Tubes

This is a short description to characterize an amp to ensure proper performance over the operating range.  read more »

I needed a reliable dummy load for testing amps that I design and repair. Over the years I've been collecting the parts I thought I would need. Finally it all came together along with the time needed to assemble it. I wanteded mono and stereo modes and at least 50 Watts of power dissipation. Finally, I wanted it to be accurate.  read more »

Univox U65RN Front CLoserHere are some of the amps I worked on that had easy fixes. Gives you an idea of some of the easier stuff.  read more »

I did a little looking into how the versions were different. Version 3 definitely sounds better - higher gain and less muddy than Version 1. The bigger output transformer must've cleared things up a bit. The output transformer primary impedance was also reduced to 5000 ohms (Version 1 was 7500) ohms. This is a much better match for the high current 6BQ5 and I'm sure it gave it some of it's additional clean headroom. Here's a link to some more info:

www.ultimate-guitar.com/forum/showthread.php?t=800422

I have some voltage Measurements somewhere...  read more »

Here are some Manuals, App Notes and Documents I have scanned in.  read more »

Pictures of my Lab Bench and Equipment, sort of a mess, but I was working on a project. I'm setup for audio vacuum tube amplifier work and antique radio repair. I have also put together a GPIB system to automate measurement of plate characteristics.  read more »

This was my first guitar amp speaker experiment. Nothing special at all, arbitrary sizes. What I focused on was to build it very sturdy and to build it deep. This is to minimize low frequency cancelation of air traveling from the front of the baffle to the back - better bass response. To aid strength, I decided to use box joints and to create slots in the box so that the baffle is built into the box rather than screwed to it.  read more »

I wanted to create a reasonably loud and simple amp without extra crap like tone control. Just a plug and play amp that sounded good with maximum one knob. I also wanted to use a 6L6 and some older types of tubes (octals), just for show.  read more »

This was my first tube amp experiment. It is based on a Fender Champ from the 50's. The Champ was designed to be a cheap practice amp. It features all-tube construction, about 5 Watts of power and tone control!  read more »

This project included a complete power supply and circuitry to enable a voice activated Magic Eye tube. The user speaks into a microphone, it is amplified by the triode in the 6T8A (the tube to the right of magic eye tube), then the signal is rectified and a peak detected signal is sent to the magic eye tube. Inside the magic eye tube, there is another triode which further amplifiers the signal and then drives the deflection grid in the cathode ray device. I will post the circuit sometime soon. I gave it to my Dad for Father's Day - what a useless gift.  read more »