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 »


erquere

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
Used to be a journalist but I prefer build comps and eqs

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? :) :)

erquere

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...
Used to be a journalist but I prefer build comps and eqs

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!


andow

Re: Neumann W492 equalizer DIY project (PCB docs added)
« Reply #790 on: October 30, 2019, 12:01:53 PM »
Just getting started with this and reading schematics I noticed the output stage is different than the original. Two 5532 in the original while this is using only one (and also omits some filtering).
Any insight what might be the reason for this?


 

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