20 foot long speaker cable: is it ok?

It’s fine and just use 10-12 gauge at minimum.  Absolutely no sonic degradation issues.  

I would respectfully disagree with an earlier comment in this thread by a member who appears to have subsequently deleted his post. In addition to the actual experiences with long speaker cables that have been reported by other members, such as Stereo5 above, I’m pretty certain that the Magico speakers used by the author of that deleted post have much lower impedances than the JBLs you will be getting. Most Magico speakers have nominal impedances of 4 ohms, and are closer to 3 ohms at many frequencies. That will significantly increase their sensitivity to cable effects compared to the impedance characteristics of the JBLs.

Regarding power cords, I have used two 13 foot lengths of 12 gauge Signal Cable Magic Power Digital Reference cords to power the two channels of a dual mono 70 watt class A tube amp, with fine results, even though that cord is nominally intended for use with digital components. I chose that model because I wanted the double shielding it provides, in part because the cords are routed near my phono stage.

The 215 watt class AB Kinki Studio solid state amplifier you are getting is a very different animal, of course, but I would still expect that cord to be a reasonable choice. Even if your amp were to be delivering full power on both channels at times, which is very unlikely considering the 94 db sensitivity of the speakers and your relatively small room size, the combined voltage drop of the two current-carrying conductors of a 12 gauge 12 foot power cord would be only around 1/4 of a volt. Probably less than the voltage of the incoming AC fluctuates between different times of the day and night.

Good luck!

-- Al

P.S: Speaker cable capacitance, that was mentioned in the post that was subsequently deleted, will not affect the speakers. Since it presents itself in parallel with the speakers if it affects anything it would be the amplifier. And in any event the 10 gauge Belden cable you indicated you would be ordering from BlueJeans has low capacitance (26 pf/foot). Many speaker cables have vastly higher capacitances.

It is the cable’s inductance and resistance that are presented in series with a speaker, and can sometimes affect the sonics of the speaker. But as I mentioned those effects are likely to be negligible for a 20 foot length in the case of a speaker having the impedance characteristics of your forthcoming JBLs.

Best regards,
-- Al

d2girls

I'm currently running 24 feet of 10 gage cables  from my Bryston 4BSST2 to a pair of Thiel 2.7s. No Problems!

I got the speaker cables from Blue Jeans, along with  some audio interconnect cables, and a 26 foot XLR  to run from a PX05 passive crossover  to my SS2.2 subwoofer.  

More than satisfied with Blue Jeans.

Disclaimer: I'd never heard of Blue Jeans Cable until I bought these on a very strong recommendation from a friend.

 - - George