I play through a Marshall dsl100 and i have had my tubes in since i got the amp coming up a year ago.

I have heard rumors that you can use different tubes to give the amp different tones to the stock configuration. I am after a heavier tone if possible maybe with more mesa/randall properties blended with that marshall tone i love soo much.

all help is apreciated!

Ibanez RG770DX Reissue

Ibanez Apex 2

Ibanez S520EX w/ EMGs

Marshall DSL100 Halfstack

There's a really good thread stickied in the gear forum, you'll be able to get all the information you need there.
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keep in mind that if you drastically switch what types of tubes in there, it is essential that you adjust the bias of your amp.