Is 60dB gain enough for Kleos?

Some 60db phono stages will be fine, and others will not be.

Assuming that your line stage preamp provides a reasonable amount of gain, say 10db or more, and that your power amp has a typical sensitivity number, say 1.5 volts or less (unbalanced), you'll have enough gain. The more important question is the signal-to-noise ratio (s/n) provided by the phono stage. If that is not particularly good, you may wind up with objectionable hiss levels.

I couldn't find a s/n spec for the Fosgate Signature. The last paragraph on this page, from the TAS review, is encouraging though.

However I would suggest that what would constitute the "pertinent experience" you are looking for would be specific experience with the Fosgate. Perhaps someone using it with a 0.8 to 1.0 mv cartridge could try turning up their volume control to a level around 6db higher than they would normally listen at, and indicate what kind of hiss levels result while no music is being played.

Regards,
-- Al

What Al says makes sense. My phono pre is an ARC PH-7 which has 57.5 db of gain. The noise and hum stat is 70db. My line-stage is an ARC Ref-5 which has 12 db of gain if the XLR output is used, which it is in my case. The noise and hum stat is 109db. So total gain is almost 70db.

ARC advised me that I should not use a cartridge that produces less than .5mV of gain, and more would be better. So far, I have used high output MC and MM cartridges that produce more than 2mV so I can't personally vouch that .5mV is ok, but what I can say is that what Al says is consistent with the advice ARC gave me.

FWIW

I am using my Kleos with a Linn Linto at 64db and it works fine. Could it have a little more gain? Yes, but I feel it is a good match, I just boost the volume a little more than I do for other sources, but I am never lacking. It is nice and quiet.

Theo, are you using the Linto without a step-up transformer? If so, that is a good testimony indeed. I trust you hear no compromise of dynamics?

I would be cautious extrapolating from experience with the Linto. In addition to the fact that it is solid state, as indicated in its manual it is a very unusual design in that it drives the input signals directly into the amplifying transistors, with no loading network (the intent being to reduce noise); and it has an unusually high input capacitance of 4700pf (which may further reduce noise). The Fosgate differs in all of those respects, and also provides 4db less gain.

Regards,
-- Al