Vac Sig MKII tube circuit upgrade

04-11-12: Drummermitchell
I believe just the MKII as the IIA has that tube swap option installed already.
Drummermitchell (Threads | Answers | This Thread)

Not true. Only the later Sig MKIIa has the tube swap option. I ordered my Sig MKIIa in mid 2011 and it has the option.

I spoke with Kevin and there's no circuit change, just a switch out of the signal path to deliver 6.3 or 12.6 volts depending on the tube type.

Drummermitchell, finally settled with 60's Siemens Cca and Telefunken 12au7 ribbed plates. From my experience, the 12au7 position is as sensitive to tube rolling as 6922/e88cc/7308. I found the stock Philips 6189w too warm and congested for my taste.

I also HGHLY recommend the Audio Magic fuses. It replaced all my HiFi Tuning Supreme and Gold fuses. It's unbelievable how a fuse can improve the sound ... bloom, tone ... This is probably one of the BEST ROI I found in this crazy hobby.