Here is another idea in case you still want to do single ended with DHT to get a very nice 3 watts in class A:
I build something similar to this amplifier. I use 2x 6sn7 (or 7n7) and 6b4g instead of 2a3.
For the input tube I use 6sn7 instead of 6sl7 - change the 2k cathode resistors to 470 ohm.
For 6b4g you need DC filaments - I prefer using chokes in the filament supply, but rod coleman's solution should also work.
If you do this circuit with 6AV5's then you won't need to filter the filament supply so much.
The only downside for this circuit is the extra preamp tube per channel. Its a relatively easy build.
I build something similar to this amplifier. I use 2x 6sn7 (or 7n7) and 6b4g instead of 2a3.
For the input tube I use 6sn7 instead of 6sl7 - change the 2k cathode resistors to 470 ohm.
For 6b4g you need DC filaments - I prefer using chokes in the filament supply, but rod coleman's solution should also work.
If you do this circuit with 6AV5's then you won't need to filter the filament supply so much.
The only downside for this circuit is the extra preamp tube per channel. Its a relatively easy build.
On the above circuit, if you use 6b4g's or 6a3's or 6av5 then you will need to use DC on the filament to eliminate hum. Of course you will only need one leg from the heater circuit to the 1K cathode resistor for DC filaments...
You can easily use AC on the 6sn7 filaments. I reference them to ground without issue, but you could raise them if you desire. If you want to try 6sl7's (or other tubes) then it is fairly easy to change the cathode resistors.
Even cheap 6AV5-GT's work well in this circuit, and the brand of 6sn7 is not important.
The coupling capacitor can be russian PIO (or PTFE), C1 can be oil-filled motor-run, C2 can be elna cerefina (or whatever you prefer).
Ian
You can easily use AC on the 6sn7 filaments. I reference them to ground without issue, but you could raise them if you desire. If you want to try 6sl7's (or other tubes) then it is fairly easy to change the cathode resistors.
Even cheap 6AV5-GT's work well in this circuit, and the brand of 6sn7 is not important.
The coupling capacitor can be russian PIO (or PTFE), C1 can be oil-filled motor-run, C2 can be elna cerefina (or whatever you prefer).
Ian
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Hi!
45 tubes dont *need* AC. They work fine with AC at very low hum levels. They can be heated with DC as well and if well implemented this will sound just as good. I have done that in one of the 45 amps I built. It was for use with an extremely sensitive speaker
Best regards
Thomas
45 tubes dont *need* AC. They work fine with AC at very low hum levels. They can be heated with DC as well and if well implemented this will sound just as good. I have done that in one of the 45 amps I built. It was for use with an extremely sensitive speaker
Best regards
Thomas
I don't need more than half a watt to drive my Avantgarde Trio clone speakers.
What transformers did you use in your build? Any schematic I could look at for reference?
I have already exchanged 2A3 tubes against 45 tubes in a Sun Audio clone amp, with great results, although I fear I am ruining the tubes by driving them like if they were 2A3 tubes.
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