When testing an amplifier, the first thing I generally do is to check voltages. This is what I advise others to do as well. However, the real trick is in determining if the measured voltages are acceptable or not. And herein lies the difficulty.
Continue readingI’ve been moving some amplifiers around today, listening to some that have been idle for a while and doing a little side-by-side comparison. And I’ve been reminded of a very important fact about amplifier performance.
Continue readingThis is a topic that rears its head periodically on vacuum tube forums and discussions. Just a couple of days ago I was reading a forum thread on preamps and someone threw out the suggestion of using a triode strapped 6V6 as a preamp tube. Now this is nothing new. I’ve been hearing this suggestion, on and off, for at least ten years. But using a triode strapped 6v6 (or any beam power tube) as a voltage amplifier is a poor idea which simply doesn’t hold up to technical scrutiny.
Continue readingThe “Color” preamp has been checked out on the test bench and everything is working per design. Bias points are good and the gain stage is operating exactly as designed. However, the buffer design I used was from a different project, and it operates differently in this project than the last one.
Continue readingI have been doing internal layout work and making some design decisions concerning the new SET amplifier. I have also been looking at different materials and I decided that I wanted to make the top plate holding the transformers and tubes of brushed copper. While this is an simple decision to make at this point, it raises the issue of what wood to choose for the chassis frame.
Continue readingSo with the 6CY7 V2.0 Zebrawood amp finished and my 6L6UL project on the back burner, I’ve been working on a new SET amplifier. I have been thinking about an amp somewhere between my small SETs and the big 6336 SET amp. But I’ve run into a hiccough.
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