Hi, recently I've been looking for a 2A3 based SE amp to build and I have come across this page:
http://www2u.biglobe.ne.jp/~tossie/YZ-2A3-J.html
(This guy has a LOT of amp designs with schematics and pictures. Delete the "YZ-2A3-J.html" from the link. Worth a look!
)
Its in Japanese but the schematic is pretty clear and there's a close up of the innards which helps a lot but, I am unsure about one thing
In the schematic there is a connection from one of the 6.3v filament wires from the transformer to between a 39k and 100k resistor. Its marked 65v. This is the first time I have seen this and I was wondering if anyone knows what it might be for? Some kind of bias?? Now I'm a bit a noob still so this might be a bit of a stupid question but I'd really appreciate some of your knowledge
Thanks!
http://www2u.biglobe.ne.jp/~tossie/YZ-2A3-J.html
(This guy has a LOT of amp designs with schematics and pictures. Delete the "YZ-2A3-J.html" from the link. Worth a look!
)Its in Japanese but the schematic is pretty clear and there's a close up of the innards which helps a lot but, I am unsure about one thing
In the schematic there is a connection from one of the 6.3v filament wires from the transformer to between a 39k and 100k resistor. Its marked 65v. This is the first time I have seen this and I was wondering if anyone knows what it might be for? Some kind of bias?? Now I'm a bit a noob still so this might be a bit of a stupid question but I'd really appreciate some of your knowledge
Thanks!
It also keeps the Vh-k rating of the driver tube from being violated. You might want to go to the TDSL and see what that rating is for the 6C8G. I'm not familiar with the tube.
I disagree strongly with the way this is implemented here. I don't like to attach it to only one side of the heaters, as we can get a hummy circuit this way. If there's a center tap on the 6.3v winding, attach it there. If there's not, use a pair of splitter resistors to attach it to both sides of the heater line, as see:
Aloha,
Poinz
AudioTropic
I disagree strongly with the way this is implemented here. I don't like to attach it to only one side of the heaters, as we can get a hummy circuit this way. If there's a center tap on the 6.3v winding, attach it there. If there's not, use a pair of splitter resistors to attach it to both sides of the heater line, as see:
Aloha,
Poinz
AudioTropic
sumo said:Thanks for the help guys
That helped a bit. But what is Vh-k ? Its not in all the spec sheets. Is it Plate voltage? Or voltage between the heater and plate or something?
It's the maximum allowable voltage between heater and cathode. It is in every full datasheet, just not necessarily identified as Vhk. V could be a U, k could be c, and so on.
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