Two identical Trends TA10.1, left channel of one hisses.

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I'm using them to bi-amp my speakers.
I'm using the left channels for super tweeters and the right channels for widrange drivers.

The left channel of one amp hisses, first I thought it was my preamp but the hiss is still there with the preamp disconnected. they are using a common power supply. I'm using them configured as power amps with the volume controls bypassed. Everything between the two amp boards is identical, so why does one hiss?

Any ideas?
I tested them before I took them apart and it didn't hiss then, I haven't been anywhere near the chip or output filter.
I have removed the volume control and moved the input caps off board, I put header pins on the board on the chip side of the input cap positions.

It hisses with the active crossover switched off which is as good as disconnected (crossover output is muted with reed relays between the XO output and the amp's input capacitor )

I have swapped speaker cables over between the two amps and the tweeter on the other speaker hisses.

A good wash of the boards sounds sensible, there was flux all over them when I got them. I'll give that a try and order a super-fine soldering iron tip and a bottle of flux.
I came across this topis while googling for solutions to the same problem. I received my Trends TA-10.1 this saturday and after about 30 seconds of play I got a hiss in my right channel.

Did any of the above solutions work for you? Have anyone managed to get rid of the hissing? Any information at this point would be very helpful. I have not modified the amplifier in any way so far.
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Hi guys.

Well, I should know what the problem is - but I'm stumped! With all the Trends I've had, never had a hiss problem. And never heard a T-Amp with hiss in just one channel - always in both. (Bad bias cap).

This is now the 3rd case I've heard about.

Will ask around to see if there's an answer to this.

Please let us know what you find.
It seems to be heat-related since the hiss doesn't start until after a short while after the amp is powered up. If I turn the amp off after the hiss starts and wait a couple of seconds (about 30 or so) before turning the amp on again the hiss is gone for a short while before returning.

I thought it might be some cold soldering so I resoldered the IC but with no luck unfortunately. I have now sent the amp back to the retailer, hopefully I will receive a fully functional this time. It sounded great for the short time it worked.

I would also like to add that "hiss" might be misleading. The sound from my amp is quite loud, it's no subtle hiss it's a noise that really makes me worry about the speakers.

I will make additional posts if I get any additional information from my retailer.
I received a new amplifier less than 48 hours after I put it in the mail, very nice and quick replacement.

I have no further information on the first amplifier that I received though, it was not working when I returned it and I don't think I'll receive more information about it either.

The new amplifier works perfectly and is really nice =)
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