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T3 problems

T3 problems

Hi,



I ordered T3 from you 2 years ago and it was quite good,

I had problems with grounding and you told me to desolder caps C19 and C20 from both boards and replace them with 270/470pf caps.

I finally did that but I realized that the old caps were 270 and 470 too.. Anyway the problem with grounding is better but certainly not fixed I still get hissing noise when I haven't got every ground on the board including input connected together which is ridiculous IMO. I wonder if R2 pot has something to do with grounds and all of this. Also when grounds are not interconnected and the amp is turned on i get loud signal noise even when nothing is connected to it, I thought it's transformer feedback but when I shielded it nothing happened.



Anyway I've got another problem just now, I didn't realize it till now. I thought I've got my table resonating but it wasn't the case, when I feed the amp with higher level bass signal (not near 300W of RMS) one of the channels of amp is sending mid to high frequency noise that sounds like sound resonating or clipping of woofer with it to the speaker. I first thought my crossover is messed up or something but when I exchanged the Amp boards (not the filter/power board). The sound came from the other speaker no matter if left or right channel is connected to it. So it's clearly something within the amp itself only in one channel.



Could you please address these and help me to resolve these problems with me? I would love to finally finish my amp. (I'm feeding it straight from my macbook to the alps pot to the amps itself, no DACs nothing.)
Hi, we suggest replace the bead on the topside of pcb (1206 package) to a wire. And it's better to use a speaker protection to work with T3 to invoice the turn on/off noise. The pot R2 on board is used to trimming the DC level.
For the last issue, I think it may be the power supply (SMPS or transformer) does not have enough power for both amplifiers.
Hi, we suggest replace the bead on the topside of pcb (1206 package) to a wire. And it's better to use a speaker protection to work with T3 to invoice the turn on/off noise. The pot R2 on board is used to trimming the DC level.

For the last issue, I think it may be the power supply (SMPS or transformer) does not have enough power for both amplifiers.



Hi nick,



Thank you for response, I will try to make the bead change (I guess it's labeled B1 cause it's only thing that is larger package on the top side), also there are relays on the input/filter boards so I don't have any on / off pop noise I just have loud noise when grounds are not interconnected. Also the transformer is rated 600W full time power transformer and I don't excite boards to draw such power (I have alps pot on the input no preamp yet) so that shouldn't be problem but I'll try to measure that too and reply with results.



Thanks.
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