See if this helps.
I also have a TA-30, sans external bias mod. Answers based on how I do it:
1.Do I need to have speakers hooked up while biasing?
No. Normally I bias at the kitchen table, so the only thing plugged into the amp is a power cord. Volume is turned all the way down.
2.I ground the black meter lead. Black speaker terminal OK?
I have always read "across the resistor" to mean I should attach leads on either side of the resistor. Voltage drop is either positive or negative depending on where I attach them, but which it is is irrelevant--the absolute value of the reading is the same.
3.Red lead to bias resister between resistor and tube socket?
See number 2.
4.I see ref to biasing to mA, the Cayin calls for .35 volts. Just a different procedure?
.35V = 350 mV
I have absolutely no formal training in electronics, so it could be that I've misunderstood and misused info I've gotten from the web. However, my amp works fine & sounds great, so what I've been doing doesn't seem to have hurt it anyway. Good luck, & if my hedging has scared you off at all, hopefully someone with more knowledge--or at least someone less careful than I am about pretending to be authoritative--will confirm my method.
Thanks Brent, that was exactly what I needed!
Cyanzky, problem is that mine doesnt have the external adjustment mod.
Paul is a great guy at bizzybee, but understandably he is reluctant to give out instructions on biasing inside the unit, given the lethal high voltages involved, and of course potential lawsuits. I dont blame him for this one bit.