Installing DBX 202C gold can on a GSSL instead of the THAT 2180

innercityman · Jul 4, 2016

Sorry for this maybe "stupid" question for the most of you guys, but I want to replace the 2180 VCA's with a pair of DBX 202C gold can that I bought for a good price. So what needs to be done, simply pull out all the components on each VCA's place and solder the 202 instead ? I guess some resistors values need to be changed right ?
Sorry, this has probably already been posted but I'm really not easy with the search engine of the site, any link would be welcome.

Thanx !

moamps · Jul 5, 2016

innercityman said:
... but I want to replace the 2180 VCA's with a pair of DBX 202C gold can..simply pull out all the components on each VCA's place and solder the 202 instead ?

Yes, check out also gyrafs schematic for parts you need to pull out (down right corner).
http://www.gyraf.dk/gy_pd/ssl/ssl_sch.gif

I guess some resistors values need to be changed right ?

Maybe, maybe not.
http://groupdiy.com/index.php?topic=32775.0

MiamiBoy · Feb 9, 2023

It hard to read in between the lines, if resistors needs to be changed or not.
There's never a straight answer here

MiamiBoy · Feb 9, 2023

When installing 202C gold cans instead of THAT2180, is there any changes that needs to be done: Yes or No?
If Yes, what needs to change?

Rob Flinn · Feb 9, 2023

MiamiBoy said:
It hard to read in between the lines, if resistors needs to be changed or not.
There's never a straight answer here

See attached document from years ago. Not my work, so if you don't like it don't shoot the messenger.

Script · Feb 9, 2023

THAT Design Note 127 – Upgrading Modular VCAs

Might be interesting ?

Ricardus · Feb 9, 2023

Just as an FYI, Peterson from DIY Recording Eqiupment measured and tested every VCA known to man for their new SSL Bus Compressor product and could find no advantage to using those vintage VCAs over the THAT 2181's.

MiamiBoy · Feb 11, 2023

Rob Flinn said:
See attached document from years ago. Not my work, so if you don't like it don't shoot the messenger.

Thank Rob... The graph looks like values from one THAT to another THAT. It doest mention DBX or 202's
Or am I totally off?!

MiamiBoy · Feb 11, 2023

Any gold cans people here..? I wanna know what you did

Script · Feb 11, 2023

You really might want to Google "THAT Design Note 127" and read that. Mentions the 202 gold and the 202 black, the 2001 and the 2002 etc, each with example schematics.

david moran · Feb 11, 2023

https://thatcorp.com/datashts/dn127.pdf

MiamiBoy · Feb 21, 2023

MiamiBoy said:
Any gold cans people here..? I wanna know what you did

Thanks guys. Ive read the .pdf.
It's very technical.. I can't read schematics

The only thing that stood out, was "if I wanted to replace a 202C with a THAT2002N" -and not the other way around. But again, I might have been blindsided from all the technicality writings.
I appreciate you guiding me this direction though...

There must be someone who done this (use a 202C instead of THAT) that knows exactly which part needs to be left out and/or replaced. I was hoping that someone like that could guide me. I don't know if that's too much to ask...

It's actually weird that there aren't any step by step pdf guide, especially because the pcb is created to go both ways

at least included in the original guide, would have been brilliant (see attachment).

When I look at the PCB (rev. 11), I see a box where the VCA is supposed to be.. im thinking the box is telling be that everything inside the square is for either 202C or 2180 circuit. I might be wrong.. but maybe someone with experience can clarify?

moamps · Feb 21, 2023

In the documents I attached, you can find a circuit diagram of one compressor with a table that contains information about which parts and which values should be used when using a particular type of VCA. In another document, you can find out how to adjust the trimmer values around the VCA. I hope that helps you.

MiamiBoy · Feb 21, 2023

This is awesome.. thanks moamps

I've been looking at the schematic for an hour now.
It describes exactly what the differences are.. unfortunately I cannot read/understand schematics.

