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Project Specific Discussions => Filters/Equalizers => Topic started by: guitarmaker on April 28, 2009, 11:42:12 AM

Title: Barry Porter "Net EQ"
Post by: guitarmaker on April 28, 2009, 11:42:12 AM
I'm wondering if anyone has any Gerber files for the Barry Porter "Net EQ" they wouldn't mind sharing/selling/trading for?  Thanks in advance.

Steve
Title: Re: Barry Porter "Net EQ"
Post by: okgb on April 28, 2009, 12:08:32 PM
what is it  , where did it come from ?
and would he mind it circulating ?
Title: Re: Barry Porter "Net EQ"
Post by: guitarmaker on April 28, 2009, 12:16:54 PM
"It" came for the late Barry Porter and is supposed to be a very nice, elegant EQ.  There is a schem here:
http://www.collinsaudio.com/NetEQ.pdf
and some PCB stuff here:
http://www.collinsaudio.com/PCB_Tracking.pdf
Which leads me to believe there are some more complete files for the DIY minded.

Steve
Title: Re: Barry Porter "Net EQ"
Post by: guitarmaker on April 28, 2009, 12:20:13 PM
I don't believe there's any secrecy or problem posting resources for this one as the schematic itself was posted on his now defunct web site.  It seemed like at the time some folks took to making some Gerber files for it but I haven't had any luck finding them.

Steve
Title: Re: Barry Porter "Net EQ"
Post by: okgb on April 28, 2009, 01:33:03 PM
Looks like the paralell filter style which
massenburg prefers [ i believe ]

Someone smarter than me will likely speak up soon ,
always fun to see different schematics
Title: Re: Barry Porter "Net EQ"
Post by: Gold on April 28, 2009, 01:45:48 PM
I bought PCB's from someone who is making them as finished units. He is willing to sell boards but I highly doubt he would give out gerbers. The boards weren't priced "non commercial" either.
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on April 28, 2009, 02:58:12 PM
Hi All,

I have gerbers for Barry's own PCB design as well as a PDF outlining the circuit.  I don't have the means to host the Gerbers so I put them up on yousendit - perhaps someone can download and host.  I don't know if they are good or not as I have neither the skills nor the Gerber reader to tell.

https://download.yousendit.com/WnBReFlZYXkzMWwzZUE9PQ

Can whoever ends up hosting this let me know and I'll email them the PDF of the circuit description.

Cheers,
Ruairi

edited for many typos - too tired. Will email to the GroupDIY account later
Title: Re: Barry Porter "Net EQ"
Post by: tv on April 28, 2009, 03:21:32 PM
None of my bussiness, but - how about uploading it to the groupdiy gmail account? Should be "it" ....
Title: Re: Barry Porter "Net EQ"
Post by: Biasrocks on April 28, 2009, 03:45:12 PM
I bought PCB's from someone who is making them as finished units. He is willing to sell boards but I highly doubt he would give out gerbers. The boards weren't priced "non commercial" either.

Interesting, I was around when the original project came together, IIRC it was back in the rec.audio.pro days.

It's a shame someone is profiting from Barry's more than generous offering.

Care to share the contact info?

Mark
Title: Re: Barry Porter "Net EQ"
Post by: diyfanatic on April 28, 2009, 04:10:26 PM
Quote
how about uploading it to the groupdiy gmail account?

go at the end of this thread!
http://www.groupdiy.com/index.php?topic=16013.msg16471#msg16471 (http://www.groupdiy.com/index.php?topic=16013.msg16471#msg16471)

cheers.
Jr.
Title: Re: Barry Porter "Net EQ"
Post by: Gold on April 28, 2009, 04:39:39 PM
It's a shame someone is profiting from Barry's more than generous offering.

It's a new board layout that includes provision for DOA's. I had to convince him to sell me boards. On the original website there were Gerbers for BP's layout. He's not selling those. I see nothing wrong with taking a public domain circuit, doing a layout and selling customized boxes that say BP Net EQ on them. If you want to give the guy a hard time spend some time with google.
Title: Re: Barry Porter "Net EQ"
Post by: okgb on April 28, 2009, 04:52:33 PM
If Barry has passed on  , it's no use to him

although open to competition from anyone else who
wants to take the time to create & market a pcb  ,
it is a nice head start from someone else's work .

like most projects , i 'd buy a pcb to save the effort
[ i wouldn't have made half the things i have without
a ready to go pcb ]

Barry got a widow ?
Title: Re: Barry Porter "Net EQ"
Post by: Biasrocks on April 28, 2009, 05:27:25 PM
It's a shame someone is profiting from Barry's more than generous offering.

It's a new board layout that includes provision for DOA's. I had to convince him to sell me boards. On the original website there were Gerbers for BP's layout. He's not selling those. I see nothing wrong with taking a public domain circuit, doing a layout and selling customized boxes that say BP Net EQ on them. If you want to give the guy a hard time spend some time with google.

Not looking to give anyone a hard time, perhaps you should take a look at some of the original threads in rec.audio.pro

Barry himself explained that he released this design because a number of manufactures copied his design and used it in commercial products.

Barry released the Gerber files himself on April 27th, 2001.

http://groups.google.com/group/rec.audio.pro/browse_thread/thread/96d8d956b2e19b56/c04b176c4c507fb5?lnk=gst&q=barry+porter+neteq#c04b176c4c507fb5

I'm uploading the entire project to the GroupDIY email account, along with the Gerber files.

From Barry Porter's website -
"This particular configuration was developed by myself, and was originally used in a Cadac console. With very few modifications, it has been used by several other console manufacturers - some with my approval, but many without!"

Enjoy!
Mark
Title: Re: Barry Porter "Net EQ"
Post by: Gold on April 28, 2009, 05:59:18 PM
FWIW they are built to order and are all a little different. You won't see an ad for them. He's not pretending like he has an exclusive license or it's anything other than what it is.
Title: Re: Barry Porter "Net EQ"
Post by: okgb on April 28, 2009, 07:39:30 PM
anyone say who the manufactures who copied it are ?
[ what it's comparable to ]

that's gotta suck getting ripped off by the big boys [ bullys ]
Title: Re: Barry Porter "Net EQ"
Post by: Biasrocks on April 28, 2009, 08:12:54 PM
Paul, I'm assuming this the product you're talking about?

http://www.tfpro.com/index.php/page/P9

anyone say who the manufactures who copied it are ?
[ what it's comparable to ]

I believe Soundcraft was one of the notable ones, it's all there in the thread on rec.audio.pro if you care to look.

Mark
Title: Re: Barry Porter "Net EQ"
Post by: guitarmaker on April 28, 2009, 08:34:09 PM
No, the TFPRO P9 is totally different than the NetEQ schem posted earlier.

Steve
Title: Re: Barry Porter "Net EQ"
Post by: Biasrocks on April 28, 2009, 08:37:46 PM
No, the TFPRO P9 is totally different than the NetEQ schem posted earlier.

Steve


Steve,

Is the P9 based on the Trident A Range then?

Mark
Title: Re: Barry Porter "Net EQ"
Post by: guitarmaker on April 28, 2009, 10:03:32 PM
Yup.

Steve
Title: Re: Barry Porter "Net EQ"
Post by: Biasrocks on April 29, 2009, 11:02:02 AM
Here's a source for the Center Tapped 10k pots.

http://www.bitechnologies.com/pdfs/p270.pdf

P271-DS21R10K

$8.49 each at Arrow Electronics

http://www.arrownac.com/

Mark
Title: Re: Barry Porter "Net EQ"
Post by: SKJGProject on February 18, 2011, 09:37:41 AM
does anybody know where i can get pcb's for this eq?
Title: Re: Barry Porter "Net EQ"
Post by: signalflow on February 18, 2011, 10:58:31 PM
look in the group gmail account. Check the meta thread for instuctions.

-Casey
Title: Re: Barry Porter "Net EQ"
Post by: seavote on February 18, 2011, 11:45:16 PM
cant find it in gmail and i see no thread in the metas. is it possible members are mixing up the net EQ  and the Night eq PROJECT?? 
Title: Re: Barry Porter "Net EQ"
Post by: signalflow on February 19, 2011, 12:45:40 AM
go to the gmail account and type in "net EQ" in the top search bar and hit "search mail" this will bring up the email with the attachment in it.  These are not nite Eq files these are the barry porter files.

-Casey
Title: Re: Barry Porter "Net EQ"
Post by: abbey road d enfer on February 19, 2011, 03:35:27 AM
I believe Soundcraft was one of the notable ones, it's all there in the thread on rec.audio.pro if you care to look.

Mark
Soundcraft never had an EQ with parallel arrangement. Neither center-tap pots.
Title: Re: Barry Porter "Net EQ"
Post by: seavote on February 19, 2011, 07:17:55 AM
thanks signalflow. my diy list is backed up quite a bit but i wanted to take a look.
 8) 8) 8)
Title: Re: Barry Porter "Net EQ"
Post by: pedroplanet on December 22, 2011, 11:02:22 AM
there's no "net eq" on the gmail account  :-\
Title: Re: Barry Porter "Net EQ"
Post by: skal1 on December 22, 2011, 11:11:00 AM
Check out the white market..

skal1
Title: Re: Barry Porter "Net EQ"
Post by: JLM Audio on February 08, 2012, 04:33:27 PM
I have 2 of the BP Net EQ PCB here we are building for a client. Does anyone have the gerber or any pcb, pcbdoc file etc for that PCB. As I would like to add the component values into the the overlay so we can print out a clear stuffing sheet for the PCB.

I will add the New files back into the GroupDIY technical documents so if anyone makes any more Net EQ PCB the component value will be on there in the overlay to make building heaps easier.

If someone has these please email the file or files to joe at jlmaudio dot com

I cannot find them online anywhere and cannot get into the groupdiy email account since the password seems to have changed. I PMed Gustav as well but haven't heard back from him yet.

Thanks

Title: Re: Barry Porter "Net EQ"
Post by: Davo on February 08, 2012, 05:45:09 PM
I have 2 of the BP Net EQ PCB here we are building for a client. Does anyone have the gerber or any pcb, pcbdoc file etc for that PCB. As I would like to add the component values into the the overlay so we can print out a clear stuffing sheet for the PCB.

I will add the New files back into the GroupDIY technical documents so if anyone makes any more Net EQ PCB the component value will be on there in the overlay to make building heaps easier.

If someone has these please email the file or files to joe at jlmaudio dot com

I cannot find them online anywhere and cannot get into the groupdiy email account since the password seems to have changed. I PMed Gustav as well but haven't heard back from him yet.

Thanks

emailed
Title: Re: Barry Porter "Net EQ"
Post by: JLM Audio on February 11, 2012, 01:02:39 AM
Thanks For the Gerbers.

I have made the below PDF overlay with full component values so far to help with the current batch of PCBs while stuffing them with parts as they have no parts values on the overlay.
All unmarked caps at the each end of the opamps are 100nF mono type. Relays are all 12v type.

http://www.jlmaudio.com/NET EQ/NET EQ component value overlay.pdf (http://www.jlmaudio.com/NET EQ/NET EQ component value overlay.pdf)

Since the gerbers are PHO types it will take a bit more playing around to make the new gerber overlay with the software I use.
But if anyone has them converted them to .G** type gerber files already let me know as it would save a lot of time.

I will add this to the "technicial documents" once i clean it up and add a bit more info to the PDF.

Title: Re: Barry Porter "Net EQ"
Post by: king-rb on March 14, 2012, 09:26:35 AM
ok great ;-) my stereo mastering net eq is up an running. i used lme49720 opamps. it seems like it sounds great. last week i ordered a frontpannel and will post pictures when the unit is finished. at the moment the only question is how to calculate the highpass filter. any ideas?
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on March 14, 2012, 09:43:24 AM
ok great ;-) my stereo mastering net eq is up an running. i used lme49720 opamps. it seems like it sounds great. last week i ordered a frontpannel and will post pictures when the unit is finished. at the moment the only question is how to calculate the highpass filter. any ideas?

wow! great! post pics ASAP (even now would be great)
Did you build it with stepped switches or pots?
I see my board laying on the workbench everytime i walk into my studio and they ask me to be stuffed and ready to work every time i pass them..  ;D
Title: Re: Barry Porter "Net EQ"
Post by: king-rb on March 14, 2012, 03:55:41 PM
i build it with palazzo switches which feels really good. will take pics as soon as i get the backside for the case.
Title: Re: Barry Porter "Net EQ"
Post by: king-rb on March 28, 2012, 04:59:37 AM
ok great ;-) im working with the bp eq a few days now and i like it a lot. sometimes the sontec 430 is better but the combination of both is great. i did some messurements and calculated the hpf frequencys:

mehr - weniger
15Hz - 20k
20Hz - 14k65
25Hz - 11k32
30Hz - 9k17
35Hz - 7k76

hope this will help you.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on March 28, 2012, 05:26:08 AM
Nice!  :)

Now.. time for some pics to get me inspired to start off..
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 06, 2012, 02:27:59 PM
Finally have the time to check things out with the schematic a bit!

I was thinking of doing a stepped stereo version with l and r control with only one knob but i think its better to make a dual mono version since the freq pot for the hi shelf is a 3 gang pot and i think a 6 deck switch in 24 steps will be a bit to much.  :-[
I will use 24 steps switches for the gain so that i don't have to make an extra switch for boost/cut. I think that will work more easy and easier to read out.
Just wondering about the steps for the gain. How are the steps calculated? 1db per step in 10db mode? same for the freq swithces, how are they? The schem i have with the switches are only 12 steps but i want to use 24 steps as well. Just wondering how you did that king-rb? 12 or 24 steps?

King-rb? any news on the pics to get me even more inspired?  ;)
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 08, 2012, 03:31:46 AM
yesterdayevening i started stuffing the boards with parts i had in stock so far. So it will finally happen i think ;-)
I noticed that there is at least one mistake on the overlay that was recently made (don't know by who)
The 2 10r resistors nearest the input opamp are marked as 10k on the overlay instead of 10r so be aware if you use that one.
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on April 08, 2012, 03:49:15 AM
I noticed that there is at least one mistake on the overlay that was recently made (don't know by who)

The board layout and overlay were done by Mr. Porter himself before his death.  He warned in his notes that there may be errors and I've flagged that many times in the Group Buy thread that this board is untested.  It comes with no guarantees.

Gustav took the Gerber and produced the boards without any changes.

Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 08, 2012, 05:04:23 PM
Doing some ordering and i was wondering if 422-6997 from RS is the relays i will be needing for the board since they are a bit different than standard relays.
Also a question concerning the L1 coil of 30uH. What about that? can't really find a source for it. Looks to me like an LC filtering on the input?
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 11, 2012, 08:02:13 AM
knock knock.. king-rb.. you still there or are you too busy playing with your new eq.  :D
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 14, 2012, 02:43:18 PM
also curious about which parts will fit the boards for relays and inductors :) Let's keep this thread going!
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 15, 2012, 11:53:43 AM
also curious about which parts will fit the boards for relays and inductors :) Let's keep this thread going!
I just ordered the relays from RS that i mentioned earlier and they will do the job. Nice and small relays.  8)
I didn't really check for the inductors to be honest but it's just a LC on the input, nothing spectacular.
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 15, 2012, 12:52:54 PM
Thanks :) I have to finish up some API's and u87's before I really get things going, but I'm ordering bits and pieces for it when I place order for repair work. Can't wait to finish it though. My Orban is really flexible but I'd never use it on the master!
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 18, 2012, 09:18:32 AM
Getting there slowely. Boards are 80% stuffed and most of the parts are in. Working on the PSU, just need a board for the +/- 18v with lm337/317.
Now it's time to get working on the stepped switches and the rest.
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 18, 2012, 04:14:34 PM
I'm just going to use the PSUniversal from diypartssupply and not populate the 48V section. I'm deciding on my stepped switches right now. Might as well make this mastering quality.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 20, 2012, 03:14:29 AM
Just wondering about the 100uf and 1000uf caps in the audio path. They should be bipolair according to the schematic but i think that regular elco's will do the job as well don't they? Bipolair caps that will fit from 100 and 1000 are hard to find.
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 20, 2012, 11:28:29 PM
A lot of designs are like this. I've repaired a few pairs of Quested monitors that have these for the same purpose. I've heard everything as a reason. Most often I'm told it's something to do with Linearity of the AC signal.

I'm using these parts:

For 1000uF: http://www.mouser.com/Search/ProductDetail.aspx?R=ECE-A0JN102Uvirtualkey99990000virtualkey667-ECE-A0JN102U

For 100uF: http://www.mouser.com/Search/ProductDetail.aspx?R=UVP1A101MEDvirtualkey64700000virtualkey647-UVP1A101MED

the 100uF is a little under voltage but I think it would be ok there. If not I'll probably have to go polarized too.

The lead spacing on either isn't perfect, but it's close enough where it won't bother me
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 22, 2012, 10:52:01 AM
I was checking out the stepped swithces for the frequencies using out the sheet that Harpo did but than i found out that it's not really easy to convert it from 11 steps to 23 steps, the way i want it.
Gain is no problem and so is q but the frequencies are out of my really bad excell skills.
Anyone? maybe Harpo can hop on?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on April 22, 2012, 12:53:00 PM
Hop (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_24step.xls)  ;D
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 22, 2012, 02:18:36 PM
Harpo, you are a hero!  8)
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 22, 2012, 10:47:54 PM
Very cool Harpo! I guess there is hope for having a stepped attenuator for lift/cut without needing a switch :)
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on April 23, 2012, 07:19:33 PM
latest Hop (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_24step.xls) updated for your +/-dB idea ... ;)
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 23, 2012, 09:34:03 PM
Harpo I am in awe of your skills :) Thank you so much. This project has definitely hit the top of my personal build list!
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 24, 2012, 10:25:42 AM
some progress here:
(https://p.twimg.com/ArQLvjtCIAA60p0.jpg)

Boards stuffed, psu ready (ok.. need to mount it on some cooling), switches coming in this week and than the fun begins  8)
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 24, 2012, 10:14:28 PM
looking good! I don't even have the boards stuffed yet! Is that a three space rack unit? I was wondering about making mine bigger. It's gonna be a tight fit at 2U with all those knobs and switches.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 26, 2012, 01:19:13 AM
yep, 3u it is :)
I will make it fully stereo and with stepped switches it won't fit in a 2u anyway or will at least be really tight.
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 26, 2012, 01:33:38 AM
have you found any good quality/low cost switches? This is gonna become a very long term project if I have to pay 30 bucks a switch
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on April 26, 2012, 09:23:48 PM
30 bucks (for a 2x24 rotary switch?) might already be low cost.
Below listed some manufacturers of >12pos.multideck/pole rotary switches, ask for quote/distributor.... (beware prices might get astronomic...)
electroswitch (http://www.electro-nc.com/productpages/rotaryswitches.shtml)
cole (http://www.cole-switches.com/Products/index.html)
seiden (http://www.tachyon.co.jp/~sichoya2/seiden/index.html)
elma (http://www.elma.com/Americas/English/Products/RotarySwitches_4/SelectorSwitches_30.aspx)
shallco (http://switch-products.shallco.com/viewitems/rotary-switches/rotary-switches-industrial-and-military-grade?)
chiefdom (http://www.e-chiefdom.com/p13.htm)
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 27, 2012, 03:53:34 AM
wow! never seen some of those switches before. Nice to know :)
I have used palazzo switches on my stepped sontec (http://www.dagoosemusic.nl/?p=ultimate-eq) and they are cheap and pretty good actually. Maybe not as good as elma's but they are about 20% of the price of an elma so it's a nobrainer for me. My switches came in yesterday so zen soldering time again  8)
http://www.uraltone.com/kauppa/product_info.php?products_id=1078
I posted somewhere on the board about modding those switches for setting the stoppoint without opening it up. Have to dig it up.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 27, 2012, 03:59:14 AM
found it!  ;D
http://www.groupdiy.com/index.php?topic=40384.msg508467#msg508467
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 27, 2012, 05:08:58 AM
Thanks guys! goose those prices are quite a bit better :) Have to get on this.....
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 27, 2012, 05:28:10 AM
Thanks guys! goose those prices are quite a bit better :) Have to get on this.....
I always buy 'm from that shop in finland but they also show up on ebay, might be cheaper for you since you're from the USA.
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on April 27, 2012, 05:32:11 AM
yup already on that. MUCH cheaper on Ebay. Last time I ordered from Hong Kong it took about a month to get here. Time to hurry up and wait
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 02, 2012, 03:57:42 AM
OK, some serious progress here!  8)
I will fire it up today to see if the boards are doing and to see if the way i did the stepped swithes will do the job they are done right now. 12steps for q, 6 steps for hi-pass (not sure yet) and 24 (23) for gain and freq.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 02, 2012, 03:44:46 PM
OK, some progress here. One of the boards kinda came alive.  8)

I have some strange action going on with the relays which looks like faulty transistors because the ones i had left in stock are powering the relays while the new ones don't seem to do that.. bad batch? have to check... no big issue.
Made 1 Q switch with a switch that i had left but that turned out to be a BBM which is not a good thing (clickedyclick) but i have MBB in already so that will solve it. I only did one switch for testing so no problem, only 12 resistors.
I only tested 1 board with one band (mid) wired with the switches (which i wired in reverse..  :-X) but it's working already which is a nice start.  ;D

More soon!  ;)
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on May 02, 2012, 10:51:21 PM
Good to hear man! I'll be in Colorado for 10 days starting tomorrow. It's gonna suck being away from the studio! But I'll be visiting other studios :P Groupdiy is gonna have to be my tech fix while I'm gone though so keep the progress reports coming!
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 03, 2012, 02:14:56 AM
I was thinking about adding a per band bypass switch and i think that it's just a matter of disconnecting the wiper of the gain to do that. It's the easiest way to do it since i want it to be near the gain on the frontpanel. Any disadvantages doing that?
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 03, 2012, 09:29:05 AM
Ok.. strange.. i had some bc182L's in there and a couple of BC182B and the L version didn't work and the B version is working.  :o
In some kind of way the collector of the L had 7v and didn't go to 0 while the B had 12v and went to 0.
Anyway.. relays are working and so is the midband right now. Curves looking good!  ;D
The only things is that i have about 10db boost and cut while heading for 6db so i have to change some resistors but that is no problem.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 10, 2012, 11:03:09 AM
Only one switch left for soldering and the frontpanel is on it's way. :)
The paper netEQ:
(https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash3/581956_451604584853238_100000111011648_1842551_1830539737_n.jpg)
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 10, 2012, 03:18:49 PM
Just did some testing with RMAA and even though i haven't calibrated yet and it's only 2 bands on 1 channel it sounds great already and the cursves look great and it's deadsilent form the first start. Nice!  8)
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on May 11, 2012, 03:36:53 AM
looks great!
are there no switches for high and low shelf? is it always in shelf, no peak/bell? can´t see it on the frontpanel and it says only low- and high shelf....
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 11, 2012, 04:11:28 AM
looks great!
are there no switches for high and low shelf? is it always in shelf, no peak/bell? can´t see it on the frontpanel and it says only low- and high shelf....

True, no swithes for that.
The thing is that on my sontec i use it 100% in shelf mode and never use the peak mode. Same goes for the highs, shelf only and if i need some peaking in the highs i have a band for that.
Not 100% sure but i think vithalda did the same and he even skipped the highpass filter.
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on May 11, 2012, 10:45:44 AM
ok but can you still use the q for the shelf? i thought the q was only for the peaking and gets disabled when shelf is engaged....
on virthalade´s eq the first q-position on the switch is for shelf it seems.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 21, 2012, 04:17:35 PM
just a little teaser pic, 1 channel 90% done!  ;D
(https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash3/p480x480/576848_459861567360873_100000111011648_1868737_1709174482_n.jpg)
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on May 22, 2012, 03:23:57 AM
GORGEOUS!! is that front panel express then? feel free to share the files :)
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on May 22, 2012, 08:39:54 AM
looks like you have added pushbuttons for the shelves. ;)
Title: Re: Barry Porter "Net EQ"
Post by: detonator on May 22, 2012, 05:23:07 PM
Great work jef.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 23, 2012, 10:17:10 AM
looks like you have added pushbuttons for the shelves. ;)

i did.. drilled extra holes myself when the panel came in.. scary sh*t..  ;D
I loved those buttons so much (have to see 'm in real life) that i thought it needed 8 of those instead of 4.  8)

@detonator: thanks! je bent altijd welkom om een keer te komen checken als je in de buurt bent hoor.
@kpearsall: it's a scheaffer panel. quite expensive, about 200 euro but it looks SO good even though the design took quite some time.
Title: Re: Barry Porter "Net EQ"
Post by: zayance on May 23, 2012, 11:51:28 AM
yes nice little switches, are these "Rafi" brand or NKK, i wanted to use the rafi ones on some builds, kind of cheap"er" i guess compared to NKK, that's what i meant.
Title: Re: Barry Porter "Net EQ"
Post by: detonator on May 23, 2012, 07:06:01 PM
@detonator: thanks! je bent altijd welkom om een keer te komen checken als je in de buurt bent hoor.
Zodra je hem kompleet af hebt, maak ik een gaatje.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 24, 2012, 11:38:47 AM
@detonator: thanks! je bent altijd welkom om een keer te komen checken als je in de buurt bent hoor.
Zodra je hem kompleet af hebt, maak ik een gaatje.
doe maar wel voorzichtig dan, zitten al genoeg gaten in het paneel.  ;D
But cool, you are always welcome to come on over!
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 30, 2012, 03:39:09 AM
all done!
Now i'm in the middle of calibrating it but i was wondering about the input common mode adjust.

The input common mode rejection is set in the following manner:
Apply a 100Hz signal to the input, and monitor the output of the stage at the top of
R11 using either an oscilloscope or AC meter capable of reading down to –80dBu.
Set the input signal level so that it is at +20dBu (7.75V) at the top of R11. Now join
the two inputs together
and apply the same signal to the junction. Adjust P1 for
minimum signal at the top of R11. Change the input signal frequency to 10kHz and
adjust C36 for minimum output. Repeat these steps two or three times to reduce
interaction between the two controls. With careful adjustment, a common mode
rejection ratio of 60 or 70dB should be attainable.


About the joining together; i think they mean that on both the + and - on the input there is a + (or -) signal so that it nulls/cancels? Am i correct?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on May 30, 2012, 05:09:10 AM
yepp.

