Thanks guys,
I had virtually given up on tubes and sold most of them, after I had nearly disappeared up my own backside, building ever more complex push pull amps and becoming thoroughly disillusioned by the end of that road.
In the end, I bought a simple 25W solid state amp and just played that.
I was persuaded by a few British forum friends to go back to basics and just build a simple SET amplifier to try to get back to what I had had 5 years ago and maybe recapture the old DIY spirit.
No complex regulation, no DC filaments, just a simple choke input supply and a straightforward, well proven "input stage, driver stage, output stage" gain structure. A friend let me have a pair of old style Hammond 1627SE output transformers and I was good to go.
Because it uses the JJ 2A3-40, I cranked up the dissipation to 27W in the output tubes, so it develops a bit more power than a bog standard 2A3 amp. The downside is that the circuit would fry any "normal" 2A3 unfortunate enough to find itself plugged into the UX4 sockets. However, the 2A3-40 is a great tube so I don't feel I'm missing out.
The amp does what it says on the tin and plays music beautifully.
I had virtually given up on tubes and sold most of them, after I had nearly disappeared up my own backside, building ever more complex push pull amps and becoming thoroughly disillusioned by the end of that road.
In the end, I bought a simple 25W solid state amp and just played that.
I was persuaded by a few British forum friends to go back to basics and just build a simple SET amplifier to try to get back to what I had had 5 years ago and maybe recapture the old DIY spirit.
No complex regulation, no DC filaments, just a simple choke input supply and a straightforward, well proven "input stage, driver stage, output stage" gain structure. A friend let me have a pair of old style Hammond 1627SE output transformers and I was good to go.
Because it uses the JJ 2A3-40, I cranked up the dissipation to 27W in the output tubes, so it develops a bit more power than a bog standard 2A3 amp. The downside is that the circuit would fry any "normal" 2A3 unfortunate enough to find itself plugged into the UX4 sockets. However, the 2A3-40 is a great tube so I don't feel I'm missing out.
The amp does what it says on the tin and plays music beautifully.
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Well done, keep up the good work, have built a few valve amps myself, but haven't built any for the last few years, been too busy designing and developing full range planars. Nearly finished building these, will probably start building valve amps in the near future. Have thousands of valves to get on with, wish me luck.
Interesting, Steve. Did I follow a thread of yours a while ago on another forum about the 6AS7 amp? If so, I remember being engaged for a while and eventually thinking I couldn't keep up. Too many changes, too much complexity for my tastes. But it DID sound enticing. Afraid I'm just into simple topologies and pursuit of the PDG (pretty damn good) as opposed to the perfect.
Oh yes, that was years and years ago
Regarding the complexity issue. It had become an obsession to be honest, and the more complexity I added, the worse the sound became, but of course, I was blind to this issue until I just thought, I've had enough, and got myself a little 25W solid state amp that got rid of the hassle and doubt.
The SET is simple, sounds frankly beautiful and will be left alone to play music.
