Before anyone asks, "why did you decide to do this rather than this??....", sorry, but it is what it is. Just hoping to keep the chatter down, and keep the thread productive.
I've attached a rough schematic of a PSU design I've been using for quite a few tube projects. I've never discovered any issues up until yesterday, when I used my scope and measured across the 12.6 AC that goes to the filament rectifier.
When I touched my ground clip from the scope, to presumably the "0v" line on the secondary, the transformer physically hummed as if I was shorting it. I'm guessing because the ground clip is physically earthed? Touching it to the 12.6V tap doesn't cause it.
Then I got to thinking about that connection between the cathode of C1 and C4. When connected, the circuit itself performs fine, with the exception of measuring across the 12.6 AC line. I dremeled the trace from the PCB, low and behold the issue is not present when probing. However, I do get a nasty 60hz hum from the audio circuit, which is at this point grounded to the cathode of C1.
Perhaps it's the way I've wired my secondary? Perhaps this transformer really isn't meant to do 12.6v the way I've implemented it? Any suggestions would be appreciated!
I've attached a rough schematic of a PSU design I've been using for quite a few tube projects. I've never discovered any issues up until yesterday, when I used my scope and measured across the 12.6 AC that goes to the filament rectifier.
When I touched my ground clip from the scope, to presumably the "0v" line on the secondary, the transformer physically hummed as if I was shorting it. I'm guessing because the ground clip is physically earthed? Touching it to the 12.6V tap doesn't cause it.
Then I got to thinking about that connection between the cathode of C1 and C4. When connected, the circuit itself performs fine, with the exception of measuring across the 12.6 AC line. I dremeled the trace from the PCB, low and behold the issue is not present when probing. However, I do get a nasty 60hz hum from the audio circuit, which is at this point grounded to the cathode of C1.
Perhaps it's the way I've wired my secondary? Perhaps this transformer really isn't meant to do 12.6v the way I've implemented it? Any suggestions would be appreciated!