Home » VintageKustom.com » Repairing Kustom Amps » 250-4 (got it burnt up to repair on my bech)
Re: 250-4 [message #28764 is a reply to message #28618] Fri, 09 September 2022 20:06 Go to previous message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
Good to hear and I am glad you had the patience to stick with it!
You customer being happy will be great word of mouth for you.
Here's a old story you will relate with I think.

I had SS Vox Beatle head that was a very late model made just before Thomas organ ditched them.

These had very long wires to the T03 output transistors on the far side of the chassis.

This guys amp would blow the outputs when others that I repaired would not.

Now in these late amps I found out that they changed the wiring layout.

At first I thought that it was because this guy used to play the amp dam loud and the amp would go into run away heat over load, so I put a big Ass fan blowing on the heat sinks but it blew yet again.

I finally look at the thing and found that it was oscillating way up there like yours.

I came to the conclusion that it was due to the long and uneven wire length feeding the outputs which was making for a uneven impeadence load on the outputs.

To counter that I added a 10 ohm 1/2 watt resistor in line with all of the four base leads right at the transistors.
The result, I never saw that amp again and in fact I know the next person who now owns it and where talking 18 years since the new owner has had it!
 
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