Neumann W492 equalizer DIY project (PCB docs added)

[jicama]

Ok, apparently connecting it with the boards, negatives drops down to -15V, but now the problem I´m having it with the positive which is -.62 is ridicules , seems that TS7815 are not the ones for this project, Im going to try it with a lm317.

Finger crossed

 

[jicama]

No luck  :-\

I´ve changed to LM317 but still mi positives are -1-62V

what can i do Im lost?

Thanks

 

[Rocinante]

For one the picture you posted showing a fragment of the psu is too big.  Please take another picture and while at it explain what transformer you are using.
Cheers
Dylan

 

[jicama]

For one the picture you posted showing a fragment of the psu is too big.  Please take another picture and while at it explain what transformer you are using.
Cheers
Dylan

This is the trafo I'm using
Thanks

 

[jicama]

With out the IC's all voltages are ok, placing the first Ic voltages ok, when I put the second IC starts sucking but survives, placing the 3rd IC positive voltages is dead  negative voltages  is always ok

 

[jicama]

I made some progress I changed the PSU and regulated the LM337 and LM317 to +-15V, but when I insert all IC's my +-Voltages a drop down to  +-11 V, Then I changed the resistors to increase to +-23V but nothing happens only a bit of change +-11.42V
I'm feeding the 2 boards to this PSU and the trafo I posted earlier getting 18V from it
Maybe I need more power from the trafo, is good Idea to join yellow and red from it to have 38V ?
Some one?

Thanks

 

[Rocinante]

Hopefully someone smarter than me will chime in here
but for starters I'm guessing it was a typo and you meant lm337 and lm317 correct?
If I was gonna guess I would say you have an ic in backwards somewhere.  It might explain the voltage jump.  Also looking at the psu (as well as trying to remember how I did mine) doesn't that area that says 'calculate' have a resistor in it?

 

[jicama]

Hopefully someone smarter than me will chime in here
but for starters I'm guessing it was a typo and you meant lm337 and lm317 correct?
If I was gonna guess I would say you have an ic in backwards somewhere.  It might explain the voltage jump.  Also looking at the psu (as well as trying to remember how I did mine) doesn't that area that says 'calculate' have a resistor in it?

Hey
Yes I'm using lm317 and lm337, and about the area with out resistor is only to illuminate a led it doesn't interfere with the circuit,
This thing is driving me crazy, all ICs are  in the correct position

 

[jicama]

The problem was the PSU,
Now it's working.

Thanks for your help  :

 

[kante1603]

The problem was the PSU,
Now it's working.

Thanks for your help  :

What exactly was the issue?


Best,


Udo.

 

[jicama]

The problem was the PSU,
Now it's working.

Thanks for your help  :

What exactly was the issue?


Best,


Udo.

The PSU,  I changed it  2 times. 

 

[kante1603]

That is no answer,nobody here can learn anything from it.

 

[noviygera]

Is one W492 board mono or stereo?

I was wondering if it is possible to use the W492 board with the following changes:
1.  vertical version of the EQ, with "zero" stops on the EQ pots. This is for a dj mixer, where vertical and zero stops are essential.
2. -25/+10 db attenuation on each of the EQ sections.  What will I need to do to make this mod?
3.  one board must be a stereo channel.

thanks,
Herman

 

[kante1603]

Is one W492 board mono or stereo?


Mono.

I was wondering if it is possible to use the W492 board with the following changes:
1.  vertical version of the EQ, with "zero" stops on the EQ pots. This is for a dj mixer, where vertical and zero stops are essential.


Zero will not work corectly because there is none in real life conditions (due to tolerances up to 20%).

2. -25/+10 db attenuation on each of the EQ sections.  What will I need to do to make this mod?


This is a different beast,so at least the -25 is not possible without completely redesigning the whole eq.

3.  one board must be a stereo channel.


You need two boards for stereo and at least two 4-layer plastic conductive pots,hard to source I think.
Definetely the wrong eq for DJs.

thanks,
Herman


Best,

Udo.

 

[noviygera]

Hello Udo,

Thanks, that answers my previous questions. Can you recommend a 4 band EQ to use in a DJ mixer application? Where the EQ is applied to a stereo channel. Any kits out there by chance?

thanks,
Herman

 

[digistu]

I thought people might be interested to see my solution for mounting the boards when using the Omeg (or indeed any other off-board) pots...

I 3D printed some simple brackets. 

Designed in Sketch-up, then fabricated by iMaterialize.  They cost about £20 for 4, but as an experiment I'm 100% satisfied!

 

[fragletrollet]

cool!  8)

 

[Brandmarc]

Hi,

iam new to this very cool Forum and to Diy World.
I only fixed Cables or burnt Opamps in my Gear

I really like the Sound of the old broadcast Equipment.
I have Filtek Mk3´s and Siemens W295 for example.

I have been offered some original w492 for 250,- Euro each.

But i think it would be fun to build them diy.

I think the originals have Transformers.
Had someone of the DIY 492 owners had done a test how they compare to the original Neumann´s?
Would be interesting how different the DIY Version Sounds.

Thank You

 

[p0ulp]

Hello there, I m new to this community but reading for quite a while all posts, I ve been trying to handle as much as a I can every problem a newbie can encouter, but ...

I ve finished to assemble my board and am now waiting for the pot order, since now I didn't thought about the PSU and I can't find a pcb layout that seems recommended for this project. I ve read that varipsu from pcbgrinder is fine , and I m sure it is, but I really don't feel like ordering only one 9 euros board with 20 euros for shipping .. ok I should have done it before :/

So I m considering etching the 9k SSL psu that can be find in documentation ,  but I have two question:
My toroid is 2x15v , If I change the 7818/7918 regulator to 7815/7915  do I have to change resistor value also ? If so which one ?
what to do with the 48V part for the phantom power ?

If somebody as already provided a pcb layout for this psu please let me know.

 

[Gustav]

I really don't feel like ordering only one 9 euros board with 20 euros for shipping .. ok I should have done it before :/

You could use the regular mail option for much cheaper shipment, but its still a lot just for a utility PSU board, so...

I m considering etching the 9k SSL psu that can be find in documentation ,  but I have two question:
My toroid is 2x15v , If I change the 7818/7918 regulator to 7815/7915  do I have to change resistor value also ? If so which one ?
what to do with the 48V part for the phantom power ?

You can change the regulators and use a 2x15V toroid.

The resistors are only there to program the voltage output of the LM317 for phantom power, so leave that whole section out (doubler circuit/regulator)

Gustav