The two amplifier circuits from the side
https://www.jogis-roehrenbude.de/Leserbriefe/Roessler-Amp/Bauanleitung.htm
https://www.jogis-roehrenbude.de/Verstaerker/GU50-Grommes/GU50.htm
inspired me to make new layouts for it and repositioned the whole thing:
For the power amplifier drivers there is a new board 100x100mm, whereby the bases of the power amplifier tubes have to be mounted separately depending on the type used, so you are very flexible with the choice of tubes. Both 8pin octal and 9pin noval tubes can be used as driver tubes. I removed the VB408 from the power amplifier PCBs and added a replacement circuit on the power supply board. Since the circuit for both variants is almost identical, it can be used for EL34 and family and GU50 and structural body by adapting a few components.
For the power supply there is a new NV board 100x100mm with direct current heating, bias voltage and switch-on delay with relay and a new HV board 100x100mm with anode voltage and UB for the preamplifier.
VB408 replacement circuit:
https://stromrichter.org/showthread.php?tid=3116&page=4
I think this will be a project for the coming winter
I discovered OPT's in my inventory, they have 4K but unfortunately no UL connections, ultralinear operation is also not possible!
would they possibly fit? I think I read somewhere that you can influence the impedance of the primary side by mismatching on the secondary side!?
There would also be a mains transformer with 12.6VAC 6A, ideal for 12.6V power tubes or 2x 6.3V power tubes with series heating.
50mA for -UG should be enough, right?
https://www.jogis-roehrenbude.de/Leserbriefe/Roessler-Amp/Bauanleitung.htm
https://www.jogis-roehrenbude.de/Verstaerker/GU50-Grommes/GU50.htm
inspired me to make new layouts for it and repositioned the whole thing:
For the power amplifier drivers there is a new board 100x100mm, whereby the bases of the power amplifier tubes have to be mounted separately depending on the type used, so you are very flexible with the choice of tubes. Both 8pin octal and 9pin noval tubes can be used as driver tubes. I removed the VB408 from the power amplifier PCBs and added a replacement circuit on the power supply board. Since the circuit for both variants is almost identical, it can be used for EL34 and family and GU50 and structural body by adapting a few components.
For the power supply there is a new NV board 100x100mm with direct current heating, bias voltage and switch-on delay with relay and a new HV board 100x100mm with anode voltage and UB for the preamplifier.
VB408 replacement circuit:
https://stromrichter.org/showthread.php?tid=3116&page=4
I think this will be a project for the coming winter
I discovered OPT's in my inventory, they have 4K but unfortunately no UL connections, ultralinear operation is also not possible!
would they possibly fit? I think I read somewhere that you can influence the impedance of the primary side by mismatching on the secondary side!?
There would also be a mains transformer with 12.6VAC 6A, ideal for 12.6V power tubes or 2x 6.3V power tubes with series heating.
50mA for -UG should be enough, right?
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