3D "AIR" EQ - "Night EQ" PCB's Complete!

[dissonantstring]

[quote author="peterc"]
The total of this value + the series resistor (currently 5k6) should be 56k2. So in this case the 5k6 should be changed to 56k2 - 43k2 = 13k.

As long as the centre value is not more than 56k2, this method will work.

Peter[/quote]

so i think these omeg 470K pots from colin will work out fine since colin has stated the average center is about 52K7 and all were between 45K and 53K from the batch he tested (so lets hope its the same in the future). So we can use these pots with a 0dB center detent by just adjusting the 5K6 resistor of each pot. :thumb:

thanks for clearing that up peter!
regards,
grant

 

[peterc]

Pics of the protoype PCB's

http://www.groupdiy.com/index.php?topic=266520&sid=d3179c5e8dbfd31d86f7c5a5b1857bd7#266520

 

[khstudio]

UPDATE:

http://www.groupdiy.com/index.php?topic=271167#271167

 

[mikeyB]

:razz: yumyumyumyumyumyumyumy :razz:

 

[dissonantstring]

for those looking for the overlay for Peter C.'s PCB and excel BOM:

here

also...

peter,
did you ever receive those center detent 470K pots from colin? How did they work out?
cheers,
grant

edit: 470K pots not 4K7

 

[Godders]

I don't know if you two are getting sick of hearing it but thanks a TON for all your work on this guys. :thumb:

Cheers

Nick

 

[peterc]

Colin sent a set of 470k pots but they STILL have not arrived here yet. Our postal system is about as disfunctional as a politician. I hope they arrive soon.

I don't know if you two are getting sick of hearing it but thanks a TON for all your work on this guys. Heck Yeah!

:grin: sigh..... :grin:

No problem at all.

Peter

 

[dissonantstring]

hi peter,
i hope that you get to try out those pots that colin sent over. i'd really like to use those in my build so hopefully they work out well.
i'd also like to add to nick's comments and say that this is a great EQ project that is possible only because of kevin's research and your pcb layout and initiative to offer these boards to all of us. so thanks again kevin and peter! :guinness: :guinness:
cheers,
grant

 

[dissonantstring]

hi peter,
just started looking over your BOM and noticed that there are two R35 but no R37 (series resistors). is one of the R35 supposed to be R37 at the 5K62 value? also, is the 2 pole/6 position rotary switch shorting or non-shorting (or does it matter)?
thanks!
-grant

 

[khstudio]

[quote author="dissonantstring"]hi peter,
just started looking over your BOM and noticed that there are two R35 but no R37 (series resistors). is one of the R35 supposed to be R37 at the 5K62 value? also, is the 2 pole/6 position rotary switch shorting or non-shorting (or does it matter)?
thanks!
-grant[/quote]

I'm 99% sure it's shorting :?
We talked about it earlier in this thread.

YES on the resistors... the prototype had no R37 & 2 R35's - they are BOTH 5k62.

It is now fixed on the NEW PCB.

 

[dissonantstring]

[quote author="khstudio"]There's a Grayhill 2x6 switch (P# 71BF30-01-2-06S)
K[/quote]

[quote author="electrog"]i believe the "s" at the end of the grayhill part number denotes shorting. non-shorting types have part numbers ending in "n".
david[/quote]

hi kevin,
doh!! i should have known this was probably answered before. stupid and lazy me. sorry about that and thanks for answering the R37 question as well. good to know it's corrected on the new PCB.
cheers,
grant

 

[sysexguy]

I have an idea....... :twisted:

If I use all 6Pdt grayhills with a resistor network and strap the left and right side in stereo, the left side controls could be the coarse tuning and the right side, the fine tuning. (6positions on each would give 36 steps of resolution per band)

So a crazy idea that requires $120+ of switches but might just be awesome. Am I risking major crosstalk or other problems by having leads x-crossing along the front panel???? Any other observations?

If it would work, the unit could be used as a mastering or output bus stereo eq with repeatability and confidence......I've had pots drift as time passes and the racks get hot......and then one only notices the problem at a bad time :roll:

Andy

 

[discobloud]

just wondering if anyone is willing to share a BOM with digikey/mouser numbers? It's not that i'm lazy, sometimes it takes me an hour figure out which part to use... if not i understand. monstermark[at]gmail[dot]com

thanks again to everyone for the time put in

mark

 

[MattiasC]

BOM questions:

1) What does cbyp mean?

2) What's the difference between a .1uf "ceramic/poly" cap and the .1uf poly cap?

3) Would this work for the .1uf "ceramic/poly" caps?

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=445-2613-ND

Thanks!

 

[Purusha]

I would be also greatful for the BOM with digikey/mouser, Slenderchap numbers :thumb: :thumb: :thumb:

 

[Godders]

[quote author="MattiasC"]2) What's the difference between a .1uf "ceramic/poly" cap and the .1uf poly cap?[/quote]I took it to mean you can use either a ceramic or a poly cap in that location.

Cheers

Nick

 

[peterc]

Matthias

"cbyp" stands for C bypass, but cbyp is the way the name comes up in my PCB programme.

"ceramic/poly" cap and the .1uf poly cap?

I use either for the power rail bypass caps (cbyp above). I prefer the sound of poly caps in the signal path, hence the 2 different types.

The listed cap looks fine.

Regards
Peter

 

[Purusha]

Can someone please help me to get the ordering code from Small Bear or anywhere else for the center detended pots?
I need 72 pcs and can't find these pots anywhere... any nice place in Europe to get these?

 

[MattiasC]

Thanks Peter. I'll go with these (much cheaper) polys . I don't anticipate 48v usage but I'm buying the higher rated caps just in case.

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P4725-ND

Got the boards yesterday, looking good.
:thumb:

 

[Godders]

[quote author="Purusha"]Can someone please help me to get the ordering code from Small Bear or anywhere else for the center detended pots?
I need 72 pcs and can't find these pots anywhere... any nice place in Europe to get these?[/quote]Hi Tat, I don't know if anyone's found an easy source for 500K, rev log with center detent.

Smallbear said he'd get some for us but the minimum order would be 1000 pieces.

Omeg has 470K rev log with center detent.

There are a few sources without the center detent (Banzai, smallbear, das musikding).

Cheers

Nick