Audio Craft AC-4400 and related AC tonearms

What is compliance of 7f cartridge? The fx tonearms are indeed lower in mass than are the s tonearms but that's like saying your friend has lost 100 lbs and now weighs "only" 300 lbs. ( the s tonearms especially the 66s are very high in effective mass). Thus the 7f may well be suited to the fx tonearms even if its compliance is on the low side.

@lewm the compliance of FR-7f is 7cu @100Hz 
http://audio-heritage.jp/FIDELITYRESEARCH/etc/fr-7f.html

@sampsa55 the first FR-7 was silver, then upgraded FR-7f was made in black. Same with tonearms, but i'm not sure the lower mass FR64FX or FR66FX are better than very high mass FR-64s and FR66s. I'm not sure which FR cartrs supposed to be used with FX tonearms then (if not the FR-7f series) ? The counterweight of the FX series is closer to the later IKEDA arms (like 407).   

Sampsa, do you use your Audio Craft with MM cartridges or only MC ? 

The fx-models are later than the s-models, I think. The difference isn’t just the weight, but also the material. Steel & aluminium resonate differently and the surface treatment might make a difference too. The FR-7 cartridges are so heavy in themselves that the arm mass makes less of a difference. For the cartridges, the f at the end means silver coil and some of the tonearms, both fx- and s-models had silver wiring though I’m not sure how to tell which ones.

I think both the fx- & s-would be great with FR-7, though there seems to be a general preference for the s-models. I have both the FR64fx & FR64s, but don’t have FR-7 cartridges. I have used both with SPUs and some other cartridges quite happily. Currently, I have FR-1 Mk3f in the FR64s and Audiocraft AC05M in the FR64fx. Both sound great.

I have used both MM & MC cartridges in the Audiocraft tonearms. I’ve been particularly happy with MC, specifically Accuphase AC1 & AC3, Audiocraft AC03, and Shelter models.

I've been listening to an acutex LPM320 (compliance 42!!!) in my 64s with a Dynavector head shell which is lighter than typical FR headshells. It's a great match, contrary to expectations.

FR tonearms bear a sticker on the arm wand that says, "silver inside ", if they're wired with silver.