rp
Well-known member
I've just built this standalone tube PSU, which I'm using to power a two-channel NYD 6sn7 one-bottle preamp. The transformer is humming a bit and running warm. Is it under spec? I figure the total heater requirements are 1.2A (2 6sn7) + 0.3A (2 lamps; one in psu, one in pre) + 0.063 (humdinger) = 1.56A. Is that running too close to the rated 2A?
Am I right to think the problem is the heater circuit? I feel like the B+ circuit is well with in the norm, and is not running close to maximum current. (I haven't measured, but the one-bottle schematic lists B+ current as 12ma, so I should be using only 24ma).
Other than the power trafo hum, everything seems to work fine: correct voltages, sounds good, low noise in the preamp. It's my first tube build completely from scratch, so I'm happy that it mostly works and I haven't killed myself.
The preamp circuit can be viewed here: https://groupdiy.com/index.php?topic=45369
Original 6sn7 one-bottle thread here: https://groupdiy.com/index.php?topic=12637.0
Am I right to think the problem is the heater circuit? I feel like the B+ circuit is well with in the norm, and is not running close to maximum current. (I haven't measured, but the one-bottle schematic lists B+ current as 12ma, so I should be using only 24ma).
Other than the power trafo hum, everything seems to work fine: correct voltages, sounds good, low noise in the preamp. It's my first tube build completely from scratch, so I'm happy that it mostly works and I haven't killed myself.
The preamp circuit can be viewed here: https://groupdiy.com/index.php?topic=45369
Original 6sn7 one-bottle thread here: https://groupdiy.com/index.php?topic=12637.0