You asked: "I guess 1/4W power resistor is enough."
I answered: "P=I*I*R. Below 100mW."
This is the power of Rset resistor of CCS.
Thanks, I'm sorry to misleading I asked about how do you know is 6R?
BTW your calculations are as follows? P= 0,12A x 0,12A x 6 R = 86,4mW?
BTW your calculations are as follows? P= 0,12A x 0,12A x 6 R = 86,4mW?
More measurements after 1 hour:
B+ both channels more or less 160V
Ia Left channel 34,80mA
Ia Right channel 40,02mA
The only solution to match the channels is to try 4P1L till I get two matched?
I ask because I bought the two 4P1L as matched pairs😡🥴
I ask because I bought the two 4P1L as matched pairs😡🥴
The left channel filament has higher resistance, than other.
These are old tubes, it's impossible to know how much was used. The factory status also unknown.
Due to the filament biasing, where the tube's bias is creating as a result of filament current flowing via filament bias resistor AND filament, it's cause higher negative bias, than in other channel.
The higher negative bias results another operating point, lower anode current at static anode voltage.
If you want almost equal operating point in both channel, must to balance bias voltage.
Decrease left channel filament current till both channel anode-cathode (in this case filament bias resistor upper point) voltage and anode current will be almost equal.
These are old tubes, it's impossible to know how much was used. The factory status also unknown.
Due to the filament biasing, where the tube's bias is creating as a result of filament current flowing via filament bias resistor AND filament, it's cause higher negative bias, than in other channel.
The higher negative bias results another operating point, lower anode current at static anode voltage.
If you want almost equal operating point in both channel, must to balance bias voltage.
Decrease left channel filament current till both channel anode-cathode (in this case filament bias resistor upper point) voltage and anode current will be almost equal.
The other method: decrease left channel filament bias resistor, add paralleled resistor next to 15R.
If the voltage on filament resistors almost equal, the anode currents must the same ... if tubes are selected as pairs.
If the voltage on filament resistors almost equal, the anode currents must the same ... if tubes are selected as pairs.
Just measured again:
Right channel
Ànode current 45,1mA
Vak 154,66
15R 9,76V
Left channel
Ànode current 43,96mA
Vak 155,65
15R 9,17V
Right channel
Ànode current 45,1mA
Vak 154,66
15R 9,76V
Left channel
Ànode current 43,96mA
Vak 155,65
15R 9,17V
Ok thank you Bela, posted at Swap Meet looking for more 4P1L https://www.diyaudio.com/community/threads/russian-4p1l-nos.413896/#post-7709395
I read at Bartola blog about output impedance of his hybrid mu-follower:
"With an BSH111BK MOSFET at 25-30mA and a 470Ω Rs, the output impedance is reduced by a factor of 120. So if you have a 4P1L with 1K6Ω anode resistance, the output impedance of the gyrator stage is as low as 18Ω."
https://www.bartola.co.uk/valves/2018/04/28/hybrid-mu-follower-output-impedance/
Will be do it to get off the OPT for the headphones HifiMan Editions XS 18R?
"With an BSH111BK MOSFET at 25-30mA and a 470Ω Rs, the output impedance is reduced by a factor of 120. So if you have a 4P1L with 1K6Ω anode resistance, the output impedance of the gyrator stage is as low as 18Ω."
https://www.bartola.co.uk/valves/2018/04/28/hybrid-mu-follower-output-impedance/
Will be do it to get off the OPT for the headphones HifiMan Editions XS 18R?
No.
The low output impedance doesn't guarantee "high" output current too.
For 100mW power on 18R requires 74.5mA current.
The low output impedance doesn't guarantee "high" output current too.
For 100mW power on 18R requires 74.5mA current.
Bela what about these specs of opt to use in place of Toroidy TTG-EL84SE?
PRI:
5.0kOhm-38Henry-105mAdc-250 Ohm-Leakage 6.5mH UL tap 37.5%
SEC: 4x0.95 Ohm da settare secondo lo schema per ottenere 0.95/3.8...4/8...9/15...16 Ohm
RDC singolo secondario: 0.475 Ohm medio ( 0.40/0.45/0.50/0.55 Ohm)
Rdc @1 Ohm: 0.117 Ohm
Rdc @4 Ohm: 0.480 Ohm
Rdc @8 ohm: 0.97 Ohm
Rdc @16 Ohm: 1.90 Ohm
Rapporto spire K 5.0k/8Ohm: 22.32
Capacità PRI/SEC + Max 2900pF
THD @20hz 5W 80mA 0.78%
THD @20hz 5W 80mA 0.23%
THD @1kHz 5W 80mA 0.012%
Avvolto in 9 sezioni
Doppio Nucleo a C HiB 0.27mm 98cm/q
BW @5W 80mA
-1dB: 22-40.000 Hz
-2dB: 15-62.000 Hz
-3dB: 12-73.000 Hz
Weight: 2.5kg
PRI:
5.0kOhm-38Henry-105mAdc-250 Ohm-Leakage 6.5mH UL tap 37.5%
SEC: 4x0.95 Ohm da settare secondo lo schema per ottenere 0.95/3.8...4/8...9/15...16 Ohm
RDC singolo secondario: 0.475 Ohm medio ( 0.40/0.45/0.50/0.55 Ohm)
Rdc @1 Ohm: 0.117 Ohm
Rdc @4 Ohm: 0.480 Ohm
Rdc @8 ohm: 0.97 Ohm
Rdc @16 Ohm: 1.90 Ohm
Rapporto spire K 5.0k/8Ohm: 22.32
Capacità PRI/SEC + Max 2900pF
THD @20hz 5W 80mA 0.78%
THD @20hz 5W 80mA 0.23%
THD @1kHz 5W 80mA 0.012%
Avvolto in 9 sezioni
Doppio Nucleo a C HiB 0.27mm 98cm/q
BW @5W 80mA
-1dB: 22-40.000 Hz
-2dB: 15-62.000 Hz
-3dB: 12-73.000 Hz
Weight: 2.5kg
For 18R headphone it's enough good.
If you want to use as 8R SE OPT for power stage, the primary DCR and (8R) secondary DCR causes high loss.
If you want to use as 8R SE OPT for power stage, the primary DCR and (8R) secondary DCR causes high loss.