SFDR - What a NAD

[Happyorange27]

That's a relief.  Well it's probably set at a good setting for those tubes.  Remember anytime you change output tubes, you need to re-bias.  You should be able to just us a multimeter and measure the negative bias voltage; that's what i do.  But you need to know where to hook up and also know what value you are seeking.  I don't have that info for you.

Not too much more you can do right now.  Carry on.

[Heady Jam Fan]

Lol, thanks. I actually don't even have a multimeter - another thing I have been intending to get (though I did order a solder sucker), along with wire clippers - since I moved, I pretty much don't have any tools.

[Happyorange27]

Santa should bring you one.  There are 2 stages of life.  The time before and after you got your first multimeter.