Neumann W492 equalizer DIY project (PCB docs added)

[rmaier]

More guts

 

[rmaier]

Channel view

 

[rmaier]

The led indicators were a nice addition. Thanks to the previous posters - great idea!

 

[darkus]

Can I skip calibration by installing fixed value resistors instead trimmers?

 

[iprovlek]

Hi Rmaier!

Your Eq looking great and green colour is awsome!!!

How much is gaining ,3db or less on your W495Eq!?

For mastering very often need 0.5 to 1 dB!


Great job!!!

8)

 

[rmaier]

Thanks, iprovlek. The eq is definitely one of the cooler looking builds in my rack. The high and low shelves are +/- 5dB in 1 dB steps. The bells are +/- 4dB in .75 dB steps (or thereabouts). A little crude for some mastering duties I guess, but I think it should work well for broad strokes. I'm surprised by the highs in particular. Sounds very nice!
Cheers,
Ralph

 

[dogfaceaudio]

I tried putting together a BOM for this project. Could anyone who has completed the project comment on the component choices I've made? Once everything has been checked I'll put together a Mouser cart to share.

Quantity​	Value​	Designation​	Mouser Part​	URL​
1​	PCB​			https://pcbgrinder.com/W492-NEUMANN-492​
2​	47P​	C1,C2​	505-FKP247/1000/5​
4​	100U​	C11,C18,C5,C6​	667-EEA-GA1HR10H​
2​	1N5​	C12,C14​	505-FKS21500/100/10​
2​	4N7​	C13,C15​	505-FKS24700/100/5​
1​	22N​	C16​	505-FKS2D022201E00JS​
1​	6N8​	C17​	505-FKS26800/100/5​
4​	100N/CERAMIC​	C19,C20,C21,C22​	810-FG26C0G1H104JNT6​
1​	47N​	C3​	505-FKS2D024701K00JS​
1​	10N​	C4​	505-FKS2-.01/100/5A​
2​	100N​	C7,C9​	505-MKS2.1/63/5​
8​	10KLIN/PA11QXF​	P1,P2,P3,P4,P5,P6,P7,P8​		http://capi-gear.com/catalog/product_info.php?cPath=50_131&products_id=446​
2​	200R​	PT1,PT4​	594-63P201​
2​	10K​	PT2,PT3​	594-63P103​
2​	20K​	R1,R2​	271-20K-RC​
2​	100K​	R10,R47​	271-100K-RC​
4​	330K​	R11,R14,R29,R48​	271-330K-RC​
10​	5K1​	R12,R13,R27,R28,R42,R43,R49,R5,R50,R6​	271-5.1K-RC​
2​	220R​	R15,R30​	271-200-RC​
2​	1K8​	R16,R31​	271-1.8K-RC​
2​	4K3​	R17,R32​	271-4.3K-RC​
5​	1K​	R18,R21,R33,R36,R9​	271-1K-RC​
4​	560R​	R19,R22,R34,R37​	271-560-RC​
4​	1K2​	R20,R23,R35,R38​	271-1.2K-RC​
2​	2K​	R24,R39​	271-2K-RC​
2​	14K​	R25,R40​	271-14K-RC​
2​	6K8​	R26,R41​	271-6.8K-RC​
2​	10K​	R3,R4​	271-10K-RC​
4​	620R​	R44,R45,R7,R8​	271-620-RC​
1​	3K3​	R46​	271-3.3K-RC​
2​	22R​	R51,R52​	271-22-RC​
4​	CK7101​	S1,S2,S3,S4​	611-7101-002​
8​	NE5532​	U1,U2,U3,U4,U5,U6,U7,U8​	595-NE5532P​

     

 

[justinheronmusic]

Hey everyone!

I am having trouble sourcing pots for this build. I would like to design a half rack unit and use the original 20mm/15.2mm spacing that is drawn out in the potentiometer assembly sheet. Is there anywhere I can get the Sfernice pots?

I am also confused as to whether or not I need single or dual gang for this build.

Links would be much appreciated!

