Neumann W492 equalizer DIY project (PCB docs added)

[benlindell]

They will work without being mounted, it'll be a bit ugly but they'll work. I have a layout that 'should' work for omeg pots, haven't finished nor tested it yet but going by my measurements and datasheets it should be good.

 

[sirzodiac]

They will work without being mounted, it'll be a bit ugly but they'll work. I have a layout that 'should' work for omeg pots, haven't finished nor tested it yet but going by my measurements and datasheets it should be good.

don't forget the first post of this thread: audiox also posted gerbers for a omeg version. just not working in purusha's case, every layout won't work there, because of the (omeg) pot's geometry...

 

[mitsos]

They will work without being mounted, it'll be a bit ugly but they'll work. I have a layout that 'should' work for omeg pots, haven't finished nor tested it yet but going by my measurements and datasheets it should be good.

Does it involve bending the leads over the top/bottom of the board to get the pots more compact? I thought to try this, but no time yet..

 

[Moses]

Almost got the first of 2 of these boxes working... (Waiting on power supply!)...  ;D

I ended up using tat's case with the Vishay pots, It's ended up being a bit of a bodge: Drilled out front panel cut outs to 7mm, and attached the mounting plate using only the pot/switch nuts as spacers. This works fine, and Elma knobs will hide the front panel bodge nicely!!

Mo

 

[dagoose]

Just wondering:
has anybody here done this EQ with stepped swithes instead of pots?
I want to build mine with 12 steps lorlins or maybe even 24 steps to use it for mastering but i'm not sure how to do it.
The gain is no problem, i just need 0.5db steps up and down and last steps at 1db but what about frequencies? I don't need an overlap in the mid frequencies so the ranges can be a bit more cut down.
Anyone?

 

[benlindell]

Hey guys, I've got my design for the omeg pots pretty finalized. I still don't have the chassis for this yet so I did a cardboard mount to test it out. I'll post a few photos and the layout. I'm making a 4 channel in 3U design for myself, I can give anyone that wants the illustrator file it if they want.

 

[benlindell]

another pic

 

[benlindell]

last pic

 

[outoftune]

hey, that looks great. would you be able to send me that file in illustrator and jpeg?

 

[mitsos]

hey Ben,

there is a "share your front panel thread" here:

http://www.groupdiy.com/index.php?topic=33888.0

cheers,
d

 

[benlindell]

UPDATE: I fixed up my front panel, accidently did 270 degress instead of 300
Here's the illustrator file. http://benlindell.com/diy/W492%20to%20Laser2.ai

 

[outoftune]

great ben, thanks so much!

does the case you are using have the 2nd front panel for mounting the pots to or are you just using a normal rack case with the single front panel.

what knobs are you planning to use for the omegs?

 

[benlindell]

I'm no frills and just mounting them on the single front panel.

I bought a bunch of knobs from mouser, couldn't find any good 4mm knobs so I'm just wrapping some metal around the shaft and mounting them. mouser part #s 450-2040, 450-2050, 450-2060, 450-2070

 

[outoftune]

great stuff.

when you say "wrapping some metal" around them...what exactly are you using?

 

[benlindell]

Haven't done that part yet, planing on getting the thinest sheet of metal I can find and cutting it into small strips.

 

[mitsos]

You could order knobs direct from Sifam for not too much money, and get all the little colored caps and all.

 

[glazer56]

Greetings! noob question, but...
Can anyone point me to the math for calculating cap values to change the frequency? Scratching my head a little trying to analyze the schematic.

Cheers!

 

[audiox]

Can anyone point me to the math for calculating cap values to change the frequency?

Google "State Variable Filter" or "State Variable Filter equations".

 

[glazer56]

Ahh! Thanks!

Here's some info I found if anyone would like some additional info on the filter design.

www.compeng.dit.ie/staff/ptobin/3chapt08.pdf

http://www.answers.com/topic/state-variable-filter

http://www.maxim-ic.com/app-notes/index.mvp/id/1762

http://www.circuitstoday.com/state-variable-filters

 

[buschfsu]

guys i need some help...

i have a pair of these eqs ready for the purusha case i bought.  problem is these omeg pots are not going to work with this case.  i need the sfernice pots.  so the omegs are for sale and i need the others.  audiomaintenance has them but they come out to 240$$$ usd...ouch.  anyone know of a better price on these in the us?

thanks