Hi Jack! Could you please confirm if the first gen wa5 has the same feature - switch between Plate and Cathode output of the 300B? If so what mode switch positions corresponds to? SPK (plate, low transformer output), K1K (plate, high trans output), SPL (cathode, low), SPH (cathode, high) - correct?

  FlemmingBach Thank you for the valuable info! Do you belive would it be possible to mod NT-503 for balanced headphone output as according to marketing info it contains the same 4 output amp circuits?

aQuote: @FlemmingBach Could you please trace power lines from toroids to ac power switch. Is it possible to reconfigure your 503 (suppose it 100-120volt) to 220-240volts?   As for your note mentioning there is only two wires for each toroid. I noticed that as well and it is by the way...

@music_man, have you switched your 501 to 220v? Have you checked is it possible to switch 503 as well?

Queston to ud/nt-503 owners. Need to figure out is 120v model could be used on 220v without stepdown transformer and vice versa. If you do not know exact answer may you pls check primary winding on any toroidal trans on your 503. Suppose that it could be two windings configuralbe in parallel on...

Queston to ud-501 owners. Need to figure out is 120v model could be used on 220v without stepdown transformer and vice versa. If you do not know exact answer may you pls check primary winding on any toroidal trans on your ud-501. On photos available on the net there are clearly visible 4 inputs...

Question to ud-301 owners. Need to figure out is 120v model could be used on 220v without stepdown transformer and vice versa. If you do not know exact answer may you pls check primary winding on the power trans on your ud-301. On photos available on the net there are visible 4 inputs to high...