Ok.. strange.. i had some bc182L's in there and a couple of BC182B and the L version didn't work and the B version is working.  :o
In some kind of way the collector of the L had 7v and didn't go to 0 while the B had 12v and went to 0.
BC182L differ in pinout, compared to BC182B. ;)
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 30, 2012, 05:15:14 AM
Thanks! So my first idea was right. 8)

Pics and things... later on!
I have it racked up in the studio right now and it sounds great! No noise and really nice warm low-end.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on May 30, 2012, 07:16:26 AM
OK.. time to show off!  8)

http://www.groupdiy.com/index.php?topic=48829.0
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on June 27, 2012, 02:05:02 AM
anyone else doing this EQ right now? Just curious.  8)
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on June 27, 2012, 03:32:47 AM
I'm slowly getting my parts together... I've been distracted by microphones. Not having enough mics is a more pressing concern unfortunately. But I got my old job back so I wouldn't think it's too far off in the future :)
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on June 27, 2012, 09:05:44 PM
i ordered almost all parts, still waiting for some to get here and hopefully can start building next week or so  8)
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 03, 2012, 09:47:49 AM
Just another hop (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_24step_2.xls) for the missing stepped highpass filter and shelfing bands ...
Title: Re: Barry Porter "Net EQ"
Post by: kpearsall on July 03, 2012, 10:55:44 AM
haha... Harpo, you are awesome :)
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on July 04, 2012, 11:24:32 AM
@harpo: i hope i don´t ask to much, but is it possible to modify the hi pass to only 6 steps with 15,20,25,30,35 and 40hz?

this would be much more usable in mastering.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 04, 2012, 12:20:30 PM
@harpo: i hope i don´t ask to much, but is it possible to modify the hi pass to only 6 steps with 15,20,25,30,35 and 40hz?

this would be much more usable in mastering.
...there are 3 type of.., those who can count and those who ... ;) ;D
sure about your 5 frequency steps for 6 positions ? You want a linear increase in frequency, not logarythmic 15, 18.25, 22.2, 27, 32.9, 40Hz ?
Keeping C86-C89, values for the P3a and P3b series string resistors would be
3k32, 2k74, 2k21, 1k87, 1k50, 6k98 for prementioned logarythmic increase
or
4k64, 2k80,1k87, 1k33, 1k00, 6k98 for your linear increase.
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on July 04, 2012, 06:12:08 PM
sure about your 5 frequency steps for 6 positions ?

hmm i still count 6 frequencies?

1) 15
2) 20
3) 25
4) 30
5) 35
6) 40

but thank you very much much for all the infos, that´s exactly what i was looking for!  :)
didn´t really thought about linear or logarithmic before, not yet sure which one is better in use and what i´ll go with.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 04, 2012, 10:40:58 PM
> ...to only 6 steps with 15,20,25,30,35 and 40hz?
< sure about your 5 frequency steps for 6 positions ?

hmm i still count 6 frequencies?
...and the 5 steps are from
1) 15 to 20
2) 20 to 25
3) 25 to 30
4) 30 to 35
5) 35 to 40
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on July 04, 2012, 11:40:52 PM
ok got you now  ;)
Title: Re: Barry Porter "Net EQ"
Post by: prescott on July 29, 2012, 08:10:43 PM
Hello!

I'm also building the Eq, almost done...

I make 2 channels with stepped switches.

In the excell sheet there is a lot a description about changing resistors/sorting out if using stepped switches.
Is it possible that my unit is doing crazy thinks just because a have the rotary switches with the original resistor values on the pcbs?

I've seen Dagoose's unit (pics), and he also have those resistors in their place...

So is it before the change, or this is the right way?

Should I change the values/sorting out as written in the excell sheet?

And where can I find the description about the calibrating?

Help me please :-\

Thanks!
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 30, 2012, 05:21:58 PM
In the excell sheet there is a lot a description about changing resistors/sorting out if using stepped switches.
Is it possible that my unit is doing crazy thinks just because a have the rotary switches with the original resistor values on the pcbs?
Depends on your definition of 'the rotary switches' for frequency, Q or boost/cut, which original resistors you are refering to and how your switched pots substitutes connect to pcb.

Quote
I've seen Dagoose's unit (pics), and he also have those resistors in their place...
Jeffrey will know better, but FI the law bending 1K5 resistors (R114,115,111,112,...) at the CCW end of the frequency pots will then be one side connected, doing nothing, when the pots get substituted with the switched string of series resistors. The calc sheet is based on listed values in the calc sheet, so if you FI keep the series resistors (R87,61,83,58,..., these are in parallel to prementioned law benders, connecting to virtual ground and 0V reference voltage, and already part of the series string at the switches), the filters center frequency will be different (FI the previous 2kHz-20kHz range would respond for a 1.528kHz-4.896kHz range instead when you keep the 3K6 resistors R61 and R87 instead of using 0Rs/shorts).

Quote
Should I change the values/sorting out as written in the excell sheet?
Do whatever matches your plan best. This is DIY. There is no hidden formula in the calc sheet, so feel free to come up with different parts values.

Quote
And where can I find the description about the calibrating?
read the 'readme.pdf', partly quoted by dagoose some posts above. ;)
Title: Re: Barry Porter "Net EQ"
Post by: prescott on July 30, 2012, 05:48:31 PM
Ok, first of all thank you for your help!

I think we are on different levels of DIY :)


I've built my unit using the ring resistor list from the sheet, and with the original cap and res values marked on the pcb.
Now it doesnt work fine.

If i change the values on the pcb to values in the sheet will resolve my problem?
example: I have all the ring resistor values from the sheet but i have 2n2 for c84,c61 instead of 6n8...

Is it a problem?


Thanks, and sorry for my beginner questions... :-\
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 30, 2012, 06:36:33 PM
I've built my unit using the ring resistor list from the sheet, and with the original cap and res values marked on the pcb.
Now it doesnt work fine.
At least different.

Quote
If i change the values on the pcb to values in the sheet will resolve my problem?
example: I have all the ring resistor values from the sheet but i have 2n2 for c84,c61 instead of 6n8...
probably 2n2 for c85,c63 instead of 6n8 and series resistors 3k6 for R87,R61 fitted as well, switched resistor strings connecting to the center and right hole of the pot outline, left side hole of pot outline unconnected, resulting in a frequency range of 4.725kHz...15.135kHz. A little different from 2kHz...20kHz, but should work.
(You could overwrite the '0.0068' caps value with '0.0022' and replace the '0' with 3600 in the R87,61 cell for the resulting series string of resistor values needed, but as you already have your switches built, an exchange of caps and shorting out these series resistors might be the smaller evil.)
Your problem more likely will be in a different spot.
Title: Re: Barry Porter "Net EQ"
Post by: mata_haze on August 22, 2012, 05:43:38 PM
Sorry guys, I am trying to get my head around this project and collect data.
is there a BOM, a PDF or something about this at all (apart from the PERFECT HARPO spread sheet).
something with description, calibration or something like this.

also how do you achieve the cutting and boosting switch feature (ala manley)

Mattia.

Title: Re: Barry Porter "Net EQ"
Post by: mata_haze on August 23, 2012, 12:49:08 PM
found the cut/boost option I did not know there was another thread.
still no BOM tho...

Mattia.
Title: Re: Barry Porter "Net EQ"
Post by: protools on August 23, 2012, 02:59:56 PM
Here the BOM...
Title: Re: Barry Porter "Net EQ"
Post by: Biasrocks on August 23, 2012, 06:48:15 PM
That appears to be the preliminary BOM I put together a while ago.

I asked for additional input, none was given.

Hence V0.

Regards,
Mark
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on August 24, 2012, 08:55:10 AM
That appears to be the preliminary BOM I put together a while ago.

I asked for additional input, none was given.

Hence V0.

Regards,
Mark
I used it and found no problem IIRC so go ahead and use it!
Title: Re: Barry Porter "Net EQ"
Post by: mastertaenia on September 02, 2012, 01:42:32 PM
Can dagoose post the plan for the faceplate?
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on September 16, 2012, 03:12:16 AM
Can dagoose post the plan for the faceplate?
No, i'm sorry.. maybe later but not now.
Title: Re: Barry Porter "Net EQ"
Post by: Treelady on October 03, 2012, 12:16:05 PM
Respectfully, mastertaenia why don't you do your own faceplate?  Set things up the way you want them to look.   What if you choose different frequencies?   etc...
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on January 01, 2013, 03:57:59 PM
Any thoughts of where to find the best PSU parts. Will one of the PSUniversal kits suffice for this EQ.
Title: Re: Barry Porter "Net EQ"
Post by: Treelady on January 01, 2013, 04:04:45 PM
Petermontg,

Please put your location (continent or country is fine) in your profile or in your post.  The answer on getting power supply parts (with lower shipping costs) is often tied to where you are and what your local power situation is.

Best, GH
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on January 01, 2013, 04:09:12 PM
I was thinking that alright I am in Ireland Euro psu. Will update now.
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on February 15, 2013, 08:54:48 PM
ok, here´s my BP Eq....almost finished, frontpanel is not done yet.

I got everything working except low and hi peaking bands acting a bit strange...

i get way more boost when i switch from hi-shelf to peak and there´s a loud feedback noise in some positions but only on the left channel hi peak and right channel hi and lo peak.

also with no input, the q on highest setting and gain boost to max, i get some sort of oscillation which follows the selected frequency.
goes away as soon as i switch to shelf, so i´m guessing the high peaking bands are somehow out of their range?
any ideas?

high and low shelves and the normal mid bands working fine.

and the low cut is not working at all, have to check again, only wired one yet...maybe i got the wires reversed

cheers
nils
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on February 15, 2013, 08:55:49 PM
another picture...
Title: Re: Barry Porter "Net EQ"
Post by: Assistant on February 18, 2013, 08:44:03 PM
Ok, i had an 100k Resistor at R 62, where it should be 10k.
i was using the "net eq component overlay" that is floating around here...small typo there!

now the hi peak bands are working correctly!  8)

not sure about the loud noise i get at some positions, i guess the switches are faulty. when i bend it a bit, it goes away.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on February 22, 2013, 05:11:16 PM
Anybody build this with band bypass would be a option I would like to add, before I order my front pate. Details?

Title: Re: Barry Porter "Net EQ"
Post by: petermontg on March 14, 2013, 11:39:20 AM
Any body willing to help me connect switches to the board, am at a loss what goes where.
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on March 15, 2013, 12:27:11 PM
Any body willing to help me connect switches to the board, am at a loss what goes where.

Your rotary switches (if that's what you mean when you say switches) will replace the pots that would normally wire to the board.  You have wiper, the center tap and both ends of the resistor ladder.

Title: Re: Barry Porter "Net EQ"
Post by: petermontg on March 16, 2013, 08:44:25 AM
Any body willing to help me connect switches to the board, am at a loss what goes where.

Your rotary switches (if that's what you mean when you say switches) will replace the pots that would normally wire to the board.  You have wiper, the center tap and both ends of the resistor ladder.

Thanks R. I know that much. Just where do these connect on the board is confusing me. Do I need the overlay.

To which solder point in the given section is what I mean.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on March 16, 2013, 03:58:44 PM
Any body willing to help me connect switches to the board, am at a loss what goes where.

Your rotary switches (if that's what you mean when you say switches) will replace the pots that would normally wire to the board.  You have wiper, the center tap and both ends of the resistor ladder.

Thanks R. I know that much. Just where do these connect on the board is confusing me. Do I need the overlay.

To which solder point in the given section is what I mean.
Peter, you don't need the overlay, but it helps to identify parts. IIRC you built the pot substitutions (dunno if for all parameters A/F/Q) according to my excel sheet.
If for all, P4, P6abc, P7, P9ab, P10, P12ab, P13 and P15abc aren't pots anymore, but switched rheostats.
Have a look at Barrys schematic, the pcb silkscreen, my substitution schematic and my excel file.

FI frequency setting pot P12 for the 400Hz-4kHz range (this is a stereo pot, so you have a variable resistor in section A and another one in section B). The bottom row rightmost pin of the pot P12a (the CW position) connects to U15A-pin1. Instead of the pot you now connect the 1st deck switch pole to this point. The last one side connected resistor (1210 ohm), connecting to your highest switch position (depending on switch maybe pos.12, 23 or 24) connects to the bottom row center pin of P12. The bottom row left side pin stays unconnected. Same goes for the other pot section P12b that gets substituted with the other deck of your switched resistor assembly (switch pole to the right, last step position resistor to center hole, left side hole unconnected). From my excel sheet either jumper R83 and R58 (these are already part of the switched resistors) or fit these last step 1k21 resistors here instead so they don't hang lose on your switches. Don't populate R111 and R112. Use cap values from excel file (IE 33nF for C61 and C84).
Same procedure for the other frequency setting switch asemblies.

FI Q setting mono pot P10. Jumper the right and center hole on pcb and connect switch pole and switch position 1 to this jumper. Last switch position resistor goes to the left side hole. Jumper R110 or fit this last switch position resistor here instead so it doesn't hang lose on your Q switch.
Same procedure for the other Q setting switch asemblies.

FI amplitude setting center tapped pot P11. Rightmost of the 4 holes goes to your +/-0dB probably center switch position on your switch. Switch pin1 goes to the leftmost hole on pcb, switch pole connects to 2nd from left hole and highest switch position connects to remaining 2nd from right hole. You could have a on/off switch between pcb and your switch pole for your wanted band bypass.

Hope this helped a little.
Harpo
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on March 18, 2013, 01:30:00 PM
Thank you Harpo, you are a true gentleman.

I am at the last hurdle so will post back when I am finished, which should be soon.

Thanks again harpo.
Title: Re: Barry Porter "Net EQ"
Post by: Jtransition on March 24, 2013, 01:42:28 PM
Good afternoon everyone I am just collecting info and parts for this build,but I seem to be missing some info,Is there another thread on this eq? so far all searches lead to this one.
My initial questions are;
1,The Bom refers to a doc re R20(input stage) Where can I find this doc ?
2,I am based in the UK. What power supply do you guys recommend ?
3,Will 0.6w resistors run cool enough in this eq?

Thanks
Jason

Title: Re: Barry Porter "Net EQ"
Post by: Gold on March 24, 2013, 02:12:01 PM
3,Will 0.6w resistors run cool enough in this eq?

Unless otherwise noted you can assume that all resistors are 0.25W.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on March 24, 2013, 03:24:16 PM
..,but I seem to be missing some info,Is there another thread on this eq? so far all searches lead to this one.
There are some. Try a search for 'Porter' or 'NetEQ' or 'Net EQ', just to name some. Result will answer your Q1, comming up with a readme.pdf as part of a maybe BarryPorterNetEQ.rar file. Some of the links expired. (R20 is setting gain for domestic low signal level, if so needed. Omit for studio level use).
Quote
2,I am based in the UK. What power supply do you guys recommend ?
A PSU that delivers bipolar +/-18V rails, fed from a dual or center tapped secondary mains transformer whos primary winding matches your local AC mains voltage.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on March 25, 2013, 01:33:00 PM
Jay, PSU I use is based upon LM317/337 Variable reg. If you still need calibration Doc. let me know.
Title: Re: Barry Porter "Net EQ"
Post by: Jtransition on March 25, 2013, 06:03:27 PM
Thanks
More newbie questions to follow :)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on April 13, 2013, 06:59:13 AM
Searching for 2 gang toggle switches to finish. What would be best to use?

Edit: I got this sorted.
Title: Re: Barry Porter "Net EQ"
Post by: protools on April 13, 2013, 07:55:08 AM
The Beast is ready to run!!!http://www.groupdiy.com/Smileys/default/smiley.gif
Title: Re: Barry Porter "Net EQ"
Post by: protools on April 13, 2013, 07:55:48 AM
and here...
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on April 13, 2013, 09:16:55 AM
That's beautiful. Mine is stereo ganged also. What did you use to gang the 6 row Q?
Title: Re: Barry Porter "Net EQ"
Post by: protools on April 13, 2013, 11:12:06 AM
Elma switch.
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on April 13, 2013, 08:16:20 PM
Nice to see all the builds coming online!

Title: Re: Barry Porter "Net EQ"
Post by: dagoose on April 15, 2013, 10:42:02 AM
nice nice nice! another blue BPEQ!  8)
Title: Re: Barry Porter "Net EQ"
Post by: protools on April 15, 2013, 01:01:11 PM
Blue is a must! Just to honour the man.... Barry Porter.
Title: Re: Barry Porter "Net EQ"
Post by: voitto on April 16, 2013, 02:03:15 PM
Harpo,
Little bit of a dumb question sorry -
I'm just putting together a parts list for this and using your spreadsheet for the stepped switches. I'm a little confused by the values in the shelving and hi-pass section. Should the 680nF and 100nF .values for C79 and 80 both be substituted with 0.78uF?

Thanks for making these available!

What have people been using for L1?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on April 16, 2013, 02:27:27 PM
I'm a little confused by the values in the shelving and hi-pass section. Should the 680nF and 100nF .values for C79 and 80 both be substituted with 0.78uF?
780nF is Barrys chosen parts value and guess what 680nF in parallel with 100nF is  ;)
Title: Re: Barry Porter "Net EQ"
Post by: voitto on April 16, 2013, 02:39:45 PM
:D
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on April 17, 2013, 07:09:12 AM
Harpo, Just a quick one. I built your 6db+/- the 0VU does this connect into the point in the section left over from your other post. The third row in both low and high where do these go and where do I connect both shelves and HPF and LPF.

Newbie gold indeed, apologies.

Peter
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on April 17, 2013, 08:53:24 AM
the 0VU does this connect into the point in the section left over from your other post.
uhmmm. from post#118 >>Rightmost of the 4 holes goes to your +/-0dB probably center switch position on your switch.
The drawing in the excel-file right side next to +/-amplitude setting calc-rows should explain it a little as well.

Quote
The third row in both low and high where do these go and where do I connect both shelves and HPF and LPF.
same as for the peaking frequency setting switched resistors. >>switch pole to the right, last step position resistor to center hole, left side hole unconnected.

You'll have to do a little homework by yourself, so groupdiY.com doesn't water down to paint_by_numbers.com.  ;)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on April 17, 2013, 09:24:52 AM
the 0VU does this connect into the point in the section left over from your other post.
uhmmm. from post#118 >>Rightmost of the 4 holes goes to your +/-0dB probably center switch position on your switch.
The drawing in the excel-file right side next to +/-amplitude setting calc-rows should explain it a little as well.

Quote
The third row in both low and high where do these go and where do I connect both shelves and HPF and LPF.
same as for the peaking frequency setting switched resistors. >>switch pole to the right, last step position resistor to center hole, left side hole unconnected.

You'll have to do a little homework by yourself, so groupdiY.com doesn't water down to paint_by_numbers.com.  ;)

Ha! Yea I know. Very grateful for your help.
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on July 12, 2013, 04:12:00 AM
Just wondering what would be the benefit of the lowpass filter (LC) on the input.
Title: Re: Barry Porter "Net EQ"
Post by: jplebre on July 12, 2013, 05:21:37 AM
Just wondering what would be the benefit of the lowpass filter (LC) on the input.

only thing I can think of is if it's set to something like 20Hz for mp3 encoding but...
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 12, 2013, 06:51:51 AM
Just wondering what would be the benefit of the lowpass filter (LC) on the input.
Keeping RF out.

only thing I can think of is if it's set to something like 20Hz for mp3 encoding but...
Operating range of this EQ limited between >0Hz ... 20Hz would make this EQ useless.

This is a L/C filter, cutoff is @ 1/(2*PI() * SQRT(L*C)) with L in Henry and C in Farad.
With given values 30uH for the common mode choke and 100pF for the caps, this LFP is set @ 2.9MHz.
Title: Re: Barry Porter "Net EQ"
Post by: jplebre on July 12, 2013, 07:12:37 AM
Blue is a must! Just to honour the man.... Barry Porter.

Sorry I misread. I confused dagoose post with this picture where there's a low-cut not low pass
disregard
Title: Re: Barry Porter "Net EQ"
Post by: dagoose on July 12, 2013, 08:05:41 AM
Just wondering what would be the benefit of the lowpass filter (LC) on the input.
Keeping RF out.

only thing I can think of is if it's set to something like 20Hz for mp3 encoding but...
Operating range of this EQ limited between >0Hz ... 20Hz would make this EQ useless.

This is a L/C filter, cutoff is @ 1/(2*PI() * SQRT(L*C)) with L in Henry and C in Farad.
With given values 30uH for the common mode choke and 100pF for the caps, this LFP is set @ 2.9MHz.
Thanks! Didn't really check the frequency myself, i'm bad at math but my guess was something like 100khz. It's way higher then I expected it to be.  8)
Just wondering why the BPEQ has it, and let's say any other EQ doesn't?
Title: Re: Barry Porter "Net EQ"
Post by: skal1 on August 18, 2013, 07:31:26 PM
ok  lads be looking at the porter eq for a whille , i was just wondering how many banks are need for each pot of the eq.

cheers

skal
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on August 23, 2013, 04:33:58 PM
it's all in the schematic Skal.  Freq is two deck, level and Q are single deck.

You'll want to build it with switches, not pots.  No need for 24 freqs per band, 12 is plenty. 

Title: Re: Barry Porter "Net EQ"
Post by: skal1 on August 25, 2013, 07:02:46 PM
R , i see it now, p9-a and p9-b is a dual pot yes.

skal
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on August 26, 2013, 09:08:21 AM
R , i see it now, p9-a and p9-b is a dual pot yes.
..as well as P12a/P12b.
There is also P6a/P6b/P6c and P15a/P15b/P15c. Same pot values, but 3-deck for the peaking or shelfing HF- and LF band.
P3a/P3b wants a rev.log.taper with differing from other pots parts value for the highpass-filter.
When substituting these frequency setting pots with switches, the attached resistors will not be all the same. Just sayin...
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on August 26, 2013, 07:05:30 PM
Skal,

If you're considering building this I'd look at simplifying things.  I'm not sure the shelves are necessary and a software HPF will work well for you. 

Cheers,
Ruairi
Title: Re: Barry Porter "Net EQ"
Post by: skal1 on August 27, 2013, 07:12:04 AM
yeah i was thinking that myself ,of ditching  the lf/hf shelf band sections, but that leads me to not having a clue about which frequencies to choose for the peaking bands .

I have seen the prism eq , and that seems to have  lots of frequency chooses , but are they need?


so i thing ithe best thing for me to do is research about the most useable frequency for a mastering eq.



skal
Title: Re: Barry Porter "Net EQ"
Post by: skal1 on August 28, 2013, 06:23:49 PM
harpo if i do not want to use the shelf , could i leave  P6a/P6b/P6c and P15a/P15b/P15c ?, this will make the frequency 2 deck yes.

cheers

skal
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on August 28, 2013, 07:13:45 PM
harpo if i do not want to use the shelf , could i leave  P6a/P6b/P6c and P15a/P15b/P15c ?, this will make the frequency 2 deck yes.
Keep P6a/P6b and P15a/P15b or substitute with 2 deck switched resistors for the peaking LF and HF bands.
You leave out the parts for the "c" connecting section, IE:
Don't fit C77,C81,C52,C38,D4,K4,LED3,P15c,Q4,R91,R54,R35,R38,R116,S3,U8 and jumper (or switch for band bypass) K4-pins2/3 for leaving out the HF shelf.
Don't fit C79,C80,C45,C37,D3,K3,LED2,P6c,Q3,R78,R50,R34,R36,R103,S2 and jumper (or switch for band bypass) K3-pins2/3 for leaving out the LF shelf.
Title: Re: Barry Porter "Net EQ"
Post by: skal1 on August 28, 2013, 07:51:29 PM
nice mate


skal
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on August 28, 2013, 10:23:17 PM
so i thing ithe best thing for me to do is research about the most useable frequency for a mastering eq.

The best thing to do is lots of mastering before committing to something in hardware.  Then you'll know what you need. 

When picking frequencies think in terms of octaves.  I could easily live with 12 steps per band on a 4 band eq if they are spaced correctly.

Title: Re: Barry Porter "Net EQ"
Post by: dirtyhanfri on August 29, 2013, 02:41:46 AM
Is there any chance to get a layout for this board for home etchers?

BTW nice build protools, and thanks for the uraltone link I didn't know that shop, but looks nice
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on August 29, 2013, 02:29:47 PM
The original Porter layout is double sided, not very home etch friendly.  There were gerbers only.

Title: Re: Barry Porter "Net EQ"
Post by: dirtyhanfri on September 03, 2013, 04:00:48 AM
The original Porter layout is double sided, not very home etch friendly.  There were gerbers only.

Ok, then I will make a order to pcbgrinder, thanks for the info
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on September 03, 2013, 04:52:27 AM
No problem, I think Gustav's boards are great value and they have been built by several people without issue.  I spent the late evening studying a 2x4 foot printout of the Porter schemo while sipping 10 year old Laphroaig Cask Strength.  Very enjoyable!

Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 09, 2013, 07:09:13 PM
but FI the law bending 1K5 resistors (R114,115,111,112,...) at the CCW end of the frequency pots will then be one side connected, doing nothing, when the pots get substituted with the switched string of series resistors. The calc sheet is based on listed values in the calc sheet, so if you FI keep the series resistors (R87,61,83,58,..., these are in parallel to prementioned law benders, connecting to virtual ground and 0V reference voltage, and already part of the series string at the switches), the filters center frequency will be different (FI the previous 2kHz-20kHz range would respond for a 1.528kHz-4.896kHz range instead when you keep the 3K6 resistors R61 and R87 instead of using 0Rs/shorts).

Harpo, can You explain more about this?
When keeping (R114,115,111,112) and also (R87,61,83,58) the full CW is right:
1/(2*PI()*SQRT((3600)*22E-08*(3600)*22E-08)) = 20095.32

But I don't understand how to calculate the R value in the middle and in the full CCW  :(

Thank You.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 10, 2013, 11:58:21 AM
When keeping (R114,115,111,112) and also (R87,61,83,58) the full CW is right:
1/(2*PI()*SQRT((3600)*22E-08*(3600)*22E-08)) = 20095.32

But I don't understand how to calculate the R value in the middle and in the full CCW  :(
You are mixing up Barry's schematic and parts values (using a 10k lin pot and 2 resistors in a Wye-config) with my adaption for a single stepped series resistor.
As Barry suggested in his readme file "If reverse log pots are used for the frequency controls, they should be wired in series with the resistors feeding the integrators, and the resistors to ground omitted. The integrator capacitors will need to be re-calculated,..", my Excel files are based on this variable series resitor and re-calculated cap value.
If you want to keep Barry's parts fitted in place and only substitute the 10K lin pot, read on wye-delta transformation to get the needed step values (your '3600' is the simplified minimum result value with the pot in CW position). The needed resistor value still is 1/(2*PI()*freq*C, and keeping Barry's 2n2 cap value, the effective resistor value will be varying between 3600 and 37600 ohm for Barry's range 1924Hz .. 20095Hz.
Title: Re: Barry Porter "Net EQ"
Post by: Bonsaimaster on October 10, 2013, 04:33:29 PM
I hope to get some help before starting this project. Sorry for the newbie questions but I have tried to collect all the data that is out there. But some missing pieces do exist. Any help would be great!

Will be purchasing two Barry Porter NETEQ boards for a Dual mono unit from PCB Grinder.

Will use PCB 1815 to power the two boards. I will be building a USA version and need suggestion for a 2x18V toroidal transformer. Can I use this Dual Primary (115V/230V) Toroidal 2X25 30VA Power Transformer?

http://www.hairballaudio.com/shop/product_info.php?cPath=33&products_id=37

I will provide all the information I get or have to anyone.

1. The "current" BOM and board overlay seems to have some mistakes. I am trusting the schematic on this one. Please any corrections welcomed.
Ex.
Board overlay shows
R6-10K
R7-10k

Schematic shows
R6-10R
R7-10R

2. Can someone verify the BOM I made.
http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=7cd513ac77
I have not included the R500 and the NE 5322 they will come from other sources.
I have swapped out resistors and caps as per HARPO excel sheet so I can use rotary switches.

3. I am unable to find a source for a 10-47pf variable capacitor. Any suggestions?

4. Does anyone have suggestions for rotary switches? My possible suggestions included.
For the
Q Band
http://www.ebay.com/itm/180931177387
1pc,1 pole 12 positions PCB Rotary switch NEW,1P12L

FREQ
http://www.ebay.com/itm/251292325032
2pole 24 step Rotary Switch Attenuator Volume Control DIY Pot Potentiometer New

FREQ with selfing
I have no source

GAIN
http://www.ebay.com/itm/251292325032
2pole 24 step Rotary Switch Attenuator Volume Control DIY Pot Potentiometer New

HIPASS
http://www.ebay.com/itm/170880281315
1,2 pole 6 positions PCB Rotary switch NEW,2P6L

I don't know much about rotary switches. Therefore excuse my ignorance if these suggests are wrong.

