Neumann W492 equalizer DIY project (PCB docs added)

[volker]

Hi

I finally finish this build…
Great sounding, also very quiet and clean…
I like to A/B and just add a true bypass…
W492 PCB are from French GC audio, power supply from dear @volker , frontpanel from @Frank frontpanel.de

Enjoy*
0-0

At some point I'm gonna have to make an official press statement if these mix-ups keep on happening . The relevant Volker is @[silent:arts]. But nice work .

 

[macleod69]

Hi

I finally finish this build…
Great sounding, also very quiet and clean…
I like to A/B and just add a true bypass…
W492 PCB are from French GC audio, power supply from dear @volker , frontpanel from @Frank frontpanel.de

Enjoy*
0-0

Nice build!

I also took 2 w492 pcbs from proaudiogc. Can't wait to do this project!

the link: https://proaudiogc.com/en/w492-eq-clone-neumann-pcb-only-equalizer-4-bands

 

[inf0]

Hey there!

I'm starting to collect all parts , does anyone happen to have a BOM ( mouser cart ) for this project?

Thank you!

 

[Double]

Hello,
i bought a W492 DIY Build from a friend for cheap. Unfortunately there is some issue with it. After turning the pots i get a really loud noise/click (almost like a kick) out of both sides. I have nothing on the input. Has anyone maybe an idea where to look first or similar experience? PSU for example or Calibrate the Gains/EQs?

Best regards!

 

[janczmok]

Nice build!

I also took 2 w492 pcbs from proaudiogc. Can't wait to do this project!

the link: https://proaudiogc.com/en/w492-eq-clone-neumann-pcb-only-equalizer-4-bands

Also got my parts together, and started wiring today. Still parts missing (PSU, knobs) but frontpanel.de made a wonderful work on the panel.

 

[lilpaula87]

Hi Everybody, I need some help. I've built this gear but mine needs to be fed with a really low signal because it overdrives really soon. Moreover I've experienced a huge HF noise starting from 1000khz to 20000khz and up. Both channels act the same. Is this a normal behaviour?

 

[TwentyTrees]

Is this a normal behaviour?

That doesn't sound normal to me, but let's check a few things to see if we can narrow it down. Which PCBs are you using, and how do you have the unit connected - line in/out on audio interface, etc? Balanced I/O?

... mine needs to be fed with a really low signal because it overdrives really soon.

How low is low? As in, what level dBu are you feeding in, and what level are you getting out assuming all controls are flat? What THD are you measuring? I use the free Room EQ Wizard (REW) software for things like that.

Moreover I've experienced a huge HF noise starting from 1000khz to 20000khz and up.

That doesn't sound right, but again, what levels are you seeing for the noise? How are you powering your unit? If you can share some photos too, that might help.

 

[janczmok]

Update. Covered caps. Not 100% happy, still looking for better ones. If somebody has an idea...

 

[TimG]

let’s try to work something out with a set of mine. If you want,

 

[TimG]

For people building Creative Clowns style, my slow pace allowed me to incorporate this new bypass kit into mine.

One thing, it collocates the ins and outs, so your rear panel labels could be affected.

https://www.creative-clowns.com/product-page/stereo-true-bypass-pcb-kit

 

[thelivingroom]

Update. Covered caps. Not 100% happy, still looking for better ones. If somebody has an idea...

View attachment 136891View attachment 136892View attachment 136893

Mine are black 11mm Selco/Sifam S111 collet knobs with C111 colored caps, but your shafts look like a bigger diameter than mine, and the biggest collet they make for those is for 4mm shafts. The frequency select pots I used are 4mm shaft Omeg’s discussed way back in this thread, and for the gain pots I used 1/8” shaft center detent that CAPI sells.

I built mine 7+ years ago; it was the first project I built from this site, simultaneously with the Gyraf G9!

 

[Dropfill]

Update. Covered caps. Not 100% happy, still looking for better ones. If somebody has an idea...

