i have this crappy little behringer composer pro that i like to use for de-essing, it apears the detector circut is working but nothing else on the compressor works, its like always in bypass.......i dont even get output control.

this has happened temporarily before, then seemed to fix itself (temporarily)
now its showing comression/gate gain reduction but audio not affected

please help me, i generally am goodw/electronics but this has me in a stand still????????????????????????????????????????? [color=red][/color]

It could be that the bypass circuit is malfunctioning. If it is relay-bypassed, it is possible that the "rest" position is a hard bypass (connecting input directly to the output) and the control for it is broken. In which case there would be no effect on the audio. A good way to see if this is the case is to turn the unit off and see if it passes audio. There could be any number of problems but it sounds to me like the bypass circuit, relay or not is a good start point. Other than that I don't know. I couldn't guess the schematic and wouldn't suggest fixing it without one.

A few questions:
1)Why do you say that the detect circuit is working? Do you get an LED readout but no signal passed? Do you get an LED readout whether signal is present or not?
2)Does it have a DBX/THAT2252 as a detector IC?

If so, check for the presence of a DC control voltage on pin 7--I can't remember exactly how much control voltage these put out, but I think it should swing from 0vdc to about 275-300 millivolts DC depending upon what the input signal looks like.

If you are getting a control voltage output on pin 7 of the 2252, look to the VCA--you should see that same control voltage on pins 2 and 3 of the VCA, which is probably a DBX/THAT2150/2151 or something similar. If there is CV on the control ports, the VCA is probably the failed component provided that the trans-impedance stage (the opamp that follows the VCA) hasn't failed.

If there is no CV present, you'll need to trace back to find where the CV dies. Many of the attack/release/threshold type compressor/de-esser units will employ some type of comparator IC configured as an envelope generator. Check to see whether this is operational, and that there aren't any bad solder joints within the CV signal chain.

As a final note (since I don't really know your situation) let me add that these types of circuits can be prone to oscillation if there has been some type of failure in the knee circuit (almost always found immediately after the detector circuit, and almost always uses an opamp). Any sort of funky impedance situation will send your detector circuit into overload (especially if there is a diode used in the circuit in question), and so it will look like the unit is detecting a signal even when one isn't present.

I hope this helps rather than confuses you.

yeah slightly cofused......

assuming detector circut works because: I/O meter is correct/gain reduction correct (shows compression/gate)
signal does pass when unit is off

the audio just remains unaffected

I don't know the type of detector circut-but will find out when i get a chance.
thanks for reply though it is slightly helpful for my understanding, i still just dont know how to fix it

That happened to me one time... so what I did was paint over the name so it didn't know it was a BEHRINGER and it sounded fantastic.


I had a composer of some sort once for live use... it sucked... everything sounded like dirt.. From what I understand the older stuff was ok, but anything made in the past few years just doesn't cut it. Maybe you should E-Bay it.

dear clyde,

thanx for the suggestion buddy. you say that when you dont know the product manufacturer your equipment sounds fantastic..,well, maybe i will try your suggestion and see how my compression sounds then.

so did you hear somewhere that behringer is crap, in recording school maybe?

its not an instance of what compressor i have or what i use it for, it was a technical problem i am having and looking for a solution not your highly sophisticated opinion on "gear"

thanks for your help though...i'll try it.

love,
me

So, listen 'Buddy' I didn't go to one of those fancy 'recording schools' which I'm sure you're referring to. If you're going to take words like that so seriously then you shouldn't be on a web forum. Sorry to ruin your day 'Stud'.

My first comment I may have been busting on you, however, my second comment was completely serious. I'm sorry, you must have read it wrong, I didn't say that I heard somewhere that they were crap, I learned from my early experience that the company sucked and I was corrected by someone that had much more experience with them, telling me that the earlier stuff was actually OK.

Oh, and I wasn't saying that if 'I' didn't know what it was it would sound better, I was saying that since the company you are referring to has a reputation for producing products that belong in a trash can, or Musicians Friend, if 'IT' didn't know it was a BEHRINGER 'It' would sound better.

Take a joke ... Maybe I should have posted this in the bar jokes thread?

signal does pass when unit is off

Can you see if there is a relay, and test it to see if it is actuating.

greg...how do i test to see if its actuating?

Assuming there is one-
You should hear a little "click" noise come from the box itself (not the audio o/p) when you hit the bypass switch. If you have the lid off, you can hear it better.
You can find it probably near the i/o connectors and see what the make is. After that, get the data sheet with its pin-out off the manufacturer's website. Look at the voltage across the coil terminals and see if it is changing when you hit the bypass switch. If the relay is a 5 volt one the voltage should switch from 0 to 4-6 volts. Make sure that the "on" voltage is close to what the data sheet specifies.
To see if the relay works by itself, remove the relay by desoldering it carefully, then check with an ohm meter to confirm that it is working. Use a battery or a dc power supply to activate the relay (find out the voltage it needs and get as close as you can).