5. Will be using switches for bypassing each channel should I use (sorry newbie questions) DPDT ON-ON?

6.
Any suggestions on how to wire the bypass switch for each channel?

Thanks for any help in advance!
Title: Re: Barry Porter "Net EQ"
Post by: voitto on October 10, 2013, 04:50:30 PM
I was able to find the trimmer capacitors from http://www.banzaimusic.com/Trimmer-Caps/
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 10, 2013, 06:47:14 PM
..but I don't realize about Wye Delta in Barry Schematic, Thank You for pointing that, my newbie common stupidity  ;D, I still build using Your calculator but need to know how Mr. Barry calculate this filter.
Maybe some 'hops', but not the final version and looking at another forum building a commercial version from Barry's work, I won't share this file.
From his readme file Barry used a simulator to get the results. He could have calculated it as well this way (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_Wye-Delta.xls).
(Part numbers used are related to your last question for the 2K..20K band)

Quote
And about the shelfing, from the schematic it doesn't have any relation with peaking band right? So if I using 2 deck for peaking freq and switch to another 1 deck for shelf freq it will be OK?
As drawn in Barry's schematic and using lin.pots, the peaking and shelfing bands have no relation and will have different cutoff points at same pots rotation angle (he already said so in his readme file). Using switched resistors you can build them for same cutoff point for correct frontpanel labeling.
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on October 11, 2013, 06:50:43 AM
Hi Bonsaimaster,

1. The "current" BOM and board overlay seems to have some mistakes. I am trusting the schematic on this one. Please any corrections welcomed.
Ex.
Board overlay shows
R6-10K
R7-10k

Schematic shows
R6-10R
R7-10R

I will buy both value and try, but I prefer the value on the schematic (10R)



10R (as in the schematic) is the right value.
Title: Re: Barry Porter "Net EQ"
Post by: Bonsaimaster on October 11, 2013, 02:44:27 PM
Thanks for the info. Very helpful. Can I use a 4 pole 24 step switch for the high shelf?

Also I got the excel spreadsheet for wiring the pots. However, I am unclear on the 2 pole pot wiring. Does anyone have a picture of one?

Thanks
Bonsaimaster
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 11, 2013, 05:09:51 PM
Hi Bonsaimaster,
yes You can use 4P 24S for the high freq selector, and please see the post by Harpo in page 6 for the wiring.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 12, 2013, 02:13:55 PM
5. Will be using switches for bypassing each channel should I use (sorry newbie questions) DPDT ON-ON?

6.
Any suggestions on how to wire the bypass switch for each channel?

I'm not sure, but I will trying the same thing and using SPDT ON-ON using Harpo Calculator last bottom in the spreadsheet and switch the wiper out from the circuit but if You build using Harpo sheet that use all step for boot or cut rotary switch gain, You will need rotary 2P3P (2P: ground and wiper, 3P: boost, cut, bypass).

Hope that will help.

Thank You.

Edited, see the bold section.

Also I just thinking about toggle 3PDT/4PDT also can be use (ala MANLEY Massive Passive) but make sure the switch is have On-Off-On configuration for taking out the wiper.

Thank You.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 13, 2013, 04:51:38 AM
Harpo,
could You please explain the formula for Q from original schematic?

I try to analyze from Your excel file
=(1/(1/(D$218)+1/(SUM(K$218:K218)+G$218))+E$218)/(2*(1/(1/(D$218)+1/(SUM(K$218:K218)+G$218))))

but still don't have clue and cannot find the right number.

Thank You.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 14, 2013, 06:38:21 AM
 ??? is this some kind of a trick question or an Excel question ?
just picking one band, Q=(R99 || (P4+R104)+R95) / (2(R99 || (P4+R104)))
As already said, P4 isn't a pot but a variable resistor/rheostat with wiper and CW position joined to the opamps non-inverting input.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 14, 2013, 07:54:55 AM
Hi Harpo,
it's more on excel question, actually my question is how ro calculate the q of the state variable filter  :)
I cannot find the formula and try to analyze from Your excel table, but still don't find the right formula.
Most of the SVF input is on the inverting amp and feed back to the non inverting that also controlled the Q, but BP using non inverting input and Q control, so how is actually the Q formula for the SVF?

And in the BPEQ if I take out the rheostat connection, is that correct that the Q calculation will be using wye configuration again (like in the attached picture)?

Thank You.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 14, 2013, 10:33:18 AM
Harpo,
maybe the previous pic in my post is not clear, so I just draw and is that correct:

Q=(((R99+RU||(RL+R104))+R95)/(2((R99+RU||(RL+R104)))

RL is Lower Section of P4
RU is Upper Section of P4

edit: I just read Barry articles in ETI and the equation is the same, just different placement, of the pot but if I calculate using Barry choosen value the Q range is not 1 to 3 but 1.169 to 0.928 and that confusing me  ???
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 17, 2013, 05:50:12 PM
With regards to switches, don't skimp ;)

http://www.goldpt.com/prices.html
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 17, 2013, 07:19:02 PM
With regards to switches, don't skimp ;)
2 pole 34 pos or 2 pole 46 pos shorting with adjustable tension for the click stops  ;)
http://www.partsconnexion.com/SEIDEN-74750.html (http://www.partsconnexion.com/SEIDEN-74750.html)
http://www.partsconnexion.com/SEIDEN-74751.html (http://www.partsconnexion.com/SEIDEN-74751.html)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 18, 2013, 05:18:37 AM
With regards to switches, don't skimp ;)
2 pole 34 pos or 2 pole 46 pos shorting with adjustable tension for the click stops  ;)
http://www.partsconnexion.com/SEIDEN-74750.html (http://www.partsconnexion.com/SEIDEN-74750.html)
http://www.partsconnexion.com/SEIDEN-74751.html (http://www.partsconnexion.com/SEIDEN-74751.html)

Wished I'd known of those Harpo. Cheers for that :'(

I used the 6 row Elma for stereo ganged. So I used all the Elma goldpoint.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 19, 2013, 07:00:01 AM
Hi,
from Barry schematic, if I want to implement bypass switch for each band, what is the most ideal way to take out the filter?

I have drawn a circle in the attached schematic for 1 band including the shelf.
1. On gain wiper only is enough
2. On Input of each filter including the shelfing of each band if available
3. Both of point 1 and 2

And the drawback, like DC noise from switching toggle switch????

Thank You and any reply will be very appreciated
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 19, 2013, 01:29:25 PM
1. On gain wiper only is enough
This. The other options change connected load to the driving stage.
Quote
And the drawback, like DC noise from switching toggle switch????
C55/R63, C34/P14 and C24/P14 already bock DC. Switching AC might cause a pop, depending on snapshot moment.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 20, 2013, 06:46:15 PM
Anybody here know why in the BOM in the high filter section, C8, C9, C23, C24 are using electrolytic bipolar but have (Film) mark? Is that means I must bypass with film cap there? And why only in the high filter section?
Typo/whishful thinking and wrong section label ? (try to source 1000uF film caps and -if you doubtfully could get them- make these fit on pcb/inside your 19" box. The 6.3 voltage rating isn't a film cap rating as well).
For your bypass question a single pole 3 throw for boost/bypass/cut at wiper position should be enough. If needed at all, two permanently connected maybe 100K resistors between rails boost/gnd and cut/gnd will keep C23 and C24 at reference voltage for your stepped 5K level switches for the case, all boost/bypass/cut switches are at the same setting.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 21, 2013, 05:45:54 AM
..at some point I have some thinking & feeling that it's not a typo but intended by Mr. Barry Porter..
The .V0 BOM isn't from Barry and there isn't even a placeholder on pcb for these caps.
http://groupdiy.com/index.php?topic=33256.msg628044#msg628044 (http://groupdiy.com/index.php?topic=33256.msg628044#msg628044)
The DC offset blocking 1000uF caps set a HPF with FI the paralleled 10K center tapped level setting pots. Your -maybe fitted from traceside- paralleled 33nFs and ignoring parts tolerances will give a 1000.033uF cap on paper..., but you could always try it (a croko-clip might come handy for an A/B test) and listen to the result.
Title: Re: Barry Porter "Net EQ"
Post by: assrael on October 21, 2013, 03:44:50 PM
Hi,

I’m planning to build a NetEQ. After thinking about some build options I’m thinking about to make my one with separate controls for the shelving bands.
That means 4 bands of peaking filters, 2 bands of shelving filters and the high pass filter for one channel. This would be at least a unit with 4U in height.

Has somebody built such a version? Do you think that this is useful? Some concerns about that?

Greetings,
Assrael
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 21, 2013, 05:50:47 PM
Hi,
I’m planning to build a NetEQ. After thinking about some build options I’m thinking about to make my one with separate controls for the shelving bands.
That means 4 bands of peaking filters, 2 bands of shelving filters and the high pass filter for one channel. This would be at least a unit with 4U in height.

Do You mean it will be 6 band both the shelving and peaking can be boost/cut simultaniously? I think no one try that yet but looks like that possible  :)
Title: Re: Barry Porter "Net EQ"
Post by: assrael on October 22, 2013, 02:49:22 PM
Yes, per channels a low shelf and a high shelf with separate gain and frequency control and four bands of peaking filters with separate gain, frequency and Q control.
It should be not that difficult to do this. Omit the relays K3 and K4 and go from the shelving circuit via a 2k2 resistor directly to an addition frequency pot/rotary like on the peaking bands. Also an additional frequency pot/rotary is needed for full control. Take a look on the schema and you will understand it.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 25, 2013, 07:24:02 AM
Hi,
for the space and lead spacing that allowed consideration, which one is better for bypass cap:

higher voltage X7R
or
lower voltage NP0/C0G

example: 220nF 100V X7R vs 220nF 50V C0G/NP0

Thank You
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 25, 2013, 09:30:45 AM
When in doubt, use same or higher voltage rating than the bypassed cap, IE >=6.3V for bypassing the 1000uF bipolar caps in question (if bypassing is needed at all).
C0G/NP0 is the better/more temperature stable dielectric.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on October 25, 2013, 10:12:32 AM
Hi Harpo,
it's for the transistor coupling C10-C29-C37-C38, sorry for my mistake  :D so which one do You prefer, X7R with higher voltage or NP0 with lower voltage? And also is that OK if I replace the C19-C20-C21-C22 with Non Polar type?

Thank You.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 25, 2013, 11:16:56 AM
...X7R with higher voltage or NP0 with lower voltage?
already told you (worst case 12V relais supply voltage across the cap, and doesn't really matter in this spot, so the cheaper one will do as well).
edit: BTW 220nF isn't a c0g/np0 parts value. These are in the pF range.
Quote
And also is that OK if I replace the C19-C20-C21-C22 with Non Polar type?
Why would you want this ? (at best similar performance with bigger parts size at higher cost).
As always YMMV.
Title: Re: Barry Porter "Net EQ"
Post by: Nescafe on December 29, 2013, 01:04:14 PM
Yes, per channels a low shelf and a high shelf with separate gain and frequency control and four bands of peaking filters with separate gain, frequency and Q control.
It should be not that difficult to do this. Omit the relays K3 and K4 and go from the shelving circuit via a 2k2 resistor directly to an addition frequency pot/rotary like on the peaking bands. Also an additional frequency pot/rotary is needed for full control. Take a look on the schema and you will understand it.

Paul Gold have try this, check this link, post no. 40 http://www.gearslutz.com/board/mastering-forum/732670-barry-porter-neteq-2.html
Title: Re: Barry Porter "Net EQ"
Post by: assrael on December 29, 2013, 03:49:50 PM
Hi Nescafe,

Sampa wrote in an German forum, that the load of the gain stage has to be recalculated if there are these two additional shelving bands. That makes sense to me, but I cannot give any detailed information, because I don’t know the math behind.

Here is the Link to this German thread (#280):
http://recording.de/Community/Forum/Recording_und_Studiotechnik/Do-It-Yourself_%28DIY%29/176376/Thema_14.html (http://recording.de/Community/Forum/Recording_und_Studiotechnik/Do-It-Yourself_%28DIY%29/176376/Thema_14.html)
Title: Re: Barry Porter "Net EQ"
Post by: prescott on February 06, 2014, 05:59:28 AM
Can u guys please help me in the pots....

What type is the 3 gang pot?
Of course I have the BOM, but its a 4 gang pot with switch on it, not a 3 gang type.

How can I use it?

Is it possible to use a dual pot for the bell frequencies, and a single for the shelvings?
Will that work?

thanks!
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on February 06, 2014, 08:45:28 AM
Of course I have the BOM, but its a 4 gang pot with switch on it, not a 3 gang type.
"The BOM" from Mark (not Barry) was partly confirmed by dagoose (AFAIK his build didn't contain a single pot but switched rheostats). PCB layout seems to be for Vishay/Sfernice series P9 conductive plastic potentiometers.

Quote
Is it possible to use a dual pot for the bell frequencies, and a single for the shelvings?
Yes, with the additional advantage of having the oportunity to scale the frequencies more correct, IE the pot(s) at same rotation angle will give different bell/shelf frequency responses. Keep in mind, potentiometers might come with up to +/-20% parts tolerances.
Title: Re: Barry Porter "Net EQ"
Post by: prescott on February 07, 2014, 06:27:44 AM
Thanks!

Finally I made it with rotary switches like for the first time, but now I found what was wrong at first!

Some wires changed....  :)
Title: Re: Barry Porter "Net EQ"
Post by: prescott on February 07, 2014, 06:52:52 AM
Harpo, can you please tell me where can I find your hop that has the 12 step Q?

I made the switches about a year ago, and now I dont find the source:)

thanks!
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on February 07, 2014, 08:23:03 AM
Harpo, can you please tell me where can I find your hop that has the 12 step Q?
this (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ.xls) 1st.version ?
Title: Re: Barry Porter "Net EQ"
Post by: prescott on February 09, 2014, 08:44:21 AM
Yes, thanks a lot!
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on March 20, 2014, 05:04:46 PM
Another one done...

(http://i60.tinypic.com/2m5kkrt.jpg)

(http://i57.tinypic.com/9ssa3q.jpg)
Title: Re: Barry Porter "Net EQ"
Post by: 3nity on March 20, 2014, 06:26:07 PM
WOW!
thats one build that makes me wanna build this eq!
Looks really well done!
Title: Re: Barry Porter "Net EQ"
Post by: kante1603 on March 21, 2014, 01:48:32 AM
Very nice looking (and I bet sounding) eq indeed!
Congrats!

Udo. 8)
Title: Re: Barry Porter "Net EQ"
Post by: druu on March 21, 2014, 08:34:26 PM
I'm just about to start building mine, can someone suggest a choke/inductor for L1 that fits the PCB?

Thanks.
Title: Re: Barry Porter "Net EQ"
Post by: skal1 on April 24, 2014, 11:36:57 AM
do the switches need to be shorting type or can i use no shorting for freq,Q and atten/boost .

cheers

skal
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on May 29, 2014, 06:15:27 AM
I'm in the process of preparing for this build... First time building stepped pots and actually first project I've looked at that is based on multi deck pots.
Probably a naive question here so humour me, but what's the deal with the dual gang and triple gang pots as outlined in Barry's original layout (I know I'll be substituting these with switched rheostats..)
For a mono channel why the requirement for dual/triple gang on the freq bands ? Usually id only seen dual gang pots used in a stereo application. I'm looking at building a dual mono build but I want to get my head around the original design first... Thanks guys
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on May 29, 2014, 09:58:01 AM
For a mono channel why the requirement for dual/triple gang on the freq bands ? Usually id only seen dual gang pots used in a stereo application. I'm looking at building a dual mono build but I want to get my head around the original design first...
For the frequency setting pots/rheostats one gang only for the high and low shelfing bands and dual/stereo gang pots/rheostats for all peaking bands. (Using stepped rheostats, the resistor values would better be different between shelfing and peaking bands to match with the frequency frontpanel labeling). In a stereo build and from Barrys schematic, this would be a 6-gang pot/rheostat for the low and high band and a switch to either operate these shelfing or peaking. Your dual mono unit would either have 4 triple gang rheostats for peaking or shelfing adjustment or have seperate knobs for peaking (4 x stereo/dual gang) and shelfing (4 x mono/single gang) adjustment. Both mid bands only use dual/stereo gang pots/rheostats for frequency selection.
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 19, 2014, 11:03:12 PM
I'm trying to decide to either use 3PDT toggle for switching bands in/out plus LED indicator or should I use a relay based solution? Any suggestion here?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on June 20, 2014, 05:50:18 AM
Andrew, 3P toggle for stereo bands+LED, 2P toggle per mono band+LED. Single throw is sufficient but DT is probably easier to source. A relay based solution at least needs a SPST switch+1 or 2 pole relay+flyback diode. For lesser stressing switch contacts from inrush current maybe use the relay activating transistor circuit as shown in Barrys HF-shelf/peak or LF-shelf/peak bands, HP-filter or EQ bypass circuit. An On-Off-On toggle could switch between different min/max amplitude settings (+/-5dB or +/-10dB or whattheheckelsedB) with band bypass in the toggles center position.
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 20, 2014, 07:49:41 AM
Thanks Harpo! I forgot to mention this will be for a stereo control unit so I'll try source a 3PST first if I can. The relay based solution definitely seems more elegant but I'll try for simple first. Thanks!
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on June 20, 2014, 12:40:52 PM
Id like to try doing these switches stepped, but Harpo's great work is confusing me. I only see one value going over the switch on each function in the calculator, but several values and multiple decks used on the actual builds. What am I not understanding? Could someone help me get started?

I have a bunch of these https://pcbgrinder.com/image/cache/data/Switches/2x23-500x500.gif
And these https://pcbgrinder.com/image/cache/data/Switches/4x23-500x500.gif


Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on June 20, 2014, 02:49:54 PM
Gustav, you've seen post#118 from this thread?
Your question is probably related to frequency selection. Parts values are for each deck, IE 2 decks for each bandpass filters per chanel needed to substitute the stereo pots such as P12a and P12b, 4 decks for single knob stereo operation. For the optional shelfing bands, shelf values (differing from peaking) in separate section for the 3-deck (or 6-deck for stereo) pots 'c' deck.
Column 'F' calculates the resistive value needed with corresponding cap value in column 'E' for wanted center frequency in column 'D'. Column 'J' shows the switched adding up series string of resistors to get close to this target value, IE for switch step 20 in the 2kHz...20kHz section (14.8kHz), the 1K580 value needed is the series string of 1K18+113R+137R+150R.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on June 20, 2014, 11:18:40 PM
Gustav, you've seen post#118 from this thread?
Your question is probably related to frequency selection. Parts values are for each deck, IE 2 decks for each bandpass filters per chanel needed to substitute the stereo pots such as P12a and P12b, 4 decks for single knob stereo operation. For the optional shelfing bands, shelf values (differing from peaking) in separate section for the 3-deck (or 6-deck for stereo) pots 'c' deck.
Column 'F' calculates the resistive value needed with corresponding cap value in column 'E' for wanted center frequency in column 'D'. Column 'J' shows the switched adding up series string of resistors to get close to this target value, IE for switch step 20 in the 2kHz...20kHz section (14.8kHz), the 1K580 value needed is the series string of 1K18+113R+137R+150R.

I think/hope part of my brain-short was not realizing, that for a dual pot with identical resistance paths on both tracks, the resistors on the switch should, of course, be identical too, which means they are only shown once in the table.

No replacement for trying, which I will do.

Thanks!

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 21, 2014, 04:30:43 AM
Gustav, just to note that the switches you posted are 23 step but Harpo's spreadsheets are based on 24 step switches. You'll need to adjust the tables to suit if you're using 23 step (I reduced mine to 21 step quite easily).
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on June 21, 2014, 07:32:01 AM
Gustav, just to note that the switches you posted are 23 step but Harpo's spreadsheets are based on 24 step switches. You'll need to adjust the tables to suit if you're using 23 step (I reduced mine to 21 step quite easily).

Thanks for the heads up. I did notice, and I was actually planning to blow off a step and labeling the unit "2K2 - 20K" and so on accordingly, and depending on which step I left out :)

If its not rocket science, Ill give the recalculation a shot leaning on Harpo's sheet.



Gustav
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 21, 2014, 08:27:00 AM
No problem. :) It's as easy as changing "...(24-1)..." to "...(21-1)..." in the original formula. Hope that makes sense!
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 21, 2014, 08:32:13 AM
Andrew, 3P toggle for stereo bands+LED, 2P toggle per mono band+LED. Single throw is sufficient but DT is probably easier to source. A relay based solution at least needs a SPST switch+1 or 2 pole relay+flyback diode. For lesser stressing switch contacts from inrush current maybe use the relay activating transistor circuit as shown in Barrys HF-shelf/peak or LF-shelf/peak bands, HP-filter or EQ bypass circuit. An On-Off-On toggle could switch between different min/max amplitude settings (+/-5dB or +/-10dB or whattheheckelsedB) with band bypass in the toggles center position.

Update: I think I may go for the relay based solution. I've just realised I'm having the first steps of the High and Low bands to be 'Shelf' switches with an LED indicator so I kinda forced to use relays.

Harpo, i have a bunch of these (http://au.element14.com/te-connectivity-axicom/d3202/relay-signal-dpdt-12vdc-2a-tht/dp/2357304?Ntt=axicom+d3202) sitting in my spares, can I simply use these in conjunction with 1N4148 protection diodes across the coil? I was hoping to put seven of them on some proto board for switching functions. Thanks in advance.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on June 21, 2014, 10:17:08 AM
No idea what your 'the first steps of the High and Low bands to be 'Shelf' switches' might relate to.
You are aware, your Axicom relays have a different pinout and different pin spacing than the NetEQ pcb calls for ?
Additional 7 relays * 12V/1028R coil resistance + 7 LEDs with maybe 1K current limiting resistor each = about additional 150 mA load. Better attach a heatsink to your onboard 7812 voltage regulator if this Vreg should supply this additional load. Relays default setting probably set for band engaged and LED indicating band bypass with relays coil powered. YMMV.
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 21, 2014, 07:23:59 PM
To elaborate, my Q rotary switches I will have the first step position as Shelf selection, hope that makes more sense.

I was hoping to have the relay default position set for band disengaged as I have the LED as an enabling indicator on my front panel. Will that be an issue? I can install a heatsink on the 7812 no problem, or I may opt to only use the relay solution for the shelving selection and use 3PDT toggles for the band selection. Thoughts here?

BTW, yes I'm aware the relays linked are different. I have already populated the netEQ boards as per the BOM, the additional relays will be on a separate pcb. Thanks again for the 101 :)
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on June 21, 2014, 10:10:14 PM
To elaborate, my Q rotary switches I will have the first step position as Shelf selection, hope that makes more sense.
Your 'first steps' plural wording was the confusing part.

Quote
I was hoping to have the relay default position set for band disengaged as I have the LED as an enabling indicator on my front panel. Will that be an issue?
From Omron datasheet:
>>>Long term continuously On contacts
Using the relay in a circuit where the relay will be ON continuously for long periods (without switching) can lead to unstable contacts because the heat generated by the coil itself will affect the insulation, causing a film to develop on the contact surfaces. Be sure to use a fail-safe circuit design that provides protection against contact failure or coil burnout.<<<
Do whatever you like best, but know your enemy ('long period' is a relative term and when you know the absolute duration of 'long period' you have it exceeded).
Quote
I can install a heatsink on the 7812 no problem, or I may opt to only use the relay solution for the shelving selection and use 3PDT toggles for the band selection.
Other than sourcing/fitting 3PDT toggles instead of SPST toggles with remote relays I can see no real advantage of relays here. The peak/shelf relays are already on board.
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 21, 2014, 10:22:41 PM
Thanks Harpo, I guess I figured the LED indication would be a nice touch but you do have a point. :)

I'll keep it simple and go ahead and remove the LED indication for the Shelf selection from my front panel design which will simplify things and just use the 3PDT switches I've sourced. Cheers!
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on June 21, 2014, 11:27:59 PM
I'll keep it simple and go ahead and remove the LED indication for the Shelf selection from my front panel design which will simplify things and just use the 3PDT switches I've sourced.
So pole and pin1 of the 3rd deck of your LF and HF Q switch connect to S2 and S3 and LED2 and LED3 show up for the shelf status. When you already have sourced the 3PDT switches for band bypass, just use the 3rd pole for LED status gimmicks (bicolour red/green LEDs might be to your taste).
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 22, 2014, 12:46:33 AM
Ahh of course! I had completely forgotten about the provision for LED's already on board.  :o
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on June 22, 2014, 04:17:22 AM
Does anyone have a layout for the front panel? (separate controls)

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: druu on June 22, 2014, 07:01:46 AM
You're welcome to modify the Igortec dual mono front panel I made, to suit.

http://amnet.net.au/~amunday/sontec/
Title: Re: Barry Porter "Net EQ"
Post by: weiss on July 01, 2014, 10:58:33 AM
You're welcome to modify the Igortec dual mono front panel I made, to suit.

http://amnet.net.au/~amunday/sontec/

hey where did you get these silver knobs from? :)
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 01, 2014, 03:22:36 PM
I went with some more spacious and "simple". Don't wanna try to take on the entire universe at my first attempt trying to build something like this.  :)

Still needs a little work, but almost there.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: druu on July 01, 2014, 05:20:01 PM
You're welcome to modify the Igortec dual mono front panel I made, to suit.

http://amnet.net.au/~amunday/sontec/

hey where did you get these silver knobs from? :)

RS Components.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 05, 2014, 02:16:15 AM
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on July 05, 2014, 08:06:33 AM
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav

Hi Gustav,

I ordered every resistor for all my switches (as per Harpos spreadsheet) from Farnell (called Element14 in Australia... Same thing).

Look for the multicomp brand, they often are cheapest and come in MOQs that aren't too insane.
Also, you can save a few dollars by not getting too pedantic about the resistor values, give or take an ohm here or there. I.e. A 499ohm resistor might be 3x the price of a 500ohm resistor. (Maybe a bad example but you get the idea). This makes a significant difference to the price. Ordering very obscure resistor values is an expensive process... Hope that helps
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 05, 2014, 08:25:50 AM
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav

Hi Gustav,

I ordered every resistor for all my switches (as per Harpos spreadsheet) from Farnell (called Element14 in Australia... Same thing).

Look for the multicomp brand, they often are cheapest and come in MOQs that aren't too insane.
Also, you can save a few dollars by not getting too pedantic about the resistor values, give or take an ohm here or there. I.e. A 499ohm resistor might be 3x the price of a 500ohm resistor. (Maybe a bad example but you get the idea). This makes a significant difference to the price. Ordering very obscure resistor values is an expensive process... Hope that helps

Thanks. I was a little worried about going off-value, because the differences will add up the way the switch is built, but Ill go for it :)

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on July 05, 2014, 08:45:49 AM
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav

Hi Gustav,

I ordered every resistor for all my switches (as per Harpos spreadsheet) from Farnell (called Element14 in Australia... Same thing).

