Changing Amp Tubes


maser
Member
Joined: 01/29/01
Posts: 85
maser
Member
Joined: 01/29/01
Posts: 85
08/30/2001 7:26 am
I have one of the new Marshall Valvestate 2000s with the tube pre-amps. Can someone explain the process of changing the pre-amp tube? I.E. safety issues and other things. I can't seem to find much on the internet about it. Thanks in Advance!
Mai Zure - So overdriven, he sh*ts distortion
# 1
Lordathestrings
Gear Guru
Joined: 01/18/01
Posts: 6,242
Lordathestrings
Gear Guru
Joined: 01/18/01
Posts: 6,242
08/31/2001 5:22 am
I don't know why you have decided to change them, since they pretty much last forever, but here goes.

Unplug the amp, and br sure it has had time to cool off. There are capacitors inside the chassis that can hold potentially [u]deadly[/u] voltage for a long time, so don't go there.

Be gentle with them. The pins that plug into the socket are not very strong. They're more like pieces of wire, actually. Rock the tube back and forth, while pulling on the bottle.

If you look at the bottom of a tube, you will see that the pins are arranged in a circle, with a gap. The tube socket has holes in the same pattern. When you plug a tube into the socket, you have to be sure to match the gap in the circle of tube pins to the 'missing' hole in the socket.

Rock the tube gently back and forth as you push it into place in the socket.

All done! Unlike the tubes in the power stage, preamp tubes don't require bias adjustment when you replace them.
Lordathestrings
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# 2

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