Hey all!

A few months back I acquired a Marshall DSL100H tube head. The other day at band practice, my singer spilled beer on the head, and after cleaning it up I noticed one of the tubes went out. I just have a few simple questions...

Should I replace all the tubes at once, or will replacing just the one tube be OK? It is not a question of money, either. I genuinely want what is best for the amp.

Next, How much does the rating on tubes matter? for example I just called my guitarcenter inquiring about what EL34's they had in stock. They had two sets of two, but one set was rated 6 and one set was a 7. What does this mean and how much does it matter?

Third, how hard is it to replace tubes yourself? Is it something an amp newb could do, or would you guys recommend bringing it to a professional? I've also heard something about "re-biasing" the amp after changing tubes. What is that, how does one do it, and again, is that something id be better of bringing to a pro to do?

Thank you so much for reading and thank you in advance for any advice.

Don't buy tubes from GC
Use a reputable tube distributer like these

For new tubes, JJ E34L (not EL34) or JJ 6Ca7 or JJ KT77

you should re-bias the amp. You may have done some more internal damage and I wouldn't really mess with it until you have it checked out. Don't take it to GC, they do not do repairs inhouse and ship it to someone else, but up charge the actual bill because they are the middle-man.

Also if 1 power tube died, then your really only using 2 power tubes and the ohms change because of that. and if you miss match ohms it can very easily kill your OT which is a $400+ repair job.

Replacing tubes is very easy this is for the older JCM DSL, but will work the same for your DSL
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
Last edited by Robbgnarly at Apr 4, 2015,
I agree with Robb, swapping tubes is easy, you can do it yourself. Shut it down, pull whatever you thing is bad replace it. Let it cool first.

However, many amps do need to be rebiased when swapping tubes, and he is right you may have something else wrong inside there.

Ask around with local musicians, chances are they know who does good work in your area. Also check at other local music stores, if GC hasn't priced them out of business already..
Hmmm...I wonder what this button does...