Who knows?
Apples and oranges ...
If you drive its with trioded 4P1L (Ra: 1k6) -if published OPTs data is valid- the toroid has -a little- better -HF behaviour, marginally lesser LF -3dB (due to the lesser primary inductance), and lesser loss.
IMO if you want to use one of them (for few hundred mW amplifier), the price will decide.
Apples and oranges ...
If you drive its with trioded 4P1L (Ra: 1k6) -if published OPTs data is valid- the toroid has -a little- better -HF behaviour, marginally lesser LF -3dB (due to the lesser primary inductance), and lesser loss.
IMO if you want to use one of them (for few hundred mW amplifier), the price will decide.
You do not need a dedicated headphone amp to drive 18 Ohm headphones. Any DHT amp should work fine from the 8 Ohm taps.
Hum is the biggest potential problem because it is much more prominent with phones.
Hum is the biggest potential problem because it is much more prominent with phones.
Yes I know that works but you increase the anode load changing the Bias.
About DHT hum I made several 26, 801A & 4P1L.
About DHT hum I made several 26, 801A & 4P1L.
There is no problem at all with the higher load until it gets extreme. The load recommendations are based on maximum possible power. That is not a concern with phones, and higher load lowers the distortion at comparable levels.
I would use 8 Ohm tap for phones even if 15 Ohm was available.
I would use 8 Ohm tap for phones even if 15 Ohm was available.
Lesser gain so lesser noise/distortion, no free lunch.
Mine experience says that if you change the Bias you change the sound....
BTW changing 8R for 18R the tube see more than the double of load!
Mine experience says that if you change the Bias you change the sound....
BTW changing 8R for 18R the tube see more than the double of load!
The gain increases when you increase the plate load.
Why does changing the load affect the bias?
Why does changing the load affect the bias?
As I wrote in #199: "For 18R headphone it's enough good."
For other purposes I would choose something else.... but it's my opinion.
For other purposes I would choose something else.... but it's my opinion.
A 2-stage SET with 45 or 46 tubes will work. No need for the OPT to have 16ohm tap - the 8ohm tap will be fine. Well implemented with AC filament, hum should not be an issue with your 92db sensitivity headphones.
I used my 45SET to drive HD650s (about 10db more sensitive than your Hifiman) - I paralleled each output with a 20ohm (ish) resistor- hum was very faint only heard when there is no music playing. Btw, I don’t use hum pot at all…
I used my 45SET to drive HD650s (about 10db more sensitive than your Hifiman) - I paralleled each output with a 20ohm (ish) resistor- hum was very faint only heard when there is no music playing. Btw, I don’t use hum pot at all…
Bela,
Could I use TTG-EL84SE for 300B or 2A3/6C4C just in case don't like the 4P1L?
Could I use TTG-EL84SE for 300B or 2A3/6C4C just in case don't like the 4P1L?
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For moderated power 300B as 5k:8 OPT it's enough good (high Lp, enough good HF behaviour).
For 2A3 the 5k transformer isn't ideal, the expected power about 2W.
"Don't like" ..... depends on 50% the amplifier design, another 50% due to the OPT.
For 2A3 the 5k transformer isn't ideal, the expected power about 2W.
"Don't like" ..... depends on 50% the amplifier design, another 50% due to the OPT.
Bela why using a cascode CCS in place of the OPT to use as lineamp only reach maximum 23-24mA, are faulty tubes?
N.B. 165Va Ih 620mA -9.3V bias
N.B. 165Va Ih 620mA -9.3V bias