I am trying to do the checkout of the new board I finished populating with all the components.
According to the old schematic (TSE) and checkout procedure on the Tubelab website, you can check the B- voltage by applying test leads between R7.
It looks like R7 has been replaced by R6 on the TSE-II board I have.
Is the sound wire connected to the gray wire on the input side of the transformer, then a ground wire to the board for checkout is not required?
There is something through i have to ask! In the one-electron UBT3 OPT datasheet they suggest a fuse rated twice the expected operation current (say 150-200mA for 300b) connected at the b+ primary side of the OPT, for protektion of the windings etc... if a bias/tube etc. error occours.
Another thing i would like to know, is about the input (audio in) connections.
Do we prefer twisted pair without screen? Or do we prefer coax with one wire with screen connected in both ends, or anything else?