur.com/zk2dZQql.jpg) (http://imgur.com/zk2dZQq)

(http://i.imgur.com/bfb6gHYl.jpg) (http://imgur.com/bfb6gHY)

And some of the inside

(http://i.imgur.com/jJ5XYotl.jpg) (http://imgur.com/jJ5XYot)

(http://i.imgur.com/WIY28bdl.jpg) (http://imgur.com/WIY28bd)

As you can tell I am no photographer.
But here's a shot of it with a few of other builds which I gotta say makes it all look pretty damn saweet.

Will be racking it soon in the studio after some more touch up calibration (I'm a little neurotic)

 :)

(http://i.imgur.com/9ewtjv7l.jpg) (http://imgur.com/9ewtjv7)



 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on August 17, 2014, 03:57:05 PM
Well done!
And calibration is easy to do.
Have fun,

Cheers,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: tuanuibi on November 05, 2014, 08:53:17 PM
Hi guys,
I'm going to be mounting off board - do you think these pots would be fine?

http://au.mouser.com/ProductDetail/Bourns/3310C-001-103L/?qs=sGAEpiMZZMtC25l1F4XBU4NnHEok4CZwvdjENCK81TE%3d

Thanks in advance!

Very excited for this one!
Josh
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Markus_Krippner on November 06, 2014, 01:21:09 PM
They look ok to me, but they're mono only.
Remember, you need 6 mono and 2 stereo pots per PCB.

...markus :-)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 06, 2014, 05:36:30 PM
Hello and welcome,


yes,Markus is right.Just remember two of them must be duals.
Technically they're a good choice because they're conductive plastic types (keyword is "pots become scratchy").
Also they give very nice feel,I used a lot of them in a different project recently.

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: tuanuibi on November 06, 2014, 08:27:59 PM
Thanks guys - good to be here!

I'll start hunting for the dual gang ones now.

I'm gutting half of a Tascam console and  replacing the EQ with this one on 8 channels - hopefully have something to show you 'soon'.. .
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Harpo on November 07, 2014, 05:10:00 AM
Not so common avail.knobs that your pots 3.18mm shaft diameter call for...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: burglar on November 24, 2014, 01:27:53 AM
Hi folks,

Planning on building two of these soon.  What power supply are most using for a dual mono unit?  If there is not a preferred kit would someone mind posting a schematic??

Many thanks

B
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 24, 2014, 02:08:37 AM
Hi folks,

Planning on building two of these soon.  What power supply are most using for a dual mono unit?  If there is not a preferred kit would someone mind posting a schematic??

Many thanks

B
Hello,


specs are to find on the first page here,see schematics last page at bottom,it's +/-15vdc.
There are a lot of suppliers here who have nice little pcbs on offer.Gustav himself has them too,any dual rail psu will work.Depends where you are located I'd say.


Best regards and have fun,


Udo.



Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: burglar on November 24, 2014, 03:58:10 AM
Thanks Udo,

Forgive my newbism, but I need + - 15vdc for both boards.  If my PSU has + - 15vdc how do I supply it to both channels of the EQ?

Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on November 24, 2014, 04:09:34 AM
Thanks Udo,

Forgive my newbism, but I need + - 15vdc for both boards.  If my PSU has + - 15vdc how do I supply it to both channels of the EQ?

Cheers

Split the supply to each.

And if you are buying boards from me, get the VARI PSU, which has a split output on the board...

Gustav

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: burglar on November 24, 2014, 05:22:21 AM
Thanks Gustav,

Finally, I should use a toroidal with dual 18v secondaries?  How do I calculate the current required on the power transformer?

Cheers

B
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on November 24, 2014, 01:25:36 PM
I'm pretty sure I used a spare mnats PSU pcb from the 1176 projects   (+)  and (-)  adjustable with trimmers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on January 18, 2015, 12:11:44 PM
Hello guys I'm very confused at the at the shopping list of this project says 8 pots 10k linear dual, but now I'm reading only 2 needs to be dual!
And I know has to be conductive plastic does anyone knows if carbon type can work I have this pots

http://www.mouser.com/ds/2/54/ptd90-35260.pdf

Thank you for your help
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 18, 2015, 12:39:33 PM
Hello guys I'm very confused at the at the shopping list of this project says 8 pots 10k linear dual, but now I'm reading only 2 needs to be dual!
And I know has to be conductive plastic does anyone knows if carbon type can work I have this pots

http://www.mouser.com/ds/2/54/ptd90-35260.pdf (http://www.mouser.com/ds/2/54/ptd90-35260.pdf)

Thank you for your help
No,they will become scratchy soon.


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on January 18, 2015, 02:42:56 PM
Hello guys I'm very confused at the at the shopping list of this project says 8 pots 10k linear dual, but now I'm reading only 2 needs to be dual!
And I know has to be conductive plastic does anyone knows if carbon type can work I have this pots

http://www.mouser.com/ds/2/54/ptd90-35260.pdf (http://www.mouser.com/ds/2/54/ptd90-35260.pdf)

Thank you for your help
No,they will become scratchy soon.


Udo.

Thanks for the replay Udo,
And what about the dual pots? How come now I only need 2 dual instead 8?  Will work the same?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 18, 2015, 02:59:06 PM
Thanks for the replay Udo,

And what about the dual pots? How come now I only need 2 dual instead 8?  Will work the same?
Replay? ;D
O.K.,let's get serious.....
Only two duals are needed,you find them in the mid bands.Look at the schematics here:


https://docs.google.com/file/d/0B_XBYPfmG8pVMDkyMmRlNjEtZmQwMS00OTgwLWJkYzMtNWRmNGYyZTE1NTRm/edit?hl=en&pli=1 (https://docs.google.com/file/d/0B_XBYPfmG8pVMDkyMmRlNjEtZmQwMS00OTgwLWJkYzMtNWRmNGYyZTE1NTRm/edit?hl=en&pli=1)


You can even see which ones must be dual by looking closely to their traces on the board.
The others were just dual for mechanical reasons,but not necessary.


Best,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on January 18, 2015, 03:13:43 PM
Thanks for the replay Udo,

And what about the dual pots? How come now I only need 2 dual instead 8?  Will work the same?
Replay? ;D
O.K.,let's get serious.....
Only two duals are needed,you find them in the mid bands.Look at the schematics here:


https://docs.google.com/file/d/0B_XBYPfmG8pVMDkyMmRlNjEtZmQwMS00OTgwLWJkYzMtNWRmNGYyZTE1NTRm/edit?hl=en&pli=1 (https://docs.google.com/file/d/0B_XBYPfmG8pVMDkyMmRlNjEtZmQwMS00OTgwLWJkYzMtNWRmNGYyZTE1NTRm/edit?hl=en&pli=1)


You can even see which ones must be dual by looking closely to their traces on the board.
The others were just dual for mechanical reasons,but not necessary.


Best,


Udo.

 :D Great news!  I can save a few bucks,  going to search them now

thank´s  Udo 4 da re-play!! ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on January 18, 2015, 03:35:36 PM
Hello guys I'm very confused at the at the shopping list of this project says 8 pots 10k linear dual, but now I'm reading only 2 needs to be dual!
And I know has to be conductive plastic does anyone knows if carbon type can work I have this pots

http://www.mouser.com/ds/2/54/ptd90-35260.pdf (http://www.mouser.com/ds/2/54/ptd90-35260.pdf)

Thank you for your help
No,they will become scratchy soon.


Udo.

I found them! this should work right?
http://www.mouser.es/ProductDetail/Bourns/91A2A-B28-B15-B15L/?qs=sGAEpiMZZMtC25l1F4XBU0lMC8qKAKdNb%2fFsrRH3ibQ%3d

Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on January 18, 2015, 04:52:18 PM
To work out the current draw, look at the ICs, look up the data sheets for them and multiple the current consumption per IC by the total number in the unit.  That's the current draw, split across two rails.  I'd multiply that by at least two to give some spare capacity.  In practice, the current draw is tiny

To work out the transformer secondary voltage, look at the voltage range of the regulator inputs.  Pick a voltage that's in range, divide by 1.4 and that's your approximate secondary voltage.  If the rails are 15 - 0 - 15, the regulators will need 18-24 Volts approx.  That's DC, post-rectifier.  AC rectified averages 1.4 times the AC voltage so an 15 - 0 - 15 transformer will give about 21 volts DC to each regulator

To make life more interesting, your 15 - 0 - 15 transformer will read about 25 - 0 - 25 VAC with no load but drop sharply as soon as you put a load on it

It's a learning process, as I have found out!

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on January 19, 2015, 03:59:14 PM
Yaeh, the difference between Peak and RMS  Voltages..
You should be 2 Volts above the needed one, lets assume +-15 DC are needed, so you should have min +-17V.

But don´t forget the Cooling at the regulator!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 02, 2015, 10:29:09 AM
Hello I'm almost finish the eq but I was testing my power supply and the out put voltage is reading -19V my L7915 is not working properly my positive voltage is ok 15V, I've changed the regulator but still reading -19V what I'm I doing wrong?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 03, 2015, 06:07:44 AM
Ok, apparently connecting it with the boards, negatives drops down to -15V, but now the problem I´m having it with the positive which is -.62 is ridicules , seems that TS7815 are not the ones for this project, Im going to try it with a lm317.

Finger crossed
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 03, 2015, 07:36:24 AM
No luck  :-\

I´ve changed to LM317 but still mi positives are -1-62V

what can i do Im lost?

Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on February 03, 2015, 10:22:59 AM
For one the picture you posted showing a fragment of the psu is too big.  Please take another picture and while at it explain what transformer you are using.
Cheers
Dylan
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 03, 2015, 12:23:25 PM
For one the picture you posted showing a fragment of the psu is too big.  Please take another picture and while at it explain what transformer you are using.
Cheers
Dylan

This is the trafo I'm using
Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 03, 2015, 12:58:46 PM
With out the IC's all voltages are ok, placing the first Ic voltages ok, when I put the second IC starts sucking but survives, placing the 3rd IC positive voltages is dead  negative voltages  is always ok

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 04, 2015, 08:40:50 AM
I made some progress I changed the PSU and regulated the LM337 and LM317 to +-15V, but when I insert all IC's my +-Voltages a drop down to  +-11 V, Then I changed the resistors to increase to +-23V but nothing happens only a bit of change +-11.42V
I'm feeding the 2 boards to this PSU and the trafo I posted earlier getting 18V from it
Maybe I need more power from the trafo, is good Idea to join yellow and red from it to have 38V ?
Some one?

Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Rocinante on February 04, 2015, 11:49:23 AM
Hopefully someone smarter than me will chime in here
but for starters I'm guessing it was a typo and you meant lm337 and lm317 correct?
If I was gonna guess I would say you have an ic in backwards somewhere.  It might explain the voltage jump.  Also looking at the psu (as well as trying to remember how I did mine) doesn't that area that says 'calculate' have a resistor in it?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 04, 2015, 12:52:49 PM
Hopefully someone smarter than me will chime in here
but for starters I'm guessing it was a typo and you meant lm337 and lm317 correct?
If I was gonna guess I would say you have an ic in backwards somewhere.  It might explain the voltage jump.  Also looking at the psu (as well as trying to remember how I did mine) doesn't that area that says 'calculate' have a resistor in it?
Hey
Yes I'm using lm317 and lm337, and about the area with out resistor is only to illuminate a led it doesn't interfere with the circuit,
This thing is driving me crazy, all ICs are  in the correct position
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 09, 2015, 03:24:27 AM
The problem was the PSU,
Now it's working.

Thanks for your help  ::)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on February 09, 2015, 11:58:33 AM
The problem was the PSU,
Now it's working.

Thanks for your help  ::)
What exactly was the issue?


Best,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: jicama on February 09, 2015, 04:34:55 PM
The problem was the PSU,
Now it's working.

Thanks for your help  ::)
What exactly was the issue?


Best,


Udo.

The PSU,  I changed it  2 times. 
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on February 09, 2015, 11:15:54 PM
That is no answer,nobody here can learn anything from it.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: noviygera on February 10, 2015, 06:34:29 PM
Is one W492 board mono or stereo?

I was wondering if it is possible to use the W492 board with the following changes:
1.  vertical version of the EQ, with "zero" stops on the EQ pots. This is for a dj mixer, where vertical and zero stops are essential.
2. -25/+10 db attenuation on each of the EQ sections.  What will I need to do to make this mod?
3.  one board must be a stereo channel.

thanks,
Herman
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on February 11, 2015, 12:29:21 AM
Is one W492 board mono or stereo?


Mono.

I was wondering if it is possible to use the W492 board with the following changes:
1.  vertical version of the EQ, with "zero" stops on the EQ pots. This is for a dj mixer, where vertical and zero stops are essential.


Zero will not work corectly because there is none in real life conditions (due to tolerances up to 20%).

2. -25/+10 db attenuation on each of the EQ sections.  What will I need to do to make this mod?


This is a different beast,so at least the -25 is not possible without completely redesigning the whole eq.

3.  one board must be a stereo channel.


You need two boards for stereo and at least two 4-layer plastic conductive pots,hard to source I think.
Definetely the wrong eq for DJs.

thanks,
Herman


Best,

Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: noviygera on February 11, 2015, 02:12:39 AM
Hello Udo,

Thanks, that answers my previous questions. Can you recommend a 4 band EQ to use in a DJ mixer application? Where the EQ is applied to a stereo channel. Any kits out there by chance?

thanks,
Herman
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: digistu on March 12, 2015, 10:43:43 AM
I thought people might be interested to see my solution for mounting the boards when using the Omeg (or indeed any other off-board) pots...

(https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpa1/t31.0-8/10914945_10155337475685707_8294980332452725156_o.jpg)

I 3D printed some simple brackets. 

Designed in Sketch-up, then fabricated by iMaterialize.  They cost about £20 for 4, but as an experiment I'm 100% satisfied!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fragletrollet on March 22, 2015, 06:23:12 PM
cool!  8)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Brandmarc on April 08, 2015, 04:25:07 PM
Hi,

iam new to this very cool Forum and to Diy World.
I only fixed Cables or burnt Opamps in my Gear :-)

I really like the Sound of the old broadcast Equipment.
I have Filtek Mk3´s and Siemens W295 for example.

I have been offered some original w492 for 250,- Euro each.

But i think it would be fun to build them diy.

I think the originals have Transformers.
Had someone of the DIY 492 owners had done a test how they compare to the original Neumann´s?
Would be interesting how different the DIY Version Sounds.

Thank You
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: p0ulp on August 29, 2015, 01:21:37 PM
Hello there, I m new to this community but reading for quite a while all posts, I ve been trying to handle as much as a I can every problem a newbie can encouter, but ...

I ve finished to assemble my board and am now waiting for the pot order, since now I didn't thought about the PSU and I can't find a pcb layout that seems recommended for this project. I ve read that varipsu from pcbgrinder is fine , and I m sure it is, but I really don't feel like ordering only one 9 euros board with 20 euros for shipping .. ok I should have done it before :/

So I m considering etching the 9k SSL psu that can be find in documentation ,  but I have two question:
My toroid is 2x15v , If I change the 7818/7918 regulator to 7815/7915  do I have to change resistor value also ? If so which one ?
what to do with the 48V part for the phantom power ?

If somebody as already provided a pcb layout for this psu please let me know.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on August 29, 2015, 03:49:42 PM
I really don't feel like ordering only one 9 euros board with 20 euros for shipping .. ok I should have done it before :/

You could use the regular mail option for much cheaper shipment, but its still a lot just for a utility PSU board, so...

I m considering etching the 9k SSL psu that can be find in documentation ,  but I have two question:
My toroid is 2x15v , If I change the 7818/7918 regulator to 7815/7915  do I have to change resistor value also ? If so which one ?
what to do with the 48V part for the phantom power ?

You can change the regulators and use a 2x15V toroid.

The resistors are only there to program the voltage output of the LM317 for phantom power, so leave that whole section out (doubler circuit/regulator)

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: p0ulp on August 29, 2015, 03:53:03 PM
thanks a lot for the fast answer.

ed
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on September 05, 2015, 04:44:37 AM
hi,
Got one of those EQ's ready to work and I measured a bit around there

PSU - Unfiltered Voltage by using a Traco TMP10215 SMPS(Switch Freq. 100kHz, Max Cap Load 1000uF each Rail)
      V               Noise-RMS(<22kHz)
+15V                         -62dBV
-15V                          -62dBV
not bad for a SMPS

I filtered the Supply Voltage from the SPMS delivering +-15DC via an two stage RC-Ladder Filter: each 10R and 470uF/V Rad FR Low Noise Cap.

Fg is 33,86Hz at -3dB,  for both Stages in common -6dB at 33,86Hz
Voltage Drop 1Vdc over each 10R
So I got +-13VDC.
measured the Voltage Noise after the Filter
here what I got:
      V                  Noise-RMS(<22kHz)              Noise-RMS(<100kHz)
+13,07V                      -104dBV                                             -83dBV
-13.03V                       -105dBV                                             -88dBV

Thats ok

Measure across +-filtered Voltage
V                          Noise-RMS(<22kHz)              Noise-RMS(<100kHz)
26Vdc                              -86dBV                                                 -64dBV


After that I checked the Symmetric Out
It was that  horrible,

Out                   Noise-RMS(<22kHz)              Noise-RMS(<100kHz)
pos                                 -72,5dBV                                               -50,5dBV
neg                                -73.3dBV                                               -53,2dBV

It is that bad!!!!!

Made a look over the Schematic, there are just 100nF across Pos and Neg Supply.
I will take 'em out and add some 100nF/MKS2 against ground, but I believe it won't change anything!
Will also try some Boucherots at 10kHz or so..

I used LME49720 OP-Amp's

My Question:
Did anyone here made a similar measurement at the Symmetric Out by using highly smoothed Voltage and a Torroid?
Perhaps i got some Common-Mode Problem or the Layout isn't that good!

Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: p0ulp on September 26, 2015, 03:03:19 AM
Ok this is a great simple and cheap build, the only thing is concerning those pot which are excessivly expensive, I did go for the OEP from buerklin and that was a mistake ( not the green one) , those OEP fits on the board after a little bend work ,  but the 4mm shaft is a pain if you are looking for usual knob ( don't want skinny knob on a 2U rack don't you ?), that's ok for a custom format console were you can fit the EQ pretty easily in compact enclosure and I think they ll go this way in my studio.

Also if anyone know replacement pots please let the next builder know with manufacturer reference or mouser n°, while sourcing the part I did contact many supplier for conductive plastique PCB mount stereo 10kA and wasn't able to find source for them that could be in my budget range . I see on gustav's website there are other one but didn't dig info at the time I was building.

I think I will definitly rebuild them with stepped switches for mastering purpose, got to work on an extra pcb though, I don't want to solder resitor lugs for hours and not be able to replace them easily. in few years.


Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on September 26, 2015, 03:13:24 AM
Alpha 10k are the standard Pots
But if you use 'em, the 492 won't fit into a 1HE 19" Rack,
You ma use other Pots as Alps RK09, mit the Footprint differs so you have to wire the Pins
And, you'll have to fix the PCB!

Cheers
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on September 26, 2015, 04:14:16 AM
Alpha 10k are the standard Pots
But if you use 'em, the 492 won't fit into a 1HE 19" Rack,
You ma use other Pots as Alps RK09, mit the Footprint differs so you have to wire the Pins
And, you'll have to fix the PCB!

Cheers
d
Hello Greg S.,


the board was designed for sfernice pots,hard to source and expensive.
So Alpha pots aren't the standard types for this build.
A lot of people including me used the green Omeg,I think it was the "Eco"- series.
Plastic conductive is imperative,so the Alps rk09 might be the wrong choice.
And why shouldn't other types fit in 1ru?I made 8 channels fit in 4ru easily.I even did not need to fix the pcbs to the frontpanel,they're happily held by the pots connected with solid wires.See my post #487.


@pOulp:


You can easily widen up 4mm shafts to 6mm,adaptors are available for this.Same as going from 1/8" to 1/4".
And you only need two stereo pots,not eight.The rest is single pots.See schematics.
For pot choices,just search for plastic conductive types,I think there are Bourns types available as well as others.
I sourced my green ones from TAW,a lady named Laura helped me and others here,she's very friendly and they even had a full set (6 mono and 2 stereo) for this project.I bought 8 sets for my 8-channel build,none of them failed so far.

Best,


Udo.


Edited typo.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: p0ulp on September 26, 2015, 11:57:06 AM
Thanks udo for this answer, I know about the only 2 stereo, but mono were almost same price so .. blind lug are just here to maintain the pot on the board :D

I have to admit that I didn't go through the whole pot question on this topic, my bad, would have been happy to meet Laura for sure :/

Anyway thank you for the shaft adapter tips, I didn't know those :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iprovlek on November 04, 2015, 08:45:11 AM
Is this Eq can be built with stepped switch(Lorlin) instead potentiometers!?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: miszt on December 07, 2015, 10:02:25 AM
If I were to use 12 position switches instead of 10K pots, would I use 910ohm resistors to make up the full 10K linear? or is there more to it than that?

(910 X 11 positions = 10.01K, plus 1 with no resistor?)


also wondering why the pots used have 6 pins, the only ones I can find with 6 pins are dual-lin/log and dual gang with 2 rails - but looking at the schematic, it seems to just be standard single rail pots?


(noobie at this, sorry if the answers should be obvious lol)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: miszt on December 11, 2015, 02:12:59 PM
so I've read nearly the whole thread, and it seems i need dual linear pots - so that would mean i want to either have dual gang switches with resistors adding to 10K, or single gang with the resistors adding upto 5K rather than 10K? ...or?

or are they dual pots simply for physical stability? the schematic doesn't show the signal being split between 2 rails on the pots?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: skeeler87 on January 07, 2016, 06:21:24 PM
Hey Guys!

New to the forum here! I'm thinking of building some of these. Would these pots work?

http://ca.mouser.com/ProductDetail/Bourns/PTD902-2015K-B103/?qs=sGAEpiMZZMtC25l1F4XBU1xwXnrUt%2fuovO4kg%2fgeLiI%3d

Thanks!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on January 08, 2016, 06:17:14 PM
I guess not!
Check the Footprint!

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on January 08, 2016, 11:58:08 PM
Hey Guys!

New to the forum here! I'm thinking of building some of these. Would these pots work?

http://ca.mouser.com/ProductDetail/Bourns/PTD902-2015K-B103/?qs=sGAEpiMZZMtC25l1F4XBU1xwXnrUt%2fuovO4kg%2fgeLiI%3d (http://ca.mouser.com/ProductDetail/Bourns/PTD902-2015K-B103/?qs=sGAEpiMZZMtC25l1F4XBU1xwXnrUt%2fuovO4kg%2fgeLiI%3d)

Thanks!
Hello,


element type is carbon so it will get scratchy soon.Use conductive plastic instead.


Best regards,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: skeeler87 on January 12, 2016, 12:32:36 PM
Hey Guys!

New to the forum here! I'm thinking of building some of these. Would these pots work?

http://ca.mouser.com/ProductDetail/Bourns/PTD902-2015K-B103/?qs=sGAEpiMZZMtC25l1F4XBU1xwXnrUt%2fuovO4kg%2fgeLiI%3d (http://ca.mouser.com/ProductDetail/Bourns/PTD902-2015K-B103/?qs=sGAEpiMZZMtC25l1F4XBU1xwXnrUt%2fuovO4kg%2fgeLiI%3d)

Thanks!
Hello,


element type is carbon so it will get scratchy soon.Use conductive plastic instead.


Best regards,


Udo.

Thanks very much, Udo! Will definitely stick to conductive plastic.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: maniman on February 17, 2016, 06:03:52 PM
Hi guys , how goes ,  I'm very happy to can say , PROJECT ACHIEVED

(http://s11.postimg.org/icr5s4d2b/492_final_1.jpg)

https://youtu.be/zgp1fZA3ZVM (https://youtu.be/zgp1fZA3ZVM)

The power transformers are momentary solution until find the right toroid for 1 u. rack.

next thing , I gonna calibrate the detents at real 0 and test L and R frequency similarity moving knobs from pots if necessary , all  checkin with SMAART ... and this goes directly to my disc cutting system chain , yes , the place where this piece go.

The POTS : The B.I. pots from capi-gear.com.....I only can say the same than mr. Steiger , "don't let the price fools you !" , because is totally true ,  THE FEELING OF THE POTS ARE ABSOLUTELY AWESOME , even better than tens I touched in glorious well made equipment , really sure an hard over the entire path , the find of the year for me (and .... ejem... have center detent version.... where people get the center detent version of the OMEGs ? I can't believe people have this project without center detent.)

The ICs = NOS Philips NE5532AN (That is where my powers problem start over the encapsulated transformers , reach 50º C easy!! hahah , but I'm very happy with the character , can be very very subtile , this is a thing I don't expect from a 553X based filters , and the sound are less metallic than I expected too , I'm very happy. )

- The boards from the man Gustav of pcbgrinder.com (Ough! how can I forget the foundations , noboody begins the house through the roof. )
- All resistor Metal Film 1% , checked In pairs at soldering time.
- All capacitors 2,5 % , 5% , and 10% on 2 or 3 values ( one can go until 1% in capacitors but become a not so cheap project as all people suggest , REALLY I don't think is a so so cheap project.)
- The case is a recycled adam hall housing case I never used at all , a crossover project in the past.
- The frontpanel is mechanized by frontpanel.de
- The relay bypass boards and the knobs are from diy-tubes.com
- The power supplies are classic Velleman regulable kits (LM317 /337)

*I do a little thing for the bypass , with a 2 color led (the 3 pins one) , playing a bit with the switching can go for :


-Geen light when both L and R are running
-Orange Light (both green and red poles) when 1 of the channels is bypassed
-Red Light when 2 channels are bypassed.


The B.I pots are soldered using a holes proto board I cutted in very little squares of 3 x 3 holes.

wire , thermo retractile and think is all friends!

Best Regards
Mani.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dribro on March 04, 2016, 08:42:45 AM
hi guys

will these do the job?

http://pt.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P0925N-FC15AR10K/?qs=sGAEpiMZZMtC25l1F4XBU7XpbFdDDzhrX9wNBWhNwoQ%3d
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: noviygera on March 27, 2016, 11:47:17 PM
Can each W492 board be used for stereo (in unbalanced mode)? Basically, I want to have a mixer with a W492 on each stereo channel. Doable?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on March 28, 2016, 07:28:18 AM
Can each W492 board be used for stereo (in unbalanced mode)? Basically, I want to have a mixer with a W492 on each stereo channel. Doable?

I am not sure I understand the question, so just to make sure its clear.

Are you asking if a single board in the current layout can be used for unbalanced stereo instead of balanced  mono?

If thats the question, the answer is no.


Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Greg S. on March 28, 2016, 08:48:46 AM
Can each W492 board be used for stereo (in unbalanced mode)? Basically, I want to have a mixer with a W492 on each stereo channel. Doable?

One Board --> One Channel,
Two Boards -->Two Channels e.g. Stereo

If you want to use one Borad in Unbalanced Mode, connect the Neg-In to GND
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pvision on March 28, 2016, 03:41:42 PM
Hi guys , how goes ,  I'm very happy to can say , PROJECT ACHIEVED

What knobs are those?

I appreciate you putting details of the parts you used, just want to know about the knobs!

Thanks

Nick Froome
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on April 26, 2016, 02:06:53 AM
I finally got around to finishing my build after being diverted by a bunch if different diy projects. Everything seems to be working as hoped. Very nice sounding eq  - thanks to everyone who helped me on this!

A few pictures:
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on April 26, 2016, 02:08:28 AM
More guts
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on April 26, 2016, 02:10:39 AM
Channel view
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on April 26, 2016, 02:17:52 AM
The led indicators were a nice addition. Thanks to the previous posters - great idea!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: darkus on July 17, 2016, 07:08:03 AM
Can I skip calibration by installing fixed value resistors instead trimmers?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: iprovlek on July 17, 2016, 10:32:18 AM
Hi Rmaier!

