Two questions regarding my allen and heath...

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

timjimbaker

Member
Joined
Feb 10, 2010
Messages
12
Hello there... I have slowly been restoring an old Allen and Heath System 8 16:8 mixer. I bought it for cheap to learn/practice some repair work. I have been making some headway and the board is almost up and running. It's been a great learning experience thus far. There are still a few things I cant seem to figure out that will probably be a no-brainer for lots of you.

The first is that there is a wind-like sound coming out of the monitor outs. It is very random and sounds almost exactly like a breeze blowing out of my monitors... Strange. Any suggestions?

I recapped some of the board so far. I have done the right and left channels, the buss section and the 16th input channel. Everything works fine except for the eq section of the 16th input channel. I believe it worked well before, but I am not positive. When you turn the high or mid knob past 12 o'clock, a crazy feedback happens. It happens even with no signal passing through the channel. Some sort of oscillation. What could be causing this. I am worried if I recap other channels the same problem will occur. Any ideas on what I might do to fix this...

As always, thanks for your time. Cheers, Tj.
 
Check your repairs........electros wrong polarity/value.....solder bridges etc.....wiring errors ,PITA but you have to check ...once twice and thrice !!
Have you recapped the PSU ?..........if a channel was ok before and working  .....then you have probably introduced the errors.
 
Yep.  It requires bright light and a magnifying glass.  I like to do it outside, or with a mag lamp.  Clean the flux too.
If an EQ oscillates the circuit has been compromised somehow.
The windy monitors- try to isolate it.  Is it only on the mix bus or also on SOLO or 2TRK?
Don't fret.  There are always some challenges when doing the big projects.  I coached a musician through a console re-cap, and by the end he is a pro, and knows more about his console than I do.
Mike
 
how much have you tried to isolate it?

when your monitors are breaking wind, does the monitor pot (or fader) affect
the level?
If not then it is after the volume pot, not much after that so is easy to isolate issue

if it does, will changing what is selected in the control room module for playback in
speakers change what's happening?

if it's coming from the stereo buss, does dead patching the mix insert returns make it stop
(and that's after seeing if the master fader affects level of sound, if so the problem is before that if not it's after)

will banging your fist on the arm rest change the sound? if so, it's a physical problem (electromechanical)
wires, connector, solder joint type of thing more that likely 

good light and a crazy ass strong magnifying glass
 

Latest posts

Back
Top