#1
So I've been doing some research on pulling tubes in my JVM210h. My goal is to make the tubes burn hotter and to achieve output tube distortion at a lower volume. I usually keep it at two or three volume-wise. I realize that it won't affect volume as much as it will tone. My question is if I have to rebias the amp. This is what I know so far, please let me know if there is anything else I need to know or if I have something wrong.

1. I need to remove either the middle two tubes, the outer two, or the first and third tubes.
2. This causes the impedance to double, so I will need to use the 4ohm output into an 8ohm cab.
3. Since the bias is the voltage going through the tubes, I will need to rebias accordingly.


Another thing, this is my first tube amp and I got it recently. I have never done any work on an amp like this. Should I take it in or should I do it myself if I have to rebias? Thanks!
#2
By pulling two power tubes you're not making them "burn hotter", you're simply cutting the power output in half. It shouldn't be absolutely necessary to rebias when you do that but it never hurts to check it. Biasing is pretty simple but you have to have the tools and knowledge to do it. When it's time for a rebias (when you change power tubes) I would take it in to a tech first.
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