Neumann W492 equalizer DIY project (PCB docs added)

[kante1603]

Welcome to the forum Markus.

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

Best regards and tschüss,

Udo.

 

[Markus_Krippner]

What is the best way to make a global bypass for the W492 (bypassing all 4 bands at once) ?
- A Kind of "Masterswitch" (e.g. Lorlin)  for the 4 "single" switches ?
- Hardwired bypass (XLR in to XLR out) with relay or switch ?
- any other ideas ?

Thank you...

...markus

 

[kante1603]

What is the best way to make a global bypass for the W492 (bypassing all 4 bands at once) ?
- A Kind of "Masterswitch" (e.g. Lorlin)  for the 4 "single" switches ?
- Hardwired bypass (XLR in to XLR out) with relay or switch ?
- any other ideas ?

Thank you...

...markus

Moin Markus,

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

Best,

Udo.

 

[Markus_Krippner]

Thank you, Udo

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

...markus

 

[kante1603]

Thank you, Udo

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

...markus

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

Best,

Udo.

 

[Markus_Krippner]

What do you think about an additional small switching powersupply built in (e.g. meanwell) for relay power (and in my case I additionally will have a lot of lights, too).

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

...markus

 

[kante1603]

What do you think about an additional small switching powersupply built in (e.g. meanwell) for relay power (and in my case I additionally will have a lot of lights, too).

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

...markus

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

Udo.

Edited:Typo (I meant smps,not sms ;D)

 

[pucho812]

been reading on this for a while. Wondering the possibility of adding in bell/shelf switch on the LF and HF bands. 

 

[ramshackles]

I've got a couple of these boards for sale on the black market. Nice looking project, but I'm concentrating on other things now..

 

[Markus_Krippner]

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

What specific voltage regulators do you use ? Never had trouble with LM78xx/uA78xx/LM79xx/uA79xx, but some, like TS7815 / TS7915, seem to be famous for hanging at power up.

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

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

...markus

 

[xazrules]

Hi, can i use a trex kit from jlm audio for the PSU?

 

[3nity]

here you need +15V, 0V, -15V.

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

Remember you need a bipolar psu.

Good luck!

 

[xazrules]

thank you 3nity, what psu do you suggest for this project?
to keep the costs low somehow. 

 

[3nity]

It depends on where are you located.
for a simple +/- supply id go with this one: https://pcbgrinder.com/index.php?route=product/product&path=59_93&product_id=97

 

[Markus_Krippner]

Here's my version of the W492 :

...markus

 

[iprovlek]

Great unit Markus!

UNIQUE...

 

[ding]

I really like the way you mounted the boards. Where did you get those mounting brackets? Are they plastic? Beautiful job!!!!

 

[Markus_Krippner]

I really like the way you mounted the boards. Where did you get those mounting brackets? Are they plastic? Beautiful job!!!!

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

...markus

 

[ding]

Beautiful craftsmanship!!!  If you ever decide to make those pcb brackets again would you consider making me a pair. I have been wanting to do the exact same thing and have been trying to figure out a way to make them at home. I imagine a CNC would help  ;D Great job!

 

[Markus_Krippner]

You can do something like that on your own without a CNC, but you have to make 2 parts instead of 1:

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


...markus