Your Eq looking great and green colour is awsome!!!

How much is gaining ,3db or less on your W495Eq!?

For mastering very often need 0.5 to 1 dB!


Great job!!!

 8)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rmaier on July 17, 2016, 11:42:37 AM
Thanks, iprovlek. The eq is definitely one of the cooler looking builds in my rack. The high and low shelves are +/- 5dB in 1 dB steps. The bells are +/- 4dB in .75 dB steps (or thereabouts). A little crude for some mastering duties I guess, but I think it should work well for broad strokes. I'm surprised by the highs in particular. Sounds very nice!
Cheers,
Ralph
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dogfaceaudio on July 24, 2016, 08:05:58 PM
I tried putting together a BOM for this project. Could anyone who has completed the project comment on the component choices I've made? Once everything has been checked I'll put together a Mouser cart to share.

Quantity
Value
Designation
Mouser Part
URL
1
PCB
https://pcbgrinder.com/W492-NEUMANN-492 (https://pcbgrinder.com/W492-NEUMANN-492)
2
47P
C1,C2
505-FKP247/1000/5
4
100U
C11,C18,C5,C6
667-EEA-GA1HR10H
2
1N5
C12,C14
505-FKS21500/100/10
2
4N7
C13,C15
505-FKS24700/100/5
1
22N
C16
505-FKS2D022201E00JS
1
6N8
C17
505-FKS26800/100/5
4
100N/CERAMIC
C19,C20,C21,C22
810-FG26C0G1H104JNT6
1
47N
C3
505-FKS2D024701K00JS
1
10N
C4
505-FKS2-.01/100/5A
2
100N
C7,C9
505-MKS2.1/63/5
8
10KLIN/PA11QXF
P1,P2,P3,P4,P5,P6,P7,P8
http://capi-gear.com/catalog/product_info.php?cPath=50_131&products_id=446 (http://capi-gear.com/catalog/product_info.php?cPath=50_131&products_id=446)
2
200R
PT1,PT4
594-63P201
2
10K
PT2,PT3
594-63P103
2
20K
R1,R2
271-20K-RC
2
100K
R10,R47
271-100K-RC
4
330K
R11,R14,R29,R48
271-330K-RC
10
5K1
R12,R13,R27,R28,R42,R43,R49,R5,R50,R6
271-5.1K-RC
2
220R
R15,R30
271-200-RC
2
1K8
R16,R31
271-1.8K-RC
2
4K3
R17,R32
271-4.3K-RC
5
1K
R18,R21,R33,R36,R9
271-1K-RC
4
560R
R19,R22,R34,R37
271-560-RC
4
1K2
R20,R23,R35,R38
271-1.2K-RC
2
2K
R24,R39
271-2K-RC
2
14K
R25,R40
271-14K-RC
2
6K8
R26,R41
271-6.8K-RC
2
10K
R3,R4
271-10K-RC
4
620R
R44,R45,R7,R8
271-620-RC
1
3K3
R46
271-3.3K-RC
2
22R
R51,R52
271-22-RC
4
CK7101
S1,S2,S3,S4
611-7101-002
8
NE5532
U1,U2,U3,U4,U5,U6,U7,U8
595-NE5532P
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: justinheronmusic on August 28, 2016, 11:03:35 PM
Hey everyone!

 I am having trouble sourcing pots for this build. I would like to design a half rack unit and use the original 20mm/15.2mm spacing that is drawn out in the potentiometer assembly sheet. Is there anywhere I can get the Sfernice pots?

 I am also confused as to whether or not I need single or dual gang for this build.

 Links would be much appreciated!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on August 29, 2016, 02:19:51 AM
Hello,


@ Justin,


you'll technically need 6 mono and 2 dual gang pots from what I remember,please look at the schematics or at the pcb and you'll see what I mean.
The Sfernice are hard to source,but you can use other small types and wire them to the corresponding pads.
I did that with Omegs and some solid wire some years ago.The populated pcb is really light-weight,so the eight pots will nicely stay it in place.
Using conductive plastic types is imperative.




@ dogfaceaudio,


can't see where you are located,you might want to update your profile.
Is it a US or european BOM?
For the pots,you don't want center detend types for frequency pots........
Also not necessary for the cut/boost pots since the single bands have a switch provision,but cool if you want it for "blind" operation.
I can't see them in your BOM,maybe you want to add some?


Hope to have helped,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: justinheronmusic on August 29, 2016, 09:27:50 AM
 Will the 10k linear OMEG pots from audio maintenance work? It looks like they no longer carry the 10k conductive plastic.

Hello,


@ Justin,


you'll technically need 6 mono and 2 dual gang pots from what I remember,please look at the schematics or at the pcb and you'll see what I mean.
The Sfernice are hard to source,but you can use other small types and wire them to the corresponding pads.
I did that with Omegs and some solid wire some years ago.The populated pcb is really light-weight,so the eight pots will nicely stay it in place.
Using conductive plastic is imperative
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on August 29, 2016, 03:20:39 PM
Will the 10k linear OMEG pots from audio maintenance work? It looks like they no longer carry the 10k conductive plastic.
Hello Justin,


sadly no,they'll soon start to scratch because of dc.
I'd look at e.g. TT/Bi-Technologies at mouser or so.......


Best regards,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: skidmorebay on April 25, 2017, 09:55:22 AM
Could someone recap the options for cutting the overall cut/boost in half? Mine is in a single rack space - no room for stepped switches really.
Would substituting 5k pots for the 10k pots for boost/cut do the job? Or adding end-stop resistors to each side of the pots?

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: groselicain on July 31, 2017, 10:26:25 AM
Just inherited someone else's old project and I'm completing it one channel at a time. I have several Haufe RK 310/2s and liked the idea of using them in this project. I read earlier where Audiox said something about leaving in the first 5532 for impedance matching, but I didn't read anyone talking about outputs.

If wanted to implement this change, does anyone have a suggestion? Thank you very much.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Whoops on August 01, 2017, 03:28:29 PM
Just inherited someone else's old project and I'm completing it one channel at a time. I have several Haufe RK 310/2s and liked the idea of using them in this project. I read earlier where Audiox said something about leaving in the first 5532 for impedance matching, but I didn't read anyone talking about outputs.

If wanted to implement this change, does anyone have a suggestion? Thank you very much.

What is the change you are talking about?
using transformers to balance the output?

If that's only what you want to do , you can just tap from the + signal, so leave out R49,R50, R51 and U7A


Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kambo on August 23, 2017, 08:30:42 PM
i am thinking of building a stereo pair for my location recording/ headphones setup!
would it work with 9VDC supply(2x9v batt for +/- supply)

what would happen if i used two trimpots stacked_up together instead pots?
(or effect of using super inaccurate dual pots)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dogfaceaudio on September 14, 2017, 10:28:17 AM
Came back to this project, still trying to find pots that will work. The original BOM lists the Sfernice pots which are 1/2W rated. I found these pots on Mouser, but they're only rated for 50mW: http://www.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P092N-FC25BR10K/?qs=gHIbTyTFUDcPxOxhQxPOzw%3D%3D

I can't seem to find any online store that sells the conductive plastic Omeg pots in 10k linear. Don't suppose anyone has suggestions as to where I can find some potentiometers that will work? Thanks!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on September 14, 2017, 10:47:30 AM
I got mine years ago from - http://www.tawelectronics.com/wima_film_capacitors.htm

  call and ask for Laura , I believe they have a "kit" that includes the Omeg pots with all the WIMA caps too.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: dogfaceaudio on September 14, 2017, 11:53:36 AM
I don't see any reference to the Omeg pots being sold by TAW Electronics. I'll try email them and find out if they have any in stock still.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: audiophreak on September 14, 2017, 12:15:51 PM
Hi dogfaceaudio,
                                         They are not an Omeg dealer , but I believe they have Omeg pots for specific projects and I think this is one of them.

  Call them and ask for Laura
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on September 14, 2017, 04:44:22 PM
Just want to share this finding.

Single
https://www.blore-ed.com/product-page/p261-conductive-plastic-long-shaft-potentiometers

Dual
https://www.blore-ed.com/product-page/p261-044a-dual-gang-10k-linear-long-shaft

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on September 16, 2017, 01:01:32 AM
@dogfaceaudio  - were the pots at CAPI not correct.  Im looking for 2 sets myself and the prices on what Jeffs got going on over there is just right as long as the pots are.  I dont mind the center detent on the freq pot and you CAN use dual where it calls for single gang (i did that on the first 2ch unit i built and stupidly lent out and even more stupidly sold.... regrets.... ).
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 28, 2017, 11:30:30 PM
Alright people long time lurker.

I have built many diy projects but this one has an issue that is stumping me.

Here's the deal:

First off no measurable output what so ever with a scope that measured the correct dbu coming out of the signal generator finds nothing on the output unless I activate hardwire relay bypass (which I believe may be linked to my other issue specifically since the eq is not getting it's + or - rails stable).

The other issue when I run the power supply unloaded I get 15v for the positive and the negative rail and 12v for a seperate rail to run the relays for hwb. Now when I attach or wire one or both channels my positive rail drops to 2v after a few minutes. I have already changed the power supply to another power supply because I speculated that maybe the psu regs were bad but the new psu does the same thing.

It is really strange that even when I get the rails to work I have no output what so ever.

Do you guys have any suggestions.