Look for the multicomp brand, they often are cheapest and come in MOQs that aren't too insane.
Also, you can save a few dollars by not getting too pedantic about the resistor values, give or take an ohm here or there. I.e. A 499ohm resistor might be 3x the price of a 500ohm resistor. (Maybe a bad example but you get the idea). This makes a significant difference to the price. Ordering very obscure resistor values is an expensive process... Hope that helps

Thanks. I was a little worried about going off-value, because the differences will add up the way the switch is built, but Ill go for it :)

Gustav

I still stayed pretty close to the spec, most of mine were exact as per Harpos spreadsheet for 23 pos switches. But a few ohms here or there is still probably going to put you within a -/+ 1% tolerence. For gain switches you'll have 500ohms the whole way around...
For freqs I guess a ohm deviation here or there would change your actual frequencies but I don't think my ears could hear the difference between say 1980hz or 1985hz
(I might add that I haven't assembled my switches yet so this is all in theroy, but I've ordered everything from element14 regardless)
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 06, 2014, 02:46:43 AM
This is what I got for the 23 step...

Not sure I did it right.

If so, could someone explain how it works? I am confused about the large jump for the final value for an RC filter in the given frequency steps.

Edit:link removed to avoid confusion. (values were wrong).

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 06, 2014, 07:57:52 AM
This is what I got for the 23 step...

Not sure I did it right.
references mixed up, negative resistor parts values, ...
Maybe try this (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_X_freqstep.xls) calc sheet for X step positions.

// excel file errors in text corrected
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 06, 2014, 08:10:29 AM
This is what I got for the 23 step...

Not sure I did it right.
references mixed up, negative resistor parts values, ...
Maybe try this (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_X_freqstep.xls) calc sheet for X step positions.

Thanks, Harpo! (Thought the negative value was just an accumulated rounding error :) )

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: weiss on July 10, 2014, 02:32:34 PM
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

ordered them here (http://www.mammothelectronics.com/1-4-Watt-1-Metal-Film-Xicon-Resistors-p/110-271-rc.htm).

weiss
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 10, 2014, 03:00:50 PM
Thanks, Harpo! (Thought the negative value was just an accumulated rounding error :) )
Sorry, but no. ;)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on July 13, 2014, 11:20:18 AM
I think I did a basket for all the resistors from Harpo's sheets. It is with mouser 1% tolerance. I'll have a look see.

Edit: Am not sure how accurate it is been some time since I did it. Some are out of stock. It has free postage to Europe.

https://ie.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=26ecaa8ea4
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 14, 2014, 02:11:56 PM
I think I did a basket for all the resistors from Harpo's sheets. It is with mouser 1% tolerance. I'll have a look see.

Edit: Am not sure how accurate it is been some time since I did it. Some are out of stock. It has free postage to Europe.

https://ie.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=26ecaa8ea4

I started one the other day - quantities are off, but I wanted a roll of each value.

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=f66bec5e1e

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 14, 2014, 06:26:46 PM
Noone could stop you to edit the calculated closest parts values from column 'J' with your availible parts values, beginning with the highest step position, and the calcsheet (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_X_freqstep.xls) will give you the recalculated values for the steps above in order to minimize total errors. ;)
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 17, 2014, 02:28:33 PM
Harpo did the thinking part - I did the monkey part...I like doing the monkey part.

This is a fun project, but way over my head  ;D

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: weiss on July 26, 2014, 07:40:19 AM
hey guys, since i am new to this project i could need some help. is there a complete bom or documentation for the net eq? i think of a dual mono unit like domc used in their studio, but i dind't find any information on the jlm website (https://scontent-a-ams.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10376288_10152150017372544_2675178422037116930_n.jpg?oh=43071c0c0e25ceac39f18554f4b72959&oe=54411A6B)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on July 27, 2014, 07:23:40 AM
Weiss send me a PM I will pass along the info. what exactly are you missing?

Has anybody given thought to sticking in some input/output transformers? Is that even possible?
Title: Re: Barry Porter "Net EQ"
Post by: prescott on July 28, 2014, 06:46:36 AM
Harpo, the calculator sheet is just fantastic...

Is it possible to extend it with the HPF, the same way, when I can change freqs and steps?

Would be welcomed:)

BTW, is there info about how to separate the peak and shelving bands?

Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 28, 2014, 09:38:11 AM
Harpo, the calculator sheet is just fantastic...

Is it possible to extend it with the HPF, the same way, when I can change freqs and steps?
my pleasure, but this is just a quick and dirty tool, far from perfect/foolproof.

Maybe reload updated calcsheet (http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_X_freqstep.xls) with your request.

Quote
BTW, is there info about how to separate the peak and shelving bands?
Look at the headlines or part numbers...
Title: Re: Barry Porter "Net EQ"
Post by: prescott on July 28, 2014, 11:29:12 AM
Thanks a lot Harpo!

But how do you mean "look at the headlines"?

Its just putting the peak and shelving bands to separated rotary switches and thats it?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 28, 2014, 01:59:59 PM
But how do you mean "look at the headlines"?
Its just putting the peak and shelving bands to separated rotary switches and thats it?
Look FI at calcsheet row17 and row 200 to get the relation to the 'headline and parts numbers' for the low band.
Separate switches or separate decks at the same switch, IE pot 15a and pot 15b (row 17) get substituted by a 2deck switch, each deck with required resistor values for the peaking low band. Pot 15c (row 200) get substituted by a 3rd.switch deck (with different from peaking band resistor values) on either the same switch (=3deck switch required) or at an additional separate switch (1deck switch) for the shelfing low band.
Title: Re: Barry Porter "Net EQ"
Post by: prescott on July 28, 2014, 03:42:53 PM
And can I simply use them in the same time without changing the gain structure?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 29, 2014, 05:51:42 AM
Yepp. The loading on the filter driving stage (U2-A) is still the same. For adding more filter bands for whatever reason, some unity gain buffers in front of the filter inputs might be needed.
Title: Re: Barry Porter "Net EQ"
Post by: prescott on July 29, 2014, 07:28:33 AM
Ok, its very good!

But how can I adjust the volume of the shelv and peak to differect positions at the same time?
Where can I connect another rotary to?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on July 29, 2014, 08:02:24 AM
But how can I adjust the volume of the shelv and peak to differect positions at the same time?
Where can I connect another rotary to?
Instead of FI relay K3, switching between the peaking and shelfing low band, you have an additional center tapped pot or rotary switch substitution in parallel to the other level pots with wiper connecting thru a 2K2 to the decoupled filter output (junction C45/R50). Leave out K3,D3,Q3,C37,R34,R36,R103,S2,LED2 and jumper K3-pin2 with pin3 at pcb.
Same for the high peak/shelf band with corresponding parts.
Consider you might run out of frontpanel real estate at some point or fingers are not small enough to comfortably fit between knobs ...
Title: Re: Barry Porter "Net EQ"
Post by: prescott on August 01, 2014, 04:50:19 PM
Thanks again Harpo!

Its time to understand, but I will save this comment:)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on August 11, 2014, 12:51:42 PM
My knobs arrived.......(http://i457.photobucket.com/albums/qq298/divinemothercrumbles/DSCN0251_zps0e6d84a9.jpg)
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on August 15, 2014, 12:37:47 PM
Hi,
Anyone care to share how much they spent to finish this project?
thanks,
JS
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on August 16, 2014, 08:34:01 AM
Anywhere, from 1-2.5k, depending what rotary switches you choose and of course less man hours.....
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 16, 2014, 09:39:05 AM
My build looks like it will land around 7-800 euros in parts. Certainly less than 1k...

But its a lot of hours in work.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on August 16, 2014, 11:00:07 AM
Thanks!
Harpo, or anybody, could you post a new link to the spreadsheet of resistor values? When I click on the link labeled "Hop" in the earlier posts I just get a screen full of random characters....
JS
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on August 17, 2014, 03:22:39 AM
JS, no link broken. Maybe use right-click / save_as for a workaround (some program might have occupied the standard file extension .XLS for a different -no more related to MS-Excel or OpenOffice calc sheet- purpose).
Title: Re: Barry Porter "Net EQ"
Post by: druu on August 24, 2014, 07:57:50 AM
Another complete! Just need to go through the calibration but so far it all checks out fine.

(http://amnet.net.au/~amunday/bpeq/BPEQ3.JPG)

(http://amnet.net.au/~amunday/bpeq/BPEQ5.JPG)

Huge thanks to Harpo, ppa and the usual guys I hassle over PM. ;)

For anyone thinking to add +/-6dB Input Gain control, see here (http://amnet.net.au/~amunday/bpeq/Input%20Gain/). Works perfectly (Thanks ppa)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on August 26, 2014, 10:03:25 AM
I have a small problem with mine.
The 10r in R18 which is on the -18v line keeps blowing out,  have checked my PS and everything is fine there.

Any ideas?
Title: Re: Barry Porter "Net EQ"
Post by: Gold on August 26, 2014, 02:19:42 PM
I haven't looked at the schematic but it sounds like those 10R in series with the rail. If this is correct the 10r are essentially fuses. If it keeps blowing something down the line is shorting out.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on August 26, 2014, 02:38:24 PM
Thanks Paul.

Checked the following Cap with the MM and it's polarity is labelled wrong.

Must of been an ebay purchase I will check it later tonight.

Edit: Some bad ceramics....
Title: Re: Barry Porter "Net EQ"
Post by: MrBlomski on September 04, 2014, 02:28:12 AM
Another complete! Just need to go through the calibration but so far it all checks out fine.

(http://amnet.net.au/~amunday/bpeq/BPEQ3.JPG)

(http://amnet.net.au/~amunday/bpeq/BPEQ5.JPG)

Huge thanks to Harpo, ppa and the usual guys I hassle over PM. ;)

For anyone thinking to add +/-6dB Input Gain control, see here (http://amnet.net.au/~amunday/bpeq/Input%20Gain/). Works perfectly (Thanks ppa)

Do I see a DR-MQ5 eq?
Title: Re: Barry Porter "Net EQ"
Post by: druu on September 04, 2014, 09:40:58 AM
No, that EQ below the BP is built using Igor's GML/Massenburg 'MEP250' boards with MS/Bypass, before the DR-MQ5 copies came out. :)
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 05, 2014, 02:47:56 AM
1.The PCB has a 6 pin footprint for the switches, and the schematic has a DPDT switch drawn up for the bypass switches, but is there any reason why I couldn't just use a single pole on/off switch and tap into the two "relevant" points on the board for each of the four switches?

2. Frame = chassis on the 10 pin connector?

If you are using Harpo's excellent excel sheets, this should be a correct list of the resistor changes on the board.

Cut (freq)

R114, R115
R111 R112
R108 R109
R105 R106


Short (freq)

R87 R61
R83 R58
R79 R55
R74 R51

Short (shelving)

R78
R91

Replace values (Q)

R99 R100 R101 R102 = 10K
R95 R96 R97 R98 = 5K1

Short (Q)
R104 R107 R110 R113

Replace values (Gain)

R13 R14 = 5K1
R77 R82 R86 R90 = 6K49

Short (HPF)

R93 R 94
Title: Re: Barry Porter "Net EQ"
Post by: druu on September 05, 2014, 07:13:16 AM
Single pole is all that's required. The extra pole would be there to add rigidity if mounted to the board.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on September 05, 2014, 07:19:03 AM
You can place the last resistor on the chain into the short positions save having them hanging off the rotary.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 05, 2014, 08:46:23 AM
You can place the last resistor on the chain into the short positions save having them hanging off the rotary.

No need - theres an extra lug on the switches Im using :)

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 05, 2014, 08:47:41 AM
Single pole is all that's required. The extra pole would be there to add rigidity if mounted to the board.

Thanks!

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: alexg on September 14, 2014, 08:53:40 AM
No, that EQ below the BP is built using Igor's GML/Massenburg 'MEP250' boards with MS/Bypass, before the DR-MQ5 copies came out. :)

Interesting to see those two in the same studio.
Could you tell us their sonic differences & character?
Thanks !

Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 15, 2014, 03:02:45 PM
Im afraid to finish this.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: yourdudeness on September 16, 2014, 03:11:50 AM
Hello, any recomendations for L1?
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 16, 2014, 03:13:25 AM
Voltages seem good.

Thanks for all the help, boys!

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 16, 2014, 03:13:48 AM
Hello, any recomendations for L1?

Jump it..
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on September 30, 2014, 02:11:06 PM
I am still having trouble with mine. Problem is on both boards voltage seems to get lost after the regulator 12V. The opamps are reading fine. In C26/27 I have 2 100V Caps where should be 25V.  Would this be causing my problem, I am not sure it is. I am reading V for the relay afterwards.

I unplug PSU to double check still checks out fine when plug it back in voltage slowly rise/increases when checked what the PSU is doing when plugged to boards and no voltages across previous checks

This has lead me to think that there is something amiss in C19/20/21/22.

Anybody want to add some insight to get my brain thinking in the right direction. I could have hit the nail on the head already?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on September 30, 2014, 07:42:16 PM
In C26/27 I have 2 100V Caps where should be 25V.  Would this be causing my problem, I am not sure it is.
You probably refer to C21/C22 (100uF/25V), not C26/C27 (100nF caps).  No problem, as long as caps voltage rating is higher than voltage across these caps (>18V in front of 7812 and >12V after 7812). Higher voltage rated caps most often come with increased outer dimensions.

Quote
I am reading V for the relay afterwards.
missing value for your V reading, probably something in range from nada up to +12VDC.

Quote
I unplug PSU to double check still checks out fine when plug it back in voltage slowly rise/increases when checked what the PSU is doing when plugged to boards and no voltages across previous checks

This has lead me to think that there is something amiss in C19/20/21/22.

Anybody want to add some insight to get my brain thinking in the right direction. I could have hit the nail on the head already?
Maybe double check polarity of C19, C20, C21, C22, orientation of diodes D1, D2, D3, D4 and transistors are BC182 for real (not different pinout BC182L).
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 01, 2014, 03:11:15 AM
Thanks harpo, all polarity and rotation is correct checked and double checked.  BC182 transistors, I have the B in there as I was aware of jeffs problem with L series.  I will try with the BC182 thanks harpo
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 01, 2014, 03:59:15 AM
I will try with the BC182
Not needed (unless your BC182Bs are broken). Problem will be in a different spot then. (Relais ?, additional LEDs with maybe missing/wrong current limiting resistors ?, insufficient current delivery from preceding +18VDC stage ?, ...)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 01, 2014, 09:42:03 AM
My current from psu is 1.5ma. Problem is still present when disconnected from switches and leds. I had calculated the limiting resistor. Going to desolder relays and transistors and check. I have Continuity across a couple of the PF and NF caps in the same places on both boards I am thinking maybe below what my MM could read?? but maybe if that was the case they all should read Continuity. Am I wrong in thinking this?
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 01, 2014, 04:13:25 PM
I have Continuity across a couple of the PF and NF caps in the same places on both boards...
Continuity test AKA beeper mode ? Only maybe useful for sorting unlabled multicore wires or hooking up a caravan, but not much use in electronics. Use your multimeters ohm setting in order to get a meaningful number. A short will give a zero or close to zero ohm readout (pcb traces and/or your measuring leads have a resistance as well). You never said what psu you are using, whats the data of the mains transformer in front or whatever circuit variations or add ons you have implemented.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 01, 2014, 10:35:46 PM
Hey all,

I finally got a chance to power up one of my Net EQ channels... for the 'smoke test', unfortunately it failed that test. At the moment all I have connected to the PCB is the bypass LED and switch, hoping to have seen a gleaming red LED looking back at me...

R1, R18 and R19 get extremely hot very quickly and start smoking after about 20 secs. I used 3W resistors in these locations.

I'm using the calrec PSU with a 2x18V toroid. I built up and tested the PSU first, I'm getting sturdy. + 18V rails so I believe the PSU board is working correctly. I also noticed the regulators seemed to heat up very quickly as well. 

I've checked the obvious things like shorts in this area and that I didn't get the neg and pos leads switched around... appreciate any other ideas...
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 02, 2014, 12:29:12 AM
Just wired up my second channel.... Exact same issue. R1 feels like a hot plate within about 10 seconds. I'm guessing I made a fundamental error with some component selection or was unfortunate enough to induce the same error on both boards
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 02, 2014, 09:37:01 AM
Thanks harpo. I have a generic PS I got on evilbay based on 337/317, tordial is 230/18v I have no mods or attached circuit. Am going to go through the whoIe thing again. I had power to the bypass led when I wriggled the ps leads to the board when I disconnected to check and reconnected, it popped  the 10r metal oxide on the minus line. I checked for coId soIder and found none.  Do you think I shouId be chasing the probIem in the ps??

I  have the same problem as you frazzman they pop, as paul says they are acting as fuses.
Title: Re: Barry Porter "Net EQ"
Post by: druu on October 02, 2014, 09:45:28 AM
frazzman: I had that issue too remember! Turned out to be the +/-18v I had reversed. :P
Title: Re: Barry Porter "Net EQ"
Post by: druu on October 02, 2014, 09:47:27 AM
I'm still convinced the schem pinout is wrong for the PSU input wires..
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 02, 2014, 10:35:45 AM
I'm still convinced the schem pinout is wrong for the PSU input wires..
Maybe only your assumption is wrong that the 10-pin connectors are populated with same orientation, IE pin1 of CON1 and CON2 are both the leftmost pin ...  ;)
(pin1 of CON2 (the +18VDC connection) is the rightmost pin)
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on October 02, 2014, 10:45:27 AM
I'm still convinced the schem pinout is wrong for the PSU input wires..

The pinout is correct on the schem, and pin 1 is marked with a square on the board for both com1 and com2.

They are not oriented identically, though.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: druu on October 02, 2014, 05:49:53 PM
Ok I stand corrected. :) I must have had a brain fart during that stage and switched my wire colours for some reason.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 02, 2014, 09:09:50 PM
Ahh thanks dudes! You were right about the the neg and pos wires being reversed.

Druu: I remember you telling me about your problem now...

I wrongly made the assumption that the pin out was the same on both connectors. I wish I'd noticed the square pad earlier ...

I can hear relays kicking in and LEDs lighting up... Hopefully some audio to follow! Thanks again
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 03, 2014, 06:06:36 PM
whats the current I need. Am still dropping voltage and drawing 1.5A
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 03, 2014, 08:40:54 PM
Looking good here so far... Wired up one band and boost/cut is working.

A few observations when analysing using RMAA:
- max boost seemed to be a bit under 4db at max position - using 21 step rotary, I was expecting 5db?
- on the freq plot the Q control looks pretty much the same at q=1 and q=3. Is there supposed to much difference here? They are both broad Q's I guess but I can't hear/see the difference. - I'm using 12 pos alpha rotaries for Q control 

I'll wire up the rest and report back...  I'm just interested on other peoples findings. Once these boards are wired up I really don't wanna have to pull them out to tweak something
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on October 04, 2014, 02:08:14 AM
Looking good here so far... Wired up one band and boost/cut is working.

A few observations when analysing using RMAA:
- max boost seemed to be a bit under 4db at max position - using 21 step rotary, I was expecting 5db?
- on the freq plot the Q control looks pretty much the same at q=1 and q=3. Is there supposed to much difference here? They are both broad Q's I guess but I can't hear/see the difference. - I'm using 12 pos alpha rotaries for Q control 

21 steps doing what? Have you measured resistance over the switches to confirm you did them correctly?

I went to Jakob to bring this to life the first time, and he made a few plots at random settings for me (attached). You can see one of them has a pretty sharp Q.  My Q ranges from 1 to 3.

Again, just to get the trivial sources for error out of the way. Did you measure the Q switch to confirm it adds up the values as expected?

Also -  Did you change/omit the resistors on the PCB mentioned in Harpo's sheet?

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 04, 2014, 09:00:46 AM
Hi Gustav,
Thanks for the reply.

For the gain switches I went with 21 steps: -/+ 5dB with step 11 as 0db (centre tap)

I checked the sum of the resistors on each gang for every switch to make sure that it matched up with Harpo's values (and the other gang(s) on the switch).  All Freq's, gain switches and Q switches

Everything was pretty dead on. As far as the gain switches go, not too much room for error since its just a continous ring of the same value resistor anyway...

I wired up a few other Q switches tonight to see if the problem still persists (they're on molex headers so easy to swap in and out). Same issue... with tests just limited to MF1 band - the plots are identical with both Q=1 and Q=3, changing the Q position has no affect. I can hear clicks in the audio as I toggle through the switch positions, FWIW.

I followed all the resistor shorts positions and omissions as per Harpo's spreadsheet(s) - (at least I think I did...)

The only thing I can think that may have caused a problem is that for the Q Switches - I used the Q calculations from one of Harpo's earlier spreadsheets. This contained calcs for a 12x1 rotary switch... (see attached)
I then used one of the the later revision spreadsheets and followed the calcs specified for 24pos freqs and 21pos gain switches.

Perhaps the 'merging' of these two different sources has caused an issue - i.e. maybe wrong shorts/ommisions of certain resistors?

The only other loose end I have is that I have only wired up 1 band at the moment, but I don't think that will be causing any issue.

Man, I wish I had have wired up the leads to switch lugs prior to populating all the switches. Trying to solder leads to the middle pole of the LF and HF switches is a total pain...

I also need to work out why I seem to be 1db short as well for both boost and cut...

This is a full on project...

Thanks for your help
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on October 04, 2014, 11:47:35 AM

The only thing I can think that may have caused a problem is that for the Q Switches - I used the Q calculations from one of Harpo's earlier spreadsheets. This contained calcs for a 12x1 rotary switch... (see attached)
I then used one of the the later revision spreadsheets and followed the calcs specified for 24pos freqs and 21pos gain switches.



Whats the R sum on your Q switch?

Cant figure out the mystery on the missing 1dB on the gain switches, other than resistor-fairies. Only reasons I am sharp enough to propose is, its either  because you're tapping them the wrong place, or have a wrong value somewhere left on the board.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on October 04, 2014, 12:21:18 PM
... with tests just limited to MF1 band - the plots are identical with both Q=1 and Q=3, changing the Q position has no affect. I can hear clicks in the audio as I toggle through the switch positions, FWIW.

I followed all the resistor shorts positions and omissions as per Harpo's spreadsheet(s) - (at least I think I did...)
you probably only missed to jumper two circuit nodes, as the quoted headline of the calcsheet snipplet already says '...and shorting out opamps non-inverting input with pin1 of the 'Q'-pot from Barrys schematic...'.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 04, 2014, 05:42:56 PM
... with tests just limited to MF1 band - the plots are identical with both Q=1 and Q=3, changing the Q position has no affect. I can hear clicks in the audio as I toggle through the switch positions, FWIW.

I followed all the resistor shorts positions and omissions as per Harpo's spreadsheet(s) - (at least I think I did...)
you probably only missed to jumper two circuit nodes, as the quoted headline of the calcsheet snipplet already says '...and shorting out opamps non-inverting input with pin1 of the 'Q'-pot from Barrys schematic...'.

Hi Harpo,
Yes - looks like I missed that instruction. I (wrongly) assumed that all the shorts and omissions listed would cover everything.

So pin  3 of opamp is non inverting input? So link pin 3 of opamp to pin 1 of Q switch? Is that correct ?
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 04, 2014, 05:44:55 PM
Okay so going back over my relay selection there is Omron G6H-2-100 in there which is non-latching. Maybe I forgot it was the other part number I wanted....... The TQ2 is latching from the data sheet I could find. The TQ2 that matches 12VDC, 1,028K is single sided stable on the data sheet. I am correct in thinking the single side stable TQ2 is the correct one.

Best
Peter
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 04, 2014, 10:33:45 PM
FI Q setting mono pot P10. Jumper the right and center hole on pcb and connect switch pole and switch position 1 to this jumper. Last switch position resistor goes to the left side hole. Jumper R110 or fit this last switch position resistor here instead so it doesn't hang lose on your Q switch.
Same procedure for the other Q setting switch asemblies.

I think I answered my own question, I think this is what you meant Harpo?
Title: Re: Barry Porter "Net EQ"
Post by: kml23956 on October 10, 2014, 06:24:51 PM
Who can explain this in simple terms? I need to know what they are and how they are wired? Are they 2 pole 24 , 4 pole 24, 2 pole 23...etc.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on October 11, 2014, 04:41:07 AM
Who can explain this in simple terms? I need to know what they are and how they are wired? Are they 2 pole 24 , 4 pole 24, 2 pole 23...etc.



These are two 2 x 23 switches for the mid bands, and two 4 (only using 3) x 23 for the high and low bands. The third gang are the values for the shelving filters.

You can use any number of steps you like. Harpo has made some great excel sheets where you just plug in your data.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: kml23956 on October 11, 2014, 10:31:18 PM
Thank you Gustav.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 12, 2014, 04:40:22 AM
Any ideas what could cause excessive boost on HF band? I fixed all other switch related issues and wired and tested each band as I go - only to find a a weird problem on my HF band.

To set the scene - I'm running off Harpos values - stepped switches set for 24 pos freq's, 21 step gain -/+ 5db with 0db at step 11. 12 step Q's.

Anyway I'm getting about +14db boost (at max) on my HF band and max +4dB on all others. No doubt there is something wrong on my HF band. There's no boost when shelving is engaged either. Tried swapping gain and Q switches with "known working" switches from other band but no go.

As per Harpos calcs - Boost and cut resistors (r13 and r14 are correct at 5k1 and r77,82,86,90 are correct at 6k49)

 I'm thinking I forgot to change a resistor value or forgot to omit or short a resistor position, but nothing is staring back at me... Any ideas?
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 12, 2014, 03:45:01 PM
Whats in R62?
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on October 13, 2014, 12:31:48 AM
Whats in R62?

Peter, you're the man... I had 100k in R62 as per the JLM component overlay pdf, where as the schematic value is 10k. HF band now works.

Looks like this channel is all good for now. Still can't get quite to +5db on any bands but maybe RMAA is off as all resistors for cut and boost are correct. Q switches are working too as I can see on the frequency plot.

Now to wire the second channel.... Arghhhh.

Did you fix your power issue? Wrong relays ?
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 13, 2014, 05:57:00 AM
I am waiting on a fluke meter to arrive to measure all these caps again.
AFAIK the relays are good. They have the same details etc as the other and test good.

It's something pretty small. I still have have a feeling it's in the summing section. There is a something out there somewhere. As when I had power before, this section worked. Bad BP/Ceramic in there not showing on the cheap meter I have now. Opamps and resistors test good. I will find it with the fluke better than the meter I have now.

Going to have a break from it and start the D-AOC soon. I tend to find problems when I step back a small bit from it.

Glad yours is working. ;)
Title: Re: Barry Porter "Net EQ"
Post by: e.oelberg on October 13, 2014, 09:01:30 AM
I have this... cheap and precise and fast shipment
http://www.seeedstudio.com/depot/Capacitance-Meter-Kit-p-268.html (http://www.seeedstudio.com/depot/Capacitance-Meter-Kit-p-268.html)
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on October 13, 2014, 04:28:27 PM
Thanks e.oelberg
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on November 10, 2014, 06:55:09 AM
Got around to having another look at these boards over the weekend.....

R27 which is 10r was reading 20r on one board. On both boards the 4r7 was reading 5r5 for some reason. Everything else is good. I will change them hopefully later this week. Fingers crossed for me......
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on November 11, 2014, 03:29:01 AM
Got around to having another look at these boards over the weekend.....

R27 which is 10r was reading 20r on one board. On both boards the 4r7 was reading 5r5 for some reason. Everything else is good. I will change them hopefully later this week. Fingers crossed for me......

