1. The old 'input tube', V1, is now two input tubes in parallel, labeled V1a and V1b. V1a is in the right-rear position (see picture) while V1b is at the left-rear. These two input tubes are physically separated by the...
2. Old and new V2 which I can never remember what to call this function--it's the Voltage-gain 'top' tube in the Mk.3.1 schematic I have. This is the rear-center tube and is the one that would be replaced with the gain-reduction plugs that A-S sells.
3. The good-old V4 cathode follower is in the front of the amp.
All of these in my amps are currently Tung-Sol roundplate 6SN7GTs. Those in the CF positions are my least-good tubes, low in transconductance and relatively high in microfonics--that are free of microfonic noise when tapped lightly with a pencil.
FWIW, even with only dozens of hours on new amps, new tubes, new Teflon-film coupling caps, etc., these amps have helped my system sound even better, particularly in transparency and spatial resolution. I'm very happy.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
