Replace transistors

huy801

Member
2007-12-11 9:40 pm
I decided to drop off the amplifier a couple weeks ago, and the repair
shop has just informed me that they want to replace all the transistors
and re-adjust the bias- they are quoting the repair job @ 1400 plus tax.

Is this amount a little excessive? They said they were going to get
matched transistors? Once the transistors are installed they would
readjust the bias, is it that difficult to readjust the bias, is it
something I can do myself? Do you all know where I can get high quality matched transistors so I can all this myself.

Any help would be greatly appreciated.

Thanks,
Huy Tran
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hello Huy,
What is the make and model of your amplifier?

I routinely match output transistors and the only amp that might approach this figure would be a Marantz 500, complete rebuild, both channel outputs (and I'm thinking $1K ~ $1.2 K). This done properly is probably a 2 day event. Anyone who has rebuilt one knows what I mean. The results are excellent when finished.

So your figure of $1,400 for one channel does sound excessive on the surface of things.

-Chris
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi djk,
I agree, unless there are extenuating circumstances.

I try to be cautious since we don't know the condition or type of amplifier as yet.

Hi Huy,
Bias is normally straight forward but can take an hour or so - depends. There are many things involved with replacing transistors. If you have not done this before, now is not the time to start.

Everything sounds easy conceptually. To an experienced technician, it is a series of well practiced steps. Also things to watch out for. Without knowing your abilities, I'd have to say that some tech should be working on it, not you. It is possible this shop is badly overcharging you - or not.

-Chris