I have no chance to measure THD 20kHz with good resolution. The measurement at 10kHz was done by a colleague of mine, not me.
I have measured THD 100kHz and shown it earlier in this thread.
Regarding BW - in this circuit, small signal BW and large signal BW are quite same, again, it indicates that the circuit is not SR limited, it has RC like step response for all amplitudes, with same rise time, as again shown in the beginning of the thread.
And yes, OLG corner is quite high.
I have measured THD 100kHz and shown it earlier in this thread.
Regarding BW - in this circuit, small signal BW and large signal BW are quite same, again, it indicates that the circuit is not SR limited, it has RC like step response for all amplitudes, with same rise time, as again shown in the beginning of the thread.
And yes, OLG corner is quite high.
hi PMA
Is it possible to purchase 2 x PCBs and BOM from you to make up a small preamp, or will you be showing the schematic here OR will you make available the gerbers?
Rob
Is it possible to purchase 2 x PCBs and BOM from you to make up a small preamp, or will you be showing the schematic here OR will you make available the gerbers?
Rob
Hi Pavel
How important is it to match devices? Does this have a major effect on distortion/sonics?
Also, can the SSE be configured for lower gain ; 3db or even unity?
TIA
How important is it to match devices? Does this have a major effect on distortion/sonics?
Also, can the SSE be configured for lower gain ; 3db or even unity?
TIA
PMA is my senseï but I never attend to his courses.
Hello
Matching device is relative. The impact, maybe you'll never ear it, do not be ashamed.
You want to set down what ? OLG or CLG ?
- If you want to set down OLG, you have to define new values for the resistors of input circuitry.
=> But you should have to face with stability matters and so on.
- If you want to set down CLG, easier. You have to modify feedback resistor value. But the unity gain may be unstable.
Only a skilled designer seems able to be right to the last question.
... or a Dispre owner who likes to experiment it.
Hello
Matching device is relative. The impact, maybe you'll never ear it, do not be ashamed.
You want to set down what ? OLG or CLG ?
- If you want to set down OLG, you have to define new values for the resistors of input circuitry.
=> But you should have to face with stability matters and so on.
- If you want to set down CLG, easier. You have to modify feedback resistor value. But the unity gain may be unstable.
Only a skilled designer seems able to be right to the last question.
... or a Dispre owner who likes to experiment it.
Re: PMA is my senseï but I never attend to his courses.
as far as the gain goes, I have no need for the 9 or 10db (CLG) provided as standard and would prefer near unity - but I understand this would need reducing of feedback resistor (or raising the resistance to ground) with possibility of instability or negative effects on sound quality.
I was wondering if anyone -PMA I guess- had done the measurements or listening to test this.
It would not be hard to experiment, but I think Pavel may have set the gain at the sweet spot; it makes sense to ask him anyway 🙂
Merci beaucoup
Hi Max,MaxS said:Hello
Matching device is relative. The impact, maybe you'll never ear it, do not be ashamed.
You want to set down what ? OLG or CLG ?
- If you want to set down OLG, you have to define new values for the resistors of input circuitry.
=> But you should have to face with stability matters and so on.
- If you want to set down CLG, easier. You have to modify feedback resistor value. But the unity gain may be unstable.
Only a skilled designer seems able to be right to the last question.
... or a Dispre owner who likes to experiment it.
as far as the gain goes, I have no need for the 9 or 10db (CLG) provided as standard and would prefer near unity - but I understand this would need reducing of feedback resistor (or raising the resistance to ground) with possibility of instability or negative effects on sound quality.
I was wondering if anyone -PMA I guess- had done the measurements or listening to test this.
It would not be hard to experiment, but I think Pavel may have set the gain at the sweet spot; it makes sense to ask him anyway 🙂
Merci beaucoup
robmil, the PCBs + documentation would be possible to purchase in a 2nd production round, no sooner than end of August. The price would depend on a production lot. The schematics with component values will not be released. I do not have good experience with releasing of schematics with component values.
float, regarding gain, the input resistor network has to be recalculated (I am not intending to make it), as MaxS has already stated. BUT - for the reason of high degeneration and resistor bias of input stages, the gain of this circuit cannot be calculated as feedback resistor ratio . Surprisingly, the gain is different and considerably higher.
float, regarding gain, the input resistor network has to be recalculated (I am not intending to make it), as MaxS has already stated. BUT - for the reason of high degeneration and resistor bias of input stages, the gain of this circuit cannot be calculated as feedback resistor ratio . Surprisingly, the gain is different and considerably higher.
PMA said:
Thanks Pavel, it must be a pain when someone wants to mess with a design you've spent ages perfecting....
The reason I want lower gain if possible is because I want to try this with an LDR attenuator that only has -45db max attenuation; with the gain of the dispre this would make the minimum volume level a little on the high side.
I could of course use a pot or a stepper like normal people 🙄
Very interesting about the gain. I think I will leave my Dispre as you designed it.
Hi,
I have only one customer for Dispre II in England. In case it is you, we can discuss possible gain change in private e-mail.
Cheers,
Pavel
I have only one customer for Dispre II in England. In case it is you, we can discuss possible gain change in private e-mail.
Cheers,
Pavel
PMA said:
I guess that's me then. No-one else here knows a good thing when they see it 🙂
I'll email.
float,
I sent you an e-mail in the morning, with recommendation to change resistors in input divider (R60/R3, R62/R29)
I sent you an e-mail in the morning, with recommendation to change resistors in input divider (R60/R3, R62/R29)
It seems there should be a 2nd round of PCB producttion in September 😉
Thanks everyone for your interest in PCBs.
Thanks everyone for your interest in PCBs.
I guess that's me then. No-one else here knows a good thing when they see it.
I do, I know a good thing when I see one, the only
problem is I am not entirely sure if my emails requesting
2 pre pcbs and 2 buffer pcbs are getting through to Pavel?
Out of Curiosity can anyone provide me with information on
the WILSON Audio presentation project pre amp on Pavels homepage?
Wow! a work of art🙄 😀
Yours Sincerely
John
I do, I know a good thing when I see one, the only
problem is I am not entirely sure if my emails requesting
2 pre pcbs and 2 buffer pcbs are getting through to Pavel?
Out of Curiosity can anyone provide me with information on
the WILSON Audio presentation project pre amp on Pavels homepage?
Wow! a work of art🙄 😀
Yours Sincerely
John
Only one piece was built, 5 years ago. The guys who distributed Wilsons had moved in the eastern direction, to the country with more potential and wealthy customers 😉 .
Today, I would say that the discrete design sounds better.
Today, I would say that the discrete design sounds better.
No global feedback mod
Dispre 2 no global FB mods
For those who have my PCB - there is an option prepared. If you want to play with no global feedback, you have a chance. There is a free resistor position for VAS load prepared (see your documentation).
Left channel: Disconnect R24 and C14, and connect R64 (free position, printed on silkscreen), about 5k.
Right channel: Disconnect R55 and C116, and connect R65 (free position, printed on silkscreen), about 5k.
No you have an open-loop design. Enjoy 😉
Dispre 2 no global FB mods
For those who have my PCB - there is an option prepared. If you want to play with no global feedback, you have a chance. There is a free resistor position for VAS load prepared (see your documentation).
Left channel: Disconnect R24 and C14, and connect R64 (free position, printed on silkscreen), about 5k.
Right channel: Disconnect R55 and C116, and connect R65 (free position, printed on silkscreen), about 5k.
No you have an open-loop design. Enjoy 😉