So far I have checked my psu wiring, the io wiring, torid wiring, measured my psu voltage and confirmed time based drop through observation (takes about 2 to 3 minutes before the pos rail drops to 2 to 3 volts). Running out of ideas hopefully someone here has some suggestions on where to go next.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 28, 2017, 11:58:36 PM
Hello,


not too many parts on this pcb.
Best too show us some clear and focussed pics of your build.
Which ICs do you have inserted,are they orientated the correct way?
If yes then remove them and measure dc on the ic sockets to rule them out of being faulty.


Best regards,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 12:28:39 AM
Thanks for the response I am using the ne5532ap made by Texas instruments.

The proto board in the photo is just a breakout for the psu rails the center stripe for the case ground was disconnected by cutting traces where the black sharpie line is.

Here are some pics
Of the psu section

You will notice the psu filter board by collective cases the issue was tested with and withour this board.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 12:29:56 AM
Here is the hardwire relay bypass section it is the hardwire relay bypass kit from diy tubes
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 12:32:28 AM
Here is the filter board with opamps in.

As a side note I tested once channel with no opamps and it held the power rails while I tested it didn't have much time as its getting late gotta get ready for work. Weird if it was the opamps what are the chances both channels are acting up unless my dumass put them in backwards.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 12:33:25 AM
More pics of the filter board
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 12:34:45 AM
Different angle of the filter board. Let me know if you guys need any other angles I will be more than happy to shoot em for the assistance. Thank you once again for taking a look.

Thanks for the reply udo
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 01:06:07 AM
Pin 4 to pin 8 on the boards measured 30v at each opamp socket. so combinated -15 and +15 potential difference of 30v

After checking this it seems they were oriented correctly according to datasheet.

Any other pinout on the ic sockets I should test?

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 29, 2017, 06:50:51 AM
Hello,


thanks for the pics.


It is impossible for me to recognize anything in your build.
All I see is a massive bunch of colored thick wires and some bad solder joints (too much solder).


You should bring the eq back to life first.That means no modifications and no add-ons!!!
I see you have a nice JLM psu there.Good.

To sort things out:

Remove everything that does´t belong to the eq per default,so the additional filter board and the relays board should (temporarily) be disconnected.
Next step is -as you can imagine now- set it up with just the psu directly hooked up to the eq board.Nothing in between.
Do not forget the 0v connection from the JLM psu to the eq.
Without any ics inserted measure pins 8 and 4 with reference to ground.You should get +/- 15 vdc there.
If all is good  insert the ics and check if the unit passes audio.
If it does´t then you´ll have to trace through the circuit.
Generally -as always- give the board a good visual inspection (parts in correct position,correct values,solder joints etc.) first.
As you have the pots off-board you should definitely check your wiring.


Best regards,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 10:22:17 AM
Thanks udo for the response.

I will take out any additions and power it up, I will double check my pot wiring and other wiring as well.

I checked the voltage going to the sockets last night it was 30v from vcc to gnd.

Psu connections to board -15 from gnd to negative lead, +15 from gnd to pos lead.

I will recheck my pots too. I will post a reply later tonight.

Thanks again.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 29, 2017, 10:45:11 AM
Thanks udo for the response.

I checked the voltage going to the sockets last night it was 30v from vcc to gnd

Thanks again.
You're welcome.
30vdc from ic socket pins to gnd is wrong,it should be +/-15vdc.Pin 4 is negative,pin 8 is positive.
Looks like a ground is missing.
Measure connectivity from JLM psu ground output to the middle psu connection (I think it was labelled "black"?),should have very close to zero ohms.
You must not power it up for this.


Best regards,


Udo.


Addendum:Have looked over the wiring diagram,"black" is the upper pad,not the middle one,pardon.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 01:41:11 PM
I will give you an update once I get off work.

I guess I forgot to mention the 30 volts i was measuring was from pin 4 to pin 8 which would be 30v collectively correct (measuring potential between them)? I will recheck when I get home.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 29, 2017, 02:12:26 PM
I will give you an update once I get off work.

I guess I forgot to mention the 30 volts i was measuring was from pin 4 to pin 8 which would be 30v collectively correct (measuring potential between them)? I will recheck when I get home.
30 volts between 8 & 4 is correct,but to be sure measure them with your black probe to 0v (audio/psu ground) on all ic sockets.
I recently helped a guy here with something similar,it turned out he forgot a groind connection.....
Better safe than sorry.

Best regards,


Udo.


P.S.:Where are you located,you might want to update your profile?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 02:27:00 PM
I am in the us located out of minnesota.

I will double check. Thanks
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 08:51:09 PM
0v filter board to 0v on psu continuity test is good ok both boards. As well as pos and negative rails.

15v +/- on each socket tested and good

All off board pot wiring checked with continuity meter.

Pulled the psu filter and now to pull the relay boards.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 29, 2017, 09:35:49 PM
Pulled the relay boards and pulled the psu filter unit came back to life super low noise all the filters work as they should.

Thanks again udo. I should of known to divide and conquer at board level first.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 29, 2017, 11:57:03 PM
Pulled the relay boards and pulled the psu filter unit came back to life super low noise all the filters work as they should.

Thanks again udo. I should of known to divide and conquer at board level first.
Good to hear/read!
Yes,kind of a golden rule,make the basic unit work first,then do your modifications.
For my taste you really don't need the additional filterboard because the JLM has heavy filtering on board anyway.
A couple of years ago I built an 8 channel unit,powered the same way as yours by a torroid and a JLM AC/DC,no issues.


Have fun,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on November 30, 2017, 12:07:15 AM
It is a very queit unit by itself. The collective cases psu filter is rated for additional 10db of improved signal to noise. I am friends with the designer I am talking to him to troubleshoot it. The psu filter drops the positive rail so I'll fix that here soon.

I have always been a fan of the jlm audio powerstations. I used em for a lot of my projects. I built an api 3124 with a di, impedance switch ,and mute switch worked great! 

For whatever reason I can't get the relay board to work I have triple checked the wiring for power and io. I'll figure it out eventually. Thanks for your help udo

This forum rules.

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Aslem on December 06, 2017, 02:50:33 PM
Guys, i'm new here, i'm from Brazil, and i can't find this potentiometers here, i wanted build with rotative key with resistors... what do you think?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: fnhscar17s on December 06, 2017, 10:04:58 PM
Got the relay bypass boards to work.... I was missing a jumper on the bottom of the board from the coupling cap to a diode leg.

Now to fix the psu filter. Looks like a bad input inductor going to order some.

Otherwise the unit is working perfectly. My portable o scope isn't so accurate so I will have to bring it over to my studio later this week and calibrate using pro tools
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pablobolche on March 23, 2018, 11:27:00 AM
Hello forum...
I am finishing a stereo/midside  492 Eq.. with Harrison Ford filters
I passed some audio yesterday and everything is great..
I did a experiment with a 3 position bypass switch...changing the value of the 330k Resistor of each eq section to 2k5 and got roughly a +-6db operation...is this oka to do or would something go wrong eventually??
I would love for this eq to have selectable +-15db/+-6db operation..
I appreciate all comments


Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on March 23, 2018, 11:48:40 AM
I don’t have an answer to your question, but just wanted to chime in and say I’m currently planning out exactly that - W492 + Harrison filters + mid/side! Great minds.  ;D

Hello forum...
I am finishing a stereo/midside  492 Eq.. with Harrison Ford filters...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on March 23, 2018, 04:55:54 PM
where'd ya get the pots pablobolche?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pablobolche on March 23, 2018, 05:41:29 PM
where'd ya get the pots pablobolche?

Gain pots from capi-gear... they have the dual 10K linear with center dent....
capi-gear does have a logarithmic version of the dual 10k but tested them for freq selection and they feel strange (freq...are all together on one end of the pot)  so I have used the center dent ones for everything...as for now atleast..

still looking for a ALPS dual 10k linear conductive plastic...or other options...




Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: sr1200 on March 24, 2018, 08:04:30 PM
That seems to be the biggest problem with this project... wish there were mods that would allow for different pots (other than doing crazy >1% switches.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Gustav on March 25, 2018, 09:38:40 AM
Just want to share this finding.

Single
https://www.blore-ed.com/product-page/p261-conductive-plastic-long-shaft-potentiometers

Dual
https://www.blore-ed.com/product-page/p261-044a-dual-gang-10k-linear-long-shaft

Gustav
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Whoops on March 25, 2018, 10:07:29 PM
some sources for possible potentiometers

Dual gang 10K Lin pots:

https://www.banzaimusic.com/Alpha-16mm-stereo-10k-lin.html

https://www.banzaimusic.com/Alpha-16-FS-STE-10k-lin.html

https://www.banzaimusic.com/Alpha-12-DS-STE-10k-lin.html

https://www.banzaimusic.com/16mm-SP-SWI-10k-lin.html

https://www.banzaimusic.com/Piher-4mm-Pot-Stereo-10k-lin.html

https://www.banzaimusic.com/Piher-6mm-stereo-10k-linear.html

http://pt.farnell.com/te-connectivity-citec/cp16dh10ip06103f/potentiometer-10k-lin/dp/1227601
No. of Gangs: 2

http://pt.farnell.com/citec-te-connectivity/27esa103mmf50n/potentiometer-d-gang-10k-lin/dp/1898452

http://pt.farnell.com/vishay/p9a2r100fisx1103ma/pot-linear-dual-10k/dp/8791350

http://pt.farnell.com/vishay/p11s2v0flsy00103ka/potentiometer-10k-dual-gang-linear/dp/1141607
No. of Gangs: 2

https://pt.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P092N-FC25BR10K?qs=sGAEpiMZZMtC25l1F4XBUyyB1mldM%252bV0qe24DBuU%2f00%3d

https://pt.mouser.com/ProductDetail/Bourns/PDB182-K220K-103B?qs=sGAEpiMZZMtC25l1F4XBU1xwXnrUt%2fuoQsg609DLUag%3d

