Is it safe to replace 12ax7 tubes with the marshall ECC83 preamp tubes?
Also, does there exist an adaptor for EL84 slots to hold EL34 tubes?
I just want to see how replacing the tubes will change my amp's sound, I've fiddled with everything else, figure might as well. I have a pretty good understanding of the dynamics of tubes, just not the properties of replacing and their tonal characteristics. And at less than $20 they seem worth the investment as opposed to experimenting with a whole new amp.
ECC83 is just a different name for 12AX7's

They're the same thing - in Europe they're known as ECC83s, here they're known as 12AX7's. You can thank Mullard-Phillips for that.
I know there's an adapter to use EL84's in place of octal based tubes, but I don't know of one that works the other way around. I don't believe PT's built for EL84's can handle an EL34. Not to mention the OT's are different.
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