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

@tomic601  @charles1dad  Thanks!  The credit goes to and is well deserved by everyone!!!

@khargon  I've been (mostly) hands-off through the build process. I'll share the design elements / approach later. 

The incoming amps will output around 3 watts... which is by design...the focus being on maximizing sound quality over power output. To illustrate the point, my current amps were designed to maximize output from the 2A3s and deliver ~ 4 to 4.5 watts.

@david_ten Thanks for the bit of info.. excited to hear your thoughts.. I used to own purposed built 300B amp for headphone listening, these builds really do bring out the best from our speakers.  Please share some photos of the amp when you get the chance.

@charles1dad From Stereophile I also see this:

The output impedance was lowest from the 8 ohm Autoformer tap, at 0.09 ohm at 20Hz and 1kHz, rising to 0.13 ohm at 20kHz. The 4 ohm tap’s output impedance was almost twice that of the 8 ohm tap—not what I was expecting—while the 2 ohm tap’s was 0.14 ohm at low and middle frequencies, rising to 0.185 ohm at the top of the audioband.

So from the 4 ohm taps, the output impedance is double (almost) of the 8 ohm taps, going to 0.18 to 0.26.. giving the damping factor of <50 (similar to the SIT-3) going into 8 ohm loads.. so yeah, crossing my fingers and toes that it’ll work out.

McIntosh has always been recommended with Zu and works beautifully. Won’t be surprised to work ok here. 

david_ten Yes, I am seriously considering the Thoress EHTs although more likely the integrated version which would allow me to sell the VR L2iSE and bank the difference towards an upgrade to a Totaldac D1 Direct. Reinhard did offer a 10 day in home audition. I am gathering info on the EHT integrated but have not been able to find anything beyond Hifi Knights review which was very positive. This is all a bit of a stretch since many of the qualities that SE enthuses over in his review of the EHT monos I feel like accurately describes the advantages the VR L2iSE had over the SIT 1s when I got to A/B them.

Look forward to hearing your impressions of your new 2A3 amp. BTW, I can’t recommend the Linlai 2A3 tube highly enough, although sad to say I blew the filaments in mine because I had the voltage switch on 5 Volts as opposed to 2.5 Volts. Must have inadvertently moved the switch dusting. Back in go the Elrog 300bs till a new set arrives. They’re great, just don’t have the delicacy and detail of the Linlai.