 

Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Mixpro on June 17, 2018, 02:29:16 PM
Is this project still active? I would really like to build this EQ and wanted to know if there are any boards available or being made for this.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 17, 2018, 02:35:01 PM
Is this project still active? I would really like to build this EQ and wanted to know if there are any boards available or being made for this.
Yes it is,there are boards available from our friend Gustav:


https://pcbgrinder.com/index.php?route=product/product&path=59_60&product_id=58 (https://pcbgrinder.com/index.php?route=product/product&path=59_60&product_id=58)


Best regards,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Mixpro on June 22, 2018, 12:01:16 PM
Hello Udo,

Thank you for helping me with locating the boards.
It seems from going through the posts on this W492 EQ is that the hardest parts to find the are the right pots. Can you please help me with where I can get them? and any other parts I may need for this build that are hard to locate. I live in N. America

Thank you,

Michael
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on June 22, 2018, 12:34:04 PM
Hello Udo,

Thank you for helping me with locating the boards.
It seems from going through the posts on this W492 EQ is that the hardest parts to find the are the right pots. Can you please help me with where I can get them? and any other parts I may need for this build that are hard to locate. I live in N. America

Thank you,

Michael
Hello Michael,
this is an old project,and there were at least two different boards with different footprints for the pots.
Pretty hard to get them,at least the sfernice ones,and they were horribly expensive.
So best is to take others/different brand and wire them to the board.
I used OMEG ECO series at that time and attached them with solid core silver bus wires for my 8-channel build.
There was a friendly  lady called Laura at TAW back then who knew about this project and sold potentiometer  bundles from OMEG to us.I donˋt know if they do that anymore.
You can do whatever you like as long as the values and the tapers are right,but it is imperative to use conductive plastic types.Otherwise they will become scratchy due to the dc in this circuit.
Since you are in North America I would start looking at mouser etc.,maybe Bourns do them.Or look at Jeffs homepage over at CAPI?
For all other parts you can derive them from the components values overlay,I have never seen a BOM for it.
You will find all the info on page one here in this thread,it is well documented,and the links still work.
The parts are all standard,including the ICs.


Hope to have helped,


best regards,


Udo.


Edit:There is (!) a BOM on page one!Sorry,mea culpa.
Have never seen it,I used the schematics and the overlays.
Also for the front panel pots,you need just two dual pots for the mid bands,the other six can be single/ mono versions.All of them are 10k Ohms linear.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mikeyB on August 27, 2018, 09:18:48 PM
Just looking at various pots for this project.
Some sellers describe their pots as having "synthetic carbon" track - is this indeed conductive plastic or something else??
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: alexc on August 31, 2018, 11:45:38 PM
I just started using my stereo build of this implementation of the w492 eq  .....  wow!

Where have these been all my life?  I have them on my mix bus feeding some el34 monitoring amps and speakers. The amps have balanced inputs with a Sowter 10K/10K transformer, and these drive it beautifully with super low hum and noise.

The bass boost out of these is very satisfying  and the mid-hi cut sooths the jangles out of my 'toppy' guitars very well.

Very easy to use, with the well spaced control layout on a 2RU racking; the individual band bypass switches are a superb feature.      I added a switchable relay channel-bypass to mine. Pots are those nice conductive plastic, centre detent types for the 'levels' and same sans detent for the 'freq'.

My new fav  eq :)  Takes a couple of seconds to dial in, and done!   Excitement to the max.

Thanks so much  to member 'audiox'  for his efforts.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on November 05, 2018, 11:58:52 AM
Hi all,

I recently finished my W492, and wanted to take a few minutes to document the build. I've modified the core EQ pretty heavily with a view to using primarily for 2-bus / mastering work, and also built a number of other functions in, so hopefully this will be useful to some folk down the line. Huge thanks to everyone who's posted on this project across the site, and of course to Audiox - I'm definitely perching on the shoulders of giants here!

(http://ringlefinch.co.uk/wp-content/uploads/2018/11/1-W492-front.jpg)

Features:

(http://ringlefinch.co.uk/wp-content/uploads/2018/11/2-W492-internal.jpg)

It sounds superb - very clean and precise, low distortion, and quieter than I expected given the amount of wiring involved (sub -94dBFS). There are 13 PCBs including filters, M/S matrix, power supplies, relays etc, and all the front panel controls are wired off-board, so hooking everything up took a good few days... The combination of fully parametric mid bands and shelves plus filters makes it really flexible, and I'm very happy with the styroflex caps for the high end in particular.

I spent a long time planning, listening and testing with this one - a good couple of years of reading and planning, and dozens(!) of iterations of front panel design. With all the potential for issues with such a complex build I was more than usually nervous when firing it up for the first time, but debugging was mercifully straightforward this time - the biggest issues were a bad solder joint in a SMT frequency switch, and popping on some switches (see below). In terms of mods to the W492, here's what I did following a ton of research, breadboarding and measuring (all component references are to the Audiox schematic, and I used REW for measurements):

Variable bandwidth
10K pot (RP) with 3k3 series on CCW (RB2) across U3A (low mid) and U5A (high mid), wiper to ground via 330R series (RB3). This involved running wires to one side of each of R16, R17, R26 (low mid) and R31, R32 and R41 (high mid) - I left little loops in the resistor leads to allow this when populating the boards. One caveat - the centre frequency wanders a little as the bandwidth is changed from wide to narrow (e.g. a few Hz at +15dB at 1k), so there may be a better way to implement variable bandwidth on this circuit, but after using it extensively on a variety of material it doesn't feel like a major issue. And ideally I would have preferred rotary switches to pots for stereo matching, but front panel space didn't permit that so I matched the pots instead as best I could.

(http://ringlefinch.co.uk/wp-content/uploads/2018/11/3-W492-bw-mod.jpg)

Gain switches
5k resistor ladder with 5k resistor from CCW switch position. The +/- (boost/cut) switch swaps the CW and CCW poles going back to the EQ board, so the CCW position on the switch is always flat. Note that the shelves popped loudly at first when switching between boost and cut - putting a 1M resistor from each end of the switch to the wiper reduced this to manageable levels.

Gain range
For low & high shelves:
R8, R45 = 620R = +/-18dB gain range
R8, R45 = 1k2 = +/-8.5dB

For the low and high mid bands:
R15, R30 = 220R= +/-15dB
R15, R30 = 4k7 = +/-7.5dB

Frequency range
High shelf x3: swap C16 & C17 28.8nF for 10nF (lovely air boost)
Low mid x0.5: use empty C8 and C10 pads to switch in an extra 100nF at each point

Here's some photos from the build:

Testing bandwidth mod (lots of wires coming off the PCB!):
http://ringlefinch.co.uk/wp-content/uploads/2018/11/4-W492-bw-testing.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/4-W492-bw-testing.jpg)

Populating the internal control panel:
http://ringlefinch.co.uk/wp-content/uploads/2018/11/5-W492-control-panel.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/5-W492-control-panel.jpg)

Control panel done:
http://ringlefinch.co.uk/wp-content/uploads/2018/11/6-W492-control-panel.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/6-W492-control-panel.jpg)

Assembling and wiring it all up:
http://ringlefinch.co.uk/wp-content/uploads/2018/11/7-W492-populating.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/7-W492-populating.jpg)

And all racked up!
http://ringlefinch.co.uk/wp-content/uploads/2018/11/8-W492-racked.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/8-W492-racked.jpg)

I'm really pleased with how my W492 has turned out - it's been a major labour of love, and a great exercise in learning about state variable filters (and pushing the bounds of established designs...). Hope some of this helps someone further down the road!

Andy
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: kante1603 on November 05, 2018, 12:15:02 PM
A serious amount of clean work you‘ve done here,congrats Andy!


Best regards,


Udo.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: [silent:arts] on November 06, 2018, 03:06:22 AM
Wow. The spirit of DIY is finally coming back!
An understatement calling it W492.
Congratulations
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on November 06, 2018, 04:59:25 AM
Thanks Udo & Volker!  ;D
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: rob_gould on November 07, 2018, 02:32:05 AM
This is the most exciting and best looking build I've seen on here for quite some time. All your efforts have paid off Andy - congratulations!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on November 08, 2018, 05:08:19 AM
Thanks for the kind words Rob!

