software

So I'm new to the tube amp world, I will be getting mine friday. I have always been a solid state guy, so I have a couple of questions about them. I have a good understading of electronics because that is what I'm in college for, but I just don't have any experience with vaccume tubes since they aren't used in hardly anything anymore. So here is my questions: 1.) I'm getting a JSX head, and it has to quot;biasquot; knobs on the rear panel that look like meter probe test areas. What are thease for and what do they do? I'm guessing that they have something to do with the switchable power amp, (6l6 or EL34) but I wasn't sure.
2.) THere is an effects loop on the rear pannel and it has knobs for effects send and effects return level. why is there two levels? I've only seen one effects level in the past, but I've only had solid state, middle of the road equiment. Thanx guys!

Yes, the bias setup has to do with tube changes. There should be a pot for adjusting bias, and one or more test points. You plug in a meter, then tweak the pot to adjust bias.

Different tubes need different bias voltages. Even when changing from old tubes to new tubes of the same type, it's a good idea to re-bias. The amp's manual probably has typical values for each type.

Actually, quot;biasquot; is the current running through the tube at idle (no sound) and the voltage you're measuring is just an indicator of that current.

I'll let someone else handle the effects-loop question. My amp doesn't even have bass and middle controls let alone a loop.

effects send is used to optimize the signal level going to the effects so as not to overdrive them into unpleasant distortion

effects return is used to optimize the signal level coming back from the effects so as to produce the desired tonal characteristics of the signal going to the power amp

there are subtleties to consider if the loop is parallel or serial and if one is running a wet/dry setup ...

hope this helps .. if you have more specific questions about your exact intentions for the loop, let us know what effect(s) you are using and what you want to do with it and we can help dial you in a bit more specifically

t4d

And if you have any more questions, make sure you ask a DREXEL grad.

I was wondering if you guys could explain to me how send and recieve sockets work when you want to do something like using another external preamp, and just skipping the internal preamp, basically muting the pre-amp. Another think I want to know is which sockets I can just plug/unplug a cable in whenever I want on standby, on, or off.