TwentyTrees

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #780 on: August 01, 2019, 12:43:11 PM »
In theory yes, it should be no more complicated than that. In practice, there may be factors at play that I’m not aware of (potential for increased noise?) - maybe spend some time comparing the W492 schematic to that of other 5 band SVF-based equalisers to see if they are doing anything different.

There’s quite a good discussion at https://groupdiy.com/index.php?topic=67088.0 about 5 band SVF EQs, worth having a look through that and reading up elsewhere on the SVF to get a sense of how well it would work.

Or just breadboard it.  ;)


winner

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #781 on: August 09, 2019, 05:34:13 AM »
In theory yes, it should be no more complicated than that. In practice, there may be factors at play that I’m not aware of (potential for increased noise?) - maybe spend some time comparing the W492 schematic to that of other 5 band SVF-based equalisers to see if they are doing anything different.

There’s quite a good discussion at https://groupdiy.com/index.php?topic=67088.0 about 5 band SVF EQs, worth having a look through that and reading up elsewhere on the SVF to get a sense of how well it would work.

Or just breadboard it.  ;)

Thank you very much for your patient reply. Have a nice day

winner

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #782 on: September 04, 2019, 11:06:24 AM »
In theory yes, it should be no more complicated than that. In practice, there may be factors at play that I’m not aware of (potential for increased noise?) - maybe spend some time comparing the W492 schematic to that of other 5 band SVF-based equalisers to see if they are doing anything different.

There’s quite a good discussion at https://groupdiy.com/index.php?topic=67088.0 about 5 band SVF EQs, worth having a look through that and reading up elsewhere on the SVF to get a sense of how well it would work.

Or just breadboard it.  ;)

Hello, I may need to trouble you again. I used f = 1 /(2 * pi * R * C) to calculate the value of specific R, but the result is different from my experimental value. I think it is because the contact resistance is 560 . I hope to use band switch. Can you tell me the calculation method

Palmito

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #783 on: September 05, 2019, 01:43:32 PM »
BanzaiMusic have these cheap Omeg pots
https://www.omeg.co.uk/wp-content/uploads/2018/10/PC16BU.pdf
Are they OK  ? (apart from the space between pins)
They dont have the dual-gang tho...
thanks in advance

ToBSn

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #784 on: September 08, 2019, 06:55:38 PM »
BanzaiMusic have these cheap Omeg pots
https://www.omeg.co.uk/wp-content/uploads/2018/10/PC16BU.pdf
Are they OK  ? (apart from the space between pins)
They dont have the dual-gang tho...
thanks in advance

Yes, these pots will work fine.
But they won't fit in 1HU if I remember correctly.
 
6 x https://www.omeg.co.uk/wp-content/uploads/2018/10/PC16BU.pdf
2 x https://www.omeg.co.uk/wp-content/uploads/2018/10/PC2G16BU.pdf


ToBSn
« Last Edit: September 08, 2019, 07:01:26 PM by ToBSn »


Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #786 on: September 29, 2019, 04:11:59 PM »
I found those ones : https://www.rapidonline.com/Catalogue/Product/65-1442

Just need to bend carefully the rear pins with little pliers to make the stereo fit in the pcb holes, i just still have to measure the distance between two pots to check it fits the faceplate I can buy here in Europe

winner

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #787 on: October 03, 2019, 11:43:46 AM »
Excuse me, I want to increase Q value and change bandwidth. What should I do? :) :)

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #788 on: October 13, 2019, 10:42:39 AM »
Question about ground wiring : do I have to leave the pcbs output ground pins unconnected, as usual ? If using shielded wires, do I have to connect thos ground pins to ground pins of the output XLR or - in my case - to the Lundahl transformers ground pins ?

Noob question I know...

TwentyTrees

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #789 on: October 15, 2019, 09:34:13 AM »
Winner - I missed a couple of your messages here:

Hello, I may need to trouble you again. I used f = 1 /(2 * pi * R * C) to calculate the value of specific R, but the result is different from my experimental value. I think it is because the contact resistance is 560 . I hope to use band switch. Can you tell me the calculation method
Yes, I also found that the experimental value was different from my calculations. If you're looking for specific frequency choices, it's probably worth breadboarding and testing things.

Excuse me, I want to increase Q value and change bandwidth. What should I do? :) :)
https://groupdiy.com/index.php?topic=28332.msg897659#msg897659 - see the section on Variable Bandwidth. There might be better methods, but this definitely works.

Good luck!


 

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