All the Series 20 components I have are not signed "series 20" to my opinion this sign was only showed on the Components for the American market..
Furthermore I found out that:
-The F-28 tuner was sold both as 110 volts version as well as a multivoltage variant with FM de-emphasis settings for europe and america. And most likely, it was for sale here in Europe as well. In Japan this tuner is known as the F-007
-The F-26 tuner was only sold in America (not counting Japan) No 220 volts euro or multivoltage version here... (that's to bad since I want one!)
-The A-27 was sold both multivoltage as 110 volts version, I have a multivoltage which I bought in Italy, It seems that this amp was sold here in Europe but very scarcely, I have found no adverts on this amp whatsoever, same as with the F-28. In Japan this amp is named the A-0012
-The M-25 is also America only, was never sold in Europe and therefore no 220 volts versions to be found.
I'll be awaiting the arrival of my PA-1000 tonearm, it has the JP-513 headshell on it marked with the "series 20" logo