I managed to get ahold of several 6DY7 tubes, which have two 15W beam tetrodes in one envelope, with a common cathode and screen. The datasheet says they can be used as independent class A amps with crosstalk down at -50dB. This is plenty for my purposes.
I've been working on a simple stereo design that uses one 6N2P per channel, because that's what I have on hand. In LTSpice, the design below yields 5.8WPC at 3% THD on a 1Vrms input. I'm running it pretty conservatively, because who knows if I'll ever be able to get any more of these!
I won't be able to build it for a few weeks still, but in the meantime I would love to hear any feedback from those with more expertise!
I've been working on a simple stereo design that uses one 6N2P per channel, because that's what I have on hand. In LTSpice, the design below yields 5.8WPC at 3% THD on a 1Vrms input. I'm running it pretty conservatively, because who knows if I'll ever be able to get any more of these!
I won't be able to build it for a few weeks still, but in the meantime I would love to hear any feedback from those with more expertise!
My $.02, ditch one tube by replacing the follower section of the input tube with a mosfet. Then you only need 2 tubes for the whole amp.
I had something like that working many years ago. I wound up making a two tube amp with a pair of 6LR8's, they are far more common.
Sylvania came up with the 6DY7 for compact stereo sets. It has a funky twin plate design on a common cathode. GE countered with their own twin pentode. They simply stuffed two 6BQ5/EL84's into one bottle and called it the 6DZ7. I had a few of both but I have no idea where they are now.
I had something like that working many years ago. I wound up making a two tube amp with a pair of 6LR8's, they are far more common.
Sylvania came up with the 6DY7 for compact stereo sets. It has a funky twin plate design on a common cathode. GE countered with their own twin pentode. They simply stuffed two 6BQ5/EL84's into one bottle and called it the 6DZ7. I had a few of both but I have no idea where they are now.
I do need to buy a pair of 6DY7 tubes for Stromberg amp. If you have some spare, would you mind selling a pair for me? Best, JonI managed to get ahold of several 6DY7 tubes, which have two 15W beam tetrodes in one envelope, with a common cathode and screen. The datasheet says they can be used as independent class A amps with crosstalk down at -50dB. This is plenty for my purposes.
I've been working on a simple stereo design that uses one 6N2P per channel, because that's what I have on hand. In LTSpice, the design below yields 5.8WPC at 3% THD on a 1Vrms input. I'm running it pretty conservatively, because who knows if I'll ever be able to get any more of these!
I won't be able to build it for a few weeks still, but in the meantime I would love to hear any feedback from those with more expertise!
The screens & cathodes are common in the 6DY7.
That creates a practical limit on the kinds of SE circuits possible.
But great as a PP amp.🙂👍
That creates a practical limit on the kinds of SE circuits possible.
But great as a PP amp.🙂👍
Not conservative enough for my OCD. Self-bias whenever possible!! When tube drifts toward melt-down, it tends to self correct, or burn-up slow. You won't get significantly more power out with fixed-bias. And self-bias lets you run the grid resistor at 470k. Now you do not need the follower which is another source of risk (high heater-cathode voltage {200V?}, momentary grid forward-biasing).