I just ordered a used BT-50 off Sweetwater's Gear Exchange. The price was too good to pass up.
I already have one of those with 2 GAR 2520 op amps and the EA2503 transformer. The one I just ordered has the same op amps but comes with the Litz transformer installed. Is there a noticeable difference in the sound of those transformers? I might consider swapping out the EA2503 in the one I already have with a Litz but it might be good to have one of each with the different configuration. I have an SSL UltraVioket stereo EQ if I need to EQ a stereo track or buss.