VladimirK, let me understand better, when you say you removed the dynamic current source components do you mean C9-1, C9-2 and R19, R18-1, R18-2 and R18-3? Hence, it is just a CCS?
Yes, just these components responsible for the CCS modulation. For making preliminary test, it is enough to unsolder R19 and shortcircuit R18.
It is great to hear about such a good result. I would only add, that listenable effects are determined by the harmonics, and some additional "substances" that are not easy to describe, like effects of electrolytics. Having accepted this, one could guess about difference between schematics with constant current consumption from PS under signal, and standard AB class schematics.
Yes. And somehow THD is a little bit misleading too... Have 0.002% 2nd HD is totally different than having 0.001% 5th or 6th HD...
Elna RFS(Silmik) is notorious for long time break-in, so I am keep playing the amp and wait the sound for maturing. One thing is for sure, even with NEW Elna in the path, add by passing 1uF cap for Alpha CS & M. Cascode definitely help the detail from mid-high to high... It's hard to describe how much detail more there, but it is there!
I would propose, for accelerating the "maturing" or "burning in" of an amp after modifications, use VHF radio, choose some frequency between stations, where maximum noise is listenable, send this noise signal to amp's input. Use resistor as a load instead of speakers. 24 hours of such "maturing" will usually be enough for transistor amps. For new tube amps, this could take from 5 to 10 days.
It works! After 5 days "burning in"... (I happen to have a short vocation)
It really changed a lot, transparency is the first thing I notice, then the high end
extension and bottom firmness. I am really happy with current result.
Only will do some minor resistor change, plan to use RA to replace original dale feedback resistors.
It really changed a lot, transparency is the first thing I notice, then the high end
extension and bottom firmness. I am really happy with current result.
Only will do some minor resistor change, plan to use RA to replace original dale feedback resistors.
Recently I did several tests by changing shunts to the output cap, also measured impedance curves for electrolytics + different shunts, trying to find correlation with listening impressions. The variants were:
1) Giant 4,7uF Teflon cap (Russian K78-2 type, half a kilo weight)
2) Mundorf polypropylene 68uF 250V
3) Solen polypropylene 80uF 400V
Conclusions:
1) impedance curves do not help, I was not able to predict which variant will sound better.
2) shunt capacitance must be maximum possible, 80-100-200uF. In spite that Teflon measures better (less loss angle), 4,7uF is not enough to compete with the bad effects of electrolytics
3) shunt must pass the widest possible frequency range through it, the Low ESR electrolytic cap must only support the Low Frequency range and could be mounted out of PCB
The effects were tested for 50W Zen9, and also with Follower 99 prototype (based on RD100HHF1 transistors, matched pairs, 3,9A total current)
Not to forget, that for AB schematics the same conclusions valid for PS electrolytics
1) Giant 4,7uF Teflon cap (Russian K78-2 type, half a kilo weight)
2) Mundorf polypropylene 68uF 250V
3) Solen polypropylene 80uF 400V
Conclusions:
1) impedance curves do not help, I was not able to predict which variant will sound better.
2) shunt capacitance must be maximum possible, 80-100-200uF. In spite that Teflon measures better (less loss angle), 4,7uF is not enough to compete with the bad effects of electrolytics
3) shunt must pass the widest possible frequency range through it, the Low ESR electrolytic cap must only support the Low Frequency range and could be mounted out of PCB
The effects were tested for 50W Zen9, and also with Follower 99 prototype (based on RD100HHF1 transistors, matched pairs, 3,9A total current)
Not to forget, that for AB schematics the same conclusions valid for PS electrolytics
In DIY one could admit what is impossible in mass production. If it leads to good sound - why not?
The thing I hate is the statement that all amps sound similar. They are very unsimilar, just dont believe and try.
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