Tube Amp Archive

Because, maybe, the pot in this schematic is like the funky four-tap ones in old Fenders? https://el34world.com/charts/images/FenderBiasBalance1.png Ah I've never seen one of those before. Is the 4th lug on these pots just a chassis ground connection, or is it an actual portion of the resistance tr...

eg https://londonpower.com/image/graphics/pwr-fig1.gif I know this is an old thread, but this schematic is confusing me, why is there a node that is on the center of the pot but not the center lug which is clearly connected to the 15k resistor? Are they both supposed to be connected to the center l...

sluckey wrote: ↑Tue Jan 24, 2023 4:06 am Look at this...

http://sluckeyamps.com/hammond_2/hammond2.htm

Thanks sluckey! Looks like exactly what I had in mind.

To be sure, use the "headphone trick". I've detailed it many time on this forum, and it's an extremely useful tool when doing your own layout. https://www.google.com/search?q=headphone+trick+site%3Aampgarage.com Can I know for sure without building the amp? I'm pretty sure this alignment should off...

Yeah I though there was maybe an issue with the voltage rating of the mosfet I was using, causing it to fail prematurely. It seems now that the main issue is propper air flow through the chassis. I really would like to avoid instaling a fan, but the b+ dropper is failing with a 200ma load and 50v d...

This may seem like a stupid question, but here it is. If I have two transformers bell-facing down, layed out as in the pic, will this accomplish the same hum reduction as having one transformer bell facing down and the other one bell facing out vertically? I know you want them to be 90 degrees out o...

I haven't read any of Blencowe's books, but what bits of his advice I've seen in forums seems to be generally OK. It's important to deduce the objective of the circuit fragments, though. I believe that the circuit fragment as shown is not well suited to your application, dropping 40-80 or so. That ...

It would seem that putting them in series would reduce the power dissipation per device. With two, each would drop half the volts and would each have the same current thru them so half the power, no? Yes, it would. So would paralleling two of them, as it's the same voltage and half the current. Par...

Something like this?

Another question, if I were to connect two of these in series, each with half of the zener voltage of the original zener amplifier, this would share the power dissipation between both, no? An amp that I"m building right now keeps destroying my irfp460's using the chassis as a heatsink. I don't want ...

The better way to do that is to have a pre-filter cap, which has a + terminal to the rectifiers and to the actual first grounded filter cap. The negative side of this first pre-filter cap goes to the rectifier negatives, and the amplified zener goes between that point and the actual circuit ground ...

There is an awesome LND-150 based tremolo on the Hoffman forum. Grid bias and works great ! I made boards for our mods and they work well. Runs off the choke/screen node, so no special power supply needed. I use surplus Fender 4-M pots for rate and the board mounts via a right angle 16-MM pot for t...

The point of bias vary trem in a push pull amp is that the modulation signal is common mode, gets largely cancelled out. With your idea, it’s no longer common mode, as I see it, the speaker will flap like crazy with the subsonics, with only the OT low frequency roll off to attentuate it. Ah, ok. So...

I am away from my home lab right now, but I was curious if anyone knew if this type of circuit would have any advantage over a standard bias wiggle trem. I, like many, have contemplated what to do with the leftover triode in a bias wiggle tremolo. It's basically just a phase shift oscilator into a c...

Sorry I'm replying to an old thread, but one could place several MOSFETs in parallel to lessen the power dissipation of each, correct? Like using pass-transistors with a linear regulator? I know that MOSFETs of the same type won't be perfectly matched, but I've seen them used in parallel in power am...