Nice looks, real Jensen style. Did you measure AC after the reg? (I can't imagine).
Very nice construction. Pleasing aesthetics. Well done.
Having some hum, it surely isn't from the B+ lines if the CCS part is working OK. Does R1 drop some voltage as it must? If you solve that issue by revising GND and/or shielding, your bass and resolution are going to improve further. Also the Simp. HV needs some further run in.
I did not know you had a tube reg before. Can you post its schematic? Had same hum with the tube reg also? You did not lose any tone quality somewhere with the Simplistic reg VS the tube reg?
Hot birth
Took a while but it's up and running. Dead silent, voltages are spot on. Will have to take it to the living room for an audit, the electroshag has no good speakers in it. Gets warm but that's no surprise. Some shots and schematic.
Took a while but it's up and running. Dead silent, voltages are spot on. Will have to take it to the living room for an audit, the electroshag has no good speakers in it. Gets warm but that's no surprise. Some shots and schematic.
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2A3 driven by C3G, either triode or penthode, powered by a Pimm current source. I'll post the plan tomorrow, it's quite simplistic.
I had to put the regs outboard, too much heat underneath. Connection is 12cm long, testing a foil cap on the OT in days to come.
Did you notice how low on capacitance I went with your design? There's 7mV residual AC at the output and I'm a cowboy on wiring
L-C is per channel, so two chokes and two 47uF. This amp is really silent.
I had to put the regs outboard, too much heat underneath. Connection is 12cm long, testing a foil cap on the OT in days to come.
Did you notice how low on capacitance I went with your design? There's 7mV residual AC at the output and I'm a cowboy on wiring
L-C is per channel, so two chokes and two 47uF. This amp is really silent.
300V B+ 46V autobias, about 50mA. 24mA to shunt.
It's open for experiment as I always build amps that can stand on their side
Disco did excellent, strong experiments. Imagine what he would do if he was nicknamed Heavy Metal.
I will be interested in the reliability of the thing. After some days with driving speakers at least. Imagine that this reg was originally made for a phono stage! Disco boldly goes where no simplistic man has gone before!
*A note on the circuit. Disco did higher reference resistor and used MJE, because in such circumstances, we concluded that the small transistor for the ref and trimmer, must run lower current to behave better, and that TO-92 is not to be trusted with so much nearby heat. The MJE sinks better.
I will be interested in the reliability of the thing. After some days with driving speakers at least. Imagine that this reg was originally made for a phono stage! Disco boldly goes where no simplistic man has gone before!
*A note on the circuit. Disco did higher reference resistor and used MJE, because in such circumstances, we concluded that the small transistor for the ref and trimmer, must run lower current to behave better, and that TO-92 is not to be trusted with so much nearby heat. The MJE sinks better.
If it does not present problems with your client circuit why change? Disco's is another trafo load and is going to swing on speakers. You have big airier board away from your phones amp, he has tiny board on 2A3s chassis surounded by warm trafos. Don't forget, he is at 300V also. Right at the MJE limit.
You run roughly as much current as he does through the 560 with half his B+ and 82k.
Higher resistor means some more noise if it ain't necesssary for helping to keep the currents low. Your TO92 works at 1/2 dissipation at 142V too. No sweat. You may do the next one like Disco's. Especially if you want to go over 250V. If it ain't broken, don't fix.
You run roughly as much current as he does through the 560 with half his B+ and 82k.Higher resistor means some more noise if it ain't necesssary for helping to keep the currents low. Your TO92 works at 1/2 dissipation at 142V too. No sweat. You may do the next one like Disco's. Especially if you want to go over 250V. If it ain't broken, don't fix.
Thank you all for the compliments. Here's the schematic for triode connected C3G at 150V. It had too high amplification for my purpose so I gave it mild feedback (1M resistor).
The CCS holds a nice high voltage drop. Setting for 230V (17mA) could also be realised by the turn of two screws. Once it's run in I'd like to try penthode connection as some report its performance superior to triode (in this case). Soundwize I have no objection to the Pimm CCS, the output impedance is comfortly low to drive Miller capacitance of the output valve.
Indeed, these are Iso Tango XE-20S and I like 'm so much they move from chassis to chassis with new amps. Originally they were gray but I sprayed 'm deep purple once. Tribute makes quality products but lead times are even longer than with Bartolucci, to my experience that is.
Oliver, at what output voltage is your regulator? I experienced irregularities when I went over 280V / 80mA.
The CCS holds a nice high voltage drop. Setting for 230V (17mA) could also be realised by the turn of two screws. Once it's run in I'd like to try penthode connection as some report its performance superior to triode (in this case). Soundwize I have no objection to the Pimm CCS, the output impedance is comfortly low to drive Miller capacitance of the output valve.
Indeed, these are Iso Tango XE-20S and I like 'm so much they move from chassis to chassis with new amps. Originally they were gray but I sprayed 'm deep purple once. Tribute makes quality products but lead times are even longer than with Bartolucci, to my experience that is.
Oliver, at what output voltage is your regulator? I experienced irregularities when I went over 280V / 80mA.
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