I have built the power stage of a single ended amp in an enclosure. It’s difficult to fit anymore stuffs in it, so the input stage has to be built separately.
While contemplating an appropriate input stage, I have a DIY single ended a headphone amplifier with a 10k:50 ohm OPT.
I am assuming the EL84 can handle the capacitance of RCA cable and the input capacitance of 300B. But I really don’t know the calculation involves so this is where you guys comes in.
If this will work well. What value of resistor should I put across the secondaries of 10k:50ohms OPT? 50 ohms? 100ohms?
Thanks for reading.
The transformer would normally work best at its rated load, 50 ohms.
The 300B won't be too bad a load, since the driver stage should be able to handle around 1nF.
The 300B won't be too bad a load, since the driver stage should be able to handle around 1nF.
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Post about how well it works, this is kind of unusual.
You may need a series RC network across the transformer primary to eq the response flat.
Check the mfr data sheet, or determine experimentally.
You may need a series RC network across the transformer primary to eq the response flat.
Check the mfr data sheet, or determine experimentally.
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Sure. Although it might take a while.
The power amp is kind of like an experimental test bed. Currently it is setup to use octal tubes. The power transformer has multiple secondaries to accommodate tubes from KT77 to KT150.
After I am done playing with them then I can get some DC filament modules and the 300B tubes. Those are expensive.
I intend to add another stage in front. Mostly because I don't know how pentode work and don't know how to design negative feedback. If anyone can do it for me I don't mind trying.
Post # 1 schematic shows the Control Grid, g1, connected to the plate.
That is either a schematic drawing error, or . . .
The control grid will be burned out (melted).
That is either a schematic drawing error, or . . .
The control grid will be burned out (melted).