There is only one way to find out.
Truth!
And I have indeed tested it.Anyway, a better power supply which doesn't cause a thump is first prize.
No (and it's an extremely good point), but no power supply (ETA: feasible for audio purposes) can discharge in half an AC cycle.
i put in better transformers in the psu and the thump is now gone.
i also built another pair of boards (this is fun!) but this time with 9530/530 pairs, hoping for more bass and darker sound from its higher transconductance and capacitance than 9610 but instead got just the opposite.
everything's the same except for the mostfet pairs, same psu, same enclosure, but 9530 pairs have 'thinner' sound and way less bass. biasing is the same also.
why is this?
i also built another pair of boards (this is fun!) but this time with 9530/530 pairs, hoping for more bass and darker sound from its higher transconductance and capacitance than 9610 but instead got just the opposite.
everything's the same except for the mostfet pairs, same psu, same enclosure, but 9530 pairs have 'thinner' sound and way less bass. biasing is the same also.
why is this?
i finally shelled out for sk170 pair and it has been well worth it. best addition to my system so far. however, the bias on mine drifts too much. over an hour of usage it rises from 0.3v to 0.8v. i'm using simplified mr.evil's cap multiplier to power it.
the headamp is built according to the original circuit, except for the feedback resistor being lowered to 200ohm from 500ohm, and the jfet pairs arent thermally coupled.
what's causing so much drift?
the headamp is built according to the original circuit, except for the feedback resistor being lowered to 200ohm from 500ohm, and the jfet pairs arent thermally coupled.
what's causing so much drift?
Sorry. Bias to me is normally measured as current, not as voltage.
So I guess he probably meant voltage across the 3.3R source resistors.
If that is the case, there seems to be insufficient heat sink on the power devices.
On my own (2107 case), heat sink temperature is never over 40°C.
Bias changes maybe from 120mA to 160mA or so after 1 hour.
So never factor of 2.5.
Patrick
So I guess he probably meant voltage across the 3.3R source resistors.
If that is the case, there seems to be insufficient heat sink on the power devices.
On my own (2107 case), heat sink temperature is never over 40°C.
Bias changes maybe from 120mA to 160mA or so after 1 hour.
So never factor of 2.5.
Patrick