This is the most exciting and best looking build I've seen on here for quite some time. All your efforts have paid off Andy - congratulations!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: 5v333 on November 08, 2018, 03:17:03 PM
I would love to take that one for a ride.
Great job!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: delaymix on November 11, 2018, 11:14:17 AM
I do not have words...! an awesome job! Congratulations!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: weiss on January 24, 2019, 09:58:57 AM
Hi all,

I recently finished my W492, and wanted to take a few minutes to document the build. I've modified the core EQ pretty heavily with a view to using primarily for 2-bus / mastering work, and also built a number of other functions in, so hopefully this will be useful to some folk down the line. Huge thanks to everyone who's posted on this project across the site, and of course to Audiox - I'm definitely perching on the shoulders of giants here!

wow, awesome work andy!!!  :o :o
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on January 24, 2019, 10:25:08 AM
Thanks Weiss, and everyone else for the very welcome feedback! Think I'll tackle something more straightforward for my next build - a new Hadron Collider or something...  ;)
Title: Neumann W492 equalizer DIY project (PCB docs added)
Post by: erquere on February 27, 2019, 10:50:46 AM
Hi ! Could someone tell me which kind of available pots I can buy for this project ? Without spending 50 bucks for one ? I've been searching and bought wrong ones at Mouser...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: erquere on February 27, 2019, 12:22:22 PM
Do these ones fit, or not ?

http://capi-gear.com/catalog/product_info.php?cPath=50_131&products_id=446
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: erquere on February 27, 2019, 02:28:02 PM
I finally found some Vishay-Sfernice pots... now the question is : if I just buy two dual-gand pots (P4 and P6 ?) and six mono pots, is it ok ?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: erquere on March 14, 2019, 03:21:07 PM
Could wirewound pots fit too ? Much much cheapier than Sfernice ones !
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: alhe on May 13, 2019, 09:14:42 AM
Some really nice builds in this thread. How is the W492 for tracking?

I see most people build this without transformers. In my experienece, most, if not all Neumann modules have had Haufes installed - is this not the case for the W492?


Edit:
So to answer my own question, the original W492 uses a Haufe T4344/90485 input transformer and a electronically balanced output.

pri: dBu 10V
2:1
200:4,7k
20-30kHz +/- 0,5dB


Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pollomartian on June 19, 2019, 12:19:38 PM
Can I use 47k potentiometers? I have some plastic conductive potentiometers, but they are 47k...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Whoops on June 21, 2019, 12:24:24 AM
Can I use 47k potentiometers? I have some plastic conductive potentiometers, but they are 47k...

The pots are dual gang 10K LIN.

Use the correct ones
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: pollomartian on July 11, 2019, 12:16:41 PM
Hi all,

I recently finished my W492, and wanted to take a few minutes to document the build. I've modified the core EQ pretty heavily with a view to using primarily for 2-bus / mastering work, and also built a number of other functions in, so hopefully this will be useful to some folk down the line. Huge thanks to everyone who's posted on this project across the site, and of course to Audiox - I'm definitely perching on the shoulders of giants here!

(http://ringlefinch.co.uk/wp-content/uploads/2018/11/1-W492-front.jpg)

Features:
  • Dual mono Audiox W492 4-band EQ with fully parametric mid bands, plus Harrison Ford Filters HPF / LPF
  • Rotary switches for frequency (24 steps/band) & gain (12 steps/band, switchable +/-)
  • Channel components matched to high tolerance (less than 0.1dB difference between channels at all settings - except when boosting or cutting 15dB on the high shelf, when there's 0.2dB difference!)
  • WIMA filter caps for low shelf and low mid bands, Styroflex for high mid and high shelf
  • Switchable mid/side matrix (a la Wayne Kirkwood)
  • Per-channel bypass (inside mid/side matrix) and master bypass
  • Vintage Jensen output transformers (switchable per channel - relaxes the sound very slightly)
  • Switchable gain range per channel (x1 / x0.5)
  • Switchable frequency range for low mid (x1 / x0.5) and high shelf (x1 / x3) bands
  • Variable bandwidth for low mid and high mid bands (Q = 0.45 to 3.6)
  • THAT1246/1646/LT1058 ICs used in HPF/LPF
  • Backlit plexiglass logo badge 8)
  • Panels and NRG case by Frank

(http://ringlefinch.co.uk/wp-content/uploads/2018/11/2-W492-internal.jpg)

It sounds superb - very clean and precise, low distortion, and quieter than I expected given the amount of wiring involved (sub -94dBFS). There are 13 PCBs including filters, M/S matrix, power supplies, relays etc, and all the front panel controls are wired off-board, so hooking everything up took a good few days... The combination of fully parametric mid bands and shelves plus filters makes it really flexible, and I'm very happy with the styroflex caps for the high end in particular.

I spent a long time planning, listening and testing with this one - a good couple of years of reading and planning, and dozens(!) of iterations of front panel design. With all the potential for issues with such a complex build I was more than usually nervous when firing it up for the first time, but debugging was mercifully straightforward this time - the biggest issues were a bad solder joint in a SMT frequency switch, and popping on some switches (see below). In terms of mods to the W492, here's what I did following a ton of research, breadboarding and measuring (all component references are to the Audiox schematic, and I used REW for measurements):

Variable bandwidth
10K pot (RP) with 3k3 series on CCW (RB2) across U3A (low mid) and U5A (high mid), wiper to ground via 330R series (RB3). This involved running wires to one side of each of R16, R17, R26 (low mid) and R31, R32 and R41 (high mid) - I left little loops in the resistor leads to allow this when populating the boards. One caveat - the centre frequency wanders a little as the bandwidth is changed from wide to narrow (e.g. a few Hz at +15dB at 1k), so there may be a better way to implement variable bandwidth on this circuit, but after using it extensively on a variety of material it doesn't feel like a major issue. And ideally I would have preferred rotary switches to pots for stereo matching, but front panel space didn't permit that so I matched the pots instead as best I could.

(http://ringlefinch.co.uk/wp-content/uploads/2018/11/3-W492-bw-mod.jpg)

Gain switches
5k resistor ladder with 5k resistor from CCW switch position. The +/- (boost/cut) switch swaps the CW and CCW poles going back to the EQ board, so the CCW position on the switch is always flat. Note that the shelves popped loudly at first when switching between boost and cut - putting a 1M resistor from each end of the switch to the wiper reduced this to manageable levels.

Gain range
For low & high shelves:
R8, R45 = 620R = +/-18dB gain range
R8, R45 = 1k2 = +/-8.5dB

For the low and high mid bands:
R15, R30 = 220R= +/-15dB
R15, R30 = 4k7 = +/-7.5dB

Frequency range
High shelf x3: swap C16 & C17 28.8nF for 10nF (lovely air boost)
Low mid x0.5: use empty C8 and C10 pads to switch in an extra 100nF at each point

Here's some photos from the build:

Testing bandwidth mod (lots of wires coming off the PCB!):
http://ringlefinch.co.uk/wp-content/uploads/2018/11/4-W492-bw-testing.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/4-W492-bw-testing.jpg)

Populating the internal control panel:
http://ringlefinch.co.uk/wp-content/uploads/2018/11/5-W492-control-panel.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/5-W492-control-panel.jpg)

Control panel done:
http://ringlefinch.co.uk/wp-content/uploads/2018/11/6-W492-control-panel.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/6-W492-control-panel.jpg)

Assembling and wiring it all up:
http://ringlefinch.co.uk/wp-content/uploads/2018/11/7-W492-populating.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/7-W492-populating.jpg)

And all racked up!
http://ringlefinch.co.uk/wp-content/uploads/2018/11/8-W492-racked.jpg (http://ringlefinch.co.uk/wp-content/uploads/2018/11/8-W492-racked.jpg)

I'm really pleased with how my W492 has turned out - it's been a major labour of love, and a great exercise in learning about state variable filters (and pushing the bounds of established designs...). Hope some of this helps someone further down the road!

Andy

This is the most impressive DIY project I've ever seen.  Thank you very much for showing it. Wonderful...

Where have you bought these rotary switches?
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on July 13, 2019, 02:05:50 PM
This is the most impressive DIY project I've ever seen.  Thank you very much for showing it. Wonderful...

Where have you bought these rotary switches?

Thanks Pollo! Appreciate the kind words.  ;D I got the frequency switches off eBay, pre-assembled with SMD resistors - seller called “tortoise6688”. I’ve got a few off them in the past with good results - the switches don’t have the nicest feel in the world, but they weren’t expensive (<£20 each I think, assembled) and have been very well matched. Their stock is very variable though, so I don’t know if they still offer them.
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mikeyB on July 18, 2019, 12:13:33 PM
been reading on this for a while. Wondering the possibility of adding in bell/shelf switch on the LF and HF bands.

Is this something that can be done easily? How would this be implemented? Just experimenting with the circuit at the moment,
May even consider re-doing the PCB if I like it enough with all mods tried!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: mikeyB on July 18, 2019, 07:26:07 PM
Slightly off topic but relevant!
I've not had time to study the schem yet, but is the topology akin to the calrec eq? If so, then that too must be DC coupled and conductive plastic pots are also needed for that eq as well.
It just so happens that the project plumped for the omegs from the start so it was not an apparent issue.
Could someone confirm if this is the case as i would like to build the calrecs at some point as well!! It would be good for others to know if this is the case and be noted in the Calrec thread.
Gyraf(Jakob-sorry!), maybe you could chime in if youre around?

Thanks in advance!!
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: winner on July 29, 2019, 05:36:14 AM
I want to know, I want to use multiple resistors to select the fixed frequency band, how to calculate the value of P4 because I want to change the value on the panel; including the values ​​of C8, C10, how to calculate, is there a formula, thank you
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on July 29, 2019, 07:02:38 AM
Hi Winner,

It’s definitely possible to calculate the filter frequencies - just google “state variable filter calculators” and go from there.  If you have specific frequencies in mind for your switch then you may also find it worth testing with a pot to find the right values before you make up the frequency switch (assuming you’re looking at a rotary switch or similar). You can dial the pot into the frequency points you’re looking for and measure the resistance at each point, then work up your own resistor ladder. It’s a super-flexible circuit!

