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

Cube Audio (Poland) designs single drivers and single driver speakers. 

Principals are Grzegorz Rulka and Marek Kostrzyński.

Link to the Cube Audio Nenuphar (with F10 Neo driver) speaker page:

Link to 6Moons review by Srajan Ebaen (August 2018):


Parameters (from Cube Audio):

Power: 40 W

Efficiency: 92 dB

Frequency response: 30Hz - 18kHz ( 6db)*

Dimensions: 30 x 50 x 105 cm

Weight: 40 Kg

* Frequency response may vary and depends on room size and accompanying electronic equipment.


In all candor I don’t believe there is a backing up statement. Certainly due to personal taste preference one might prefer a 45 /2A3, nothing unusual there. By the same token other listeners may prefer the 300b. Normal variance depending on numerous audio system factors.


Here's some food for thought:  I think this a question for Cube Audio with respect to the V1 and they will see it as a mute point.  Why did Cube Audio have a list of compatible amplifiers when they offered the V1s?  You don't see a recommended list for the V2s. Why did the Mono & Stereo Review state: "For tube amplifiers, Cube Audio recommends such designs based on 2A3, Px4, 45 tubes" and not 2A3, Px4, 45, and 300B tubes.  Have you ever seen Cube or Refined Audio specifically demo with 300B based amps? I remember addressing this exact question at some point in my search.  

Seems like considerable conjecture in all honesty. I can’t think of any logical reason why a 300b amplifier would not be a fine choice. Certainly no technical reason. I’d love a comment directly from Cube Audio on this topic. I would be very surprised if they said there is some reason to avoid the 300b. Again, to me it appears to be a terrific pairing.


@mikeg Mike, in addition to simple preference, perhaps the industry association for shows, etc. may have been a factor. Tektron Audio and Cube Audio in Europe. Refined Audio being a Pass Labs dealer factors for the US shows.

If Grzegorz has reasons for not recommending a 300B or for putting it lower on Cube’s recommended list...I’d love to know the reasons.

Here is a screenshot of the recommended amplifiers (I believe this was the list when the V1 was in existence) from Cube Audio.

A number of 300B amps are in the "Amplifiers that work well with Cube Audio speakers" list.

[Note: I was not able to re-format the font size, etc. below] In other words, I'm not shouting!!! 😊


Amplifiers that are working very well with all Cube Audio speakers

Up to 4’000 Euro

  • First Watt SIT-3

  • Feliks 300b Arioso

  • Fezz Audio Lybra 300B

  • Fezz Audio Mira Ceti 300B

  • Music book 250 Power

  • Naim Audio XS2

  • Naim Audio Uniti Atom

  • Sun Audio 2A3

  • Quad Artera Pre + Power

  • Tsakiridis AEOLOS PLUS EL34

  • Tsakiridis Hermes EL84

  • Tsakiridis ORPHEUS 211

4’000 - 10’000 Euro

  • Aesthetix Mimas

  • Bakoon amp13r

  • FANTINI 2 GM-70

  • First Watt SIT-1

  • Manley Stingray II

  • Quad II Classic

  • Sun Audio 300B

  • Tektron TK211SI REF

  • Tektron TK2A3/300BPSE-I-REF

  • Tektron TK300BS-I-ECY

  • Verdier 300B

  • Viva Solistino integrated

Over 10’000 Euro

  • Absolare Intergrated SE

  • Aesthetix Calypso Eclipse + Quad II80 Monos

  • Aesthetix Janus Eclipse Pre + Line Magnetic 503 Monos

  • Aries Cerat GENUS integrated

  • Aries Cerat Incito-S + Concero 25Aries Cerat GENUS integrated

  • EAR 509

  • Grandinote Genesi + Demone

  • Grandinote Shinai integrated

  • Shindo Cortese 300B

  • Wyred4Sound Pre + Quad II 80 Monos

  • Tektron TK211MPSE REF Mono Pair

Thank you for bringing this thread to my attention, and for linking my video in!
I am using the Fc8 V2 in my traditional Voigt pipe cabinet (close to Paul Voigt's original, with cabinet volume adjusted to Fostex Fe204 Vas), and have about 7 hours of break in so far.
My observations are right on with @mikeg 's observations (post above, his 75hr break in report):
*Superb center fill
*Complete lack of directionality, sweet spot opened up (after 15min break in): image stays 3D in the entire room, I can sit / stand, move to the side, move between speakers - 3D integrity stays. Ear does not get cues about the actual place where the speakers / drivers are.
*Superb low end extension. First hour of break in bass was loose (yet extended), and it started tightening up, cleaning up. Level is lower as of now than mids & highs, but getting louder (catching up to mids) noticeably as break in progresses.
*They do not seem to mind silver. Using copper IC and speaker wire, but amp is fully silver wired internally and speaker cable has silver terminals.
*They do not need a sub. They reach very deep (my Voigt pipe cabinet has the ability to convey to 30Hz in my room). Church organ rendered beautifully. The low bass is better integrated and cleaner than a sub could render it, even when the sub goes lower than 30Hz. I agree, sub takes away from FR bass quality and integrity.
*They are getting louder as they break in. I think the spider has to break in mechanically, so it can allow the cone to move freely. As the spider is quite strong (not the usual soft material), this break in is expected, and should be pronounced. In the first hour louder passages were compressed and got a little confused, but this is disappearing with break in, and they can play louder and louder. Mind it, I'm still under 10hrs of break in...
*Softer / mid volume parts are all beautiful, exquisite 3D rendering. Precise, holographic, yet NOT FORCED nor FAKE. With most hi-rez multi-way speakers I get the impression that something's not right with their hi-rez rendering. Here, I'm not getting that feeling, the presented space is natural and comfortable.
*The sound is very much energized, with excellent, very precise HF reproduction. Yet, it's not fatiguing! HF and air without distortion, which is a feat I heard only from the best compression drivers.
*Whizzer cone: whizzer cone artifacts typical to FR drivers are missing. No "Lowther shout" whatsoever.
*I was worried about the magnet material being Neo / ferrite and not Alnico. My worries are gone, the motor was implemented superbly. The tone is the opposite of Alnico drivers, but that's something I welcome. (I have a bunch of Alnicos, varietas delectat, I was actually looking for the complementary flavor!)
These are my initial impressions...