"On the board", meaning - in circuit? Cant measure resistance on an individual resistor in circuit, and the difference between 10/20R and 4R7/5R5 would not mess up anything anyway.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: DAN_000 on November 11, 2014, 10:22:07 PM
Hi,

I really like to use this EQ with broad Q settings.  But there are some limitations with this and noise, like mentioned in Porter doc.
There are some NetEq builds with extended band bandwith. like   20 to 200hz  ---->  20 to 510hz
Is there any benefit of extended bandwith  band vs  Q (broad setting) noise ?
And another question to Harpo,  how you calculate new optimal integrator capacitor values if you change freq bandwith ?

Thanks
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on November 12, 2014, 02:27:37 PM
Got around to having another look at these boards over the weekend.....

R27 which is 10r was reading 20r on one board. On both boards the 4r7 was reading 5r5 for some reason. Everything else is good. I will change them hopefully later this week. Fingers crossed for me......

"On the board", meaning - in circuit? Cant measure resistance on an individual resistor in circuit, and the difference between 10/20R and 4R7/5R5 would not mess up anything anyway.

Gustav

One leg disconnected. Am going to get PSU board from you in a bit Gus, just to rule that area out. It outputs 18v can never be TOO sure.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on November 14, 2014, 06:51:42 AM
Hi,

I really like to use this EQ with broad Q settings.  But there are some limitations with this and noise, like mentioned in Porter doc.

Is this in theory or in practice ? I haven't observed any drastic noise changes with broad Q, also the Q at it's broadest setting actually isn't that broad compared to some other EQs of a similar ilk.... 
Title: Re: Barry Porter "Net EQ"
Post by: vilddyr on November 16, 2014, 04:51:36 AM
Hi Guys.

I have seen this build around, and I really don't know how to identify the parts. I'm of course not looking to copy, but I do know, that I don't care about switches, but just about getting a great sounding EQ. So this stereo controlled style, with regular pots is much more appealing to me, than using hours and hours soldering cheap switches up with resistors, since I'm not really keen on using 100's of $ on ELMA switches.

Gustav, maybe you can help me out, are these board not more or less identical to yours? So maybe someone could point me in the direction of where to get the pots used here, that fit directly on the PCB?

Is there anyway to get some kind of pcb for metering, like the one in this unit? Any standard stuff, easily implemented?

Great to see people doing this thing.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on November 17, 2014, 12:08:33 PM
Hi Guys.

I have seen this build around, and I really don't know how to identify the parts. I'm of course not looking to copy, but I do know, that I don't care about switches, but just about getting a great sounding EQ. So this stereo controlled style, with regular pots is much more appealing to me, than using hours and hours soldering cheap switches up with resistors, since I'm not really keen on using 100's of $ on ELMA switches.

Gustav, maybe you can help me out, are these board not more or less identical to yours? So maybe someone could point me in the direction of where to get the pots used here, that fit directly on the PCB?

Is there anyway to get some kind of pcb for metering, like the one in this unit? Any standard stuff, easily implemented?

Great to see people doing this thing.

There was a document in the folder on pots. Maybe if you find the link somewhere it could be still there. It alludes to...

Model P270/271/272
27mm Rotary Potentiometer
TT Electronics.
Title: Re: Barry Porter "Net EQ"
Post by: vilddyr on November 17, 2014, 12:16:01 PM
Yeah I looked into it a little more, and the PCB in those units are of course stereo boards, while Gustav's is "dual" mono. So I was kind of way off. And I guess it does need to be switches, if it's to be mastering capable. Not so much for the steppings, but for the lack of accuracy with standard pots.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on November 17, 2014, 12:32:09 PM
Not so much for the steppings, but for the lack of accuracy with standard pots.

Exactly.

During the last year or so, I have really come to love the way an EQ can impact the sonics of the program more than any other type of processing, and this EQ is nothing special in that regard.

What it does, in my opinion, is unnoticeable accuracy, which is really pretty boring as a "sound". So ditching the pots would be a bad move.

I saw some prepared switches on ebay recently, but I didn't notice the price, and I can't seem to find a link again.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: vilddyr on November 17, 2014, 12:42:35 PM
Yeah, I have seen some of those, with pre installed resistors. I assume these could be useful for the gain switches, since this is just a string of the same resistors (right?), but there's not really any way of avoiding having to make your own frequency switches. Which is of course fine, as this is how to choose your values!

Would you guys recommend ordering the frontpanel as the absolutely last thing on a build? I'm kind of getting ready to order the different parts, but still haven't really figured out what to do about the back panel. Guess it would be best to just have schaeffer make on that could fit on the back of the modu enlosure. It seems modu also does custom panel stuff though, anyone have experience with that?

Title: Re: Barry Porter "Net EQ"
Post by: kante1603 on November 17, 2014, 01:08:12 PM
Would you guys recommend ordering the frontpanel as the absolutely last thing on a build? I'm kind of getting ready to order the different parts, but still haven't really figured out what to do about the back panel. Guess it would be best to just have schaeffer make on that could fit on the back of the modu enlosure. It seems modu also does custom panel stuff though, anyone have experience with that?
Hello,


we don't know where you are located,best to update your profile.
Just in case you're in europe I would highly recommend Frank at NRG (http://www.frontpanels.de),he does all panels for me.Same as Schaeffer,but cheaper and you always get help from him.He's cool!Just create a file with FPD like you would for a Schaeffer order,send it to him and ask if you need any(!) help.He can do a lot of things with frontpanels (I mean that!),he works with aluminium and acrylic.


Check it out and have fun,


Udo.
Title: Re: Barry Porter "Net EQ"
Post by: vilddyr on November 17, 2014, 09:44:06 PM
Yeah Sorry. I'm in Copenhagen denmark.

I'm doing a little research still. Trying to get a grasp on everything, since I'm pretty much a rookie, who wants to go all in  :o I'm good with a soldering iron, and have done other stuff, but I have probably zero understanding of what is actually going on. But I am very keen to learn ! The case and back panels from don-audio looks like quality stuff :)

Does it make sense to go for the more expensive switches? Or will the actual switches have absolutely nothing to say in regards to audio quality, since the resistors soldered to them is pretty much the determining factor? In my head the switches does not pass audio as such, but are only a way of controlling whats going on, on the PCB... As said, I am a total noob, and probably wrong  ???
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on November 17, 2014, 11:03:14 PM
Yeah Sorry. I'm in Copenhagen denmark.

I'm doing a little research still. Trying to get a grasp on everything, since I'm pretty much a rookie, who wants to go all in  :o I'm good with a soldering iron, and have done other stuff, but I have probably zero understanding of what is actually going on. But I am very keen to learn ! The case and back panels from don-audio looks like quality stuff :)

Does it make sense to go for the more expensive switches? Or will the actual switches have absolutely nothing to say in regards to audio quality, since the resistors soldered to them is pretty much the determining factor? In my head the switches does not pass audio as such, but are only a way of controlling whats going on, on the PCB... As said, I am a total noob, and probably wrong  ???

The switching mechanism type is really just for the "feel" - i.e. The ELMA switches feel nicer and smoother than the cheaper Uraltone counter parts. I used cheap uraltone / chinese switches in my build and they worked fine.

Just my 2 cents... I don't think this is a very good beginner project. It's somewhat complicated, there are lots of parts and lots of decisions to make about how to achieve what you need. It isn't nearly as comprehensively documented as say any of the Gyraf projects.

Personally I would start off on a more straightforward build than this.
Title: Re: Barry Porter "Net EQ"
Post by: vilddyr on November 18, 2014, 05:45:26 AM
Yeah, I see your point. But I'm way too stubborn, so it's not gonna make much of a difference :D
Title: Re: Barry Porter "Net EQ"
Post by: DAN_000 on November 18, 2014, 10:40:42 PM
Hi,

I really like to use this EQ with broad Q settings.  But there are some limitations with this and noise, like mentioned in Porter doc.

Is this in theory or in practice ? I haven't observed any drastic noise changes with broad Q, also the Q at it's broadest setting actually isn't that broad compared to some other EQs of a similar ilk....

Original Porter broadest Q is 1.    There is no noise issues with this original value.   But things start to change if you modify input and feedback integrator resistors values. 
There are some modified extendend freqs per band builds.    And there is a value of Q=0.3  in this builds (exactly what Im looking for).  Maybe this extended freq range helps noise figure ?

Anyone who builds with modified broad Q range please can give me some help ?



 
Title: Re: Barry Porter "Net EQ"C
Post by: frazzman on November 27, 2014, 05:01:29 AM
Hi guys,
Almost finished my build so close I can taste it!
Just finished wiring on my right channel. All checks out except for an issue on HF band. Shelf is fine but peak isn't working for boost or cut., just stays at 0  - freq plot is flat.
I'm using stepped switches as per Harpos spreadsheet.
This channel is built identically to my (working) left channel. Any ideas ? If shelf works, where should I focus for peak issue ? I'm reading the right resistance on at the pcb so I'm know switch is wired correctly.
Thanks a lot
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on January 15, 2015, 12:17:58 AM
hi all,
i'm getting started on my Net Eq build and i was looking for LED illuminated DPDT toggle switches.  i'm having a bit of trouble finding a suitable set.  anyone have any suggestions or what has worked for you guys?  i'd prefer illuminated, circular pushbutton...

thanks in advance,
 - nick
Title: Re: Barry Porter "Net EQ"C
Post by: Gustav on January 15, 2015, 08:38:15 AM
Hi guys,
Almost finished my build so close I can taste it!
Just finished wiring on my right channel. All checks out except for an issue on HF band. Shelf is fine but peak isn't working for boost or cut., just stays at 0  - freq plot is flat.
I'm using stepped switches as per Harpos spreadsheet.
This channel is built identically to my (working) left channel. Any ideas ? If shelf works, where should I focus for peak issue ? I'm reading the right resistance on at the pcb so I'm know switch is wired correctly.
Thanks a lot

Did you figure this out?

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on January 15, 2015, 03:26:45 PM
hi all,
i'm getting started on my Net Eq build and i was looking for LED illuminated DPDT toggle switches.  i'm having a bit of trouble finding a suitable set.  anyone have any suggestions or what has worked for you guys?  i'd prefer illuminated, circular pushbutton...

thanks in advance,
 - nick

Try Deca if you can find DPDT. I cant see where you would have any problems really.
Title: Re: Barry Porter "Net EQ"C
Post by: frazzman on January 21, 2015, 07:53:45 AM
Hi guys,
Almost finished my build so close I can taste it!
Just finished wiring on my right channel. All checks out except for an issue on HF band. Shelf is fine but peak isn't working for boost or cut., just stays at 0  - freq plot is flat.
I'm using stepped switches as per Harpos spreadsheet.
This channel is built identically to my (working) left channel. Any ideas ? If shelf works, where should I focus for peak issue ? I'm reading the right resistance on at the pcb so I'm know switch is wired correctly.
Thanks a lot

Did you figure this out?

Gustav

Hey Gustav,
Yes I did, thank you mate. Wrong resistor value somewhere.

Everything is pretty much working except for one overall anomaly, affecting both channels - even in bypass.
I'm observing some noise/ripple in the higher frequencies...Very prevalent with a HF boost. The plots from RMAA explain all....

It's quite audible, even though the unit is very quiet and hum free with no audio passing. With audio present  you can hear this 'ripple'.

Did you ground your pcbs ? I haven't done that and I am wondering if that's where my problem is?

Thanks a lot
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 21, 2015, 07:55:34 AM
And now with HF boost...
Title: Re: Barry Porter "Net EQ"C
Post by: Gustav on January 21, 2015, 12:51:25 PM
Hi guys,
Almost finished my build so close I can taste it!
Just finished wiring on my right channel. All checks out except for an issue on HF band. Shelf is fine but peak isn't working for boost or cut., just stays at 0  - freq plot is flat.
I'm using stepped switches as per Harpos spreadsheet.
This channel is built identically to my (working) left channel. Any ideas ? If shelf works, where should I focus for peak issue ? I'm reading the right resistance on at the pcb so I'm know switch is wired correctly.
Thanks a lot

Did you figure this out?

Gustav

Hey Gustav,
Yes I did, thank you mate. Wrong resistor value somewhere.

Everything is pretty much working except for one overall anomaly, affecting both channels - even in bypass.
I'm observing some noise/ripple in the higher frequencies...Very prevalent with a HF boost. The plots from RMAA explain all....

It's quite audible, even though the unit is very quiet and hum free with no audio passing. With audio present  you can hear this 'ripple'.

Did you ground your pcbs ? I haven't done that and I am wondering if that's where my problem is?

Thanks a lot

I had ripple on a band which turned out to contain a cold solder in one of the cold solder (I realised at some point, the ripple only occurred when I had it over a specific frequency and checked the spots). That may be worth checking out!? Also, check for shorts/near shorts on the switch.

Remember, the shelf is separate from the bells, so you are switching to a totally different part of the circuit/different part of the switch between the two. If you see a problem in one and not the other,.

I am not sure what you mean about grounding the PCBs. I connected the ground points to chassis as marked in the schematic, of course, but maybe "grounding the PCBs" covers something I am not aware of.

Gustav
Title: Re: Barry Porter "Net EQ"C
Post by: frazzman on January 21, 2015, 04:31:50 PM
Hi guys,
Almost finished my build so close I can taste it!
Just finished wiring on my right channel. All checks out except for an issue on HF band. Shelf is fine but peak isn't working for boost or cut., just stays at 0  - freq plot is flat.
I'm using stepped switches as per Harpos spreadsheet.
This channel is built identically to my (working) left channel. Any ideas ? If shelf works, where should I focus for peak issue ? I'm reading the right resistance on at the pcb so I'm know switch is wired correctly.
Thanks a lot

Did you figure this out?

Gustav

Hey Gustav,
Yes I did, thank you mate. Wrong resistor value somewhere.

Everything is pretty much working except for one overall anomaly, affecting both channels - even in bypass.
I'm observing some noise/ripple in the higher frequencies...Very prevalent with a HF boost. The plots from RMAA explain all....

It's quite audible, even though the unit is very quiet and hum free with no audio passing. With audio present  you can hear this 'ripple'.

Did you ground your pcbs ? I haven't done that and I am wondering if that's where my problem is?

Thanks a lot

I had ripple on a band which turned out to contain a cold solder in one of the cold solder (I realised at some point, the ripple only occurred when I had it over a specific frequency and checked the spots). That may be worth checking out!? Also, check for shorts/near shorts on the switch.

Remember, the shelf is separate from the bells, so you are switching to a totally different part of the circuit/different part of the switch between the two. If you see a problem in one and not the other,.

I am not sure what you mean about grounding the PCBs. I connected the ground points to chassis as marked in the schematic, of course, but maybe "grounding the PCBs" covers something I am not aware of.

Gustav

Thanks Gustav, I don't think the problem is specific to a particular band though as you can see the ripple even in bypass. Also both channels exhibit the problem so probably not a cold joint unless both channels have the same cold joint.

I'm guessing it's something like a wrong component on both boards.

As for grounding PCB, what I meant was - do you have 0V pin on molex XLR connector connected to chassis?

Another thought was maybe the issue is related to the psu. I'm using the Calrec psu here. This board is obviously common to both channels so that's a thought... (Since the problem affects both boards) Although the voltages from psu board are stable and correct.

Thanks again

EDIT: some sound clips to help further describe the problem:

- First clip is a  short unprocessed 1khz sine wave as a reference:
https://www.dropbox.com/s/uf18igqs1ui3lfu/sine_wav.mp3?dl=0

- Second clip is  then the exact same tone as above but this time through the net EQ in circuit but with no boost or cutting on any bands:
https://www.dropbox.com/s/r1lt4xuu2du5tq2/sine_wav_netEQ_BYP.mp3?dl=0

If you toggle between the two clips you can clearly here that something is a miss on the net EQ clip. It almost sounds like there is weird resonance in the high end, in line with what you can see in the frequency plots posted. The problem present in bypass is then of course exacerbated when doing a HF boost etc.
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on January 22, 2015, 12:07:05 AM
thanks for the help, guys.  working on frequency calculations now.  i found harpo's spreadsheet :)

thanks,
 - nick
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 28, 2015, 09:29:43 PM
Sorry to keep hijacking this thread but just looking for input on this issue I am having.

As per the attached frequency response graph, there is a "ripple" in the high frequencies when the EQ is engaged. As it turns out this is not an issue when both channels are in bypass mode.

This "ripple" manifests itself audibly as a kind of resonant/oscillating sound in the high frequencies as soon as the channels are taken out of bypass - even with no cutting or boosting occurring on any bands.

It is less obvious on a whole mix but with a sine wave test signal it is quite dominant and is driving me crazy!

I have been through the input and output stages with a fine tooth comb but cannot find any wrong components.

Truly appreciate any pointers or theory's anyone may have that could assist!
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on January 28, 2015, 10:18:38 PM
Frazzman,
It's hard to tell from the MP3 files, but it sounds like distortion of some kind. Maybe an impedance mismatch or level too hot on the record input?  Does the problem go away if you patch the eq out (disconnect the eq in and out and plug the wires together to capture just the signal looping through the cable)?

 - nick
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 28, 2015, 11:45:09 PM
Frazzman,
It's hard to tell from the MP3 files, but it sounds like distortion of some kind. Maybe an impedance mismatch or level too hot on the record input?  Does the problem go away if you patch the eq out (disconnect the eq in and out and plug the wires together to capture just the signal looping through the cable)?

 - nick

Hey Nick,
Thanks for the reply. No issue when running the cables in a loop... Flat response...
The levels are adjusted to meet what RMAA wants, adjusted for -1 in the software.

As I mentioned there's a slight ripple in bypass on the frequency response curve but I can't hear a problem in bypass.

It seems as soon as the eq is engaged (out of bypass) that the problem occurs - even with no boost or cut on any bands.

The frequency response I provided was with a HF boost just to show the problem at it's worst. It seems to be exacerbated by boosting the high frequencies but it is still there regardless.

It's a total head f%#^!

Thanks for the reply mate.

Edit: FWIW - it's running into an RME fireface 800 (running at +4) incase someone has maybe encountered a similar problem , I doubt it's related but can't hurt to mention.
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on January 29, 2015, 02:53:22 AM
Have you checked for oscillation with a scope and square wave combo?

What kind of THD figures are you getting in RMA for a loopback and for the unit?

Are you sure you are running the RMA sweeps at low enough levels to avoid clipping on output or input?
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 29, 2015, 04:52:52 AM
Have you checked for oscillation with a scope and square wave combo?

What kind of THD figures are you getting in RMA for a loopback and for the unit?

Are you sure you are running the RMA sweeps at low enough levels to avoid clipping on output or input?

RMAA levels are definitely low enough... I wish they weren't as it would be an easy fix. Damn.

Anyway, the figures are pretty alarming:

FF800 with In/Out level set for -1.5dB which is what RMAA seems to like.

Loopback - THD: 0.0015
Net EQ - circuit in but no boost or cut on any band - THD: 0.763

I don't have a scope unfortunately so I'm behind the 8 ball for sure.

Cheers for your help. I will persevere... such is the joy or (un)joy of DIY!
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on January 29, 2015, 11:54:44 AM
If that's -1.5dBFS it seems awfully high, any small response deviation or gain will cause your RMA rig to clip.  I'd be running that at at least -6dBFS, sure you'll have a 6dB higher noise floor but that's not a big deal IMO.

So it definitely looks like you have oscillation.  Have you built this with super trick op amps or the stock NE5532?

Title: Re: Barry Porter "Net EQ"
Post by: kante1603 on January 29, 2015, 12:13:25 PM
If that's -1.5dBFS it seems awfully high, any small response deviation or gain will cause your RMA rig to clip.  I'd be running that at at least -6dBFS, sure you'll have a 6dB higher noise floor but that's not a big deal IMO.

Exactly what I thought!
Also in the general RME preferences check the i/o presets for proper high,4dBU,-10dBV or Low settings!These alter the reference points!


Good luck,


Udo.


Edit:For potentially important infos here on pages 43 & 45,tech. data start at page 82:


http://www.rme-audio.de/download/fface800_e.pdf (http://www.rme-audio.de/download/fface800_e.pdf)


So e.g. the outputs are set to "high" means +19dBu for 0dBFS etc.,that would be on the pretty high side.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 29, 2015, 04:48:25 PM
Hey guys,

Cheers for helping out.

Just to clarify, when I referred to those input and output levels I was referring to the levels in RMAA as per the attached pic. I basically just adjust the in and out faders in totalmix until RMAA is happy. The FF800 is set for +4dbu.

I'm using standard ne5532s, I haven't substituted these for anything more elegant. Admittedly, I did buy a bulk lot of these from ebay - I'm hoping maybe they're bad quality but I doubt it as I've used them in other builds without issue.

I was thinking the fault must be in the input or output stages since the problem is present even with no boost or cut on any band....
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on January 29, 2015, 06:26:30 PM
I would ignore the RMA suggested levels, that is sailing way to close to the wind for a device with any gain at any frequency.  That said I don't think that's your issue.

Do you have any local access to a buddy with a scope?   That's really the best tool to track down the issue as you can feed a square wave in and scope after the input stage, after the EQ bands, and again after the output stage.

It would probably also be a good idea to confirm that your PSU bypass caps on the NE5532 are all the right value, did you measure each one as it went in?
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 29, 2015, 07:11:24 PM
I would ignore the RMA suggested levels, that is sailing way to close to the wind for a device with any gain at any frequency.  That said I don't think that's your issue.

Do you have any local access to a buddy with a scope?   That's really the best tool to track down the issue as you can feed a square wave in and scope after the input stage, after the EQ bands, and again after the output stage.

It would probably also be a good idea to confirm that your PSU bypass caps on the NE5532 are all the right value, did you measure each one as it went in?
Yep, all those 100nf caps are ok. I tried dropping my input and output levels drastically but it didn't affect the oscillation/distortion. It was prevalent even with low levels.

I don't know anyone who has a scope but I'm going to try and find one!

Just a thought - in regards to r20 and r26, these have been omitted as per the guidelines in Barry's doc, I take it that they don't need to be jumpered right ?
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on January 30, 2015, 03:11:01 AM
Yep, all those 100nf caps are ok. I tried dropping my input and output levels drastically but it didn't affect the oscillation/distortion. It was prevalent even with low levels.

Cool.  Good practice to run that at lower levels especially if you are looking at EQ band sweeps with gain.

Quote
I don't know anyone who has a scope but I'm going to try and find one!

It will make light work of this.


Quote
Just a thought - in regards to r20 and r26, these have been omitted as per the guidelines in Barry's doc, I take it that they don't need to be jumpered right ?

Just took a quick look and both should be omitted completely and not jumpered.

Are your inputs and outputs to your RMA rig balanced?  If so perhaps you can make a cable to unbalance them one at a time by connecting pin 3 and ground.  Then you might be able to inject a balanced signal and probe the circuit with an unbalanced alligator clip - at several points along the circuit to see where the oscillation is creeping in?

Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 30, 2015, 03:45:46 AM
Yep, all those 100nf caps are ok. I tried dropping my input and output levels drastically but it didn't affect the oscillation/distortion. It was prevalent even with low levels.

Cool.  Good practice to run that at lower levels especially if you are looking at EQ band sweeps with gain.

Quote
I don't know anyone who has a scope but I'm going to try and find one!

It will make light work of this.


Quote
Just a thought - in regards to r20 and r26, these have been omitted as per the guidelines in Barry's doc, I take it that they don't need to be jumpered right ?

Just took a quick look and both should be omitted completely and not jumpered.

Are your inputs and outputs to your RMA rig balanced?  If so perhaps you can make a cable to unbalance them one at a time by connecting pin 3 and ground.  Then you might be able to inject a balanced signal and probe the circuit with an unbalanced alligator clip - at several points along the circuit to see where the oscillation is creeping in?

Good advice, thank you....

I'm regards to a signal probe - perhaps something like this :

http://web.archive.org/web/20050310014839/http://www.diyfactory.com/data/mbsignaltracing.htm

Mnats had a link on his site to this page and I made one of these probes but never had a need for it... (Until now)
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on January 30, 2015, 08:12:17 AM
These -different project- posts from you might be related to your problem ...
Just have an issue with a the Calrec mini PSU board. Basically I etched one to use for another projector (2x net EQ). Anyway, I used alternate regulators to get a 18v supply. The only issue is on my 30VA toroid, the secondaries seem to be a bit hotter than normal. So I end up with about -/+ 20V rather than 18v.
20V at unload condition? That is OK in most cases, try that with some load and measure again, BTW if You use NE5532 op amp that's OK (+/-22V Max).

Thanks for the quick reply....yes at unload - actually closer to 21v

 It turns out I'm an idiot and I accidentally ordered a 30va 2x25 instead of 2x18...
Will 7818 and 7918 regs play nice with this extra voltage ?
The net eq is jam packed with ne5532s so I'm glad to hear they will cope with the surplus voltage...
With your 2x25VAC secondaries unloaded and kept a secret mains transformer in front you operated the fixed voltage regulators above their abs.max. 35VDC input voltage (and as well maybe the storage caps), so these might be damaged and maybe still are with your now 2x18VAC transformer in front. If you once have connected this maybe faulty supply to your NetEq pcbs (from Gustav or self etched as well?), not all of the populated NE5532s might have survived. Just an idea.
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on January 30, 2015, 01:18:50 PM

Good advice, thank you....

I'm regards to a signal probe - perhaps something like this :

http://web.archive.org/web/20050310014839/http://www.diyfactory.com/data/mbsignaltracing.htm

Mnats had a link on his site to this page and I made one of these probes but never had a need for it... (Until now)

I don't think you need to go that far.  Without a scope what you are looking to do is measure just parts of the circuit through RMA, first input stage, then after first eq bands, then after HPF, then after output stage.  It should help you find the area of the circuit that's oscillating.

To do that you'll need to go balanced out of and unbalanced in to your RMA.  It's crude but lacking a scope it could help narrow down the trouble spot.
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on January 30, 2015, 03:36:17 PM
hi all,
i'm currently working on my first build and have a few questions about the harpo spreadsheet with frequency calculations and the resistor calculations for stepped switches.

the resistors and diagram are very clear and i understand the center-tapped pot replacement for the level switches.  we are making a string of resistors that all add together from the pole/filter to the boost/cut with the middle of the string attached to ground.  even steps make for even resistor values.  they all add up to 5k on each side. that all makes sense to me to replace 10k linear pots.  i order the values in the column "closest e96" of 500R and count for the quantity.  they are all the same and it makes sense for a linear pot they are the same value on every step.

my question is with the Q and frequency selectors.  they are also center tapped linear 10k pots, but the calculator does not give a string of similar values like the level calculator.  i'm using even steps, so shouldn't the values also be evenly spaced?  from what i see i'm order ing one 1k, one 953R, one 845R, etc...  does this seem right?  maybe i'm misunderstanding this?  am i going to use separate values for each step and wire them independently?  not like the string of resistors for the level switch?  they each seem to be 500R apart or so, could i wire them like the level switch with all the same 500R value and re-create the 10k pot?  are there noise implications?

i know that's a lot of questions, but that part of the spreadsheet hasn't quite clicked with me yet.

thanks,
any clarification would be nice.

 - nick
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on January 30, 2015, 05:14:01 PM
my question is with the Q and frequency selectors.  they are also center tapped linear 10k pots, but the calculator does not give a string of similar values like the level calculator.

Welcome Nick, good to have you here.

Just a small correction, the Q and frequency pots/rotaries are not center tapped.

