systemtruck
Well-known member
Hey everyone,
Somewhat unusual mindset here, since I’m doing a number of projects that involve external power supplies and want to make sure i have some important principles lined up.
I learned from one (successful thus far) project that the PT output HV, let’s say for example 360/0/360, needs to have it’s 0V connected to the rectifier tube’s output negative. So let’s say 320V / 0V. And then, that pair of 320V / 0V wires physically should go, after some length since this is an external supply, as directly as possible to the output power tubes GND and the output transformer GND.
But by default, that stuff is all connected to the chassis. So, although some distance is involved, it is still connected to mains earth. But what happens if we delete the entire chassis in concept? Does our HV 320V / 0V output DC need to make it’s 0V connection to mains earth somewhere? If so, where would be the best place in principal to make this connection? Back on the power supply at the rectifier tube’s 0V? Just a short wire from that to the mains earth input?
And again, if our chassis is deleted and the entire imaginary point to point system is just floating mid air… where do we now need to install some heat sinks? I believe that a chassis also provides heat sinking, albeit in messy fashion. So if that’s gone in principal.. maybe add some heat sinks at the output tube grounds, and also the output transformer ground (which is possible the same point) ? And also back on the power supply.. on the PT’s lugs (which are earthed) ? And the rectifier 0V (which may or may not be earthed, depending on question above) ?
I have one old Fisher amp that physically has the OT’s negative be brought back via a long wire to the phase inverter’s ground at the cathode bias point. So maybe i need to be tying together all grounds in the phase inverter and output tubes and output transformer, and send the power supply’s 0V DC to that conglomeration as one input point on audio segment.
Thank you!
Somewhat unusual mindset here, since I’m doing a number of projects that involve external power supplies and want to make sure i have some important principles lined up.
I learned from one (successful thus far) project that the PT output HV, let’s say for example 360/0/360, needs to have it’s 0V connected to the rectifier tube’s output negative. So let’s say 320V / 0V. And then, that pair of 320V / 0V wires physically should go, after some length since this is an external supply, as directly as possible to the output power tubes GND and the output transformer GND.
But by default, that stuff is all connected to the chassis. So, although some distance is involved, it is still connected to mains earth. But what happens if we delete the entire chassis in concept? Does our HV 320V / 0V output DC need to make it’s 0V connection to mains earth somewhere? If so, where would be the best place in principal to make this connection? Back on the power supply at the rectifier tube’s 0V? Just a short wire from that to the mains earth input?
And again, if our chassis is deleted and the entire imaginary point to point system is just floating mid air… where do we now need to install some heat sinks? I believe that a chassis also provides heat sinking, albeit in messy fashion. So if that’s gone in principal.. maybe add some heat sinks at the output tube grounds, and also the output transformer ground (which is possible the same point) ? And also back on the power supply.. on the PT’s lugs (which are earthed) ? And the rectifier 0V (which may or may not be earthed, depending on question above) ?
I have one old Fisher amp that physically has the OT’s negative be brought back via a long wire to the phase inverter’s ground at the cathode bias point. So maybe i need to be tying together all grounds in the phase inverter and output tubes and output transformer, and send the power supply’s 0V DC to that conglomeration as one input point on audio segment.
Thank you!
