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I think the 'S' is the thing. When Shigeki-San of Yamamoto Soundcraft revised his 45-based A-08 SET to 'S' level, the world took notice and that amp remains my favorite valve machine to this day. Now the 'S' has cozied up to the A-09 300B SET and I've got a hunch that a true classic is in the offing.

As usual with kit from this design house, an impregnated, very attractive Japanese Cherry deck gains Bakelite properties to justify itself also sonically. The turned Ebony footers, speaker terminals, RCA inputs, tube sockets and meters are all Yamamoto issue as are the toroidal transformers (the filter chokes and output transformer are Yamamoto's unique split-core design).

A 2A heater current supply makes most all 300Bs interchangeable. Particular Yamamoto favorites are the Emission Labs 300BXLS and JJs. The rectifier is a 5U4G and the driver tubes are unusual C3ms from 1960's German telephony supplies.

Though an auto bias design, the A09-S sports two bias meters, one per output tube, confirming proper operation and tube life. If history repeats itself, the A-09S will be another slam dunk like the earlier A-08S. Given how Shigeki-San has referred to his
new 8-watt muscle amp as the flagship of his micro-power line, believers already fully conversant with his creations should be particularly stoked by this launch indeed. It looks like good things are coming down the pike from Japan...
Yamamoto website