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

I believe in quality parts, monoblocks, and overbuilt power supplies, but also simple, well-known circuits without negative feedback that can be implemented cheaply. Most of those set circuits were fully detailed/explored decades ago and modern flagships are just very careful/thoughtful instantiations. All that's to say that you may find your little tekton hanging right along with much more expensive offerings.

Came across this video explaining damping factor while researching amplifiers. Coincidence(?) or is Google / YouTube keeping track... : )

A primer on damping factor from Hans Beekhuyzen:

https://www.youtube.com/watch?v=idxT7VVYyxo

[Note: if someone previously posted this, my apologies. Let me know?] 

Would the Allnic T1500 integrated 300b SET Amp work well?

Key Features:

• 10 watts per channel of pure class A high power output. The T-1500 MK2 is a single ended, stereo integrated amplifier. Almost all other 300B amplifiers are under, and distortion, driven. This is a result of the use of conventional “Resister-Capacitor” circuits, which give only up to around a 70V swing voltage, with high distortion. This means that an already distorted signal of a lower than optimum swing voltage is directed to the deep biased 300B grid. Allnic’s powerful “Inductor Drive” circuit gives up to a 150V swing voltage, with very low distortion (about 0.3%). It is this drive delivered to the T-1500 MK2 that allows for a higher output (10w) with much less distortion than can be expected from standard 300B circuits.

• Real power drive. The drive tube, 6SN7 is a moderate-mu (about 20) twin triode. We use this to drive the 300B’s via a choke plate inductor. Our choke inductor (100% nickel permalloy PC core) has very low power loss and infinitely high load impedance. This configuration is an ideal drive stage for 300B SET. And as the first tube, a twin triode 6SL7, has a very high-mu (about 70), the T-1500 MK2 has a total gain of +35dB.

• Nickel alloy output transformer. Allnic uses sophisticated ratio mixed nickel permalloy PB cored output transformers. Because of their extremely high initial permeability, it is possible to use fewer turns on the primary winding while retaining very high ‘open circuit inductance”. That means a resulting very wide frequency range and low distortion bass response. This is another reason why the T-1500 MK2 excels over other 300B integrated amplifiers. Allnic also uses a very big nickel core, so as not to be magnetically saturated at a high current level of 100mA.

• Long life and trouble-free operation. Allnic employs a “soft start circuit” to protect the tubes and other parts. It applies the high B+ voltage only after tubes are fully warmed-up.

• Self-bias control grid.

• Analog Power Tube Current Monitors. Allnic uses analog current meters to display the condition of each channel’s power tube. The meters make it exceptionally easy to see the status of each tube at any time and offer a simple, unambiguous indication of each tube’s status compared to conventional LED bias monitors.

• Natural negative feedback. The T-1500 MK2 applies about -6dB of negative feedback. This is a very complimentary amount of negative feedback that differentiates the Allnic 300B single ended amplifier from the standard, which has a very coloured and weak speaker driving force. With this natural feedback, the T-1500 MK2 has a relatively high “damping factor’, very low distortion, and a higher S/N ratio, without losing the signature single ended natural sound quality.

• We use a NEW remote controlled high quality 41 step silver contact attenuator Ver.2 (all resistors non-inductive) instead of a carbon filmed slide potentiometer.

• Beautiful 20KHz square wave response.

Technical Specifications:

• Output Power: 10w + 10w (4, 8 or 16Ω load, at 1KHz)
• Distortion: 0.3% at 1KHz, 2.83V
• Frequency Response: 20Hz – 20KHz Flat
• S/N Ratio: -80dB (CCIR, 1KHz)
• Damping Factor: 10 at 8Ω load at 1KHz
• Voltage gain: +35dB
• Input Impedance: 10KΩ (single-ended, unbalanced)
• Input Sensitivity: 230mV for rated power
• Tubes: 300B X 2 (power triode), 6SL7(6N9P) x 1 (First tube), 6SN7 x 1 (Second tube)
• Fuses:   AC Mains – 3A / 250V (110W) (two supplied – one is a spare). Tubes -0.5A, 250V, 20mm glass type
• Dimensions: (W x D x H) 430mm x 380mm x 240mm (17 x 15 x 9.5 in)
• Weight: 22kg net. 26kg shipping weight.

 https://www.hammertoneaudio.com/product/t-1500-mk2http://

@yorkshireman Based on gut feel, I believe it will be a great pairing.

You will have to compare with another amp to determine how the negative feedback of -6dB and the -80dB S/N ratio play out for you.

Have you made a choice between the Nenuphar and Nenuphar Mini?

Coincidently, I recently considered a permalloy ’based’ amp. : )

Based on the provided specifications (Modest level of NFB =6 and relatively low damping factor=10 and probably less into the 6 ohm Nenuphar) suggest a favorable match with the Nenuphars. 
Charles