Ibanez JEM Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
240 Posts
Discussion Starter · #1 ·
Hi all, I am wondering if you can help me. I want, basically, to be able to check and repair my peavey valveking (and other tube amps) and replace tubes etc safely and properly (noone local to do it for me). Could you please give me some advice or links or give me a guide on what to do?
Thanks alot :p
Regards
Jonny
 

·
Registered
Joined
·
240 Posts
Discussion Starter · #2 ·
Anything is appreciated, I don't have any local people/workmen etc that can/could do it so I want to learn how to do it myself- if you could tell me anything that may help even in the smallest way I would be very grateful :)!
Thanks
Regards
Jonny
 

·
Registered
Joined
·
112 Posts
Anything is appreciated, I don't have any local people/workmen etc that can/could do it so I want to learn how to do it myself- if you could tell me anything that may help even in the smallest way I would be very grateful :)!
Thanks
Regards
Jonny
There is only one _really important_ thing to understand when working on tube amps.

The DC voltages inside in the cabinet are very high, lethal in fact. The filter caps store enough electrical charge so there is enough voltage to kill you even if the amp is unplugged, and even if it has been unplugged for days.

Therefore, you need to know how to safely discharge the filter caps before you start any work inside the chassis. The simplest way (although perhaps not the best way) is to use a heavy screwdriver with an insulated handle to short the caps. This will usually result in a substantial spark, and you may even get a bit of spontaneous spot welding of the screwdriver to the cap leads.

Better methods drain the caps a bit more slowly, using something like a lightbulb as a resistive load.

Anyway, read up on the discharging techniques (lots of good sites on amp maintenance and building), get that sorted, don't take short cuts with safety, and then learn the rest.

The rest is secondary -- that's just a matter of having a guitar amp that works or not. The info above is what determines whether you live or not.

But once you get comfortable with the rules, working on and understanding tube amps is not terribly difficult. They aren't space shuttles. Very simple circuits by today's standards -- but that's not to say they don't have their subtleties of design. Some of it is very clever and sophisticated, actually.

But all of that is what makes them a good proposition for hobbyists to work on.
 
1 - 5 of 5 Posts
Top