I'm very disappointed, (looking for the best SQ I used both devices togheter because both separately the SQ is top notch) the SQ togheter is very bad: cutt off highs & the left the sound only one dimension & lifeless.
I post here to know if other people is in the same situation as me, also asking if there is a technical reason for the bad sound.
I post here to know if other people is in the same situation as me, also asking if there is a technical reason for the bad sound.
SSHV2 has a CCS on its input, and the controlled shunt on output.
R6 (1R8) AND C1 0.33uF is the snubber on output.
Without knowing the whole schematic and voltage/current values, helping is a little difficult.
Is SSHV2 working without error (with test load) at appropriate voltage and current?
R6 (1R8) AND C1 0.33uF is the snubber on output.
Without knowing the whole schematic and voltage/current values, helping is a little difficult.
Is SSHV2 working without error (with test load) at appropriate voltage and current?
Hi Felipe
Personally I think is a complete waste of a shunt regulator to be placed in front of the hybrid mu-follower. You have already a very high PSRR with the cascode MOSFET in the gyrator board. No point, at all.
It looks like you may have some oscillation playing around. I notice you have no HT decoupling between the SSHV2 and the input (MOSFET drain) of the gyrator. Bad combination due to the high impedance of the gyrator presented to the SSHV. You may want to try a 100uF cap plus a stacked film 100nF right at the +B and -B connections of the gyrator PCB to see if that's the cause of your audio degradation.
Otherwise hard to follow without sniffing with the right tooling....
Hope this helps
Ale
Personally I think is a complete waste of a shunt regulator to be placed in front of the hybrid mu-follower. You have already a very high PSRR with the cascode MOSFET in the gyrator board. No point, at all.
It looks like you may have some oscillation playing around. I notice you have no HT decoupling between the SSHV2 and the input (MOSFET drain) of the gyrator. Bad combination due to the high impedance of the gyrator presented to the SSHV. You may want to try a 100uF cap plus a stacked film 100nF right at the +B and -B connections of the gyrator PCB to see if that's the cause of your audio degradation.
Otherwise hard to follow without sniffing with the right tooling....
Hope this helps
Ale
1 st. : why did you omitted the grid stopper in preamp?
in gyrator
C1:
R7:
Desired operating point of 5687: Ua, -Vg, Ia
Preamp anode current (voltage on 10R in gyrator, voltage on 470R in preamp):
Anode voltage:
p.s. I agree with Ale. Without SSHV2 the preamp should work.
p.s.2 the 17V margin on SSHV2 CCS is very low.
in gyrator
C1:
R7:
Desired operating point of 5687: Ua, -Vg, Ia
Preamp anode current (voltage on 10R in gyrator, voltage on 470R in preamp):
Anode voltage:
p.s. I agree with Ale. Without SSHV2 the preamp should work.
p.s.2 the 17V margin on SSHV2 CCS is very low.
Hi Felipe
the gyrator doesn't change with "warm-up" time. It's pretty stable from a tempco point of view. I have not noticed any changes over time am afraid.
Perhaps is something else in your system. I'd also suggest trying without the cathode bypass capacitor, it will sound better in my view....
Cheers
Ale
SSHV2 -> Gyrator works great for me. Overkill, yes.
The voltage drop across your SSHV2 is way too low at 15.6volts. The instructions call for 20v drop across the regulator, but in testing i found it needed more like 35v to work properly while sinking 27ma.
My final implementation has 50v across is, 200v in -> 150v out into the Gyrator for a 01A tube.
The voltage drop across your SSHV2 is way too low at 15.6volts. The instructions call for 20v drop across the regulator, but in testing i found it needed more like 35v to work properly while sinking 27ma.
My final implementation has 50v across is, 200v in -> 150v out into the Gyrator for a 01A tube.
R6 Ale's schematic is 10M not 4.7M
Good question: "BTW why did you choose the 5687?"
You have reason Bela have too much gain but sounds very good, isn't a preamp, it's the analog output amp of the noDac, with something half power or less will be good, I have 4P1L but it's really expensive the PSU & the comments about the sound it's not my cup of tea.
Wow output total THD 0.04%
Could you simulate with 0.5VAC of input, thanks?
Good question: "BTW why did you choose the 5687?"
You have reason Bela have too much gain but sounds very good, isn't a preamp, it's the analog output amp of the noDac, with something half power or less will be good, I have 4P1L but it's really expensive the PSU & the comments about the sound it's not my cup of tea.
Wow output total THD 0.04%
Could you simulate with 0.5VAC of input, thanks?
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