symetrix 501 problems!

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xhavepatiencex
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symetrix 501 problems!

Post by xhavepatiencex » Mon Feb 09, 2009 7:10 pm

I just picked one of these up fairly cheap. It does not seem to be working properly though. It either does not compress or will give me like -18db of gain reduction. Sometimes way above where I know the level of the incoming signal is. This is pretty regardless of where I set my attack and release controls. I can't seem to get it to compress lightly. Anyone has any clues on what could be wrong, bad opamps? caps? could the VCA be dead?

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Post by chris harris » Mon Feb 09, 2009 8:06 pm

what about threshold and ratio?

there's not much info to go by in your post... and, sorry if this is offensive.... but, you're crystal clear on how a compressor functions and what all of the controls do?

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xhavepatiencex
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Post by xhavepatiencex » Mon Feb 09, 2009 8:09 pm

haha yes, I will have the threshold at say... -10 and will be getting no gain reduction while the level is higher than that though. If i move the threshold slightly it will all of a sudden be a huge amount of gain reduction, and this is regardless of where I set the ratio. I know how to work a compressor. I am just curious if anyone has any insights on where I should start poking around to try to fix this.

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Post by The Scum » Mon Feb 09, 2009 10:04 pm

Sounds like an intermittent connection or bad cap in the threshold circuit.

Check for bad solder/breaks/shorts in that neighborhood.

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xhavepatiencex
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Post by xhavepatiencex » Mon Feb 09, 2009 10:10 pm

nice, I am checking for bad solder connections as we speak. thank you!

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Post by Jim Williams » Tue Feb 10, 2009 9:03 am

Could be a cracked pot.
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xhavepatiencex
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Post by xhavepatiencex » Tue Feb 10, 2009 11:53 am

Jim Williams wrote:Could be a cracked pot.
that is what I am thinking, the guy that I bought this from just sold me two cl-100s for 60 dollars which do work properly. I have doubled my outboard compressors in the last two days. :twisted:

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Post by Spindrift » Tue Feb 10, 2009 12:37 pm

I'm having a similar problem. I just picked up two of them yesterday. One of them is working great, but the other one won't compress or limit at all, regardless of the settings. The output gain works fine, but that's it.

I then tried using the broken one as a stereo slave to the good one and that worked properly, so I guess the VCA is fine. I opened it up and nothing looked obviously fried or broken. Not having much experience with soldering and circuit design, I'm not sure the best place to start looking.

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Post by ballpein » Tue Feb 10, 2009 12:43 pm

I wish I could offer some specific advice - those are great comps, definitely worth getting them into working order.

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Post by xhavepatiencex » Fri Feb 13, 2009 10:56 pm

Here is an update on my issue if anyone has any futher insight. So when I power the unit up, even if I am feeding it no signal and the threshold is at +10, which is its maximum setting. The gain reduction light is all the way to 25. After its on for about 5 minutes it starts to go down to zero gain reduction.

From there it seems to be working fine and it sounds good. I am just not sure what is causing this initial start up problem. If I turn it off then back on its fine, only after its off for a few minutes do I have this problem.

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Post by Dakota » Sat Feb 14, 2009 1:30 am

Spray caig deoxit into all of the pots, then work them up and down a lot. See if the behavior changes. This would start a diagnosis.

I've certainly had older compressors off ebay and craigslist act wonky in the detection circuit from something bad in the pots.

Cracked or dirty pot, yes, first suspect here.

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Post by lacquer_monkey » Tue Feb 17, 2009 5:24 pm

Symetrix has schematics of all their old stuff up on their website in pdf format. Having a schematic usually makes debugging a lot more straightforward. Schematics for 501 are under techsupport/products with limited support.
uh... what??

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Post by Spindrift » Wed Feb 18, 2009 5:56 am

lacquer_monkey wrote:Symetrix has schematics of all their old stuff up on their website in pdf format. Having a schematic usually makes debugging a lot more straightforward. Schematics for 501 are under techsupport/products with limited support.
thanks!
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