Fidelity-Research products in order by release dates:
1) FR-7 (1978):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-7.html
2) Tonearm FR-64s (1976):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-64s.html
3) Tonearm FR-66s (1977):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-66s.html
4) FR-7f (1980):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-7f.html
5) Tonearm FR-64fx has been released in 1980 and discontinued in 1990 as far as i know: http://www.jupiteraudio.com/5005/5005.html
According to this logic the FR-7f cartridge and FR-64fx tonearm were introduced in the same year (1980) and supposed to be made for each other with W-250 counterweight.
P.S. I wish to continue with release dates of the FR-7fz and FR-702 cartridges, but i have zero information about it. Anyway these models appeared to be released later than FR-7f. They are all black, so the latest Ikeda-San's tonearms under Fidelity-Research brand are the FR-66fx and FR-64fx. Normally any tonearm designer is trying to upgrade his products in the latest versions.
1) FR-7 (1978):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-7.html
2) Tonearm FR-64s (1976):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-64s.html
3) Tonearm FR-66s (1977):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-66s.html
4) FR-7f (1980):
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-7f.html
5) Tonearm FR-64fx has been released in 1980 and discontinued in 1990 as far as i know: http://www.jupiteraudio.com/5005/5005.html
According to this logic the FR-7f cartridge and FR-64fx tonearm were introduced in the same year (1980) and supposed to be made for each other with W-250 counterweight.
P.S. I wish to continue with release dates of the FR-7fz and FR-702 cartridges, but i have zero information about it. Anyway these models appeared to be released later than FR-7f. They are all black, so the latest Ikeda-San's tonearms under Fidelity-Research brand are the FR-66fx and FR-64fx. Normally any tonearm designer is trying to upgrade his products in the latest versions.