The Amp Garage

Splitting the cathodes made it work, thanks.

Thanks, I'll split them. I also want to reduce the huge cap.

I am working on converting a Webster Electric PA. It has three separate EF86 inputs that join at a simple mixer into another EF86 followed by a James stack. Up to that point, it matches this schematic: http://2.bp.blogspot.com/-JySFGsgNk0k/Tdhn3QBaUuI/AAAAAAAAAsA/_0Z3XUzdVJw/s1600/TP45schematic.gif ...

I did a little test this morning, removing the speaker. You guys are right. It's not the speaker. I'll start checking other stuff. Thanks.

I can make a bag, and I can see the advantage for isolation, but that wouldn't affect the hum, would it?

Thanks for the replies. I've moved the tank all around the box to try to find a quieter spot, no dice, although some are louder. With the speaker moved away from the box the noise goes away. There is no bag in mine, I plan on making one once I figure out the shielding issue. I may have to go to a 10...

I've been working on an old Gibson Scout lately. The other day I put in a speaker, a 12" Pyle Driver. Everything says the Scout had a 10", but the baffle is cut for a 12", shrug. With the speaker in, the reverb is humming like crazy. I've moved the tank around, the only place I lose the noise is a c...

I spent some time playing through it last night. Definitely saw some reduction in noise, but not the magic bullet I was hoping for. That said, I really like the difference in sound. It feels a bit more 3D somehow, and although it gets dirty lower on the dial, it has more of a range of gains than it ...

Thanks. Last night I wired it up in parallel with a 47k plate resistor, 820 cathode resistor and I think a 44uF cathode cap. I only got a chance to verify that it was working, so I'm not sure if it helped much. There is still hiss and a small amount of hum (I redid the heater wiring, too), but it mi...

Seems like I need to use a single half value plate resistor, not two separate ones. My question is moot. Thanks!

geetarpicker wrote:The Ceriatone had 6V6s in it, and even with those "smaller" tubes it was still louder than my original Express which has EL34s!

My express started as a ceriatone kit. The voltages coming out of the PT are way higher than the docs here say. I ended up using zeners to pull the voltages down.

...or did I have it all wrong, and I am supposed to use a single shared 47k plate resistor (meaning my question is moot?)

I'm thinking of rewiring my express with v1 in parallel. I've seen several posts saying to use separate 47k plate resistors, and 820 (or thereabout) cathode resistors. The only amp I can think of with a parallel v1 is the matchless lightning, and it uses a shared plate resistor. My question is, how ...

I recently inherited a non-working gibson scout. I fixed a number of issues, but can't seem to get the trem figured out. It has a cathode bias trem--the problem is that it distorts on the trem peaks. I've replaced the .01 and .022 caps and the 330k and 150k (the one going to the speed, not the plate...

I've never had a problem with a MC transformer before, but after adding NFB, I have to admit it's a lot darker than I expected. Adding a 0.68 uF bypass cap on V1b helps quite a bit, though. I may have to tweak the NFB resistor to compensate.