The Amp Garage

SoulFetish; Here's a one-handed shot of a 1kHz signal on the 8 ohm tap with a 6.5 ohm dummy load. I had to do this fast. The resistors don't fail with no signal. The MV was dimed. It is the type that shorts the power tube grids with a 1ma pot. Roe; I'm not married to the choke. I can put a big 1k re...

Thanks gents. resistance to ground from the grid is 185k on both pins. No whiskers (been rewired several times). I've tried four tubes in that socket. No continuity to ground from either side of the screen resistors (tubes out). However, I left the supposedly good tube in and now that resistor is bu...

Hi Slucky, Nope. none of the extra pins are used for tie points. I usually lick a chopstick and leave a glob on the resistor. With no tubes it doesn't evaporate quickly. With a tube it only takes about 15 seconds if they are already warm. sh PS OT is ultralinear with the between taps taped-off. Resi...

Hi all, It's been a while. I pulled an amp out of the closet I hadn't messed with in about fifteen years. It started sounding bad and I never got around to investigating. As it happened, our cat at the time felt the need to personalize it. After I got it cleaned-up, I got it on the bench and found t...

It could have been any of several things but I gutted the board, shielded some of the wires and isolated the input jack. The latter made a big difference in ground hum. Works well. Sometimes, I just have to blow it up and start over for niggling problems.

thanks, sh

Thanks guys. It might be a while before I can crack it open again but I'll let you know how things go. sh

Hi Guys, I just replaced the board in a homebrew combo and am having some trouble with a low-end buzz/crackle. The amp is basically a single-channel 6L6 blackface with no trem. Tubes are known good. The speaker is a WGS 12 smooth cone. It is installed flush with a good seal around the baffle. The ba...

Thanks guys. This project is behind another amp and two guitars but you can never have enough spare parts

Any bites on current production 12AX7's? Thanks, sh

I was mostly fishing for what is on the market today that best approximates the original preamp tubes. My experience with ANOS has been a bit spotty. Cheers, sh

Hi Guys, I'm designing the winter project and needed some ideas on preamp tubes. The tube chart on these was a mix of 12AX7's and 7025's. With modern glass I'd be happy to get the quality of either but does anybody have a good experience replicating brown or early black Fender tones with current man...

Maybe something like this, sh

Has anyone tried pulling the signal off one of the plates and fed it back in at the PI with a blend pot (like the Hoffman tweed reverb circuit except further upstream)? Here's an old musing on the cathodyne Fenders of yore but with the dual pentode/triode circuit in my first schematic. It's mostly o...

I see the possibilities. Hope you're well, BTW. Is the Send pot a trimmer? That's where I'd put the Neunaber. AT 12 VDC it handles line-levels. If it bogs down I might put the trimmer on the send entrance and run it straight into the recovery with a 220k grid-leak. This will be a head serving either...

The one-tube reverb circuits on the Dumble side work a bit like that.

Attached is another possibility, Thanks, sh