Phoenix Gold Phorum

Hi.
Just tested a MQ-430 and the right rear channel sounded lower in volume than the left.
So is there a trimpot or something that can fix this? if so where is it? don't want to mess with the wrong thing.

Thanks.

How much lower? What happens if you swap the RCA wires from left to right? Does the same channel stay low in volume?

There is no trim for this, and the gain pot itself may be to blame, or other problems in the amp may be occurring.

enough to notice. did not hear it when i tried the front channels.

one possibility would be the diff of bias settings of that channel....

i had that one time in a zx450...nothing blown/damaged, just the bias was not set right again.....

but don't touch the bias pots if you don't know what you are doing.......

try first out the things Eric is telling.....

The right channel puts out about half the power of the left and if i measured as if bridged it shows the same as for the left channel. All this in stereo mode, if i put it in bridged mode it works as the front part and both channels at the same level just mono signal and dubble as bridged.
Could this be the ste-brdg switch thats the problem.

The seller told me he cleaned the pots and switches when he got it as it had the same problem and then it worked, then now after it had sat on the shelf for a while its not working again.

Thanks for all the help.

If I am understanding you correctly, yes, it seems like the stereo/bridge switch is to blame.

There are a few components though, between the RCA input jack, and the stereo/bridge switch. One of them could be bad, causing the problem when in stereo mode.

I have a guy locking at it that service the new Phoenix gold amps. Does any of you have the schematic for the mq430 or is it possible to get hold of?
It has som kind of noise in the channel thats not working right and he might need the schematic to now what to look for.

Mostly all amplifiers are a "copy and paste" design and PG did a good job at mirror layout so you can actually use the working channels as a reference to compare to the channel that is having the problems. Might have to track down the signal starting with the rca's and see if the problem is at the pre-amp section or later down in the pre-driver section.