I want to know, I want to use multiple resistors to select the fixed frequency band, how to calculate the value of P4 because I want to change the value on the panel; including the values ​​of C8, C10, how to calculate, is there a formula, thank you
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: winner on July 30, 2019, 01:28:20 AM
Hi Winner,

It’s definitely possible to calculate the filter frequencies - just google “state variable filter calculators” and go from there.  If you have specific frequencies in mind for your switch then you may also find it worth testing with a pot to find the right values before you make up the frequency switch (assuming you’re looking at a rotary switch or similar). You can dial the pot into the frequency points you’re looking for and measure the resistance at each point, then work up your own resistor ladder. It’s a super-flexible circuit!


Thank you for your patience. I understand the use of adjustable resistors to determine the resistance value, but I don't quite understand the capacitance value in schematic 2/3. Forgive me for my ignorance. I am a newbie. The description says the

presence/absence filter +/- 15dB, 0,063-1 kHz
 - presence/absence of filter +/- 15dB, 1-16kHz,

why in schematic 2, C7 + C8 and C9 + C10 determine the filtering range 0.063-1KHZ, in schematic 3, C12 + C13 and C14 + C15 Decide on the filtering range 1K-16KHZ,

I saw that schematic 2/3 is identical except for the four capacitor values. I want to know their way, how to determine this value, I only know the RC filter, but the corresponding, thank you for your reply
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on July 30, 2019, 07:25:09 AM
... Forgive me for my ignorance. I am a newbie...

There’s nothing to forgive, we all start at the beginning!  ;)

The W492 uses a pretty straightforward state variable filter topology. The choice of capacitor value at, eg, C7+8 and C9+10 effectively sets the frequency range that the 10k pot can deliver, and it’s an inverse linear relationship - frequency goes down as capacitance goes up. As you can see from the schematic, the capacitance in the High Mid section is about 16 times lower than the Low Mid section (100nF vs 6.2nF), and the frequency range is about 16 times higher.

With that in mind, if you’re looking for a different overall range for a given band, it should be pretty straightforward to just extrapolate. So for example, if you wanted a range of 125Hz to 2kHz (double the Low Mid values), you should be able to get there by using half the capacitance at C7+8 and C9+10 - so 50nF (which you could get quite neatly using 47nF at C7 and C9, and 3.3nF at C8 and C10). I used exactly this principle in my build when I put an additional 100nF switchable at C8 and C10, to give the option of halving the frequency range in the Low Mids (from 60-1000 to 30-500). I did the same with the High Shelf too, adding a switch to reduce the capacitance from around 28nF to 10nF to triple the frequency range (lovely air boosts!).

Hope that helps. If I’ve misunderstood your question and you’re actually looking to understand the theory of how it all works, I’d point you to this really useful overview of the SVF topology (it gets heavy on the math, but that’s not essential to understanding the high level picture):
https://www.electronics-tutorials.ws/filter/state-variable-filter.html (https://www.electronics-tutorials.ws/filter/state-variable-filter.html)

Andy
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: winner on August 01, 2019, 12:03:45 AM
There’s nothing to forgive, we all start at the beginning!  ;)

The W492 uses a pretty straightforward state variable filter topology. The choice of capacitor value at, eg, C7+8 and C9+10 effectively sets the frequency range that the 10k pot can deliver, and it’s an inverse linear relationship - frequency goes down as capacitance goes up. As you can see from the schematic, the capacitance in the High Mid section is about 16 times lower than the Low Mid section (100nF vs 6.2nF), and the frequency range is about 16 times higher.

With that in mind, if you’re looking for a different overall range for a given band, it should be pretty straightforward to just extrapolate. So for example, if you wanted a range of 125Hz to 2kHz (double the Low Mid values), you should be able to get there by using half the capacitance at C7+8 and C9+10 - so 50nF (which you could get quite neatly using 47nF at C7 and C9, and 3.3nF at C8 and C10). I used exactly this principle in my build when I put an additional 100nF switchable at C8 and C10, to give the option of halving the frequency range in the Low Mids (from 60-1000 to 30-500). I did the same with the High Shelf too, adding a switch to reduce the capacitance from around 28nF to 10nF to triple the frequency range (lovely air boosts!).

Hope that helps. If I’ve misunderstood your question and you’re actually looking to understand the theory of how it all works, I’d point you to this really useful overview of the SVF topology (it gets heavy on the math, but that’s not essential to understanding the high level picture):
https://www.electronics-tutorials.ws/filter/state-variable-filter.html (https://www.electronics-tutorials.ws/filter/state-variable-filter.html)

Andy

Thank you very much for your reply, I fully understand. If I want to add another band, I just need to add (copy) a schematic 2 or 3, change its capacitance value to the frequency I need, and say that they are completely connected in series. Is that right? thank you
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on August 01, 2019, 12:43:11 PM
In theory yes, it should be no more complicated than that. In practice, there may be factors at play that I’m not aware of (potential for increased noise?) - maybe spend some time comparing the W492 schematic to that of other 5 band SVF-based equalisers to see if they are doing anything different.

There’s quite a good discussion at https://groupdiy.com/index.php?topic=67088.0 (https://groupdiy.com/index.php?topic=67088.0) about 5 band SVF EQs, worth having a look through that and reading up elsewhere on the SVF to get a sense of how well it would work.

Or just breadboard it.  ;)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: winner on August 09, 2019, 05:34:13 AM
In theory yes, it should be no more complicated than that. In practice, there may be factors at play that I’m not aware of (potential for increased noise?) - maybe spend some time comparing the W492 schematic to that of other 5 band SVF-based equalisers to see if they are doing anything different.

There’s quite a good discussion at https://groupdiy.com/index.php?topic=67088.0 (https://groupdiy.com/index.php?topic=67088.0) about 5 band SVF EQs, worth having a look through that and reading up elsewhere on the SVF to get a sense of how well it would work.

Or just breadboard it.  ;)

Thank you very much for your patient reply. Have a nice day
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: winner on September 04, 2019, 11:06:24 AM
In theory yes, it should be no more complicated than that. In practice, there may be factors at play that I’m not aware of (potential for increased noise?) - maybe spend some time comparing the W492 schematic to that of other 5 band SVF-based equalisers to see if they are doing anything different.

There’s quite a good discussion at https://groupdiy.com/index.php?topic=67088.0 (https://groupdiy.com/index.php?topic=67088.0) about 5 band SVF EQs, worth having a look through that and reading up elsewhere on the SVF to get a sense of how well it would work.

Or just breadboard it.  ;)

Hello, I may need to trouble you again. I used f = 1 /(2 * pi * R * C) to calculate the value of specific R, but the result is different from my experimental value. I think it is because the contact resistance is 560 . I hope to use band switch. Can you tell me the calculation method
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Palmito on September 05, 2019, 01:43:32 PM
BanzaiMusic have these cheap Omeg pots
https://www.omeg.co.uk/wp-content/uploads/2018/10/PC16BU.pdf
Are they OK  ? (apart from the space between pins)
They dont have the dual-gang tho...
thanks in advance
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: ToBSn on September 08, 2019, 06:55:38 PM
BanzaiMusic have these cheap Omeg pots
https://www.omeg.co.uk/wp-content/uploads/2018/10/PC16BU.pdf
Are they OK  ? (apart from the space between pins)
They dont have the dual-gang tho...
thanks in advance

Yes, these pots will work fine.
But they won't fit in 1HU if I remember correctly.
 
6 x https://www.omeg.co.uk/wp-content/uploads/2018/10/PC16BU.pdf
2 x https://www.omeg.co.uk/wp-content/uploads/2018/10/PC2G16BU.pdf


ToBSn
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: Palmito on September 09, 2019, 06:12:02 AM
Thanks

i found even cheaper at buerklin, and they have the dual-gang

https://www.buerklin.com/en/Products/Passive-Components/Potentiometers-and-trimmers/Potentiometers/Stereo-conductive-plastic-potentiometer%2C-2-x-10-K%2C-0-25%C2%A0W%2C-Solder-pins/p/75E730
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: erquere on September 29, 2019, 04:11:59 PM
I found those ones : https://www.rapidonline.com/Catalogue/Product/65-1442

Just need to bend carefully the rear pins with little pliers to make the stereo fit in the pcb holes, i just still have to measure the distance between two pots to check it fits the faceplate I can buy here in Europe
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: winner on October 03, 2019, 11:43:46 AM
Excuse me, I want to increase Q value and change bandwidth. What should I do? :) :)
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: erquere on October 13, 2019, 10:42:39 AM
Question about ground wiring : do I have to leave the pcbs output ground pins unconnected, as usual ? If using shielded wires, do I have to connect thos ground pins to ground pins of the output XLR or - in my case - to the Lundahl transformers ground pins ?

Noob question I know...
Title: Re: Neumann W492 equalizer DIY project (PCB docs added)
Post by: TwentyTrees on October 15, 2019, 09:34:13 AM
Winner - I missed a couple of your messages here:

Hello, I may need to trouble you again. I used f = 1 /(2 * pi * R * C) to calculate the value of specific R, but the result is different from my experimental value. I think it is because the contact resistance is 560 . I hope to use band switch. Can you tell me the calculation method
Yes, I also found that the experimental value was different from my calculations. If you're looking for specific frequency choices, it's probably worth breadboarding and testing things.

Excuse me, I want to increase Q value and change bandwidth. What should I do? :) :)
https://groupdiy.com/index.php?topic=28332.msg897659#msg897659 (https://groupdiy.com/index.php?topic=28332.msg897659#msg897659) - see the section on Variable Bandwidth. There might be better methods, but this definitely works.

Good luck!