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[silent:arts]

903-51X Comp / Limit New
« on: March 25, 2015, 05:35:11 AM »
« Last Edit: March 09, 2018, 02:19:34 AM by [silent:arts] »
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[silent:arts]

Re: 903
« Reply #1 on: March 25, 2015, 05:35:47 AM »


« Last Edit: March 25, 2015, 11:26:39 AM by [silent:arts] »
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bernbrue

Re: 903
« Reply #2 on: March 25, 2015, 09:30:33 AM »
 8)
Bernd
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culteousness1

Re: 903
« Reply #3 on: March 25, 2015, 10:17:11 AM »
Ah, the prototype PCBs have arrived! Nice, Volker!
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"What's all this analog stuff anyhow?" - Bob Pease
"My favorite programming language is ... solder." - Bob Pease

Patrick from Davis

Re: 903
« Reply #4 on: March 25, 2015, 03:09:45 PM »
I see you picked sonically superior yellow for the PCB's.  Good call.
Patrick

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tzman

Re: 903
« Reply #5 on: March 25, 2015, 03:10:56 PM »
Awesome!
Nice to see how you managed to shrink the size! Ow, and are we seeing a little teaser in the background?
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[silent:arts]

Re: 903
« Reply #6 on: March 25, 2015, 03:23:00 PM »
First test (without VCA,  just with a jumper wire): passes audio fine, +21,5dB gain.
Without (VCA and) any calibration 0,004% THD in the audio path. Cool.

Anybody knows how to calibrate the 903 correctly?
Can't find anything. However, we will find out ...
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[silent:arts]

Re: 903
« Reply #7 on: March 25, 2015, 03:25:59 PM »
Quote from: Patrick from Davis on March 25, 2015, 03:09:45 PM
I see you picked sonically superior yellow for the PCB's.  Good call.
Patrick, my PCBs are color coded. Yellow needs +/-24V ;-)

Quote from: tzman on March 25, 2015, 03:10:56 PM
Ow, and are we seeing a little teaser in the background?
No. Just my eight slot Backplane with SubD25 only.
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tzman

Re: 903
« Reply #8 on: March 25, 2015, 04:04:05 PM »
Quote from: [silent:arts] on March 25, 2015, 03:23:00 PM
Anybody knows how to calibrate the 903 correctly?
Can't find anything. However, we will find out ...

I think you can get a lot from the 160X service manual in the Tech Docs section...
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usekgb

Re: 903
« Reply #9 on: March 25, 2015, 10:30:47 PM »
I was thinking about taking this on at some point.  I'm glad to see it's in good hands!
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Zach Griffen Audio
EvilTone

peterc

Re: 903
« Reply #10 on: March 26, 2015, 04:56:27 AM »
Very nice! Love the dbx stuff.

Peter
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If opportunity doesn't knock, build a door.

mitsos

Re: 903
« Reply #11 on: March 26, 2015, 06:35:23 AM »
Cool! What's the second pushbutton?  Overeasy toggle?   Can you elaborate on what features you guys are adding?  Very curious!
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gyraf

Re: 903
« Reply #12 on: March 26, 2015, 07:21:25 AM »
GREAT idea making the DBX903 for 51X-format!

What do you use for the obscure RMS-converter chip?

Jakob E.
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..note to self: don't let Harman run your company..

[silent:arts]

Re: 903
« Reply #13 on: March 26, 2015, 08:34:39 AM »
Quote from: mitsos on March 26, 2015, 06:35:23 AM
Cool! What's the second pushbutton?  Overeasy toggle?   Can you elaborate on what features you guys are adding?  Very curious!
the 2nd pushbutton is for stereo link. not tested yet. just summes up the CV signals.
further features are the choice of unbalanced output (original), impedance balanced output or transformer balanced output.


Quote from: gyraf on March 26, 2015, 07:21:25 AM
What do you use for the obscure RMS-converter chip?
the same dbx used on a daughter PCB: 1 x CA3083, 1 x BC550, 1 x 1N4148 (see attached pic)
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mitsos

Re: 903
« Reply #14 on: March 26, 2015, 10:53:30 AM »
cool. Are you going to do the original gold VCA?
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gyraf

Re: 903
« Reply #15 on: March 26, 2015, 11:16:57 AM »
Nice! I've only seen 903's with DBX's own obscure semi-pro RMS chip - that sub circuit makes a lot of sense!

Jakob E.
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..note to self: don't let Harman run your company..

culteousness1

Re: 903
« Reply #16 on: March 26, 2015, 02:53:54 PM »
Would be great to replace the obsolete CA30823 in the emulation circuit as well  :o
THAT300 series only features 4 NPNs in an array. Don't know of any other array of 5 elements though...
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"What's all this analog stuff anyhow?" - Bob Pease
"My favorite programming language is ... solder." - Bob Pease

[silent:arts]

Re: 903
« Reply #17 on: March 26, 2015, 05:23:24 PM »
CA3083 are no problem, I can still get them way cheaper than any THAT array.
Looking at the THAT 2252 and THATs product politics I'm not sure how long the arrays will be available ...

Jakob, attached a foto of the dbx replacement. Never have seen any without, and even found some PCB overlays for the 902 with the substitute PCB drawn on top of the 146221.
However, looks like there have been many different revisions, even with 1252 and 1253 ICs.
« Last Edit: March 27, 2015, 04:15:38 PM by [silent:arts] »
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Bassniac

Re: 903
« Reply #18 on: March 27, 2015, 01:11:55 PM »
Hey

When do you start to sell them? I will be one of you first customers. Then I can finally get rid of my 160A.

Cheers.
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[silent:arts]

Re: 903
« Reply #19 on: March 28, 2015, 05:16:59 AM »
Quote from: Bassniac on March 27, 2015, 01:11:55 PM
When do you start to sell them? I will be one of you first customers. Then I can finally get rid of my 160A.
First it must be up and running and completely tested  ;)
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