 

[kante1603]

Hello,


@ Justin,


you'll technically need 6 mono and 2 dual gang pots from what I remember,please look at the schematics or at the pcb and you'll see what I mean.
The Sfernice are hard to source,but you can use other small types and wire them to the corresponding pads.
I did that with Omegs and some solid wire some years ago.The populated pcb is really light-weight,so the eight pots will nicely stay it in place.
Using conductive plastic types is imperative.




@ dogfaceaudio,


can't see where you are located,you might want to update your profile.
Is it a US or european BOM?
For the pots,you don't want center detend types for frequency pots........
Also not necessary for the cut/boost pots since the single bands have a switch provision,but cool if you want it for "blind" operation.
I can't see them in your BOM,maybe you want to add some?


Hope to have helped,


Udo.

 

[justinheronmusic]

Will the 10k linear OMEG pots from audio maintenance work? It looks like they no longer carry the 10k conductive plastic.

Hello,


@ Justin,


you'll technically need 6 mono and 2 dual gang pots from what I remember,please look at the schematics or at the pcb and you'll see what I mean.
The Sfernice are hard to source,but you can use other small types and wire them to the corresponding pads.
I did that with Omegs and some solid wire some years ago.The populated pcb is really light-weight,so the eight pots will nicely stay it in place.
Using conductive plastic is imperative

 

[kante1603]

Will the 10k linear OMEG pots from audio maintenance work? It looks like they no longer carry the 10k conductive plastic.

Hello Justin,


sadly no,they'll soon start to scratch because of dc.
I'd look at e.g. TT/Bi-Technologies at mouser or so.......


Best regards,


Udo.

 

[skidmorebay]

Could someone recap the options for cutting the overall cut/boost in half? Mine is in a single rack space - no room for stepped switches really.
Would substituting 5k pots for the 10k pots for boost/cut do the job? Or adding end-stop resistors to each side of the pots?

 

[groselicain]

Just inherited someone else's old project and I'm completing it one channel at a time. I have several Haufe RK 310/2s and liked the idea of using them in this project. I read earlier where Audiox said something about leaving in the first 5532 for impedance matching, but I didn't read anyone talking about outputs.

If wanted to implement this change, does anyone have a suggestion? Thank you very much.

 

[Whoops]

Just inherited someone else's old project and I'm completing it one channel at a time. I have several Haufe RK 310/2s and liked the idea of using them in this project. I read earlier where Audiox said something about leaving in the first 5532 for impedance matching, but I didn't read anyone talking about outputs.

If wanted to implement this change, does anyone have a suggestion? Thank you very much.

What is the change you are talking about?
using transformers to balance the output?

If that's only what you want to do , you can just tap from the + signal, so leave out R49,R50, R51 and U7A

 

[kambo]

i am thinking of building a stereo pair for my location recording/ headphones setup!
would it work with 9VDC supply(2x9v batt for +/- supply)

what would happen if i used two trimpots stacked_up together instead pots?
(or effect of using super inaccurate dual pots)

 

[dogfaceaudio]

Came back to this project, still trying to find pots that will work. The original BOM lists the Sfernice pots which are 1/2W rated. I found these pots on Mouser, but they're only rated for 50mW: http://www.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P092N-FC25BR10K/?qs=gHIbTyTFUDcPxOxhQxPOzw%3D%3D

I can't seem to find any online store that sells the conductive plastic Omeg pots in 10k linear. Don't suppose anyone has suggestions as to where I can find some potentiometers that will work? Thanks!

 

[audiophreak]

I got mine years ago from - http://www.tawelectronics.com/wima_film_capacitors.htm

  call and ask for Laura , I believe they have a "kit" that includes the Omeg pots with all the WIMA caps too.

 

[dogfaceaudio]

I don't see any reference to the Omeg pots being sold by TAW Electronics. I'll try email them and find out if they have any in stock still.

 

[audiophreak]

Hi dogfaceaudio,
                                        They are not an Omeg dealer , but I believe they have Omeg pots for specific projects and I think this is one of them.

  Call them and ask for Laura

 

[Gustav]

Just want to share this finding.

Single
https://www.blore-ed.com/product-page/p261-conductive-plastic-long-shaft-potentiometers

Dual
https://www.blore-ed.com/product-page/p261-044a-dual-gang-10k-linear-long-shaft

Gustav