Tube Amp Questions (Alot of questions)

[strat_master]

Hi just wondering since im soon to be the owned of a marshall tube amp, i wanted to know, a few things for the dsl401 combo;

1) When do you change the tubes and pre amp tubes
2) What is biasing exactly? And do i need ot do that?
3) Do i need a guitar tech or repair man to change the tubes? Or can i do it myself fairly easily with little effort.
3) Do tube amps over heat alot? and does the dsl401 have a reputation for overheating?
4)HOw much do tubes cost and pre amp tubes as well?
5) what brand does marshall use? and whata re the differences among the brans ie: mesa/boogie, to marshalls ( both pre amp and regular tubes)
6) What is the most common way people blow tubes and how is it best avoided?
7)Lastly what is this pencil tapping technique ive heard about? To see if its blown or something??!?!


Well thank in advance guys for the help, i just want to be sure what im getting myself into when i buy the dsl401 as its my first tube amp and first decent amp im gonna own, I only play a crappy 10 watt marshall mg10 or something and its ss of course.

[arvid4prez]

Re: Tube Amp Questions (Alot of questions)

1) Depends on how much you use them. Generally Powertubes last about a year and preamp tubes about tubes. But that differs big time. I am using mine 1.5 years now.

2) Biasing is matching your tubes (the voltage) with your amp (adjusting your amp that is). It is absolutely necessary if you change from one type of power tube to another (eg from EL34 to 6L6). Whether it's necessary if you replace them with the same type, ... Let's just say opinions differ on that one. I'd say do it anyway just to be sure since voltages vary between tubes (which is why you buy them in matched pairs/quartets). It will make your tubes last longer. Biassing isn't necessary for changing preamp tubes.

3) Changing preamp tubes is pretty easy: just replace them. Biassing takes some experience though. For the best results contact a qualified (or experienced) technician for that. Also, even an amp that isn't plugged in contains electricity, so it's also safer if you let a specialist do it...

3) Generally, as technology evolves, amps get more reliable. For the experiences with the DSL 401:

http://www.harmony-central.com/Guitar/Data/Marshall/JCM_2000_DSL_401-01.html

4) Differs from brand to brand: about $25 per power amp tube and about $15 for preamp tubes.

5) Neither Mesa or Marshall make their own tubes. They buy them from other companies (same goes for Groove tubes, Ruby tubes (which I use)
and so on... I think they are Svetlana's, but I am far from sure...

6) Turning their amp on without speakers connected is one way,... But for the rest I have no idea. I couldn't do it if I wanted to...

7)Slightly touching a tube with a pencil to see if it's gone bad. This is done when you're amp is squealing for some reason (that isn't your guitar feedbacking)...