Cube Audio Nenuphar Single Driver Speaker (10 inch) TQWT Enclosure

Bob, you will probably need longer spikes if the carpet is thick, in order that one maintains the gap as intended. Or arrange for them to stand on something solid.

Since many people in here are considering the bakoon 13r, I thought I'd quote a post from @almarg on the input impedance:

"Re the Bakoon 13R, be aware that the input impedance of its RCA input is only 10K, which will not be a good match for many and perhaps most tube-based components.

I believe the other input choice provided by the 13R, a "Satri Link," would only be usable if driven by a Bakoon component providing that kind of output.

Regards,
-- Al"

Not sure that's going to effect too many people. Multiply by 10 to get your number.  REF 10 by Audio Research comes in about 60% of the Input Limit.  The Luxman C900 comes in at 10%. I'd love to see a list of how many amps would go over that 10K figure....maybe some Boutique stuff.

Chris ( @cal3713 ) thanks for quoting my post from another thread in this one, where it is also relevant as you indicated.

@riaa_award_collectors_on_facebook, keep in mind that the majority of tube-based components having line-level outputs employ coupling capacitors at their outputs, which often cause their output impedance at deep bass frequencies to rise to **much** higher levels than the specified output impedance (which is usually based on a mid-range frequency such as 1 kHz). So in those cases the 10x ratio should be applied to the 20 Hz output impedance, if it is known. (If the component has been reviewed by Stereophile JA’s measurements will indicate that number).

If the 20 Hz output impedance is not known, and there is reason to believe that the tube-based component employs an output coupling capacitor as most of them do, I suggest applying a ratio of 50x to 75x to the specified output impedance. Some here have even suggested 100x.

Also, the minimum recommended load impedance ARC almost invariably recommends for their line stages and preamps is 20K, including for the Ref 10, even though its specified output impedance is 600 ohms balanced and 300 ohms single-ended. And for a few of their designs I’ve seen recommendations of "60K recommended, 20K minimum."

And just to cite one further example, the Herron phono stage which I use has a specified output impedance of 400 ohms, but its manual recommends a minimum load impedance of 50K "for optimum performance."  Although Keith Herron has indicated that 20K would usually be acceptable, in most systems.

Perusing JA’s past measurements of tube-based line-level components will reveal numerous other such examples.

Regards,
-- Al