dbx 202 pics? or pcb layout?

[quadwould]

I just got a ton of used 2150's and would like to make 4 to 8 DBX 202s with them.

does anyone have any high resolution pictures of both sides of the units, or better yet a mock-up drawing of the pcb layout.

these are double sided right?

I will make 2 on perfboard.. just to try out different configurations, but then I would like to draw up gerbers and have some made. (after which I can send the gerbers to you Gustav if you would like...)

 

[Greg]

Now you're talking... a DBX 202 PCB... good idea. But sorry, I don't have any of the info you need. :sad:

 

[SSLtech]

...You mean 202X, right? -Not 202 or 202C or whatever...

In other words the 8 x 2151 with a 5534 etc...

I know that you have to use the super- close-tolerance SIL-9 resistor packs, they're basically all paralleled apart from one pin on each (from memory) which is connected to the SIL-9 8 pack resistors, then there's a 5534 involved... Look at Jakob's sub-assembly on the SSL comp and imagine 8 VCAs paralleled with individual series resistances... that's the circuit, from what I see.

Keith

 

[Kev]

we had a few cut-away pictures of this group of DBX VCAs at the old place
I think it was even one of the Give-Away questions for a Group DIY Update.

pehaps someone could re-post them

 

[SSLtech]

Drink! -Feck!

I'll take a few pics...

Gurls! -Arse!!!

 

[quadwould]

I am thinking of whichever one uses 8 2150s and a 5534. XT.. not sure.

i am looking at thesolder side of a 202 (?) in an SSL SL597 film panning module i have.... i cannot tell what version itis....

cannot tell what VCA's are on it either.... there are 3 VCA and a SIL-9 epoxied something, i guess its the resistor pack that you menmtion Keith.

i would unmount it and use it as a prototype, but the motherboard its on is looking a bit dodgy.. (not sure it itwould like me taking the 202 away and putting it back, without giving me some trouble afterwards)



Here is a pic of the 202 i have in the film pan module....

Hey Keith, who makes these 5 gang pots? do you know where I could get 6 and 12 gang versions?

Where would one get the SIL-9 resistor array? what are the specs/model number

 

[radiance]

Ok, good idea.
But what about a black can, or gold can version. That would be a discrete version right?

I suspect there might be some critical transistor matching involved or so...no newbe stuff I suppose.

So what's the reason it has not been done yet?

BTW, I'm also really interested in the "8 2150s " version, just wondering.....

 

[quadwould]

right now i am just loking to make the 8 VCA version. i think it is the most well known. and seems very easy to make (the only thing might be the SIL-9 resistor array)...

 

[gyraf]

(the only thing might be the SIL-9 resistor array)

Why? You could just use a row of resistors..

who makes these 5 gang pots?

Vishay/Sfernice

Jakob E.

 

[Kev]

I found that VCA Quiz picture from the old place
and re-located it

this and the image above
and a look at Jakob's site
and you may be able to put something together

SORRY !! BIG picture
and no time to fix it right now
:sad:

 

[sintech]

Found these pics of a Vca clone that maybe of interest.

ProAudioDesign 2002TS vca with a row of resistors, and also a version with an array

 

[mnats]

Hmm...A, B or C?

How about none of the above?

 

[SSLtech]

[quote author="radiance"]Ok, good idea.
But what about a black can, or gold can version. That would be a discrete version right?[/quote]
Good luck with that...
[quote author="radiance"]I suspect there might be some critical transistor matching involved or so...no newbe stuff I suppose.[/quote]
Egg-zackley.
[quote author="radiance"]So what's the reason it has not been done yet?[/quote]
You answered your own question. Transistor matching -and across a temperature band- with thermal coupling issues pretty much guarantee that what you'll end up with is a VCA that has all of the issues that got VCAs a bad name (remember that!) and few of the good points, having spent more than you can buy an excellent, quiet, thermally-stable, reliable 218x series VCA for.

It's an all-round bad idea in my book.

As for using seperate resistors, the matching is actually rather helpful, I suspect; -you can make a better overall VCA with closer matched resistors. 1% is okay, but 0.1% is better.

Keith

 

[radiance]

[quote author="mnats"]Hmm...A, B or C?

How about none of the above?[/quote]

Wow, was about to open up one of mine's...
Luckely I saw this picture first.

Thanks!

 

[Tekay]

I've been searching my old drives and found the complete drawings for the VCA202r (dual layer).
Can't export it as pdf on this PC so I'll do it at my workshop tomorrow.

Hope it will help someone

 

[quadwould]

Tekay,
Sounds great! is this the one with 8 VCAs on it?

cheers!

:guinness: :thumb:

 

[Tekay]

OK here we go!
This is what I have, no schematics and it's UNTESTED
It's just a trace layout, some of the tracks may have to be thicker?

http://www.vintagedesign.se/diy/VCA202R.pdf

Goodluck!

 

[quadwould]

very nice. :thumb: doesn't look like the ones i've seen before. with al 8 vcas all bunched together. what model is this based on?

 

[Tekay]

Don't remember what unit I found it in, think it was some kind of DBX like DBX165?

 

[Sammas]

why 8 vca's on one?