The Amp Garage

Here is the completed cab.

This design borrows heavily from Fender/Dumble circuits, though it runs 6550s for power. The first two gain stages are sort of Fendery, though I used 150k RN65 resistors on the plates, a la Dumble. The bass and treble pots are 1MA with a 100k mid pot. The PI is pretty close to a Fender Twin, though ...

Here are some pics of the bass amp I'm building. First, sorry for the poor quality. They are from my phone. I was keeping the client updated. Second, the gut shot is of V 1.0, which is cathode bias. He wanted to try it first that way, but I have since rebuilt it as fixed bias. He currently has it fo...

Loud is one key. I saw Carlos do a sound check once. When he's all alone you get a sense of just how loud that thiele cab is when the Mark I or Mark IV is cranked! He walks around and marks the floor with tape where he gets certain notes to ring. That's how he gets that one note to sustain for 11 be...

I drill after the chassis is bent. Since most of my work (except for regular Pocket Rockets) is one-off custom, components don't get laid out until the chassis is ready. Also, I forgot to mention earlier that this amp will have a 12AX7 as V1 (per customer request) instead of the 5879 in the regular ...

There may be picks of one of my Pocket Rockets on some other thread, but I'm not sure. I'll post some later on for y'all. There's a metal/roofing shop about a mile from my house, and a guy there bends chassis for me out of 0.062 or 0.09 aluminum. The small chassis, like I use for the Pocket Rocket, ...

I apologize for not posting for so long. I owe y'all so many pictures of my projects, particularly the bass amp I've made (though it's out with the client for some beta testing). Here's the story behind this 15 watt build. Last month I had Veterans Day off, so I planned to take one of my 5 watt Pock...

I have had great results (read: built/sold five of them) building amps that use the 5879 as V1. From there on, think Plexi cathode-driven tone stack. In other words: 5879 > gain control > V2a > V2b cathode follower > tone stack > LTP, etc. The trick to taming microphonics (in my experience) is to ru...

The signal from the first triode is coupled to the grid of the second, as you can see. Because the grid of the second triode is at the same DC potential as the plate on the first, the second plate needs to be at a higher DC potential. That's why the second plate is tied to the B+ rail.

I've used iron from Weber, MPS, Hammond, Edcor and Allen, all with good results. I like a particular Hammond PT for a low wattage model I build. The only complaint I have with many Hammonds is a low filament current rating. For many models they offer, adding another amp of filament current could inc...

yes. You want a cap between any pot (guitar or in the amp) and the grid it feeds. This will block the DC grid emission.

Plate voltages can also affect bandwidth, which, in turn, changes the tone. I suspect the high end coming off a 12AX7 @ 285vdc is harsh. I prefer to run my peanuts at 150 - 175 vdc for a browner tone and, as has been noted, more dynamics and chewiness. I build input gain stages for harp at 85 vdc, s...

You can certainly keep the one channel dry and still keep it in phase, as long as you bring it into the post-reverb mixing stage with the other channel's signal.

I've got this client who plays guitar and keys, and he bought a passive Leslie to go with his M110 Hammond. He got a Leslie 25 amp off ebay, and he wants me to mod it to take either guitar or organ. So my plan is to install one more tube, a 12AX7, and add vol/treb/bass controls. It'll have a jack be...

Here are some more pics