specification help

im considering an upgrade to simaudio's w-7 and p-7 pre and amp. ive heard them at the rmaf and liked the sound. but no way to home audition with my sonus faber cremonas. im currently using cairn audio nitro pre, ko2 amp and fog 3 cdp. ive been very happy for the last couple of years, but have the upgrade bug.my question is,that in trying to educate myself as much as possible , i find i really dont know alot about what certain specs. are or what they mean for sound quality.i was hoping someone could assist.
first the cairn pre, its fully balanced, dual mono, input impendence is 18000 ohms, freq. response 2hz to 200 hz, input sensitivity is 0.05vrms, and signal to noise is above 120db. compare that to the sim. inp. impend. is 22,000 ohms, freq. response is 5hz to 100 hz, inp. sensitivty is 200mv-4.0vrms and signal to noise is 115db.
on paper , i think my cairn specs. are better? the amp has a similar situation but this post is getting long.
Most specs, including the ones you have cited, have little if any relation to sound quality, and should not be the basis of a choice between high quality components. Since you can't audition the Simaudio's at home, I would suggest simply researching reviews and user comments as thoroughly as possible, and if possible auditioning at a dealership.

I am not particularly familiar with either make, but I looked over the specs and literature on the W-7 and P-7 at the Simaudio site, and I looked at the very limited information which is available at the Cairn site.

The main thing which struck me is that the W-7 claims it is a no feedback design (in the manual; the brochure claims "no global feedback," which leaves the door open to local feedback around individual stages), yet its spec on output impedance (and damping factor, which is output impedance divided into 8 ohms) is exceptionally low (high in the case of damping factor). The lower the better, everything else being equal, but usually such good numbers are obtained by using large amounts of feedback, with its possible adverse side-effects. Harmonic distortion numbers, which are also helped by feedback, are also significantly better than average for a no-feedback or low-feedback design. It would be worthwhile to gain an understanding of what their "Lynx technology," which is claimed to make all this possible, actually does.

The W-7 has excellent peak and continuous output current ratings, and doubles its output power into 4 ohms, relative to the 8 ohm rating. I'm not familiar with your speakers, but if they are rated at or near 4 ohms, and/or if their impedance dips to low values at certain frequencies, that will be beneficial.

The only other spec I find notable is the Cairn preamp's 50 mv input sensitivity, which is more sensitive (a lower number) than usual. That conceivably could present a gain mismatch with some amplifiers (correctable with an attenuator pad in between), but since you would be replacing both the preamp and amp together that is not really relevant.

One minor correction: The upper end of the frequency response ranges you listed should be "kHz," not "Hz."

Hope that helps,
-- Al
The W7 was reviewed and measured by JA in this month's Stereophile. The P7 was reviewed and measured last month.


It's hard to place much value in manufacturer specifications, because many specs vary with frequency and load and the manufacturer does not fully disclose how they performed the measurement.

In your case, since JA has measured both you know exactly what you're getting. Plus, John's subjective evaluations are usually not over the top.
thanks for the input.very useful .
Hello, I have been trying now for nearly two months to find the specifications for the Cairn KO-2. No source online, no person I've queried, no previous owner I've discovered, and not Cairn's own site (they have not responded to any of several emails, both in English and French) have revealed the answer to any of the following:

Total Gain?
Unbalanced Input Impedance?
Balanced Input Impedance?
Class A output (wattage) at 4ohms?
Minimum ohms unit is stable into?
Minimum input signal (voltage) for full power?

Any help with any of these questions would be exceedingly, finally, blessedly appreciated!