khstudio
Well-known member
I need to add additional +/- rails to an existing tube power supply that already has 120v (B+) & 12v (Heater)...
it's basically the PRR Vari-Mu PSU.
I tried hooking up a second transformer to the Main (AC) for the +/- 17v supply but things got screwed up & even after unhooking the second TX, the original supply has a lot of noise EVERYWHERE... even the Ground (measured on my scope) that wasn't there before trying this.
I'm not sure what the "Rules" are when it comes to using 2 separate TX's in one unit & how the Ground &/or Center taps should or shouldn't be connected?
Is it even possible or should it be avoided?
I was considering building a NEW PS similar to the G9 Mic pre, that hooks the second TX backwards to generate the B+ (120v:17v > 17v:120v) but I'm not sure how to correctly connect the Grounds or Center taps?
I'd appreciate any help or advise I can get.
Thanks
it's basically the PRR Vari-Mu PSU.
I tried hooking up a second transformer to the Main (AC) for the +/- 17v supply but things got screwed up & even after unhooking the second TX, the original supply has a lot of noise EVERYWHERE... even the Ground (measured on my scope) that wasn't there before trying this.
I'm not sure what the "Rules" are when it comes to using 2 separate TX's in one unit & how the Ground &/or Center taps should or shouldn't be connected?
Is it even possible or should it be avoided?
I was considering building a NEW PS similar to the G9 Mic pre, that hooks the second TX backwards to generate the B+ (120v:17v > 17v:120v) but I'm not sure how to correctly connect the Grounds or Center taps?
I'd appreciate any help or advise I can get.
Thanks