What power for 300R resistors between anode & pins 3 (2nd grid) & 4 (3rd grid)?
It's a fixed value or can be other value aprox.?
TIA
It's a fixed value or can be other value aprox.?
TIA
No problem, only wanna be sure about dissipation & value, I have 330R rated more than 1W so I will use thank you Bela.
24VAC is too much, if you want to reach 21-22V at 0.65A load.
Try 18VAC transformer.
Try 18VAC transformer.
If you can see #90 post, 18V DC raw supply is even enough, so beefy (at least 2.5-3A) 15VAC transformer requiring.
sample:
https://www.tme.eu/en/details/ts40_020/transformers-with-fastening/indel/ts-40-020/
sample:
https://www.tme.eu/en/details/ts40_020/transformers-with-fastening/indel/ts-40-020/
The calculated (simulated) PT dissipation is 27.5VA.
The 30VA PT will working .... and it will also heat up.
The 30VA PT will working .... and it will also heat up.
Felipe, the 30VA is the bottleneck.
If you use large first capacitor, the charging current will be large so, even multiple of DC load current.
If you choose just enough power (no headroom) for PT, it will be heating. Hot transformer efficiency will be degrading.
If you use large first capacitor, the charging current will be large so, even multiple of DC load current.
If you choose just enough power (no headroom) for PT, it will be heating. Hot transformer efficiency will be degrading.
Shinkoh?????
Did you rob a bank?
Use the cheapest CC resistor here.
For power tube the filament raw supply ripple isn't very important. R.C. V4 regulator has enough large PSRR, so even 1Vpp is acceptable.
Did you rob a bank?
Use the cheapest CC resistor here.
For power tube the filament raw supply ripple isn't very important. R.C. V4 regulator has enough large PSRR, so even 1Vpp is acceptable.
71A is another DHT that makes for a nice headphone amp. They are still pretty reasonably priced.