500.4 Titanium amp distorting in one channel

[winno]

Hi everyone.
I have a Phoenix Gold 500.4 amp. One of the really nice Titanium coloured ones from a few years back.

It's got a bit of a problem.
One of the 4 channels goes quite and starts to pop and distort once the amp comes up to operating temp.

If I bridge this channel with its sister channel, the driver being driven by this channel gives a little more volume but wobbles out of time with the music and the cone is kinda sucked in a little.

Lovely sounding amp with three working channels so want to hang into it.

Any ideas on what the issue could be?

Cheers guys.

[trickyricky]

It may be one of the predriver transistors, may be leaking. Check the dc offset on all channels (no input signal, no speakers hooked up) and am sure you'll find the channel in question/faulty over 100mv.

[sunshinefc3s]

Hey there. I had a similar problem with my Ti 500.4. I had static in one of the channels. I sent it to valeks1 (his screen name) at Altser for repair http://www.altser.com/ . I think he is the only authorized PG repair shop, but I could be wrong.

I see that you are in AUS, might not be worth it to ship to Oregon.

Good luck.
-a

[Drock]

Try a different speaker on the channel. And check the RCA. At least then you'll know if it's the amp or not. I'm assuming you haven't already done this of course


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[dwnrodeo]

Ti amplifiers are also notorious for having dirty potentiometers (gain, bass boost, etc...). Try turning the knobs back and forth a few times and see if it alleviates or changes the problem. It's a quick easy check before you start diagnosing and opening up the amplifier.

[valeks1]

Look for damaged components on that channel.

[winno]

Thanks guys.
Yes, I've been through the process of elimination and ruled out everything else.
It is definitely the amp.
I've also had the pots 'cleaned' and still the issue remains.

I'll need to have it fixed here in Australia and wAs seeking pointers from others with experience to help any tech who might look at it for me.