Read an article a while back.
https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/50s/Audio-1956-May.pdf
And finally thought I'd build it with mostly UTC Iron.
https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/50s/Audio-1956-May.pdf
And finally thought I'd build it with mostly UTC Iron.
In addition to this:
Where is the 6SJ7? And where is the third voltage regulator tube?
The maximum cathode to heater voltage for the 6080 series regulator, is listed as 300 volts. To avoid tube failure the centre-tap of the heater winding should not be directly earthed. A capacitor should be fitted between the centre-tap and ground.
In the schematic of the power supply the center-tap of the heater winding that feeds the 6080's and the 6SJ7 is not grounded but connected to point "Y" which is a point on the voltage divider made up of R40, R41, and R42.
Point Y sits at 149 Vdc. So, the cathode to heater voltage of the 6080 sits at 301 Vdc and the cathode to heater voltage of the 6SJ7 sits at 41 Vdc.
But since the maximum cathode to heater voltage of the 6SJ7 is 90 V it would make sense to me to lower the value of R40 somewhat, causing the voltage at point "Y" to get a little higher. With R40 = 120K the voltage at point "Y" would become 171 Vdc. The cathode to heater voltage of the 6080's would become 278 Vdc and the cathode to heater voltage of the 6SJ7 would become 63 Vdc.
Point Y sits at 149 Vdc. So, the cathode to heater voltage of the 6080 sits at 301 Vdc and the cathode to heater voltage of the 6SJ7 sits at 41 Vdc.
But since the maximum cathode to heater voltage of the 6SJ7 is 90 V it would make sense to me to lower the value of R40 somewhat, causing the voltage at point "Y" to get a little higher. With R40 = 120K the voltage at point "Y" would become 171 Vdc. The cathode to heater voltage of the 6080's would become 278 Vdc and the cathode to heater voltage of the 6SJ7 would become 63 Vdc.
Yeah the schematic as drawn does show the diode in the wrong direction. But as I used a Bridge rectifier in the circuit the point is moot.
And the 12ay7 is in the back of the amp back by where the input jack sits.
As for the 6V6 I used it as the voltage regulator.
And the 12ay7 is in the back of the amp back by where the input jack sits.
As for the 6V6 I used it as the voltage regulator.