THe pic attached is the CCS.
A friend assembled the CCS boards and discovered a problem.
The circuit has a "direct connection" between the 6SL7 and the 6SN7 stage. This means the CCS will have about 261 volts at its collector. The current is about 14.5 mA . So dissipation is about 3.8 watts in the MPSA340 used there. This is too much for the MJE340.
Note that if the stage was " ac coupled " with a dc blocking capacitor in between then the cathode would be at just about 7 volts.
FYI...
this is the amp
http://www.diyaudio.com/forums/attachment.php?s=&postid=811638&stamp=1136905599
The power supply http://www.diyaudio.com/forums/attachment.php?s=&postid=509305&stamp=1100080737
A friend assembled the CCS boards and discovered a problem.
The circuit has a "direct connection" between the 6SL7 and the 6SN7 stage. This means the CCS will have about 261 volts at its collector. The current is about 14.5 mA . So dissipation is about 3.8 watts in the MPSA340 used there. This is too much for the MJE340.
Note that if the stage was " ac coupled " with a dc blocking capacitor in between then the cathode would be at just about 7 volts.
FYI...
this is the amp
http://www.diyaudio.com/forums/attachment.php?s=&postid=811638&stamp=1136905599
The power supply http://www.diyaudio.com/forums/attachment.php?s=&postid=509305&stamp=1100080737
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