Hi Brian,
Please look
Alembic's History The Long Story.
1979 We moved Alembic to 45 Foley Street in Santa Rosa, CA. It was home to the company for 12 years. We developed the Distillate Bass and Guitar. Yamaha was our distributor for the Pacific Rim countries. They wanted to promote us in a very big way and so we signed a $990,000.00 contract with them, all based on the purchase of the Distillate bass and guitar. They were pretty fond of the F2B preamp as well and ordered hundreds of them.
Yes, It means All Distillate guitars and basses were purchased and distributed by YAMAHA.
Of course I know Distillate series were continued with serial No. D.
But first series of Distillate was 1PU Guitar.
Then Distillate Bass was announced. (I was waiting for bass version for several months.)
Now, I talk about the confusion of serial number.
Alembic produced only series 1 and 2 models at that time.
Distillate series has quite different looks and specs, so it was not necessary own model code.
Therefore the serial number of 1PU Distillate is simply Year-Number USA.
It is my opinion, but I have seen Alembic in Japanese market from late 1970's.
This guitar is first Distillate guitar from 1979 brochure by YAMAHA.
It has different shape of top plate.
Eiji