Hi to all,
Because of the big success of the I/V SRPP Tube Stage in my finished 4x TDA-1541A DAC,
i am planning a PCB Group Buy for those who want to have a optical and technical perfect solution.
Because i am no technical guru who could answer Tube circuit details,
i would like to open this new thread to discuss questions arround this SRPP-Stage.
The values of the resistors in the SRPP Stage are for use with a 6N2P Tube but could be changed for other tubes.
Best regards,
dvb-projekt
Because of the big success of the I/V SRPP Tube Stage in my finished 4x TDA-1541A DAC,
i am planning a PCB Group Buy for those who want to have a optical and technical perfect solution.
Because i am no technical guru who could answer Tube circuit details,
i would like to open this new thread to discuss questions arround this SRPP-Stage.
An externally hosted image should be here but it was not working when we last tested it.
The values of the resistors in the SRPP Stage are for use with a 6N2P Tube but could be changed for other tubes.
Best regards,
dvb-projekt
Last edited:
Hi Bas,
i forgot to write that the 28R are the I/V value for my 4xTDA1541 DAC...Surely this resistor value depends on the DAC you will use (Tolerance +10/-50%):
1x TDA1541A: 90R ; AD185x: 500R ; PCM 56/58: 500R
2x TDA1541A: 60R ; AD1862: 500R ; PCM 63: 100R
4x TDA1541A: 28R ; AD1864: 250R ; PCM 170x: 100R ; 2x PCM170X: 55R
Why the light load on the 1541? Normally we see ca 30ohm/dac to avoid distortion.
And why SRPP? Even Broskie who have talked so much about this circuit dumped it years ago. At these very low signal-levels it might not be noted but PP makes uneven harmonics be dominant and the circuit is also load-sensitive.
But as you have found it well-sounding, go for it!
And why SRPP? Even Broskie who have talked so much about this circuit dumped it years ago. At these very low signal-levels it might not be noted but PP makes uneven harmonics be dominant and the circuit is also load-sensitive.
But as you have found it well-sounding, go for it!
Hi Lars,
as a simple Tube-Buffer-Stage with only a few needed parts instead of a normal SS Buffer-Stage and the resultant advantages , it runs like hell in my DAC.
I had absolute no problems at all and the circuit is well proven as a great upgrade to standard Output-Stages in CDP´s and DAC´s.
I absolute agree that you could make many various stages at this point, but i opened this thread to discuss questions around this SRPP-Stage.
Best regards,
Oliver
As i wrote, i had insert this stage in my DAC project and being absolute satisfied of the sound.
Because i am not a developer, i could only state about the sound performance and not to any technical data from a SRPP or other stages.
BTW, for me the only interesting thing.
We could discuss so much about linearity, NonOverSapling yes or no etc., but this is not the part of this thread.
Here i would like to focus question around this circuit.
I don´t see any problem to integrate this circuit after a V-Out DAC.
You must only insert a small capacitor around 0,47µF between the V-Out DAC and the input of the PCB.
Here is a little excel application where you can calculate the output impedance of several tubes in a srpp stage.
http://www.ict-net.net/tube.xls
http://www.ict-net.net/tube.xls
Well, my question was specifically about this circuit. So I'll ask again- since you're decreasing linearity and degrading signal-to-noise compared to a simple voltage amplifier, and at the same time you've increased parts count and complexity, what is the advantage of this circuit? Unless the motivation for this topology is explained, how can anyone suggest improvements?
Please do.
But... my question was not advantages over a poorly-designed SS output stage, my question was the advantage over a much simpler, properly designed common-cathode voltage amplifier stage (or, for that matter, a well-designed simple SS output stage). SRPP is useful for large signal swing applications (which this certainly isn't), but trades off linearity and gain to achieve that. So, for the extra parts count and complexity, the performance for the 2V or so of a digital source would seem to be degraded. If you can point me to data to the contrary, I'd be grateful.
But... my question was not advantages over a poorly-designed SS output stage, my question was the advantage over a much simpler, properly designed common-cathode voltage amplifier stage (or, for that matter, a well-designed simple SS output stage). SRPP is useful for large signal swing applications (which this certainly isn't), but trades off linearity and gain to achieve that. So, for the extra parts count and complexity, the performance for the 2V or so of a digital source would seem to be degraded. If you can point me to data to the contrary, I'd be grateful.
HERE you could read the experiances from other members.
For you again, i am not a developer to answer questions about different stage technics.
I opened this thread around the SRPP Tube-I-zator circuit.
For any questions beyond, there are threads like the linked thread, where you get answers to your question.
Regards,
Oliver
For you again, i am not a developer to answer questions about different stage technics.
I opened this thread around the SRPP Tube-I-zator circuit.
For any questions beyond, there are threads like the linked thread, where you get answers to your question.
Regards,
Oliver
Sy : I think the improvements is in sound and it is only in the ears and not in measurements !
( As a friend of mine say : I do not care about measurements and benchmarks and oscilloscope but I always care about what I hear : the music ! )
Some time we tend to be to precise and academic .....
I really do understand SY´s questions, but I don´t think I fully understand the answers?.
Could the reason for the SRPP be that it is (very close to?) a circuit used by Audio Note? AFAIK Audio Note are extremely careful when designing circuits, and I know that Mr. Fikus is a big fan of Audio Note. Mr. Fikus has made a lot of experiments and maybe this type of tube circuit is the best for his ears?
However, in the other thread which Oliver links to, DIYAudio member regal (#48) shows a SET stage which he claims to be superior to the SRPP circuit. Might be something like this SY has in mind?
Have anybody tried both topologies against each other?
Karsten
Could the reason for the SRPP be that it is (very close to?) a circuit used by Audio Note? AFAIK Audio Note are extremely careful when designing circuits, and I know that Mr. Fikus is a big fan of Audio Note. Mr. Fikus has made a lot of experiments and maybe this type of tube circuit is the best for his ears?
However, in the other thread which Oliver links to, DIYAudio member regal (#48) shows a SET stage which he claims to be superior to the SRPP circuit. Might be something like this SY has in mind?
Have anybody tried both topologies against each other?
Karsten
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