The Amp Garage

C'mon ya'll ........ wake up and smell the bacon! Gerry Rzeppa - Scrambled Eggs & Toast http://4praise.com/cgi-bin/files/m3u/6007.m3u Incidently, every instrumental note in that composition was generated by a home-grown computer program written in interpreted BASIC (with little bits of assembler) o...

Another way of saying this is that the cathode bypass caps shunts any AC that would otherwise appear in the (unbypassed) cathode resistors to ground. In case that might confuse Gerry; in terms of 'electron flow', the electrons are being pulled from the ground return, through the cathode resistor, o...

Thanks, guys. Your responses, in conjunction with a nifty calculator I found, tell me all I need to know. The calculator is here:

http://www.ampbooks.com/home/amplifier- ... capacitor/

I came across this little beauty today and was wondering how they manage to get away with leaving out the usual caps on the cathode circuits. What effect does that have on the amp's performance, reliability, etc?

http://www.allaboutcircuits.com/vol_1/chpt_1/7.html The NEETS course also covers electron vs conventional. In troubleshooting or just going over a circuit conventional flow is easy to follow and probably more intuitive for most people. But if things worked the way conventional flow says then a tube...

A bit of internet searching has led me to believe that the "electronic–hydraulic analogy" (derisively referred to as "drain-pipe theory") is what I've been picturing:

http://en.wikipedia.org/wiki/Hydraulic_analogy

But with specific application to tube guitar amps, of course. Still looking...

Check out Merlin Blencowe... He likes to talk about electrons... Thanks for the suggestion, xtian. Unfortunately, Merlin does not appear to be the guy I'm looking for. Quoting from his book: "This [speaking of current as positive] sometimes causes consternation among students who argue that convent...

Second question, I just imagine electrons marching down those wires. Little ones can fit thru picofarad caps, and fat ones thru big electrolytics. JUST KIDDING! The reason I asked is because I built a modified Bassman AA864 a while back and had serious hum problems -- until I started thinking about...

Thank you, Leo_Gnardo and rdjones. I've read up on cathode followers and I see what you're saying. While I'm here, I have two other (unrelated) questions: 1. I notice on the MOD-101 schematic below that they're sharing the resistor and capacitor on the two pre-amp cathodes; what is the effect/advant...

Just wondering... Can I take the circled portion of the equalizer circuit below and insert it in place of the circled portion of the AA764 circuit (also pictured below). Why or why not?

There are plenty of folks who went before you, following the route of simplification (and, really, lowering costs as much as possible). Indeed. That's why I went with the Leo's tried-and-true 5c1 on the previous Coppertone. No sense re-inventing the wheel. But it's not just low-cost I'm interested ...

If there wasn't some RC "decoupling" between the amp stages in the power supply, then the PS would become a feedback route. No telling what kind of howling, shrieking and rumbling would ensue... As for all the same tubes, power tubes don't have much voltage gain, a tenth at best what pre tubes do.....

Jeez Christo, we've got ourselves a poet. Or a jester Seuss. That was a spank dandy missive, Gerry. Where's the auction? Thanks for the encouragement, xtian. The auction, together with more (and better) pictures of the finished Model T ("T" for "tubes"), is here: http://www.ebay.com/itm/17137973758...

Forgive me, guys, but I was forced by circumstances beyond my control to use microscopic valves in this one. I did, however, manage to include seven very large "tubes"!

Glad the amp arrived (almost) safely, Matt, and very glad you like it. I think we have to thank the real-life Leo Fender (with his remarkably simple yet robust circuitry, including that 6SJ7 pentode pre-amp), and the fabled Professor Cheswick (with his legendary "transmission-line resonator") for th...