Cheers,
Ruairi
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on January 30, 2015, 05:18:35 PM
Plus they are log pots. You can build the resistor chain the same. Check back through the thread for wiring.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on January 30, 2015, 06:00:08 PM
These -different project- posts from you might be related to your problem ...
Just have an issue with a the Calrec mini PSU board. Basically I etched one to use for another projector (2x net EQ). Anyway, I used alternate regulators to get a 18v supply. The only issue is on my 30VA toroid, the secondaries seem to be a bit hotter than normal. So I end up with about -/+ 20V rather than 18v.
20V at unload condition? That is OK in most cases, try that with some load and measure again, BTW if You use NE5532 op amp that's OK (+/-22V Max).

Thanks for the quick reply....yes at unload - actually closer to 21v

 It turns out I'm an idiot and I accidentally ordered a 30va 2x25 instead of 2x18...
Will 7818 and 7918 regs play nice with this extra voltage ?
The net eq is jam packed with ne5532s so I'm glad to hear they will cope with the surplus voltage...
With your 2x25VAC secondaries unloaded and kept a secret mains transformer in front you operated the fixed voltage regulators above their abs.max. 35VDC input voltage (and as well maybe the storage caps), so these might be damaged and maybe still are with your now 2x18VAC transformer in front. If you once have connected this maybe faulty supply to your NetEq pcbs (from Gustav or self etched as well?), not all of the populated NE5532s might have survived. Just an idea.

Hey Harpo,

Thanks for the reply. I didn't actually connect the PSU to the mainboard at that stage. All I did was connect the (wrong) toroid to my self etched Calrec PSU.

When I measured the voltages and observed that they were too high, I stopped and replaced the toroid with the correct 2x18v one.

So all in all - the circuit never saw this increased voltage...
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on January 30, 2015, 06:24:27 PM
Plus they are log pots. You can build the resistor chain the same. Check back through the thread for wiring.

Oh, I'll have to look at the schematic again. I thought the boost/cut, frequency and Q were all 10k linear. The HPF is 20k reverse log though...  I'll go double check

 - Nick
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on January 30, 2015, 08:07:54 PM
Plus they are log pots. You can build the resistor chain the same. Check back through the thread for wiring.

No.  The original circuit and notes from Porter are very clear that it was designed for all pots to be 10k linear for ease of sourcing, with center taps on the gain pots only.

Of course you can go log on the frequency pots/switches and remove the law bending resistors that Porter used to make linear work.

Log is not suitable for either Q or Gain switches.  I've never seen log used in either position in any SVF design,
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on February 05, 2015, 07:52:41 PM

Good advice, thank you....

I'm regards to a signal probe - perhaps something like this :

http://web.archive.org/web/20050310014839/http://www.diyfactory.com/data/mbsignaltracing.htm

Mnats had a link on his site to this page and I made one of these probes but never had a need for it... (Until now)

I don't think you need to go that far.  Without a scope what you are looking to do is measure just parts of the circuit through RMA, first input stage, then after first eq bands, then after HPF, then after output stage.  It should help you find the area of the circuit that's oscillating.

To do that you'll need to go balanced out of and unbalanced in to your RMA.  It's crude but lacking a scope it could help narrow down the trouble spot.

I'm still digging away here on my problem. I ended up building the signal probe as I thought it would be useful.

So far the probing has me thinking that the issue is in the input stage. I have 1khz sine wave feeding in which sounds ok until I get to C7/R11 where it sounds to me like it is becoming slightly distorted.

I then probed the output stage components and it sounded to me like the distorted/oscillating signal was present at every point, therefore I figured that the problem is not in the output stage as I should have been able to detect a point where it goes from 'good' to 'bad' if it was being introduced in the output stage.

The problem is that listening to a sine wave with varying (subtle) differences plays tricks on your ears.

I have a few more observations/questions
- THD is at 0.2 when the unit is in full bypass. The problem is then worsened when the circuit is in (even with all bands bypassed), THD rises to nearly 0.7
- If the problem is present in bypass can that mean that I can at least exclude the areas in the circuit pertaining to each of the bands?  Can I concur that the problem has to be in the input or output stage?

Hopefully I am getting closer to narrowing down the problem... Thanks again for everyone's help
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on February 05, 2015, 08:07:18 PM
try replacing U5...  swap with U6 maybe?  see if the problem migrates to output stage only.  that would indicate a bad IC, i would think,...

 - nick
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on February 05, 2015, 08:31:35 PM
try replacing U5...  swap with U6 maybe?  see if the problem migrates to output stage only.  that would indicate a bad IC, i would think,...

 - nick


Thanks Nick, yep tried that...

I replaced the ICs already but they are all from the same "batch", I've got some "fresh" ICs coming in soon for the sake of being thorough
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on February 06, 2015, 02:20:40 AM
0.2% distortion in bypass is awfully high, I need to look at the schematic again but from memory it's a full relay bypass.

What does your analyzer rig measure from output to input?  Within nothing in line.

I didn't mean for you to probe with tone and ears, use your probes to measure the distortion with your analyzer, again isolating each stage.

I would never buy ICs from ebay, too many fakes these days!  Hoping that maybe that is part of your issue.

Title: Re: Barry Porter "Net EQ"
Post by: druu on February 06, 2015, 04:34:03 AM
0.2% distortion in bypass is awfully high, I need to look at the schematic again but from memory it's a full relay bypass.

The unit uses relay to bypass but will only pass audio when powered on. So it's not true relay bypass by the schem.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on February 06, 2015, 04:34:25 AM
0.2% distortion in bypass is awfully high, I need to look at the schematic again but from memory it's a full relay bypass.

What does your analyzer rig measure from output to input?  Within nothing in line.

I didn't mean for you to probe with tone and ears, use your probes to measure the distortion with your analyzer, again isolating each stage.

I would never buy ICs from ebay, too many fakes these days!  Hoping that maybe that is part of your issue.

Hi there,

Yeah the THD is ridiculously high, even in bypass. With nothing inline it's almost 0.

I've used RMAA to bench mark many other builds and it's always looked ok. This is the first time I've incurred something so severe.

In a normal test passing some drums for example , the problem is obvious but I can still hear respective the boost and cuts, it actually sounds quite nice if you can get passed the weird sound in the background. It almost sounds like radio noise (but it's not...).

I will use the probe in conjunction with RMAA, I just thought that the problem is so evident under normal circumstances that I thought it would be just as evident under test circumstances - that said, listening to a sine wave for an hour does funny things to your brain !

I'm holding hope that it's dodgy opamps, I  am guilty of  buying a bulk amount of ne5532s on ebay. They always worked fine in the ssl stuff that Id built.

Thanks for your help!

EDIT:
- Here are the metrics from RMAA

1) BYPASS:
(https://dl.dropboxusercontent.com/u/108741277/neteq-bypass.png)

2) CIRCUIT IN - all bands bypassed
(https://dl.dropboxusercontent.com/u/108741277/neteq-in-bands_bypassed.PNG)

3) FF800 Interface loopback
(https://dl.dropboxusercontent.com/u/108741277/ff800-loopback.PNG)


Title: Re: Barry Porter "Net EQ"
Post by: frazzman on February 06, 2015, 04:36:55 AM
0.2% distortion in bypass is awfully high, I need to look at the schematic again but from memory it's a full relay bypass.

The unit uses relay to bypass but will only pass audio when powered on. So it's not true relay bypass by the schem.

Thanks man, you're right... My d-la2a is relay bypass too but passes audio with no power.

I'm just trying to work out if it's mainly the input and output stages that are in effect when in bypass, aside from the relay circuitry of course...
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on February 06, 2015, 09:27:59 AM
The relay bypass does not bypass the input or output stages. In bypass signal passes through the input stage all the way to C7 and goes directly to C30 in output stage. Still lots of parts in the signal path even in bypass.

 - nick
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on February 08, 2015, 05:21:38 AM
The relay bypass does not bypass the input or output stages. In bypass signal passes through the input stage all the way to C7 and goes directly to C30 in output stage. Still lots of parts in the signal path even in bypass.

 - nick

Thanks Nick!

There's absolutely no doubt in my mind that my problem is in the input stage.

Signal probing at C7, I can hear the distortion/oscillation. Just trying to work out what point it kicks in.

I tried some "known working" opamps but no luck!

Thanks for your help
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on February 08, 2015, 12:40:00 PM
0.2% distortion in bypass is awfully high, I need to look at the schematic again but from memory it's a full relay bypass.

The unit uses relay to bypass but will only pass audio when powered on. So it's not true relay bypass by the schem.

Thanks man, you're right... My d-la2a is relay bypass too but passes audio with no power.

A little off topic.

 I think of it as more correct to use relays as: Resting position = most natural path.

So when I do "hard" bypass, the unit will not pass audio with no power, since I see bypass as the intrusive state.  It still jumps the input to the output when I send voltage to the coil and make the switch jump. 

I just want to make sure I dont label anything incorrectly, so are you saying that the correct terminology would not be hard bypass for what I am doing?

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: druu on February 08, 2015, 04:48:56 PM
Hard/True bypass means the in ties straight to the out when in bypass, completely skipping the circuit. Whether you have this in the relays 'resting' state is up to you but generally is the normal practise.

The BPEQ uses a 'buffered' bypass that maintains the in and out buffers and bypasses the main circuit but of course still needs power for the signal to 'skip' through when in bypass.

I'm currently waiting for some bypass PCB's to arrive to add a 'true' bypass to my unit as I'd rather not have my BPEQ turned on at all times to use another piece in my analog chain.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on February 10, 2015, 04:56:53 PM
Got some spare time to take another look at mine.
Power issue is solved no more 10r smoking and everything lights up, relays click etc etc 8)
Next step is some test.
Title: Re: Barry Porter "Net EQ"
Post by: druu on February 10, 2015, 06:34:00 PM
Got some spare time to take another look at mine.
Power issue is solved no more 10r smoking and everything lights up, relays click etc etc 8)
Next step is some test.

Nice. What was it? Swapped +/-18v wires from PSU?
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on February 11, 2015, 04:41:41 AM
Got some spare time to take another look at mine.
Power issue is solved no more 10r smoking and everything lights up, relays click etc etc 8)
Next step is some test.

Nice. What was it? Swapped +/-18v wires from PSU?

I put it down to 2 bad ebay PSU in a row, failed regulators. I got a vari psu from Gus and works perfect now. I was chasing my tail there for a bit.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on February 17, 2015, 12:03:59 PM
A couple of things presented themselves in the right channel.

Mostly freq selection switch with only the last 90 degress of selection working the rest of the switch is boosting the entire spectrum. Cap problem?

right HPF drops volume when engaged.

Not major problems but does anybody have any hints.

Best
Peter
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on February 18, 2015, 03:04:50 AM
A couple of things presented themselves in the right channel.

Mostly freq selection switch with only the last 90 degress of selection working the rest of the switch is boosting the entire spectrum. Cap problem?

right HPF drops volume when engaged.

Not major problems but does anybody have any hints.

Best
Peter

Would check the resistors on the switch at the point between where it works and it doesn't (check for a bad solder connection with your meter)

Would compare left/right channels for your HPF problem. See schematic for what is switches in on the HPF setting. Its a pretty simple signal path that way through.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on February 18, 2015, 03:55:34 AM
Thanks Gus, I figured it was a switching problem last night checked the board and everything is fine.
The resistor chain checks out on the MM going to pull it out of the EQ tonight and check it thoroughly

Really nice eq of what I heard so far. I think I might need a second ::)

Edit: So it turned out the switch was missing the internal part of the wiper. Guess that one got through QC. Luckily there are some spare switches laying around.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on February 23, 2015, 06:17:06 AM
Just when I was about to pack it in and check myself into the mental institution...

I got to the bottom of my tricky problem. It's kind of embarrassing...

It was the damn toroidal transformer, or more so it's internal location in the enclosure. If I moved the toroid about 12" from the unit the noise disappeared.

After months of chasing my tail I'm very relieved.

I think I will build a separate enclosure for the psu board and toroid.

Gustav - I seem to recall you housed your psu seperately, any tips?

Thank you to all who helped me!
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on February 23, 2015, 03:24:34 PM
Just when I was about to pack it in and check myself into the mental institution...

I got to the bottom of my tricky problem. It's kind of embarrassing...

It was the damn toroidal transformer, or more so it's internal location in the enclosure. If I moved the toroid about 12" from the unit the noise disappeared.

After months of chasing my tail I'm very relieved.

I think I will build a separate enclosure for the psu board and toroid.

Gustav - I seem to recall you housed your psu seperately, any tips?

Thank you to all who helped me!

Cant be me...

https://pcbgrinder.com/index.php?route=product/product&path=59_70&product_id=52 (check the internal picture, toroid on the back of the unit)

Worked like a charm here.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on March 06, 2015, 06:41:51 AM
Hi again guys,

Not sure what I was smoking when I thought I'd found my problem. Turns out I was wrong about the toroid.

To minimise anymore guesswork, I got my hands on an oscilloscope. The results are pretty telling but I wouldn't mind some insight as this is my first Forray into the scope world.

So far what the scope tells me is that my problem is not in the input stage as I had initially thought. I have injected a 1khz sine wave and recorded the following results. All feedback welcomed. Am I on the right track ?

See attached pic for probes shots at:
- Input XLR
- Output XLR:
- C7 (end of input stage?)
- R24 (start of output stage?)

Sorry for bombarding the thread and thanks for all your help.
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on March 06, 2015, 10:21:34 AM
Yes, you're on the right track.  Input looks good.  Something before the output looks messed up. And the output looks even more messed up.  Try measuring the input and output of each band too. Maybe opamp related or power supply related? Looks like it may be crossover distortion? 

 - nick
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on March 08, 2015, 10:49:19 PM
hi all,
i'm having trouble finding a 30uH common mode choke that fits the board in the input section.  what have you guys found in the past?  this is the closest i've found, but it's over 4x too big.

http://www.mouser.com/ds/2/445/744841330-86680.pdf

thanks,
  - nick
Title: Re: Barry Porter "Net EQ"
Post by: druu on March 09, 2015, 12:39:27 AM
I think most had trouble sourcing this part so a lot of us jumpered instead without any issues.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on March 17, 2015, 08:14:33 AM
Yes, you're on the right track.  Input looks good.  Something before the output looks messed up. And the output looks even more messed up.  Try measuring the input and output of each band too. Maybe opamp related or power supply related? Looks like it may be crossover distortion? 

 - nick

Hi nick/all:

I followed Nick's suggestion of tracing the signal through each of the bands. Given I am an oscilloscope newbie, I think I made some oversights in my previous measurements. This time I've tried to be more accurate in following the signal path as per the schematic.

I used the scope to measure the sine wave at the beginning of each band @ R99/R100/R101/R102.
- What I found was that the sine wave was already looking messed up at the beginning of the band(s) circuit path. Given this, I had to concur that the problem must be in the input stage.

It wasn't until I changed the VOLTS/DIV on the scope that I was able to see that at C7 in the input stage, the sine wave formation is already showing distortion.

I then went through tracing the signal path through the input circuit from the XLR input through to C7.

I checked off each component on the schematic as I went and noted any points where the sine wave form was incorrect. (Apologies for the crude image - my checklist + scope measurement)

The exact point where the distortion is introduced is at R32. (see attached).
I then measure the components immediately before R32:
- At U1-A pin 1 (opamp output) - sine wave form looks ok
- At R6 (10R resistor) - sine wave form looks ok
- At C12 (33pF cap) - sine wave form looks ok

Given that, I don't know what to make of the obvious problem introduced at R32.

Logically, the problem at R32 flows through the remaining components of the input circuit.
- The waveform is messed up at U5 pin 2(-) but not pin 3(+)
- The waveform is messed up at C33 (33pF cap)
- The waveform is messed up at R33 (3k3 resistor)

It is then most certainly messed up at C7 (end of input circuit).

Any thoughts? I just want to make sure I'm not misinterpreting what I am seeing on the scope and in turn possibly going down another rabbit hole...
Title: Re: Barry Porter "Net EQ"
Post by: biigniick on March 17, 2015, 09:32:43 AM
So, your problem is most likely U5 or C33, I think. The inverting input of U5, the negative feedback loop of C33 and R32 are all wired together. The components most likely to fail are IC's. Then caps. Resistors are unlikely to do this, I think. Try swapping U5 and see what happens.

 - nick
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on March 21, 2015, 04:29:22 AM
So, your problem is most likely U5 or C33, I think. The inverting input of U5, the negative feedback loop of C33 and R32 are all wired together. The components most likely to fail are IC's. Then caps. Resistors are unlikely to do this, I think. Try swapping U5 and see what happens.

 - nick

Hey Nick,
Thanks for your reply. I had a chance to try your suggestions but no luck :(

- replaced u1 and u5
- replaced c33 - had a film cap there, put in a ceramic just incase my batch of 33pf film caps was bad
- checked values (visually) of r32 and r33

I was hopeful that the c33 replacement was it.

Here's an exhaustive list of what I've tried (unsuccessfully):
- replaced opamps
- substituted "known working" psu board and toroid from my nite eq
- xlr rewire
- test with oscilloscope to narrow down problem area - problem appears to be localised to the input circuit

Running of ideas now... I'm stumped
Title: Re: Barry Porter "Net EQ"
Post by: Gold on March 21, 2015, 01:24:14 PM
Running of ideas now... I'm stumped

Look at the problem area carefully under a magnifying glass. Look for cracks, solder bridges and general nastiness. Clean the flux from the board with alcohol and a toothbrush. Reflow all the solder joints and check again under a magnifier. Bang on the problem area and components with a non conductive object like a pencil eraser. See if anything strange happens.
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on March 22, 2015, 03:40:33 PM
Here's an exhaustive list of what I've tried (unsuccessfully):
- replaced opamps
- substituted "known working" psu board and toroid from my nite eq
- xlr rewire
- test with oscilloscope to narrow down problem area - problem appears to be localised to the input circuit

Running of ideas now... I'm stumped
Just so I get it right, from all previous posts you reveiled the parts values of R6, C12, C33 and R33, you used a psu board and toroid from your nite eq, you tested the NetEQ at a frequency of 1kHz and you exchanged some parts (caps, opamps) with other kept a secret parts, except C33 that is now a 33pF ceramic cap.

It might be helpful to at least post your DC supply voltage numbers, the type of opamps used, the level of your 1kHz test frequency and if you fitted pots or substituted these pots with switched resistors because length and position of wires to these switches might make a difference, ... Some pics of your build might help as well.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on March 23, 2015, 05:28:22 AM
Hi all,

My net eq saga is finally over. The problem is finally resolved... For real. After many months and desperate posts.

Harpo - what you said to me in the beginning has once again proven to be true. It was the opamps...

With regards to testing the opamps - I (wrongly) assumed in the past that I was dealing with the possibility of only 1 faulty opamp. My approach then involved substituting  each opamp 1 by 1 (with a known "working" opamp). If the problem wasn't resolved, I changed the opamp back and moved onto the next.

Now that I have an oscilloscope I tried a more strategic approach. This time with a sine wave present, I measured sine wave at pin 1 of each opamp. If it looked distorted I replaced it.

On both boards I systematically replaced the opamps until the frequency response was perfect. I had to replace U1,U2,U4,U5 and U6 on both boards.

Attached is the frequency response now (you will recall earlier how much of a ripple there was) THD was nearly 0.7 compared to 0.0015 now.

More likely than not, the opamps were fried when I had the neg and pos leads the wrong way around (misread schematic).

Thanks to everyone who helped me and took interest in my issue. I made some significant oversights here but I am glad for what I have learnt along the way and I now understand what an invaluable tool an oscilloscope is.

Thanks again
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on March 23, 2015, 05:42:42 AM
Hi all,

My net eq saga is finally over. The problem is finally resolved... For real. After many months and desperate posts.

Harpo - what you said to me in the beginning has once again proven to be true. It was the opamps...

With regards to testing the opamps - I (wrongly) assumed in the past that I was dealing with the possibility of only 1 faulty opamp. My approach then involved substituting  each opamp 1 by 1 (with a known "working" opamp). If the problem wasn't resolved, I changed the opamp back and moved onto the next.

Now that I have an oscilloscope I tried a more strategic approach. This time with a sine wave present, I measured sine wave at pin 1 of each opamp. If it looked distorted I replaced it.

On both boards I systematically replaced the opamps until the frequency response was perfect. I had to replace U1,U2,U4,U5 and U6 on both boards.

Attached is the frequency response now (you will recall earlier how much of a ripple there was) THD was nearly 0.7 compared to 0.0015 now.

More likely than not, the opamps were fried when I had the neg and pos leads the wrong way around (misread schematic).

Thanks to everyone who helped me and took interest in my issue. I made some significant oversights here but I am glad for what I have learnt along the way and I now understand what an invaluable tool an oscilloscope is.

Thanks again

Excellent news!

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on March 23, 2015, 05:44:11 AM
Congrats frazzman ;D
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on March 23, 2015, 06:27:02 AM
Thanks dudes. I'm really stoked. A few days ago I was pretty much ready to put it on the black market as I was so sick of looking at it.

Also thanks to my buddy Druu who helped me over many many dozens of emails.

Now back to making some music!
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on March 23, 2015, 11:34:30 AM
Thanks dudes. I'm really stoked. A few days ago I was pretty much ready to put it on the black market as I was so sick of looking at it.

Also thanks to my buddy Druu who helped me over many many dozens of emails.

Now back to making some music!

Never give up the DIY spirit.
Title: Re: Barry Porter "Net EQ"
Post by: therecordingart on April 07, 2015, 09:25:07 PM
Does anyone have these Gerbers? All of the links I've found are dead.
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on April 07, 2015, 10:50:30 PM
Gustav sells finished PCBs, why bother with Gerbers?

Title: Re: Barry Porter "Net EQ"
Post by: therecordingart on April 07, 2015, 11:03:03 PM
Gustav sells finished PCBs, why bother with Gerbers?

Because I fabricate boards for a living and it's easier for me to just make them.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on April 09, 2015, 06:36:02 AM
Gustav sells finished PCBs, why bother with Gerbers?

Because I fabricate boards for a living and it's easier for me to just make them.

Even this one ? It's a whopper in size and double sided
Title: Re: Barry Porter "Net EQ"
Post by: druu on April 11, 2015, 09:37:46 AM
https://www.sendspace.com/file/55klo1 :)
Title: Re: Barry Porter "Net EQ"
Post by: therecordingart on August 19, 2015, 11:42:53 PM
I bought two of these boards from Gustav, and they are populated with the exception of the pots. I want to replace the pots with rotary switches, but I can't figure out the math for the life of me to select the correct resistors. Can any of you folks help me out or point me in the right direction? I feel like an idiot, but can't seem to get my head around the schematic. Even the math for the gain isn't coming to me even though I know that the db formula for an inverting opamp is 20*LOG(Rf/Ri)...but for some reason I can't get the numbers to pan out and make sense.

I would be super grateful if one or more of you can school me on this.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 20, 2015, 12:37:37 AM
I bought two of these boards from Gustav, and they are populated with the exception of the pots. I want to replace the pots with rotary switches, but I can't figure out the math for the life of me to select the correct resistors. Can any of you folks help me out or point me in the right direction? I feel like an idiot, but can't seem to get my head around the schematic. Even the math for the gain isn't coming to me even though I know that the db formula for an inverting opamp is 20*LOG(Rf/Ri)...but for some reason I can't get the numbers to pan out and make sense.

I would be super grateful if one or more of you can school me on this.

Harpo posted some great cheat sheets in this thread.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: p0ulp on September 04, 2015, 08:27:04 AM
Hello, just ordered those board from gustav,  gathering part etc ... bref

I ll start it with pot and make it run first, but I m looking for stepped switch at last ... the thing is , it look like a pain to make, and a real source of disfunction for a bad solder( how do you call a guy soldering ? :D )  like me ...

Can someone guide me to make modular pcb for 24 position switch, 12 position switch etc, thanks to Harpo for his calculation sheet,  I m really new to eagle so I need some input :D... then  of course I would publish the PCB (selft etch friendly) for those wanting to etch their board

Would like to use Electrotech C4 switch, but hopefully whole those 24p switch have the same footprint and those pcb could be used with some other.

If that's a stupid idea for whatever reason, please let me know
Title: Re: Barry Porter "Net EQ"
Post by: therecordingart on September 04, 2015, 08:51:28 AM

Harpo posted some great cheat sheets in this thread.

Gustav

I found the one for freq, but how do I go about calculating the resistors for stepped gain?
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 04, 2015, 01:15:34 PM

Harpo posted some great cheat sheets in this thread.

Gustav

I found the one for freq, but how do I go about calculating the resistors for stepped gain?

Harpo posted some great cheat sheets in this thread.

http://groupdiy.com/index.php?topic=33256.msg611681#msg611681

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: p0ulp on September 19, 2015, 07:15:23 AM
Working on this unit too, and starting to order the "special" component for this build, and after whatching carefully the BOM and component overlay (thank you guys !)   I am still unable to find proper part reference for the 30uH self .. I ve found another one which is twice bigger and won't fit properly on the board.

( http://fr.rs-online.com/web/p/inductances-traversantes/6694197P/ )

I ve tried to find inside view of other people barry porter to catch any info but this component is in the top corner of the pcb and have no chance to even see how does the package should be like.

Also I m not sure about the variable (adjustable ?) capacitor , on the pcb track document , C36 is only relied by one pin I don't have the board but I suppose the two other pins are relied to GND plan of the board , please correct me if I m wrong ?  also C41 seems to have 2 pins, I don't find variale capacitor with 3 pins, my choice would be this one , which is in a good range , but only 2 pin ...

http://fr.rs-online.com/web/p/condensateurs-ajustables/2470423/

Please confirm me that it is the way that board have been designed, I have the same question about the trimmer P1 also ...

Please also note that poly capacitor package are mixed (5mm and 7.5mm) ... wouhou so fun :D

thank you
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 19, 2015, 10:37:33 AM
Working on this unit too, and starting to order the "special" component for this build, and after whatching carefully the BOM and component overlay (thank you guys !)   I am still unable to find proper part reference for the 30uH self .. I ve found another one which is twice bigger and won't fit properly on the board.

( http://fr.rs-online.com/web/p/inductances-traversantes/6694197P/ )

I ve tried to find inside view of other people barry porter to catch any info but this component is in the top corner of the pcb and have no chance to even see how does the package should be like.

Also I m not sure about the variable (adjustable ?) capacitor , on the pcb track document , C36 is only relied by one pin I don't have the board but I suppose the two other pins are relied to GND plan of the board , please correct me if I m wrong ?  also C41 seems to have 2 pins, I don't find variale capacitor with 3 pins, my choice would be this one , which is in a good range , but only 2 pin ...

http://fr.rs-online.com/web/p/condensateurs-ajustables/2470423/

Please confirm me that it is the way that board have been designed, I have the same question about the trimmer P1 also ...

Please also note that poly capacitor package are mixed (5mm and 7.5mm) ... wouhou so fun :D

thank you

I think most people just jump the inductors on the input instead of mounting them.

