PopPulse T-amp with Remote - modding

[marvin42]

Hello,
I bought a PupPulse T-AMP 1 from AudioMagus 18 months ago and was really enjoying it. I had thought about modding it better never found the time to dig into the resources necessary to get comfortable poking around in my t-amp.

Fast forward to a week ago and I was listening to some music at normal volume when there was a slight pop follow by silence. The amp turns on but no sound comes out - not even the quiet hissing that I used to hear when the amp was powered up.

I am a totally newbie at electronics tinkering and didn't see anything blatantly wrong when I cracked open the case, but I was hoping someone here might be able to suggest a good starting point to finding out what went wrong and if I can fix it.

Thanks!

[adawson68]

Originally posted by marvin42
Hello,
I bought a PupPulse T-AMP 1 from AudioMagus 18 months ago and was really enjoying it. I had thought about modding it better never found the time to dig into the resources necessary to get comfortable poking around in my t-amp.

Fast forward to a week ago and I was listening to some music at normal volume when there was a slight pop follow by silence. The amp turns on but no sound comes out - not even the quiet hissing that I used to hear when the amp was powered up.

I am a totally newbie at electronics tinkering and didn't see anything blatantly wrong when I cracked open the case, but I was hoping someone here might be able to suggest a good starting point to finding out what went wrong and if I can fix it.

Thanks!

Hi marvin .. did you pull the board and look for signs of discolouration (near the solder) on both sides of the board or caps that seem to not be quite regular in shape? Failing that you are going to have to do some testing to isolate the failed components .. something that I cant really help with (having not played around with the board)

[marvin42]

Originally Posted by adawson68

Hi marvin .. did you pull the board and look for signs of discolouration (near the solder) on both sides of the board or caps that seem to not be quite regular in shape? Failing that you are going to have to do some testing to isolate the failed components .. something that I cant really help with (having not played around with the board)

Yeah, I pulled out the board - didn't see any bulging caps or obvious discoloration that I could fault for the failure. I did notice that there is a chemical smell coming from the unit when it's powered up with the case open - a little unsettling, but nothing is smoking so that's a plus. The one thing I did notice is that the heatsinks on one of the MOSFETs (I think) gets warmer than everything else in the amp. I'm a relative novice so this could be totally natural and unrelated to my problems, but it's the best I could do until I can find my multimeter.

[ChuckT]

Originally Posted by marvin42

Yeah, I pulled out the board - didn't see any bulging caps or obvious discoloration that I could fault for the failure. I did notice that there is a chemical smell coming from the unit when it's powered up with the case open - a little unsettling, but nothing is smoking so that's a plus. The one thing I did notice is that the heatsinks on one of the MOSFETs (I think) gets warmer than everything else in the amp. I'm a relative novice so this could be totally natural and unrelated to my problems, but it's the best I could do until I can find my multimeter.

Sorry to hear about your Poppulse. By MOSFETs, do u mean the 3-leg regulators 7815, 7915, or 7805? It is normal that they get warm.
It would be difficult to id the problem. I think they once had some problem with the relays (big rectangular plastic thing next to the big caps), not sure. Either case, best to email your supplier and see if they will fix it, maybe you can just send the detached pcb board just to save some shipping. They will probably direct u to http://diykits.com.hk
Good luck!

[ChuckT]

For the noise problem, I discover that the output noise can be reduce by replacing the 100uf cap just next to the ta2022 chip (it is the closest e cap to the left of the ta2022, view from front).
I change it to a 330uf/16v Rubycon ZL.
This cap decouples the VN10 power pins (this is an internal regulated 10v above the -v feedback into the ta2022). Unfortunately, Poppulse has not use an external linear supply for this pin (there is an example using lm317 in the datasheet), unlike the Hilly 90 which spec for linear regulator for the VN10 pin.

[marvin42]

Originally Posted by ChuckT

Sorry to hear about your Poppulse. By MOSFETs, do u mean the 3-leg regulators 7815, 7915, or 7805? It is normal that they get warm.
It would be difficult to id the problem. I think they once had some problem with the relays (big rectangular plastic thing next to the big caps), not sure. Either case, best to email your supplier and see if they will fix it, maybe you can just send the detached pcb board just to save some shipping. They will probably direct u to http://diykits.com.hk
Good luck!

Thanks for your reply.

Ah yes, the regulators are what I was referring to. I'm obviously new at the electronics thing and the only thing I'd seen that came in a similar 3-leg package like that were mosfets.
I contacted my supplier and they told me that shipping it back to Hong Kong would cost more than they think it's worth so they'll give me a discount on a new amp. I'm thinking of checking out the Trends TA-10.1, possibly with the new PA 10.1 tube preamp.

[ChuckT]

Originally Posted by marvin42

Thanks for your reply.

Ah yes, the regulators are what I was referring to. I'm obviously new at the electronics thing and the only thing I'd seen that came in a similar 3-leg package like that were mosfets.
I contacted my supplier and they told me that shipping it back to Hong Kong would cost more than they think it's worth so they'll give me a discount on a new amp. I'm thinking of checking out the Trends TA-10.1, possibly with the new PA 10.1 tube preamp.

I suggest u directly contact with diykits and see what they think. The Poppulse is a higher power amp than Trends and no remote. I would rather go for the new Poppulse T150, same power, no remote but some comment it sound better than the original.
That is, assuming u still trust the Poppulse quality. The Hlly Tamp-90 is another choice that uses the ta2022 chip (higher power) and I believe the design is a bit better than the Poppulse (due to the external VN10 supply regulation I mention earlier).

[marvin42]

Originally Posted by ChuckT

I suggest u directly contact with diykits and see what they think. The Poppulse is a higher power amp than Trends and no remote. I would rather go for the new Poppulse T150, same power, no remote but some comment it sound better than the original.
That is, assuming u still trust the Poppulse quality. The Hlly Tamp-90 is another choice that uses the ta2022 chip (higher power) and I believe the design is a bit better than the Poppulse (due to the external VN10 supply regulation I mention earlier).

How do the Trends sound that you would not recommend them?

I mostly use this amp in my bedroom so high volumes are not a requirement. The Pop Pulse T-amp 1 was 45WPC @ 8ohms which was more than enough except when I wanted to listen to music from the opposite end of the house, I'm a little afraid that the 77wpc of the T150 would be so much that I couldn't turn it down quiet enough to listen to music at my desk.

[ChuckT]

I just prefer more power, that's all, and the ta2022 does bass better than the lower power chips. If u use it in the bedroom, than the Trend is good enough.

[ChuckT]

Originally Posted by ChuckT

For the noise problem, I discover that the output noise can be reduce by replacing the 100uf cap just next to the ta2022 chip (it is the closest e cap to the left of the ta2022, view from front).
I change it to a 330uf/16v Rubycon ZL.
This cap decouples the VN10 power pins (this is an internal regulated 10v above the -v feedback into the ta2022). Unfortunately, Poppulse has not use an external linear supply for this pin (there is an example using lm317 in the datasheet), unlike the Hilly 90 which spec for linear regulator for the VN10 pin.

The noise now is so low I'll have to put my ear 1 inch from the tweeter to hear any noise (for ref, my speaker eff is only 85db ).
I just got some high quality Epcos 25uH inductor, I'll replace the original 10uH for the VN10 later.