No audio from dbx 166a compressor

stealth51 · #1 08-14-2007, 06:02 PM

I'm trying out a dbx 166a compressor that a friend had laying around. He got it used but never used it. I hook it up in the FX loop of my GK but no sound. I think taht is the way to connect to my amp. Any ideas on what else I could try?

bongomania · #2 08-14-2007, 07:37 PM

What are the settings you have it at? And are you sure you're plugged into the same channel as the knobs you're twiddling? And is there an fx return "level" or "blend" control on the amp? And what kind of cables/plugs are you using?

stealth51 · #3 08-14-2007, 08:44 PM

Using 1/4" patch cables(mono).
Compressor connected in FX loop
GK 400RB boost set to 12 o'clock
Threshold=0
compression 1:1
output gain 0dB

With bypass on I get sound ouput. Turn bypass off, nothing. I even tried connecting it, bass> dbx > amp input. Result is the same no ouput. Maybe the unit is broke.

niftydog · #4 08-14-2007, 09:17 PM

Do the meters respond?

bongomania · #5 08-14-2007, 10:13 PM

Try turning the threshold and output gain all the way to max. That's not a good setting, but it helps eliminate some potential issues. Also, is the gate switched on or off? Make sure it is switched all the way off, and double check yourself (seriously!) by turning the gate threshold knob all the way the other direction too. Also, the bit about the blend or other loop controls on the amp head.

stealth51 · #6 08-15-2007, 05:33 AM

Quote:

Originally Posted by niftydog

Do the meters respond?

No

stealth51 · #7 08-15-2007, 05:52 AM

Quote:

Originally Posted by bongomania

Try turning the threshold and output gain all the way to max. That's not a good setting, but it helps eliminate some potential issues. Also, is the gate switched on or off? Make sure it is switched all the way off, and double check yourself (seriously!) by turning the gate threshold knob all the way the other direction too. Also, the bit about the blend or other loop controls on the amp head.

I made sure the gate was switched off. I rotated the controls just to see if I can get any kind of sound from the unit but, nothing.

I do have a boost control that controls the gain after the effects loop (see attachment).

niftydog · #8 08-15-2007, 05:26 PM

Sounding ominous...

Have you got any line-level audio sources you can connect directly to troubleshoot the compressor alone?

bongomania · #9 08-15-2007, 05:32 PM

Have you tried both channels?

stealth51 · #10 08-15-2007, 05:53 PM

Quote:

Originally Posted by niftydog

Sounding ominous...

Have you got any line-level audio sources you can connect directly to troubleshoot the compressor alone?

So far I've tried a turntable, cassette deck and a Boss Digital recorder. Even though the lights come on I think it's toast.

stealth51 · #11 08-15-2007, 05:58 PM

Quote:

Originally Posted by bongomania

Have you tried both channels?

I've tried both channels. If the unit is processing an input signal should there be some activity on the gain reduction LEDs? I was going to buy it if it worked

bongomania · #12 08-15-2007, 05:59 PM

Have you tried cursing, and smacking it with your fist?

chutsk10 · #13 08-15-2007, 06:04 PM

Quote:

Have you tried cursing, and smacking it with your fist?

I have fixed many a tings using this method.

stealth51 · #14 08-15-2007, 06:18 PM

Quote:

Originally Posted by bongomania

Have you tried cursing, and smacking it with your fist?

I actually did give it a good smack

I fixed a lot of tube amps back in the day with that method. Do you think it's worth having a service tech take a look at it or should I go trolling on ebay?

Johnny Crab · #15 08-15-2007, 06:53 PM

Quote:

Originally Posted by bongomania

Have you tried cursing, and smacking it with your fist?

Percussive maintenance!
Also lets you know if a tube amp has any microphonic tubes.

You also may want to CALL dbx techfolks with the unit on and a line level device running into it.

Beachcoma · #16 08-15-2007, 07:08 PM

If at first you don't succeed, whack it with a hammer...

after that, its time for some techie to be called and offered cookies

Rob

**Horny Toad** · #17 08-15-2007, 09:00 PM

Quote:

Originally Posted by stealth51

Do you think it's worth having a service tech take a look at it or should I go trolling on ebay?

Depends what your friend is asking for it and how much you'd have to pay a tech to troubleshoot/fix it.
You can find working 166a's on eBay all day for around $100 - $125. I picked up a mint one for $100 and it's great.

bongomania · #18 08-15-2007, 10:16 PM

I also bought a mint 166A for $100.

DbNBassist · #19 08-16-2007, 01:25 AM

I dont what the problem is here, im not an expert but it seems he has his output gain on nothing, there for no sound would come out of it.

niftydog · #20 08-16-2007, 01:47 AM

Not nothing, 0dB, there is a difference!