I can't remember what I did for the variable inductor, but board is set up for a standard 3 terminal, variable trimpot.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: p0ulp on September 20, 2015, 10:48:19 AM
Ok just to update , if everythings fit to the board I will rearrange the board that biasrock provided earlier, for now I ve ordered :

C86/C89   -  470n  -  5mm  Code commande RS 312-1481  / Code commande RS 191-991 / Code commande RS 108-2744 (Wima)
C56/C82  -   220n  -  5mm  Code commande RS 108-2722
C80              -   680n  -  5mm   Code commande RS 875-1983
C83/C59  -     47n - 7,5mm  Code commande RS 668-9993
C61/C84   -    10n - 7,5mm  Code commande RS 622-4634 Panasonic
C85/C63   -   2n2  -  7,5mm ebay
C77             -   6n8    -  7,5mm ebay
C81            -    1n      -   7,5mm ebay
Cxx             -    100n  -  5mm


I supposed that every capacitor in the nF range is polyester ( depends on the value the voltage specification can goes up to 400v  ... )  and pF is ceramic (multi/simple layer ?? )I have simple in stock but also ordered multi anyway , I ll make some research about what is better for this application if there is any difference .

Title: Re: Barry Porter "Net EQ"
Post by: rafafredd on September 21, 2015, 01:21:43 AM
You can use Polyester, but generally polypropylene will perform better. Other types of film caps may also work great, like Polycarbonate, Polyethylene naphthalate, Polyphenylene sulfide, Polytetrafluoroethylene, etc may also work great.

For the smaller caps, use Film and Foil, or maybe Polystirene or MICA if you can find it.

If you have to go Ceramics, make sure you use only COG / NPO types (but I think you won't find it in the values needed). Anything else ceramics will be bad for this.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on September 26, 2015, 08:59:05 AM
Hi folks,

Having finally completed my dual mono build  - I stupidly agreed to building a stereo build for a friend. Yesterday I powered up the first channel. First test was with no ICs present - measured voltages on the sockets and all good voltages there.

Next step - I populated all the opamps and powered on. I Immediately got a plume of smoke around U2. It almost looked like it was coming from the 1000uf /6.3v BP caps. I couldn't tell for sure, however they all look ok and they certainly didn't leak.

Needless to say I pulled the power plug promptly. I noticed that my 10R/3W - R18 and R19 heated up and now look a tiny bit scorched but measure ok.

I removed all opamps and powered on again - all voltages checked out on opamp sockets. I progressively added in each IC one at a time and test powered on at each stage thinking that I would replicate the first scenario, but that didn't happen.

So now I'm in a situation where all opamps are present, no smoke now... Voltages look ok on the opamps. So in the absence of any other apparent issue, I wired up the XLRs and ran in a sine wave. It passed audio but the signal was relatively low - however there are no switches/pots connected except for a bypass switch.
 
Given the low output - I Can't help but think something is fried or maybe this is normal behaviour in the absence of any switches/pots ? Also I am puzzled about the root cause of the plume of smoke.

Maybe a duff opamp but It seems like a pretty drastic response. The second channel is ready to power up but I am reluctant to power it on until I come to some conclusion on the first channel.

Seeking any guidance/thoughts on this one.

Many thanks
Title: Re: Barry Porter "Net EQ"
Post by: p0ulp on September 26, 2015, 01:24:41 PM
I ve partially receive my component once again ( more to come, it's a never ending story) ... and would like to know if the decoupling capacitor on each opamp could be multi-layer ceramic ... I m running out of money for those fancy Wima 2,5mm pitchn and don't want to bend my regular 100nF 5mm to fit the pcb, also if there is no point (cause no audio path)  I ll skip high quality component on this one.

thank you
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on September 26, 2015, 11:31:12 PM
I ve partially receive my component once again ( more to come, it's a never ending story) ... and would like to know if the decoupling capacitor on each opamp could be multi-layer ceramic ... I m running out of money for those fancy Wima 2,5mm pitchn and don't want to bend my regular 100nF 5mm to fit the pcb, also if there is no point (cause no audio path)  I ll skip high quality component on this one.

thank you

Hi poulp - I used multi layer ceramics in those positions on my first build without any issue, doesn't seem to be any compromise in terms of fidelity and what not.
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on September 26, 2015, 11:34:35 PM
Hi folks,

Having finally completed my dual mono build  - I stupidly agreed to building a stereo build for a friend. Yesterday I powered up the first channel. First test was with no ICs present - measured voltages on the sockets and all good voltages there.

Next step - I populated all the opamps and powered on. I Immediately got a plume of smoke around U2. It almost looked like it was coming from the 1000uf /6.3v BP caps. I couldn't tell for sure, however they all look ok and they certainly didn't leak.

Needless to say I pulled the power plug promptly. I noticed that my 10R/3W - R18 and R19 heated up and now look a tiny bit scorched but measure ok.

I removed all opamps and powered on again - all voltages checked out on opamp sockets. I progressively added in each IC one at a time and test powered on at each stage thinking that I would replicate the first scenario, but that didn't happen.

So now I'm in a situation where all opamps are present, no smoke now... Voltages look ok on the opamps. So in the absence of any other apparent issue, I wired up the XLRs and ran in a sine wave. It passed audio but the signal was relatively low - however there are no switches/pots connected except for a bypass switch.
 
Given the low output - I Can't help but think something is fried or maybe this is normal behaviour in the absence of any switches/pots ? Also I am puzzled about the root cause of the plume of smoke.

Maybe a duff opamp but It seems like a pretty drastic response. The second channel is ready to power up but I am reluctant to power it on until I come to some conclusion on the first channel.

Seeking any guidance/thoughts on this one.

Many thanks
Just a second thought to my rather long winded post.
I guess if I could ascertain whether a level drop in the absence of pots/switches connected is "normal" then maybe my "issue" may be a non issue.

It's just that with the initial plume of smoke with all opamps in place, you can't help but wonder what's going on.

In saying that - with all new opamps in the sockets, no sign of smokes signals... Level drop is about -12db.
-/+ 18v reading on opamp pins are correct
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on September 27, 2015, 12:18:49 AM
Why are you powering up with no switches/pots? 

If I absolutely had to power up without the above I'd be simulating them with resistors.  You could try to understand how the circuit will work without pots connected but it would be much quicker to simulate using dummies.

Title: Re: Barry Porter "Net EQ"
Post by: frazzman on September 27, 2015, 01:05:22 AM
Why are you powering up with no switches/pots? 

If I absolutely had to power up without the above I'd be simulating them with resistors.  You could try to understand how the circuit will work without pots connected but it would be much quicker to simulate using dummies.

Only powering up as a diagnostic process I suppose, I haven't built my stepped switches yet - I just wanted to make sure my main boards are operating as expected before diving into  the switches.

I did the same on my previous build and I'm pretty sure it passed a full output signal with all the pots omitted. I've just got the bypass led and toggle switch wired up.

Anyway, I can't replicate it on my working unit as the switches are hard wired.

Cheers
Title: Re: Barry Porter "Net EQ"
Post by: druu on September 27, 2015, 01:40:08 AM
Just perform the voltage checks only for now. Don't bother testing with audio until completion. :)
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on September 27, 2015, 01:50:27 AM
I know man.... But my backwards logic is that I don't want to bust my chops on these monster 6 pole switches if the main board is cooked :)

I've checked all the -/+ 18v on the opamp sockets... Can you recall if there any other docs that reference other voltages on the board ? Otherwise I might have to unrack my dual mono unit and start comparing.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on September 27, 2015, 05:11:15 AM
I know man.... But my backwards logic is that I don't want to bust my chops on these monster 6 pole switches if the main board is cooked :)

I've checked all the -/+ 18v on the opamp sockets... Can you recall if there any other docs that reference other voltages on the board ? Otherwise I might have to unrack my dual mono unit and start comparing.

With no switches and pots, you have open input pins on quite a few opamps. I would have made sure to analyse the circuit or at put in dummy loads if it was beyond my capability. If nothing else, just to make sure I wouldn't be driving an opamp death somewhere

Looking at the schematic on the bands, I am having a hard time figuring out how  you are passing audio at all with no switches or pots installed, but I am not a wizard :)

Your safe bet is to apply the dummy resistors as Ruairi suggested, if you want to see how it behaves before wasting time doing switches and pots.


Gustav
Title: Re: Barry Porter "Net EQ"
Post by: frazzman on September 27, 2015, 08:38:25 AM
I know man.... But my backwards logic is that I don't want to bust my chops on these monster 6 pole switches if the main board is cooked :)

I've checked all the -/+ 18v on the opamp sockets... Can you recall if there any other docs that reference other voltages on the board ? Otherwise I might have to unrack my dual mono unit and start comparing.

With no switches and pots, you have open input pins on quite a few opamps. I would have made sure to analyse the circuit or at put in dummy loads if it was beyond my capability. If nothing else, just to make sure I wouldn't be driving an opamp death somewhere

Looking at the schematic on the bands, I am having a hard time figuring out how  you are passing audio at all with no switches or pots installed, but I am not a wizard :)

Your safe bet is to apply the dummy resistors as Ruairi suggested, if you want to see how it behaves before wasting time doing switches and pots.


Gustav

Hi Gustav,

Yes, you a right. I think it's my methodology which is a bit nonsensical. I did build one unit successfully with a few hiccups along the way.

I guess my aim was to tackle it in blocks but realistically that's not a very logical approach. I could easily sub in resistors as dummy pots, I probably should have considered that earlier.
Anyhow thanks for the feedback. It's onto the switches now.  This is an epic build, it's easy to want to try to dissect it into logical stages.
Title: Re: Barry Porter "Net EQ"
Post by: druu on November 03, 2015, 05:03:14 PM
I had some boards made up and if anyone is interested, I have three sets left over. Asking AUD$70/set (2) plus shipping/paypal. They are blue in colour.

Image here (http://www.amnet.net.au/~deerpark31/files/forsale/BPEQPCB.JPG). Please email (click my username > Email) as my PM box is almost full, cheers.
Title: Re: Barry Porter "Net EQ"
Post by: Unit-8 on November 21, 2015, 09:05:44 PM
After working in stealth mode all the time on it, I show you what I got.
But first of all I want to say thanks to Gustav to have provided the main PCBs, PSU PCB and for his valuable tips, Harpo for his own fantastic excel sheets and lots of useful informations, as well as to say thanks all those who have built this EQ before me and that have given many good ideas and solutions for its build. And last but not least, thanks to Barry Porter father of this terrific design which is passed to a better life some years ago. R.I.P.
And now some pics... Ok just one :)





Title: Re: Barry Porter "Net EQ"
Post by: Unit-8 on November 21, 2015, 09:08:27 PM
Another one?

Title: Re: Barry Porter "Net EQ"
Post by: Unit-8 on November 21, 2015, 09:10:50 PM
...and last one.



Title: Re: Barry Porter "Net EQ"
Post by: Gustav on November 22, 2015, 02:06:04 AM
...and last one.

What a great looking cable layout!

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on November 22, 2015, 01:10:22 PM
Not running short on the old Marlboro.... ;D

Tidy build.
Title: Re: Barry Porter "Net EQ"
Post by: Unit-8 on November 22, 2015, 02:53:12 PM
Yeah it's true! But all Marlboro cans you see are already empty... unfortunately  :-\
Title: Re: Barry Porter "Net EQ"
Post by: Vac11 on January 11, 2016, 02:40:33 AM
Hello,

can sombody explain me - how can I proper recalculate the Q value to 0,7 - 1 - 1,5 - 2 - 3 - 4 and gain value to +- 0,25 - 0,5 - 0,75 - 1 - 1,5 - 2 - 2,5 - 3 - 4 - 6 - 9?

Eventually how can I do a switch between the maximum amplitude (on +- gain switch with 20x 499R ) from 5 to 10 dB (0.5 vs. 1 db steps steps)? Would it be enough to make a separate switchable PCB with alternative values of R77,82,86,90 changed to 2K37 resistor?

Harpo´s excel sheet are very useful and clear (thank to Harpo!!!), but this not explain complexly...

Thx

M.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on March 27, 2016, 05:40:51 AM
like to share my version of the porter eq with you... unit has 6 bands now, first and last switchable to shelf by last q-position. all stepped with chiefdom switches. i did my own pcb with single band operation amplifier and also space for 2520 footprint.

(http://fs5.directupload.net/images/160327/i5kwo6vr.jpg)

Beautiful work.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: G-Sun on March 27, 2016, 07:15:36 AM
like to share my version of the porter eq with you... unit has 6 bands now, first and last switchable to shelf by last q-position. all stepped with chiefdom switches. i did my own pcb with single band operation amplifier and also space for 2520 footprint.
Yes, very nice looking indeed.
This is for mastering-use?
How does it sound/ work for you?
Pics of inside?
Title: Re: Barry Porter "Net EQ"
Post by: AD797 on April 18, 2016, 10:04:11 PM
Hello!

I am very close to finish my build and need to say: this thread is soo usefull! Thanx to all.
And now my question: i plan to do my last band up to 25k. Is there a limit/filter at the board? Or just calculate the switch and all is fine?

Thank you!
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on April 19, 2016, 07:55:06 AM
Welcome.
Replace the 20000 Hz value with 25000 in both peaking and shelfing calculation sections. Resulting recalculated resistive load of the driving circuit when keeping corresponding caps values seem still within NE5532s parts limits.
Title: Re: Barry Porter "Net EQ"
Post by: AD797 on April 19, 2016, 08:39:41 PM
Thank you Harpo! Youre calculation is great by the way. But i have a question regarding it... would it possible to do the chart with wish frequency´s and q´s? Or is there a way to do it anyway?

Title: Re: Barry Porter "Net EQ"
Post by: AD797 on May 06, 2016, 01:41:09 PM
ok, now i am at a point where i need some help.  ::)

i don´t own a oscilloscope but need to do the in/out balance.
would it be possible to replace the input section by a that 1206 and the output section by a that 1646? At which point of the circuit should i connect the out of the 1206 and at with point should i connect the in of the 1646? has someone experience here?

thank you!
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 31, 2016, 08:29:08 AM
ok, now i am at a point where i need some help.  ::)

i don´t own a oscilloscope but need to do the in/out balance.
would it be possible to replace the input section by a that 1206 and the output section by a that 1646? At which point of the circuit should i connect the out of the 1206 and at with point should i connect the in of the 1646? has someone experience here?

thank you!

Do you still need help with this?

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 31, 2016, 09:09:08 AM
I am redrawing the schematic in Eagle (I'll share the Eagle file when I am done with a first draft).

1.The values of the bipolar caps seem excessive throughout  (and needlessly bipolar?). Also, I can't see why C7 is even there. Am I missing something obvious?

2.I dont understand the transistor in the relay switching supply. As far as I can tell, it works as a current amplifier, but if thats it, I am guessing its there to limit current in the supply rail until the short distance from the transistor to the relay in the board design.

I found the current draw for the relays I use to be  very modest, so I have a really hard time figuring out how and why this is beneficial. I'm tempted to scrap the transistors and supply the 12V direct.

3. In and output seems like a design aimed at better-than-usual /best-possible CMR. Like the second last poster, Im leaning towards replacing this with a 120x/164x combo with no needed trimming.

Any input?

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on July 31, 2016, 02:37:46 PM
I am redrawing the schematic in Eagle (I'll share the Eagle file when I am done with a first draft).

1.The values of the bipolar caps seem excessive throughout  (and needlessly bipolar?). Also, I can't see why C7 is even there. Am I missing something obvious?

2.I dont understand the transistor in the relay switching supply. As far as I can tell, it works as a current amplifier, but if thats it, I am guessing its there to limit current in the supply rail until the short distance from the transistor to the relay in the board design.

I found the current draw for the relays I use to be  very modest, so I have a really hard time figuring out how and why this is beneficial. I'm tempted to scrap the transistors and supply the 12V direct.

3. In and output seems like a design aimed at better-than-usual /best-possible CMR. Like the second last poster, Im leaning towards replacing this with a 120x/164x combo with no needed trimming.

Any input?

Gustav


1. The value of the caps is indeed a bit high... lower values would work as well. Mr. B.P. was probably a bit paranoid about DC offset and phase shifting.

2. The transistor switching of the relais comes from good mixing desk design. It's better to have only a small switching voltage running through some distance of a mixing desk instead of a much higher current when switching the relais directly.
In mixing desks there is also the possibility of having some sort of logic  chips behind the switch functions which need to have a transistor as a relais driver.

3. THAT 1XXX series chips as in and output work just fine. I already did this in a prototype channel of the BP and it can easily replace the complete circuit blocks without any noticable change in sound.

You have to keep in mind that this EQ was designed to be used in a mixing desk, so some of design decicions where surely due to that.

Title: Re: Barry Porter "Net EQ"
Post by: Gustav on July 31, 2016, 03:08:45 PM
Thanks for covering it all, M.

On this point...


1. The value of the caps is indeed a bit high...

Unless theres something I am not incorporating for total R in RC calculations, I am seeing slots where even a 6,8uF poly would be plenty high, but of course, I am not considering  the DC offset and phase shifting mentioned.

I'll finish up drawing it and keep the bipolar caps for now.

When the porting of the existing circuit is done, I want to experiment with digital potentiometers and a little programming.

Gustav





Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 02, 2016, 09:50:33 AM
Last question before finishing up the first draft.

I attached a portion of the schematic


Is this correct?

RC filter (R73, C71), then a voltage divider (R71, R72), followed by a non inverting opamp (U12), functioning as a unit gain buffer?

In case it is correct - is the opamps input impedance affected by R73? I realise it wouldn't make much difference, being parallel to R71, but I am curious.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: abbey road d enfer on August 02, 2016, 12:06:56 PM
Last question before finishing up the first draft.

I attached a portion of the schematic


Is this correct?
Not knowing what's connected to R73, it's difficult to say if it's necessary or not. If it's directly connected to the output of an opamp, it's useless, if it is connected to a coupling cap, it's recommended/necessary/despised for DC removal.
Quote

RC filter (R73, C71),
No. It would be a high-pass (low-cut or DC removal) filter if C71 was before R73. ATM the HPF is the combo of C71 and R72+R71.
Quote
  then a voltage divider (R71, R72), followed by a non inverting opamp (U12), functioning as a unit gain buffer? 
That is correct.
Quote

In case it is correct - is the opamps input impedance affected by R73?
The input impedance of the opamp is not dependant on whatever resistor is connected there.  The impedance seen by whatever drives this circuit is affected by R73, although very little. The dominant branch is R72 + R71, for a total of 5.5k.  R73, with 100k accounts for only 5% in the input impedance of the stage.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 02, 2016, 01:36:27 PM
Last question before finishing up the first draft.

I attached a portion of the schematic


Is this correct?
Not knowing what's connected to R73, it's difficult to say if it's necessary or not. If it's directly connected to the output of an opamp, it's useless, if it is connected to a coupling cap, it's recommended/necessary/despised for DC removal.
Quote

RC filter (R73, C71),
No. It would be a high-pass (low-cut or DC removal) filter if C71 was before R73. ATM the HPF is the combo of C71 and R72+R71.
Quote
  then a voltage divider (R71, R72), followed by a non inverting opamp (U12), functioning as a unit gain buffer? 
That is correct.
Quote

In case it is correct - is the opamps input impedance affected by R73?
The input impedance of the opamp is not dependant on whatever resistor is connected there.  The impedance seen by whatever drives this circuit is affected by R73, although very little. The dominant branch is R72 + R71, for a total of 5.5k.  R73, with 100k accounts for only 5% in the input impedance of the stage.

Thanks for the correction and clearing up the rest.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 02, 2016, 01:45:58 PM
Heres a first draft - I am sure it contains other errors, but I know that...

Some footprints need to be corrected (bipolars, obviously, but also just the size of others, and anything else I might've missed).

Some values are probably wrong here and there.

Connectors for supply nets (nets not verified), and interface pins for relays were not added (use the invoke function for the relay pins)

Changes from the original.

- Replaced in/output circuits with THAT circuits
- Added an MS encoder and decoder
- Separated the shelving filters

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 04, 2016, 02:45:04 AM
I tried doing a single sided self-etch-friendly layout of the project, but had to give up and go double sided.

I dont know if its practical to self etch a double sided board, but if it is, there are not a whole lot of holes that need a through hole connection. This could be done using a component terminal as a stud and solder to the pads on both sides.

The project zip contains sch and brd file for 160 x 100mm layout. It loads into hobby Eagle's hobbyist license version, and fits a eurocard for self etch.

MainBPrev1
FilterBPrev1

I cleaned up the schematic drawing and values, but there may still be errors, and the project is untested. (I just realised, I forgot to run a DRC before uploading, but you can do that in Eagle yourself).

(look further down - new file up)

Its not perfect, but you can rip it up and create your own layout, if you have grievances. Please share if you come up with a good design :-)

Next

I started looking into this, because I wanted to play with digital pots and LCDs.

I had set my sights on the AD5204. Data sheet states a 30% tolerance chip to chip, but 1% tolerance within the chip, so I figured using it in gangs of 4 for this would be perfect

Unfortunately, I understood it to be some sort of digitally controlled relay matrix where signal path headroom would not be limited by the 5V max supply voltage. I realised I was wrong, but only after digging into coding and solutions.

Although I have found alternative 30V capable DCPs, I haven't found any quad packages, and for single or dual chips, the relative tolerance between them seems to make it impossible to get perfect, stereo tracking.

Any inputs for a forward direction would be welcome, since I am a little stumped for now.

I'd use Arduino to control it and share it openly. I am looking to learn and share.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: abbey road d enfer on August 04, 2016, 05:51:04 AM
Although I have found alternative 30V capable DCPs, I haven't found any quad packages, and for single or dual chips, the relative tolerance between them seems to make it impossible to get perfect, stereo tracking.
In that respect, you would be exactly in the same situation as using a "real" 'mechanical) pot, with an edge. Tracking, when used in potentiometer mode, would be much better.
There are ways to make sure the response of a circuit does not depends on the actual end-to-end value of a pot. But it would mean a redesign of the BPEQ.
Digital pots are perfect for the boost/cut in the BPEQ, but if you want to use them for frequency control, you will need to adjust the capacitor values.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 04, 2016, 11:59:12 AM
Although I have found alternative 30V capable DCPs, I haven't found any quad packages, and for single or dual chips, the relative tolerance between them seems to make it impossible to get perfect, stereo tracking.
In that respect, you would be exactly in the same situation as using a "real" 'mechanical) pot, with an edge. Tracking, when used in potentiometer mode, would be much better.
There are ways to make sure the response of a circuit does not depends on the actual end-to-end value of a pot. But it would mean a redesign of the BPEQ.
Digital pots are perfect for the boost/cut in the BPEQ, but if you want to use them for frequency control, you will need to adjust the capacitor values.

Thanks again for the input.

I found some pots that should work. I'll create a thread in the lab if I get anywhere with it and specific questions pop up, since these issues are not related to the NetEQ per se.

Hope it turns out to be as fun as I think it'll be (although, I am aware frustrations will arise).

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 14, 2016, 02:19:15 AM
Attached,

rev2 of the eagle files for the alternative layout I did.
LTSplice model of the EQ

I boiled it down to the 4 bell filters, changed the Q a bit, and added the MS (hasn't been tested yet).

I think thats it for now. I tried to make sure all Frequency and Q selectors ran on identical resistor ladders (thats a matter of taste and degree of OCD, of course).

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: rafafredd on October 13, 2016, 06:49:11 PM
I see some NetEQ units with lowpass filters. What circuit are you using for this? The original unit has only hi pass...
Title: Re: Barry Porter "Net EQ"
Post by: rafafredd on October 17, 2016, 09:32:18 AM
Bump. Anyone?
Title: Re: Barry Porter "Net EQ"
Post by: trashcanman on October 24, 2016, 06:54:29 AM
Attached,

rev2 of the eagle files for the alternative layout I did.
LTSplice model of the EQ

I boiled it down to the 4 bell filters, changed the Q a bit, and added the MS (hasn't been tested yet).

I think thats it for now. I tried to make sure all Frequency and Q selectors ran on identical resistor ladders (thats a matter of taste and degree of OCD, of course).

Gustav

Thanks for these. I just thought I'd mention that there's a broken connection on one of the diodes at the right output.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on October 25, 2016, 12:01:23 PM
Thanks for these. I just thought I'd mention that there's a broken connection on one of the diodes at the right output.

Thanks for the feedback. I just checked, and there is a dead-end trace, but that should be removed, not connected.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: rafafredd on October 31, 2016, 10:12:57 PM
Hey Guys... someone must have the answer to this:

"I see some NetEQ units with lowpass filters. What circuit are you using for this? The original unit has only hi pass..."

I posted it up there, and it was completely ignored.

Gustav, did you took the lo pass out of this?
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on November 01, 2016, 01:07:40 AM
Hey Guys... someone must have the answer to this:

"I see some NetEQ units with lowpass filters. What circuit are you using for this? The original unit has only hi pass..."

I posted it up there, and it was completely ignored.

Gustav, did you took the lo pass out of this?

I have added the LPF circuit myself since there is no such thing on the original pcb design.

The circuit is a simple active sallen-key filter based around an opamp and inserted just before the output stage of the EQ.

http://images.google.de/imgres?imgurl=http%3A%2F%2Fwww.changpuak.ch%2Felectronics%2Fimages%2FSK-LOWPASS.png&imgrefurl=http%3A%2F%2Fwww.changpuak.ch%2Felectronics%2Fcalc_08.php&h=229&w=508&tbnid=whLyqCt5mWCDoM%3A&docid=WBSt7khrSv_2bM&ei=eB8YWLeQFoH0UomukJAJ&tbm=isch&iact=rc&uact=3&dur=1880&page=0&start=0&ndsp=42&ved=0ahUKEwi3rMmx4YbQAhUBuhQKHQkXBJIQMwghKAMwAw&bih=1072&biw=1920
Title: Re: Barry Porter "Net EQ"
Post by: rafafredd on November 01, 2016, 03:12:23 AM
I see...

So, you are actually switching cap values??
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on November 02, 2016, 01:41:12 AM
I see...

So, you are actually switching cap values??

No, resistors R1 and R2 get switched to change the cutoff frequency
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on November 14, 2016, 12:19:05 PM
Harpo, or anybody in the know,
Just wondering if I want to have 12 frequency selections for each band, can I just pick 12 of the values I want from Harpo's spreadsheet? Or, do the resistors add up in series in a way that wouldn't allow this to work?
thanks,
JS
Title: Re: Barry Porter "Net EQ"
Post by: Harpo on November 15, 2016, 05:16:54 AM
maybe use my previously linked Excel-file "Porter_NetEQ_X_freqstep.xls" in order to overwrite the content of corresponding cells 'wanted step positions' in column F and change FI. 23 with 12 for your wanted 12 positions ...
same goes for center frequency range from / up to, just have an eye on parts limits and maybe adapt frequency setting cap value to archieve this ...
couldn't be so hard to do.
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on November 16, 2016, 08:11:12 AM
Perfect, thank you.
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on November 19, 2016, 10:38:05 AM
Anyone see any issue with substituting a THAT 1200-series line receiver, and 1600-series line driver for the input and output?
I assume you would inject the output of the lines receiver at C7 (after? or before?), and take the input of the line driver from either R24 or R25...

I've got Gustav's boards. I would use a couple of the small utility pcb's that DIYrecordingequipment.com sells for the THAT chips.
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on November 19, 2016, 12:11:09 PM
Anyone see any issue with substituting a THAT 1200-series line receiver, and 1600-series line driver for the input and output?
I assume you would inject the output of the lines receiver at C7 (after? or before?), and take the input of the line driver from either R24 or R25...

I've got Gustav's boards. I would use a couple of the small utility pcb's that DIYrecordingequipment.com sells for the THAT chips.


I quote myself:



3. THAT 1XXX series chips as in and output work just fine. I already did this in a prototype channel of the BP and it can easily replace the complete circuit blocks without any noticable change in sound.


