The Amp Garage

That's old....

but still bad....

I forwarded it....

All depends on how much range you think you need and the size of the fixed resistor that is being replaced. Usually the new pot equals the old fixed R and is in series with a new fixed R of 1/2 the value. That gives you a range centered at the original resistance value. Always contrive it so that if...

For a Twin the tradition is to turn it from a Twin Reverb into a Single Reverb by pulling two tubes and disconnecting one speaker. That gets your impedance ratio back in range reduces power by 3dB and a comparable reduction in speaker efficiency.

My big decision was thirty years ago, whether to keep the corkscrew hair (you know I'm no square) or get the mullet. I chose poorly. Rather, my girlfriend did.

Now, God is my barber.

There are a few ways to approach this. There's the pages of calculation method, boring and no fun. There's the "Let's try what others have done, introduce some variables then see what it sounds like." This is the usual thing and far more entertaining. Or, take a graphic approach to calculating what'...

Bettie!

Pretty pedal, nice clean work. Gotta love it.

Another weird oversight was no diodes on any of the relays and they were not on the original schematic either. It popped like mad until I added them. :roll: Curious, almost all small signal relays come with those built in nowadays. So much so that getting parts for amps that use relays with the "wr...

The solid state stuff in a 12AX7-shaped can has been done before. Am I the only one who remembers the FETRON in V1 on the Mesa Boogie Mark I? First thing that popped in my head, too. Is this awesome? We'll see. That's the standard here. Especially at that price. It isn't like NOS AX7s have to be re...

I've heard him do that song before but with an almost completely different set of tributes. And he nailed those too. Yeah, good guitar and good amp, but Spedding does an amazing job of copping the feels and sounds.

I am optimistic, though will surely find myself among the loyal opposition. So many people seem to have expectations and aspirations that simply cannot in reality be met. The problems that plagued President Obama's predecessor are indeed extraordinary and difficult. If they weren't, honest, they wou...

Here are some comparisons in hifi trannies done some years ago by John Atwood. There's more info there on transformer characteristics and function and testing. http://www.one-electron.com/Trans_Tests.html The thing it comes down to more than anything else is suitability for a particular application....

Any general thoughts on oversized OT's? I am itching to build a 50W JCM-800'ish (2204) amp and have a mint Ampeg V-4 OT lying around. It's a 100 Watter intended to match up to 4 X 7027'ish tubes. I am clear on how to match speaker impedances of this OT to 2 X EL34's but not so clear on how, tonally...

Maybe you guys can clear something up that a friend asked me. We were discussing output transformers and I was talking about matching the primary impedance with the type output that an amp has. He stated that the power of an amp can be increased by using a different OT. For example you have an amp ...

No worries Ron! I have numerous amp builds/repairs and lots of high voltage engineering experience under my belt. Thanks for the concerns though. The amp gig is a hobby and I don't have a lot of instrumentation in the garage (e.g., signal generators, other unique stuff). Just the nomal DVM's and a ...

Jay, I measure 108 ohm total and equal 54 ohm side-to-center. Never tried to measure impedance before. Do you have a technique for that? Measure the voltage drop of a defined AC current maybe? Dave O. The impedance ratio is the voltage ratio squared (voltage ratio = turns ratio). With nothing conne...