I'm also not sure which of the THAT2080 version I have.. it doesn't say on my pcb.
The cool thing is that there are numbered components on the pcb that you've attached, unfortunatly I don't have a pcb with any numbering on it -mine only have the actual values on each.

I see that component #R132 needs to be replaced from a 36K resistor to a 9K resistor.
My pcb don't have any 36K resistor anywhere.. so i'm not sure of this even applies to my pcb !?

So I tried to look for the 36K on the schematic you've sent, to compare it to my pcb and hopefully find the correct spot. It also don't have a 36K resistor anywhere

or maybe im just not understanding it correctly?

Please keep helping me.. it's been very helpful with the two files you've sent.

ps. I also don't think my pcb have any POTS !?

Script · Feb 22, 2023

MiamiBoy said:
I've been looking at the schematic for an hour now.
It describes exactly what the differences are.. unfortunately I cannot read/understand schematics.

YouTube has tons of videos on learning how to read schematics and acquire some very basic electronics skills (e.g. use a DMM, trace a board, etc etc). Maybe give it a go ?[/]

gyraf · Feb 22, 2023

im thinking the box is telling be that everything inside the square is for either 202C or 2180 circuit.

..yes, that's the thought. The only reservation is the the original circuit was made for 2150 VCA's, later to be upgraded to 2180's with slight component changes.

But if you just mount the 202's in stead of what's in that pcb area, it should work, only +/- some precise ratio and such, probably not important. It won't break.

/Jakob E.

JohnRoberts · Feb 22, 2023

Just curious why would you want to use old obsolete VCAs?

JR

MiamiBoy · Feb 22, 2023

Script said:
YouTube has tons of videos on learning how to read schematics and acquire some very basic electronics skills (e.g. use a DMM, trace a board, etc etc). Maybe give it a go ?[/]

Ive been looking at all the videos there are.. I can understand a basic "battery connected to an LED" circuit. But audio equipment schematics are very chaotic and gibberish to me. I understand simple things.. these schematics are not made as simple as they can be.. all the rules aren't always followed and that messes with my head. I like math, you can count on math every time, anywhere.

I have had explained to me how airplanes work.. I get it, but I still don't understand it, no matter how many times it's explained to me. I see the logic, but no. There's just some stuff you can't wrap your head around.

gyraf said:
But if you just mount the 202's in stead of what's in that pcb area, it should work, only +/- some precise ratio and such, probably not important. It won't break.

I better wait for someone who have done this themselfs and have them tell me which components needs the change/replacement.. im guessing its less than 8 components that needs changing.. a very simple procedure, but I don't know which yet.

JohnRoberts said:
Just curious why would you want to use old obsolete VCAs?

Because I want this unit to sound and behave like the original as much as possible. Old wiring and components have their sound & charm, I don't wanna replicate that, I want the real thing.. And also because I have them, so why not

This is my biggest build ever, so im going all the way with turbo and HPF. If that wasn't important to me, I would have bought a 500 series Bus directly from SSL, costs the same as this project... but even that doesn't sound like an old ssl Bus

JohnRoberts · Feb 22, 2023

MiamiBoy said:
Because I want this unit to sound and behave like the original as much as possible. Old wiring and components have their sound & charm, I don't wanna replicate that, I want the real thing.. And also because I have them, so why not This is my biggest build ever, so im going all the way with turbo and HPF. If that wasn't important to me, I would have bought a 500 series Bus directly from SSL, costs the same as this project... but even that doesn't sound like an old ssl Bus

The VCA is only a fraction of a dynamic processors sound signature. You need to copy the topology and side chain closely.

Have fun...

JR

FIX · Feb 22, 2023

I wouldn’t swap the VCAs. There are many things that need to change, and the sonic differences aren’t worth the pain. The only thing you can do to improve things is parallel more vcas for slightly less noise.

Installing DBX 202C gold can on a GSSL instead of the THAT 2180

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