You can insert your signal right after C7 and put the output stage directly after R24. You don't need all those DC blocking caps in front and after the THAT chips.
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on December 06, 2016, 08:40:18 PM
I'm putting together a Mouser cart for my build. I'll share it here once I've got it assembled.

So, what was the final decision on C8, C9, C23, & C24? The BOM and schematic say 1000 uF/6.3V film caps, which is an error, right?
What's the real value? Gustav's pcbs have a round pad in those positions, like you would use for an electrolytic.
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on December 07, 2016, 01:06:54 AM
Those are 1000uf bipolar, electrolytic caps.

Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on December 07, 2016, 10:50:56 AM
Thanks.
Now I'm looking at C15, C16, C64.
C15, for example, is a 33pf cap in the feedback path for U2-B. The pcb has a 9mm leading spacing for these. I haven't found a 33pf cap in that size (WIMA's a 5mm lead spacing, for instance).
What cap have you used here?
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on December 07, 2016, 01:38:01 PM
Thanks.
Now I'm looking at C15, C16, C64.
C15, for example, is a 33pf cap in the feedback path for U2-B. The pcb has a 9mm leading spacing for these. I haven't found a 33pf cap in that size (WIMA's a 5mm lead spacing, for instance).
What cap have you used here?

Just a ceramic capacitor with long leads that can be bend to fit the footprint.
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on December 08, 2016, 11:33:03 PM
Moving on... Transistors Q3 & Q1 are BC182's. They aren't stocked by Mouser any more. An internet search shows 2N3903 as substitute. The leads are reversed, though.
The NTE123AP is another possible substitute, but it isn't stocked by Mouser (which I would prefer).
Is there a better substitute?
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on December 09, 2016, 12:13:25 AM
Just use BC547. Those transistors only switch the relays and are not in the audio path at all.
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on December 13, 2016, 03:53:50 PM
I put together a Mouser cart and a slightly updated BOM for the Barry Porter eq:

Bill of Materials spreadsheet, includes copies of Harpo's stepped switch calculators:
https://www.dropbox.com/s/1pq3trtareuc8ub/Barry%20Porter%20EQ_BOM%20AND%20STEPPED%20SWITCH%20CALC.xlsx?dl=0 (https://www.dropbox.com/s/1pq3trtareuc8ub/Barry%20Porter%20EQ_BOM%20AND%20STEPPED%20SWITCH%20CALC.xlsx?dl=0)

Mouser Project:
http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=e2a0493bc6 (http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=e2a0493bc6)

This cart is for a build that uses pots for the frequency and Q controls (I'll add rotary switches later.) I'm using Grayhill switches for High Pass and Level, but I didn't include parts for them in the documents. But, I copied Harpo's calculators into the spreadsheet so you can decide how you want to set yours up.
Also, the BOM and cart don't include components for the input and output sections. I am going to use Collective Case's M/S matrix instead:
http://collectivecases.com/?product=mastering-grade-ms-matrix-pcbs (http://collectivecases.com/?product=mastering-grade-ms-matrix-pcbs)

All told, I'm up to about $1,000. That includes a case with blank front panel from Collective and mostly pots instead of switches, and knobs I already own.
Title: Re: Barry Porter "Net EQ"
Post by: trashcanman on December 27, 2016, 06:04:03 PM
Thanks for the feedback. I just checked, and there is a dead-end trace, but that should be removed, not connected.

Gustav

How did things go with this layout? I'm looking at maybe getting some of your boards made at some point and was wondering if you managed to get your design working.
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on December 28, 2016, 01:39:53 AM
How did things go with this layout? I'm looking at maybe getting some of your boards made at some point and was wondering if you managed to get your design working.

I havent tested it yet (life happened - won't have a bench to work at until february), but I do have a set you can get if you pay for shipping.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on January 02, 2017, 07:59:13 PM
I updated my earlier post with a modified BOM and Mouser Cart.
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on January 20, 2017, 01:30:37 AM
What is the purpose of J1 and J2? Why would I want to install this jumper?
Looking through photos on this thread, it seems like no one installed the jumper.
Title: Re: Barry Porter "Net EQ"
Post by: Majestic12 on January 25, 2017, 05:55:49 AM
What is the purpose of J1 and J2? Why would I want to install this jumper?
Looking through photos on this thread, it seems like no one installed the jumper.

This jumper connects the Audio Ground to the chassis ground. You don't really need it. It's just there in case you want to connect both grounds together (which in most cases isn't a good idea)
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on January 31, 2017, 01:44:21 AM
I got my Barry Porter eq working today. It's still a work in progress... stepped switches for Frequency and Q will come later. I'll also add mid/side capability with the Collective Cases MS Matrix soon.  (And a real faceplate, eventually.)

By using on-off-on switches with the gain controls I have boost/band bypass/cut all on one switch. Cool.

I used THAT 1200 & 1600 IC's for input and output instead of the I/O on the pcb. One problem now is that one channel is 0.8 db louder than the other. How could I balance them? I know I could adjust the feedback resistors on U2 (R13 & R14), but this would also change the amount of boost and cut on each channel (by changing the ratio of R13 & R14 to R77,82,86, &90).

Is there some way I could install a trimmer on each channel so I can fine-tune the channel balance? I could install a pad on one channel, but I think that would add a little Johnson noise from the extra resistors.

Title: Re: Barry Porter "Net EQ"
Post by: Harpo on January 31, 2017, 06:38:57 AM
...one channel is 0.8 db louder than the other. How could I balance them? I know I could adjust the feedback resistors on U2 (R13 & R14), but this would also change the amount of boost and cut on each channel (by changing the ratio of R13 & R14 to R77,82,86, &90).
A rheostat in series to R12 should decrease/fix it. A 1K trimmer in series to the 5K1 allows a 0...-1.55dB range, so will be dialed in about centered. Good luck
Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on February 01, 2017, 12:36:40 AM
Thanks, Harpo. I will order a trimmer to do that with.

Here's a pic. I've only played with it for an hour, but it sounds very nice. The low shelf sounded really nice across a mix, and the high is not grainy or harsh at all. Glad I built it.

Title: Re: Barry Porter "Net EQ"
Post by: skidmorebay on February 01, 2017, 12:38:00 AM
and the inside:
Title: Re: Barry Porter "Net EQ"
Post by: AD797 on March 02, 2017, 02:06:17 AM
Hello Gustav!

Seem´s i am to stupid to download your attachment... how is it working? I get always just the website data.
Like to try this new version!

Thank you!
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on March 02, 2017, 11:19:56 AM
Hello Gustav!

Seem´s i am to stupid to download your attachment... how is it working? I get always just the website data.
Like to try this new version!

Thank you!

Might be that you are clicking a link to an earlier revision that I removed - look at post 426 here - should be the "last" version attached.

I havent tested it myself yet, so feedback is welcome :)

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on March 09, 2017, 01:12:05 PM
Waiting for a few connectors to arrive to wire it up and see if theres any smoke to let out.

Did anyone try the design?

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: AD797 on March 13, 2017, 02:36:11 PM
Thank you Gustav, found it. But why do you use a 6u8 at the input of the 1646?  ???

Title: Re: Barry Porter "Net EQ"
Post by: Gustav on March 17, 2017, 09:37:42 AM
Thank you Gustav, found it. But why do you use a 6u8 at the input of the 1646?  ???

Its a standard DC blocking cap copy/pasted from the design notes of the chip.

For C63, you have C61 or C33, depending on the switched in path, so just leave it out.

Gustav

Title: Re: Barry Porter "Net EQ"
Post by: Gustav on March 17, 2017, 09:38:35 AM
I can verify the circuit is working.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on March 17, 2017, 11:17:28 AM
Just curious, has anyone done a side-by-side comparison to the Sontec EQ?
Thanks!
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on March 19, 2017, 10:32:35 AM
A real Sontec?  Not side by side but I have used 3 or 4 different Sontecs and I use a Porter every day for my mastering work (tweaked).  Despite the hoopla I have no love for Sontecs, they are fine but are too much of a service liability in my mind.  Sonically I absolutely prefer the Porter.

Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on March 19, 2017, 10:40:03 AM
A real Sontec?  Not side by side but I have used 3 or 4 different Sontecs and I use a Porter every day for my mastering work (tweaked).  Despite the hoopla I have no love for Sontecs, they are fine but are too much of a service liability in my mind.  Sonically I absolutely prefer the Porter.

Thank you!  I really liked the Massenburg (sp?) long ago (same idea as Sontec?) and have the 51X version (not built yet) but thought I might try something  different (NetEQ)
What did you tweak on the NetEQ?
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on March 20, 2017, 12:31:00 AM
One more question for the group, for those who used switches instead of pots.  How many "Q" positions did you incorporate?
Thanks!
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on March 20, 2017, 08:15:49 PM
Thank you!  I really liked the Massenburg (sp?) long ago (same idea as Sontec?) and have the 51X version (not built yet) but thought I might try something  different (NetEQ)
What did you tweak on the NetEQ?
Best,
Bruno2000

The Massenburg topology is very close to the Sontec and the build quality is much better.  The opamps used impart a different coloration but it's a good EQ.  That said I had one available to me for 3 years at my last space and I used it twice ever.

The Porter I use is not my build, the PCB was a Frank Lacy and the opamps are all tweaked.  Input and output sections are much simpler unbalanced affairs.  It sounds fantastic.
Title: Re: Barry Porter "Net EQ"
Post by: mross on April 07, 2017, 09:31:38 PM
The original unit is on eBay right now!  :)

http://m.ebay.com/itm/Barry-Porter-Mastering-EQ-/132142345625?hash=item1ec44c2d99%3Ag%3Ah6AAAOSwSlBY1H70&_trkparms=pageci%253Ad8792050-1bfa-11e7-b9c1-74dbd1a0ba42%257Cparentrq%253A4b2e694815b0a60637852ecbffff74db%257Ciid%253A1 (http://m.ebay.com/itm/Barry-Porter-Mastering-EQ-/132142345625?hash=item1ec44c2d99%3Ag%3Ah6AAAOSwSlBY1H70&_trkparms=pageci%253Ad8792050-1bfa-11e7-b9c1-74dbd1a0ba42%257Cparentrq%253A4b2e694815b0a60637852ecbffff74db%257Ciid%253A1)
Title: Re: Barry Porter "Net EQ"
Post by: peterbach on May 29, 2017, 02:42:55 AM
anyone has any Gerber files for the Barry Porter "Net EQ" ?
all links is dead  :-[
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on June 07, 2017, 03:39:11 PM
New Project!  Heating the iron now.......
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: Sinkia on June 07, 2017, 05:11:54 PM
New Project!  Heating the iron now.......
Best,
Bruno2000

May I ask where have you bought those wonderfull pcbs? :-)
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on June 07, 2017, 06:49:06 PM
May I ask where have you bought those wonderfull pcbs? :-)

Thank you!  I designed them myself, and I have a few extras.  I'm going to build up 2 stereo units, and will post as I go.
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: ruairioflaherty on June 08, 2017, 01:28:21 AM
Awesome Joe!

What have you added or taken away from the original design and layout?  Or put another way, why did you feel the need to design your own board?

Cheers,
Ruairi
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on June 08, 2017, 08:31:15 AM
Awesome Joe!

What have you added or taken away from the original design and layout?  Or put another way, why did you feel the need to design your own board?

Cheers,
Ruairi

Thanks Ruairi,
A several reasons.  1. Mental therapy.  2. to see how much I could cram in a small package.  Front panel will be 4"x7". 3. Added features (5 bands added HPF, added gain control, M/S encode/decode individually selected, optional XF output) 4. Mental therapy.
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on June 09, 2017, 03:41:05 PM
P.S.  That's 4"x7" for a stereo unit, and #5, I already had the Grayhill switches.........
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: febo2609 on June 09, 2017, 03:48:22 PM
I download a file and I can  not open brd file with eagle 5.8.0. What version open it ? Do you have gerber file for this eq?
Best regads.
Title: Re: Barry Porter "Net EQ"
Post by: frederickalonso on June 16, 2017, 06:59:38 PM
Another one done...

(http://i60.tinypic.com/2m5kkrt.jpg)

(http://i57.tinypic.com/9ssa3q.jpg)

Amazing!  :o ;D
Title: Re: Barry Porter "Net EQ"
Post by: trashcanman on June 20, 2017, 05:39:51 PM
I download a file and I can  not open brd file with eagle 5.8.0. What version open it ? Do you have gerber file for this eq?
Best regads.

Newest version of Eagle works for me.
Title: Re: Barry Porter "Net EQ"
Post by: gabriel on June 21, 2017, 06:44:40 PM
Hi everyone, I'm new here and I need your help, please!

I just finished my NetEQ and it sounds good, but I have a problem
When the equalizer is activated but al bands are baypaseed, everything is well, but when activating a band there is a very evident noise, mainly in the hi frequency band.
I use potentiometers for al controls, for gain I use a swithc on / off / on.
I check the connections, the elements, and there are no cold soldering, everything seems to be correct, but the noise persist.
Seems to be an electric noise coming from the psu, I thought to get it out of the box, but I have seen that in most of the eq that have built here have the psu inside, I would like to know if they have the same problem
Please if anyone can give me some idea of what may be happening

Thanks and regards to all
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on June 25, 2017, 11:48:50 AM
wasnt there something about the span of freq must be within 4 octaves per band otherwise instability/noise would accour..?


local bypassing of opamps is another one i can think of...
Title: Re: Barry Porter "Net EQ"
Post by: Cardinen on August 03, 2017, 09:45:50 AM
I can verify the circuit is working.

Gustav

Hi Gustav !

I'll like to try your design of this eq in the next months, i have a few questions:

- I'll split the channel bypass in L and R instead of stereo ( just using 2 relays) what will the MS do ? (single M-S bypass is possible?)
- Did you used 100uF bipolar caps like the original in the audio path or just standard audio electrolytic ?
- Have you encountered any problems in the project?

thanks  ;)
Title: Re: Barry Porter "Net EQ"
Post by: Gustav on August 04, 2017, 08:11:25 AM
Hi Gustav !

I'll like to try your design of this eq in the next months, i have a few questions:

- I'll split the channel bypass in L and R instead of stereo ( just using 2 relays) what will the MS do ? (single M-S bypass is possible?)
- Did you used 100uF bipolar caps like the original in the audio path or just standard audio electrolytic ?
- Have you encountered any problems in the project?

thanks  ;)


 If you think about how M/S works, you will realise what will happen if you mute one channel.
Think of it in terms of soloing M and S as solo functions if you want to implement that.

I attached an example from a different project showing how I did it around the decoder section. There may be easier ways, but this works..

Bipolars used where called for.

Gustav
Title: Re: Barry Porter "Net EQ"
Post by: Cardinen on August 04, 2017, 03:33:31 PM
Ok i got it now.

thank you, M/S solo will be a great function!  :D
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on August 16, 2017, 07:23:34 PM
I have built some Net EQ modules and have found that the "linear" implementation of the boost cut ladder (using a switch) does not exactly correspond to the desired boost/cut figures.  I have worked out values for the resistors that come really close (+/- 0.1 dB) for what I wanted.  I'll publish my values if anyone is interested.
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: Cardinen on August 29, 2017, 06:25:50 AM
I have built some Net EQ modules and have found that the "linear" implementation of the boost cut ladder (using a switch) does not exactly correspond to the desired boost/cut figures.  I have worked out values for the resistors that come really close (+/- 0.1 dB) for what I wanted.  I'll publish my values if anyone is interested.
Best,
Bruno2000

Yes i could be interested if you can post it;

Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on September 01, 2017, 08:13:04 AM
Here you go.
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on September 05, 2017, 07:13:40 PM
My version.
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on September 14, 2017, 09:33:44 AM
bruno thats sick tight!


i have been planning for a while on my own version of the bpnet eq. i have downloaded this schematic
http://www.collinsaudio.com/NetEQ.pdf
 and i see that it differs some from harpos schematic.
http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_H.pdf

the pots around q, freq, and gain are wired differently and some resistors are different around thoose pots.

is there a right version here?

the gain setting in harpos version seem to disconnect the juction to one of the two summing amps depending on cut or boost operation. seems like a cool idea but shouldnt the disconected end be terminated to ground atleast..?

Title: Re: Barry Porter "Net EQ"
Post by: bruno2000 on September 14, 2017, 04:54:03 PM
bruno thats sick tight!


i have been planning for a while on my own version of the bpnet eq. i have downloaded this schematic
http://www.collinsaudio.com/NetEQ.pdf
 and i see that it differs some from harpos schematic.
http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_H.pdf

the pots around q, freq, and gain are wired differently and some resistors are different around thoose pots.

is there a right version here?

the gain setting in harpos version seem to disconnect the juction to one of the two summing amps depending on cut or boost operation. seems like a cool idea but shouldnt the disconected end be terminated to ground atleast..?

I used Harpo's circuit, (x5) with a 5k equivalent boost / cut pot with a switch, and did use a 5k resistor from the unused summing amp input to gnd.  Harpo was amazingly helpful with his explanations and spread sheets.  I should have put his name on the front panel as well.........
I also added the M/S encode/decode circuit from Wayne Kirkwood, and the SSL 18 dB/oct HPF.
Best,
Bruno2000
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on February 03, 2018, 10:19:49 AM
http://www.americanradiohistory.com/Archive-Wireless-World/80s/Wireless-World-1984-01.pdf

page 73
Title: Re: Barry Porter "Net EQ"
Post by: Bonsaimaster on March 11, 2018, 05:11:36 PM
Can someone help me figure out how to make the HF shelf switch allow for selectable freq? Also what is the HF shelf set?
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on March 13, 2018, 12:30:04 PM
hi!

the hi shelf freq is set by (1/2πRC) C77+C81 (1nf+6.8nF) and R91+P15 (1K+Pot). when the P15 is turned to minimum resistance, only R91 is part of the formula and sets the freq to about 20Khz.
when P15 is turned for maximum resistance, the total resistance should be about 11K for 2Khz.

the HI shelf and HI bell are separate filter circuits. with the switch, one of them is disconected from the gain pot of that band, while the other is in effect.
Title: Re: Barry Porter "Net EQ"
Post by: Bonsaimaster on March 13, 2018, 01:38:39 PM
Thanks that was a great explaination. So my question is that is there a way to put another gain pot in play when the HF switch is engaged to change the freq of the shelf? Also if the HF self is engaged what freq is it set?
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on March 13, 2018, 02:41:58 PM
the HF freq is variable - both in the bell circuit and in the shelf circuit - with the same pot. the LF and HF freq pots  are triple ganged.

each band has its own gain pot.
LF bell and shelf shares a common gain pot.
HF bell and shelf shares a common gain pot.

if you want  to separate bell and shelf in any band you need to split the tripleganged freq pot in to one dual pot and one single pot.
if you want to have separate gain for shelf and bell you have to insert an additional gain pot and wire it similar to P14 P11 P8 P5.

Title: Re: Barry Porter "Net EQ"
Post by: Bonsaimaster on March 14, 2018, 03:24:59 PM
Ok that is what i needed! thx Can i ask which set of three connections would effect the shelf?

Ones
toward the outside of board
middle or
 inside board?
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on March 14, 2018, 03:40:21 PM
i am only refering to the schematic. i have never seen a pcb...

if you tell us which pcb you have, maybe some one can help you with that.

Title: Re: Barry Porter "Net EQ"
Post by: Bonsaimaster on March 14, 2018, 04:09:02 PM
looks like the pot connections that go to R91.
Title: Re: Barry Porter "Net EQ"
Post by: leitmo on July 25, 2018, 10:24:19 AM
I finally got a couple of boards to build my own Net EQ

It's intended for mastering at studio and mix duties. I need transparent parametric EQ with stereo ganged controls. Surgical EQ is done ITB so I tend to use hardware for broad strokes, sometimes with evident sonic imprint and sometimes invisible. No need dual mono controls as it kills my workflow. Want to keep EQing eyes closed.

Features:

- HPF stereo ganged (4 decks 24 pos or a simple 4 decks x 3 pos). Frequencies not decided.

- OUTPUT GAIN dual mono (1 deck 24 pos). +/- 5'5dB

- Q stereo ganged (2 decks 6 pos). Standard values

- GAIN stereo ganged (2 decks 24 pos). +/- 6dB

Due to expensive 6 decks rotary switches i decided to split HF selectors

- HF BELL FREQUENCY stereo ganged  (4 decks 24 pos). Standard values

- HF SHELF FREQUENCY stereo ganged (2 decks 24 pos). Standard values

So this way I can A/B between different frequencies and shape by pressing a button


I will source switches from Uraltone (4 decks 24 pos):

http://en.uraltone.com/electronic-components/switches/rotary-switches/rotary-switch-4x24.html (http://en.uraltone.com/electronic-components/switches/rotary-switches/rotary-switch-4x24.html)

Don Audio:

https://www.don-audio.com/Rotary-Switch-2024-2-Pole-24-Position (https://www.don-audio.com/Rotary-Switch-2024-2-Pole-24-Position)

and  Banzai:

https://www.banzaimusic.com/Rotary-Switch-BR-2x6-Pins.html (https://www.banzaimusic.com/Rotary-Switch-BR-2x6-Pins.html)

https://www.banzaimusic.com/Rotary-Switch-BR-4x3-Pins.html (https://www.banzaimusic.com/Rotary-Switch-BR-4x3-Pins.html)

I'll post progress as soon as I order parts.

Attached a very preliminar front panel design. I'm open to suggestions on ergonomy and workflow
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on July 26, 2018, 06:14:24 PM
Hi!

Hope youll have a great build with good results!!

Looking at your panel.. are thoose holes for switches or do they represent the knobs on the switches?

The far left and far right switches seem like they might be too far out to the sides..?

Title: Re: Barry Porter "Net EQ"
Post by: leitmo on July 27, 2018, 02:14:50 AM
Looking at your panel.. are thoose holes for switches or do they represent the knobs on the switches?

The far left and far right switches seem like they might be too far out to the sides..?

Thanks for your kind words

Holes represent switches. They are 40mm diameter.

Had some "ouch" moments in the past designing a nice panel forgetting switches and pots attached to haha

Still not decided between Manley or Sontec style Knobs. I'll operate this eq without looking at it so it must have recognizable shape at touch.

I'll post updated pics and sketches when sourcing parts.

Yes you're right on gain  switches at far left. I should place them better. I was just trying to figure out global layout.

I'm still not sure about F, G and Q placement. It seems like there are two ways:

- controls placed top to bottom F, Q, G or Q, F, G. Most Net EQ builds, Prism, Sontec...

-controls placed top to bottom G, Q, F so workflow leads from bottom to top like Manley Massive Passive

Both have pros and cons. I like traditional way top to bottom but I also love to have Manley having Gain at top so can put my hands on it with out accidentally touching Q and F



Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on July 27, 2018, 07:12:39 AM
If you buy a 19" case you prob get a blank front panel with it.
You could use that for a try out before you order your design from the panel manufacturer.
Its so easy to miss something out.
Title: Re: Barry Porter "Net EQ"
Post by: petermontg on September 18, 2018, 04:32:54 PM
Is there any boards floating around or does anybody know where to pick a set this weather.

Best
Peter
Title: Re: Barry Porter "Net EQ"
Post by: weiss on May 05, 2019, 01:00:24 PM
Is it correct that the onboard variable hpf is going from 75 to 200 hz?
what would be the easiest way to lower the values when using a potentiometer?
Title: Re: Barry Porter "Net EQ"
Post by: 5v333 on May 05, 2019, 05:01:22 PM
Hello.

The schematic i have on my computer states clearly 15hz-400hz.

The filter is made up of two sets of RC (12db/oct). R varys when you turn the dual pot.

If you want higher min/max freq, lower the capacitors.
For lower min/max, increase the caps.


Title: Re: Barry Porter "Net EQ"
Post by: weiss on May 05, 2019, 05:46:48 PM
Hello.

The schematic i have on my computer states clearly 15hz-400hz.

The filter is made up of two sets of RC (12db/oct). R varys when you turn the dual pot.

If you want higher min/max freq, lower the capacitors.
For lower min/max, increase the caps.
Thank you very much !
Title: Re: Barry Porter "Net EQ"
Post by: weiss on June 05, 2019, 11:02:46 AM
anyone ever tried taking lundahl transformers into the circuit?
i saw hcl doing this with the thermos!
Title: Re: Barry Porter "Net EQ"
Post by: duende on June 11, 2019, 05:25:55 AM
Hello,

I'am building a Net eq and i would like to know what switch is the best for this circuit , shorting or non-shorting ?

Thanks
Title: Re: Barry Porter "Net EQ"
Post by: weiss on July 01, 2019, 02:31:13 PM
finally done with my build.


(https://i.ibb.co/Lhy8cM0/DSC06121.jpg) (https://ibb.co/6JSmT2y)

(https://i.ibb.co/LNVM2ps/DSC06111.jpg) (https://ibb.co/LNVM2ps) (https://i.ibb.co/f8Mtjf8/DSC06125.jpg) (https://ibb.co/f8Mtjf8)
Title: Re: Barry Porter "Net EQ"
Post by: weiss on July 01, 2019, 03:19:43 PM
So after some minor testing, i just think this eq sounds amazing!!

I became aware of 2 issues though:

First, when i look at the low-mid band (band 2 from the left), it seems to have less effect when turning the +/- gain knob compared to all the other bands. This problem exists on both channels!

Second, the Highpass filter on the left channel shows some weird behaviour: When i turn the knob from the lowest setting (about 15Hz towards maximum value, it already cuts the lowend a bit on the fully ccw position (which shouldn't be, at least not hearable). Turning it further cw actually makes the bass frequencies LOUDER instead of cutting it. This continues until 9 o clock position. Only then the hi-cut frequency increases to its maximum value.
The one on the right channel works without issues...

What are you thoughts on these misbehaviours?

Thank you all for the support!
Ansgar
Title: Re: Barry Porter "Net EQ"
Post by: iprovlek on July 02, 2019, 02:07:11 PM
Weiss great piece of gear
 ;)
Looks amazing and Im bet sound too....
Title: Re: Barry Porter "Net EQ"
Post by: stybljan on July 04, 2019, 03:30:21 AM
Do somebody have a gerber files for this project? All the links I tried are broken.

Thanks a lot
Title: Re: Barry Porter "Net EQ"
Post by: weiss on November 28, 2019, 10:09:29 AM
Anyone ever used Lundahl LL2801 transformers in the Net eq?
Title: Re: Barry Porter "Net EQ"
Post by: Ricardus on November 28, 2019, 10:21:21 PM
Wow. Another amazing looking project to do!
Title: Re: Barry Porter "Net EQ"
Post by: trashcanman on December 01, 2019, 12:18:40 AM
For those wanting all the files for this you can download them from this link.
https://we.tl/t-3vQVRxHjak
Title: Re: Barry Porter "Net EQ"
Post by: stybljan on December 07, 2019, 06:31:19 PM
Thanks a lot.
Title: Re: Barry Porter "Net EQ"
Post by: alexc on December 08, 2019, 04:42:58 AM
finally done with my build.


(https://i.ibb.co/Lhy8cM0/DSC06121.jpg) (https://ibb.co/6JSmT2y)

(https://i.ibb.co/LNVM2ps/DSC06111.jpg) (https://ibb.co/LNVM2ps) (https://i.ibb.co/f8Mtjf8/DSC06125.jpg) (https://ibb.co/f8Mtjf8)

Lordy - that is the most awesome diy eq I think I have ever seen  :)

Congrats and much, much aclaim.  I mean, just wow man!