Join Date: Oct 2010
Location: San Jose
Originally Posted by VladimirK
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
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
thanks for sharing... did you ever want to try nichicon BP (bi-polar) series?
It looks like my by pass value this time is not enough. But I really don't have such big value polypropylene...