Question that might seem stupid, but I'd like to think is not well known...

[Metaltastic]

So what exactly do tubes "do?"

That is to say, pre- and power-tubes. For example, a rectifier tube stands in for a silicon-diode or other solid-state rectifier (if another exists), which converts AC to DC current (or maybe it's the other way around, forgive my electrical ignorance). But what exactly is the function pre- and power-tubes?

Also, what is the function specifically of each of the pre-amp tubes (V1-V3) in, say, my peavey XSr? Cuz it seems odd to me that this 3-channel amp has 4 tubes, yet my old 2-channel 5150 had 5. Also, I know the last one is a phase inverter, so does the type of tube really make much of a difference in that spot?

All this has been dancing around my mind since I got a Tung-Sol 12AX7 and two Shuguang 9th gen 12AX7's; I'm trying to understand what to listen for in terms of changes depending on which slots I stick 'em in (I'm keeping my old balanced JJ ECC83S in the PI slot because I didn't think swapping it would make that noticable of a difference, is this indeed the case?)

Thanks a lot!

 

[JBroll]

They amplify. That's basically it.

Jeff

 

[2012]

The last tube in the series is the phase inverter, so it should be balanced. Also, using matched tubes in the V1 and phase inverter positions makes a positive difference in the performance of the amp. The rest are generally just more preamplification & buffer the input and output of the fx loop. Preamp tubes (triodes) preamplify, and power tubes (pentodes) supply the power. The harder you push the preamp, the more you'll hear the preamp tubes working. The harder you push the output section, the more you'll hear the power tubes cooking.

For a good read on how tubes work, read the section on triodes, pentodes, & irishmen.

 

[Metaltastic]

Wow, thanks man, those Mesa crackas really know how to write a manual (unlike the stupid buttholes at Peavey)