View attachment 136891View attachment 136892View attachment 136893

If you are looking for knobs then you might like https://www.etsy.com/shop/SwedenKnobs

 

[lilpaula87]

That doesn't sound normal to me, but let's check a few things to see if we can narrow it down. Which PCBs are you using, and how do you have the unit connected - line in/out on audio interface, etc? Balanced I/O?


How low is low? As in, what level dBu are you feeding in, and what level are you getting out assuming all controls are flat? What THD are you measuring? I use the free Room EQ Wizard (REW) software for things like that.


That doesn't sound right, but again, what levels are you seeing for the noise? How are you powering your unit? If you can share some photos too, that might help.

Hi TwentyTrees, thanks for your reply.
For psu and eq I’ve used are Creative Clowns’ PCBs.
The unit is connected via Behringer ultragain to my RME Fireface 802. Inputs and outputs are balanced.

It sound already distorted to my ears at low levels but I’ve tried to feed in a 0Db sine wave at 1khz measured at input (0,775v ac) and this is what I get.


Tha converter is not clipping at all and the level is -14db.
I get the same wave with all bands engaged at 0 gain or with without engaging any band. I have no true bypass on the unit.
I have to lower input to 0.483v to have a good waveform.

This force me to push the volume gain on return but this brings up all the noise and this is what I have


The noise is not caused by Ultragain. Even if I connect the unit directly to RME the result is the same.
As for Toroid, I’m using the suggested Triad.

Here are som pics of my unit



Any suggestion would be greatly appreciated

 

[Dropfill]

Hi TwentyTrees, thanks for your reply.
For psu and eq I’ve used are Creative Clowns’ PCBs.
The unit is connected via Behringer ultragain to my RME Fireface 802. Inputs and outputs are balanced.

It sound already distorted to my ears at low levels but I’ve tried to feed in a 0Db sine wave at 1khz measured at input (0,775v ac) and this is what I get.
View attachment 137002

Tha converter is not clipping at all and the level is -14db.
I get the same wave with all bands engaged at 0 gain or with without engaging any band. I have no true bypass on the unit.
I have to lower input to 0.483v to have a good waveform.

This force me to push the volume gain on return but this brings up all the noise and this is what I have
View attachment 137004

The noise is not caused by Ultragain. Even if I connect the unit directly to RME the result is the same.
As for Toroid, I’m using the suggested Triad.

Here are som pics of my unit
View attachment 137005
View attachment 137006
View attachment 137007
Any suggestion would be greatly appreciated

I´m building this EQ my self and noticed some things on your PCB , Resistor R51,R52 are mislabeled on your board, The correct value is 22R and I know that PT1 also is mislabeled and has the wrong value should be 200R but I think it says 10K on the board.
Plus double check the voltage in to your PCB so you have 15v+-
And I also noticed that C13 on the board looks a little melted. maybe nothing to worry about.

I hope you get it working.

 

[lilpaula87]

I´m building this EQ my self and noticed some things on your PCB , Resistor R51,R52 are mislabeled on your board, The correct value is 22R and I know that PT1 also is mislabeled and has the wrong value should be 200R but I think it says 10K on the board.
Plus double check the voltage in to your PCB so you have 15v+-
And I also noticed that C13 on the board looks a little melted. maybe nothing to worry about.

I hope you get it working.

Thanks Dropfill, I’ve checked values and R51, R2 are correct. The PSU delivers 15.02v and -15.02v.
Other ideas?

 

[Dropfill]

Thanks Dropfill, I’ve checked values and R51, R2 are correct. The PSU delivers 15.02v and -15.02v.
Other ideas?

So both channels are behaving the same? are both distorting? If it´s distorting on both channels then you must have made the same mistake on both PCBs.
I would check the schematics from Creative Clowns and go through every point from the input to the output, double check that all the values are correct.
Check your Trim pots, do they have the correct value. have you set them correctly.

 

[Dropfill]

Thanks Dropfill, I’ve checked values and R51, R2 are correct. The PSU delivers 15.02v and -15.02v.
Other ideas?

Ohh and check that all the OP amps are seated all the way. I got some noise when mine were loose.