To my knowledge there's no coherence between good sound quality and low or lower distortion. We often seek low distortion as a Design goal, but in realty speakers contribute with so much distortion that the number of zeros in the source component is a non issue.
I believe that the number of junctions really matters.. This we saw this clearly in the Paradise, where the simpler circuit, with on paper inferior performance, was when built vastly the superior performer, Here we have the same, a real simple circuit VS a more complex better specified circuit. I my mind I know the winner. Seems like the reduction of in circuit nodes is a BIG benefit to the music. where as the housekeeping may be rather complex to max out the performance of the simple circuit.
I believe that the number of junctions really matters.. This we saw this clearly in the Paradise, where the simpler circuit, with on paper inferior performance, was when built vastly the superior performer, Here we have the same, a real simple circuit VS a more complex better specified circuit. I my mind I know the winner. Seems like the reduction of in circuit nodes is a BIG benefit to the music. where as the housekeeping may be rather complex to max out the performance of the simple circuit.
OK! thanks for your input. The discrete circuit has far fewer active elements than the two IC chips in the other circuit.
I have now put the balanced version into the system and it certainly does it´s job to suppress the last bit of hum. Hiss is also extremely low so at insane volumes you think that the system is not on at the listening seat. Ear on my 95dB sensitive speakers the quality of the hiss is very soft with no aggressive tendency in the highs and no flicker noise. 1/F corner is very low too so there is not that typical low volume rumble that tubes and JFets can have. I knew that the BC327-337 are very good in this regard but this is even more quiet then our Pardise stage.
I also think that the sound has improved further. The size of the stage, focus, clarity and dynamics are amazing. Since the hum is gone the bass is now very articulate and powerful. Still there is this airy, low distortion quality. I am quite astound how well the Nichcon ES electrolytics work without any foil bypass. The next step could be to build the circuit again with medium power BJTs like the BD139, 140 and make a matching RIAA stage. I tried though several times medium power BJTs at the input and i always preferred low power trannies.
I also think that the sound has improved further. The size of the stage, focus, clarity and dynamics are amazing. Since the hum is gone the bass is now very articulate and powerful. Still there is this airy, low distortion quality. I am quite astound how well the Nichcon ES electrolytics work without any foil bypass. The next step could be to build the circuit again with medium power BJTs like the BD139, 140 and make a matching RIAA stage. I tried though several times medium power BJTs at the input and i always preferred low power trannies.
In my opinion the complexity of the circuit is not a indicator of the final sound quality, but the character of the distortion is. normally the brain is more forgiven with 2º and 3º harmonics, and most of the times this types of harmonics can make it sound better.
Normally i design for lower distortion and speciality for low order harmonics because of the interaction between the different elements of the audio chain (power amp, pré, speakers).
I have in the past, design single end amplifers with relative high distortion, and they sounded very good with jazz and vocals , but not so good with orchestra and more complex music,
one of my next project is a circuit that permit to chose the distortion we want to add to the sign (the distortionator
)
Normally i design for lower distortion and speciality for low order harmonics because of the interaction between the different elements of the audio chain (power amp, pré, speakers).
I have in the past, design single end amplifers with relative high distortion, and they sounded very good with jazz and vocals , but not so good with orchestra and more complex music,
one of my next project is a circuit that permit to chose the distortion we want to add to the sign (the distortionator
)
Wow, that's great! wonderful! Time to write an article for Linear Audio!
As I understand these circuits, they are current conveyors, so there isn't any voltage gain except what ever is produced as a result of the I/V resistor choice.
In my circuits, the transformer is acting as a current conveyor, since there is virtually no voltage on the primary or secondary (only a few millivolts).
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The output of the version i build is a good constant current source with a lot of drive capability. There is plus-minus 32mA on tab. Bandwidth is high too so i think to make a phono stage a transimpedance RIAA plus buffer is enough. I would run the input stage then maybe on 20V and the buffer needs his own supply when we want the input stage to be run floating. We could run the input stage on a plus-minus supply also but i am not sure if that sounds better.
Ok guys, i will go for a short vacation, so my i/v project has to be on hold for a wile, i have new and different ideas how to do that, and maybe my soluction will pass by a differential discrete op amp.
but i am curious to know if using just one output of the dac is that bad. if someone has done that, i would like to hear a opinion.
but i am curious to know if using just one output of the dac is that bad. if someone has done that, i would like to hear a opinion.
The circuit is already very good as it is. It is very difficult to improve it further,
It has low distortion at the voltage levels that it work, and the dominant harmonic distortion is the 2º and much less of 3º.
Joachim, I took your idea and applied to my 2SA970 IV converter. Distortion went down a little (0.0003% at full output) and the very low frequency peak disappeared. I connected the negative side of the secondary of the transformer to the union of the two emitters in the current mirror. (J1-J1) Thanks!
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Thanks. I got the transformers today. I'm also working on the circuits boards in Pad2Pad. I need to get my test gear together though, that's really important.
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