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Old 13th April 2005, 07:01 AM   #1
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Default A bizarre Sonic Impact experience

Aware that I might damage the amp by doing so, I connected a 14V, 0.6A linear power supply to my Sonic Impact amplifier and gingerly turned it on. For about 10 minutes it produced very nice sound indeed, and I began to think that maybe it could actually function fine with such high voltage. But then came a distinct "Bang!" and a tiny puff of smoke. I immediately turned the amp off and replaced the 14V P/S with a 9V P/S. Amazingly, when I turned the amp on again, both channels still sounded excellent. I have not yet tried to disassemble the amp to examine the board, but I am very curious to know: what component could I have destroyed through over-voltage without noticeably impairing the amp's functioning?
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Old 13th April 2005, 07:12 AM   #2
rha61 is offline rha61  France
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one or several capacitors !

alain
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Old 13th April 2005, 08:08 AM   #3
dgo is offline dgo  Netherlands
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Interesting. I've heard about people running the amp at 16V for some time without damaging the amp. Also some 12V household wall adapters give varying voltages ranging between 12V and 18 V running the amp have been reported.

I'm running it on a regulated 4/6A DC 13,8 V PSU (giving a rock steady 13,65 to be exact) and it's been playing for about 60 hours now without any problems, sounding very good.

When I first bought the amp, I followed the statements made in the 6moons review about the PSU. In some part of the
interview, one of the readers state that 'Tripath's published maximum voltage for this chip is 13.2V but they told me that a tightly regulated 13.8V supply is okay'.

So the chip, apart from getting a little warmer at higher voltages, seems to be ok.

Maybe the caps don't like the higher voltages or this was a bad one... Hmm... makes me think about my setup .... Hope this is an exception.

Actually, this is the first time I've read about a T-Amp amp smoking it's caps due to high voltage. Does 'linear ' mean regulated? Did you measure the voltage the PSU gives?
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Old 13th April 2005, 11:10 AM   #4
rha61 is offline rha61  France
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you have just to find the capacitors that are hot and replace them with higher voltage ones
running hot reduce the cap life

alain
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Old 13th April 2005, 01:37 PM   #5
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Default Re: A bizarre Sonic Impact experience

Quote:
Originally posted by cdwitmer
Aware that I might damage the amp by doing so, I connected a 14V, 0.6A linear power supply to my Sonic Impact amplifier and gingerly turned it on. For about 10 minutes it produced very nice sound indeed, and I began to think that maybe it could actually function fine with such high voltage. But then came a distinct "Bang!" and a tiny puff of smoke. I immediately turned the amp off and replaced the 14V P/S with a 9V P/S. Amazingly, when I turned the amp on again, both channels still sounded excellent. I have not yet tried to disassemble the amp to examine the board, but I am very curious to know: what component could I have destroyed through over-voltage without noticeably impairing the amp's functioning?
You might want to check the unloaded voltage coming from your supply. Just turn it on and measure what it is.
This is how I ran a 5066 at 16.6 volts for a week. I got around to checking the power supply. It was 18 volts unloaded, and 16.6 volts connected to the 5066. This was a 13.8 volt supply.
The weak link is the stock 330 ufd 16v electrolytic cap on the SI board. The cap most likely can handle 17 - 17.5 volts for a short period of time. But it will live longer if the input voltage is kept down to 14 volts or lower.
The pop was most likely the electrolytic cap exploding. They look like a flower after blowing the can off.

George
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Old 13th April 2005, 07:28 PM   #6
BillyM is offline BillyM  United States
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I'm with panelhead, I bet your PSU was putting out more than it said on the exterior, and blew the electrolytic cap supply.

Open it up, in the middle of the 4 inductors, should be round black capacitor, dont be suprised to see two little leads and little lead shavings in the bottom.

--BillyM
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Old 23rd April 2005, 04:25 AM   #7
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Default Boy, talk about STUPID !

"Sometimes it really helps to read the fact-filled manual."

It turns out that my 14V linear P/S has TWO DC power output channels, and I had inadvertently connected both of them to my Sonic Impact T-Amp. So instead of 14V I was feeding it with 28VDC ! Little wonder that I blew capacitors on the amplifier. After reconnecting the P/S correctly, the little amp sings amazingly well for a cheap piece of equipment that has been so abused.

So I doubt anyone has anything to worry about feeding their SI T-Amp 14VDC, especially from a high quality supply.
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Old 23rd April 2005, 06:18 AM   #8
Pano is offline Pano  United States
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Wow, that's an amazing story. At least we now know that the little beasty is more robust than we thought.

Doubt it would live long on 28V, tho...
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Old 25th April 2005, 12:22 AM   #9
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So did you open it up to see what popped? This sounds like a good opportunity to upgrade stuff for a few bucks.
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Old 25th April 2005, 08:23 AM   #10
opentop is offline opentop  Netherlands
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Quote:
Originally posted by dgo
Interesting. I've heard about people running the amp at 16V for some time without damaging the amp. Also some 12V household wall adapters give varying voltages ranging between 12V and 18 V running the amp have been reported.

I'm running it on a regulated 4/6A DC 13,8 V PSU (giving a rock steady 13,65 to be exact) and it's been playing for about 60 hours now without any problems, sounding very good.

When I first bought the amp, I followed the statements made in the 6moons review about the PSU. In some part of the
interview, one of the readers state that 'Tripath's published maximum voltage for this chip is 13.2V but they told me that a tightly regulated 13.8V supply is okay'.

So the chip, apart from getting a little warmer at higher voltages, seems to be ok.

Maybe the caps don't like the higher voltages or this was a bad one... Hmm... makes me think about my setup .... Hope this is an exception.

Actually, this is the first time I've read about a T-Amp amp smoking it's caps due to high voltage. Does 'linear ' mean regulated? Did you measure the voltage the PSU gives?
Well, yesterday I blew mine. And I also was using a regulated 13.8V supply (3/5A DC). Did nothing weird. Just turned it on, listened tot some music and suddenly......the sound was gone. And there it was: the smell of something burning. Bad luck or too high a voltage?
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