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Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: Simarde on January 03, 2011, 05:19:45 PM

Title: Amp turns on, then volume falls and sound gets distorted
Post by: Simarde on January 03, 2011, 05:19:45 PM
Hi guys,

I've been given an old Traynor TS-50 amp, which semi-works. Here's the problem: Let's say I plug my guitar in the amp, while is it turned off. I then strum a chord, and turn the amp on. I can hear the chord for a fraction of a second at normal volume, then the volume falls and the sound gets distorted.

What can it be? A lot I guess, but if it works for a few second, the problem can't be that complex? ???
Title: Re: Amp turns on, then volume falls and sound gets distorted
Post by: joecool85 on January 03, 2011, 06:18:37 PM
Quote from: Simarde on January 03, 2011, 05:19:45 PM
Hi guys,

I've been given an old Traynor TS-50 amp, which semi-works. Here's the problem: Let's say I plug my guitar in the amp, while is it turned off. I then strum a chord, and turn the amp on. I can hear the chord for a fraction of a second at normal volume, then the volume falls and the sound gets distorted.

What can it be? A lot I guess, but if it works for a few second, the problem can't be that complex? ???


The problem could be quite complex, or it could be quite simple.  How much electronics experience do you have?

I'm thinking it is a problem with the power supply.  Sounds to me like faulty (read: exploded, ruptured, leaking) capacitors on the PSU.
Title: Re: Amp turns on, then volume falls and sound gets distorted
Post by: Enzo on January 03, 2011, 07:05:47 PM
My first thought is that somewhere in your preamp you have a serious DC offset, and you hear the sound come through as the system comes up to voltage and stabilizes.
Title: Re: Amp turns on, then volume falls and sound gets distorted
Post by: Simarde on January 03, 2011, 07:07:46 PM
Oh I see. Is there a way I can test the capacitators? And/or repair these? If they're broken I guesse I have to change 'em
Title: Re: Amp turns on, then volume falls and sound gets distorted
Post by: J M Fahey on January 04, 2011, 12:05:10 AM
Start by googling its schematic and posting it here, so we all speak about the same.
Title: Re: Amp turns on, then volume falls and sound gets distorted
Post by: Enzo on January 04, 2011, 02:39:38 AM
I for one did not mention capacitors, I am more expecting an op amp skewed over to one rail.
Title: Re: Amp turns on, then volume falls and sound gets distorted
Post by: joecool85 on January 04, 2011, 08:40:16 AM
Quote from: Enzo on January 04, 2011, 02:39:38 AM
I for one did not mention capacitors, I am more expecting an op amp skewed over to one rail.

I did mention caps, specifically power supply caps.  And I still think that may be the issue.

If you open up the amp and look for the big soda can looking capacitors, if they have failed they are normally blackened, bulged or split open.
Title: Re: Amp turns on, then volume falls and sound gets distorted
Post by: Enzo on January 04, 2011, 08:53:02 PM
You are right, you did, I am sorry.  I lost my focus there.  Winter blues...
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