When I first bought the old MKIV’s I was very confident…. a couple of weeks later I felt I just might have overestimated
my skills….. but then after all, it’s all about learning, isn’t it ?
My first problem about the wiring of the output transformer (faded colours) was kindly resolved by Kevin and Bob.
This amp is now ready for testing (after a triple & quadruple check of the wirings has been done)
Ready to start the second amp…..
This 2nd amp is probably of later manufacture as the power transformer has no colour coded “cloth isolated” wiring,
but rather plastic (PVC?) isolated wiring with different colours. It might also have been assembled by some other person
in the 1960’s, since the wiring has been done in a slightly different way.
The transformer is 230V of which there is no mention in the assembly manual. I guess there has been a “addendum” concerning
the 230V tranny, but I do not have that description. It might be fun to obtain a copy....
#1 I rewired exactly as it was. Noticing that there are two wires twisted together (white/black and yellow, as far as the faded
colours allow me to describe. It was there, so I left it there…. Same situation occurs with the 230V version of the VTA-ST-120
I built last year, which gives me confidence that it is the right way)
But in the second amp, I notice that these two (otherwise coloured) wires have been soldered to the GND of the 5-lug strip……
and there I have a question….. should this be done that way ?
Actual wiring of the PWT :
White/red fuse holder
White/orange on/off switch
Orange (1) pin #4 of V1 (rectifier)
Orange (2) pin #6 of V1
Black (1) (cloth isolation…..!) pin #2 of V1
Black (2) (cloth isolation…) pin #8 of V1
Light green pin #2 of V2 (EL-34)
Dark green pin #7 of V2
Black (pvc) GND
Pink (!) lug 4 of 5-lug strip
Of course I can copy this wiring, I just wonder if it is OK to have 3 PWT leads to GND……
Pictures to show both wirings (the new #1 and the still old #2) in the following link :
Thanks in advance for some good advice