• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Favorite Threads and Posts in "Tubes" Forum

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diyAudio Editor
Joined 2001
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Favorite Threads and Posts in this Forum

This permanent thread is a place for links to threads or posts in this particular forum that are useful and/or exemplify the best of DIY Audio.

This is so others- especially newer members can find them. Feel free to post with these links and a brief comment on what the thread discusses. Occasionally the moderators will consolidate them into fewer posts.
I must mention two threads that I was involved in a while back. I still find myself referring to them and referring others to them. Both are quite long, but educational for those who take the time to dig in.


A forum member asked for design assistance on an AB2 amp using 6L6GC's or other similar tubes. There was some initial confusion as to just what AB2 is. By post 90 or so some ideas had been tossed around, but no concrete design had formed. I had been working on a universal P-P driver board, so I agreed to work up a version using octal tubes that would work for his application and a zillion others. This design was really a collaboration of two people on opposite sides of the world, that worked together to come up with a really good amp. I have stuffed everything from DHT's to sweep tubes in mine with excellent results. All design decisions and results are in the thread.


Pete designed a mild mannered conservative 18 WPC sweep tube amp. It was intended for a first time builders, and works well in that regard. I bought a board and publicly stated that I would be disappointed if I couldn't get at least 50WPC. That took about 15 minutes (OPT change and a bit more B+). Over time I succeeded in squeezing 250 WPC or 525 Watts in mono out of Pete's board. I settled on a stable and reliable 125 WPC version, and published the construction details. At least 15 of these were built (I made 3) and all worked good.
I can't believe we don't have an output transformer manufacturer list sticky. Some of them have very little presence on the internet.

Output Transformer - Silicon Steel or Amorphous?
Output transformers ? sound quality ?
Can't edit this into my previous post. Not quick enough to find everything in 30 minutes time. I'm not a speed reader, too slow, too curious. Can't delete last post.

Does O-netics make SE OPTs?

I had never heard of Onetics, Transcendar, Intact Audio, or Tribute transformers before I saw this post.
ISO-TANGO to quit

A few more transformer brands. Thanks to kevinkr. Hammond, Heyboer, Edcor, MagneQuest, Electra Print Audio, Lundahl, Sowter. Some of the ones I'd never seen before. Bartolucci, Monolith Magnetics, Automatic Electric, Trafomatic, IG-Transformatoren, S&B, Megahertz Audio, and the new ISO.
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