I replaced my Single Stage 60 watt 300b, 100 KOhm monoblock amplifier with a 7.5 watt PX25 tube amplifier and can not be any happier. So far no trade off's noted. Low wattage amplifiers work well for the Daedalus Zeus!!!
The Allnic 311's have been produced for a while. This new version is not on their website - with the interstage transformer - which isolates the first gain power pentode-triode e810f tube from the signal path making the amps DEAD SILENT. I place my ear to my 99 dB efficient speakers - silence.
These amps at 7.5 Watts, single-stage, no capacitor and of a very simple design have no issue driving 99 dB Daedalus Zeus speakers. So the entire Daedalus product line will be driven well by these amps. This leads me to believe the reason why my A6000 tubes have lasted 7 years of significant use is likely they have not been driven hard. There has not been much time in the amps yet so I will limit my impressions to Increased clarity along the frequency spectrum. No compression at the higher frequencies. Some loss at the low end but the amps are again new. This, I anticipate will open up over the next month.
The A6000's 60 Watts 100 KOhm impedance will drive any speaker without issue regardless of their rated efficiency. Pretty complex point-to-point wiring. They are still produced, but with hesitation due to the complexity and time (read hands on labor) to build. However, where the new amps shine could result from a lack of the parallel circuits that give the wattage the A6000's are known for.
That said, if you have highly efficient speakers 97 dB or better and listen to your music at non-ear damaging levels, go with the 311's. Invest the cost savings into some rare U52 rectifier tubes and PX25 tubes. They do not need to be matched pairs. Few are required. There is no biasing in this amp. If a tube blows, the meter direction tells you which one is bad. The circuitry is super simple. One fuse (not 5 fuses seen in the A6000), No capacitors or parallel circuits. This applies to ALL Daedalus speakers.
The circuit design and transformer design allows for stable topography and increase current through the tubes from 6 watts to 7.5 watts without a predicted increase in tube wear.
If you are looking for an amp to pair with your speakers, regardless of the model, I would give these an audition.
The size of the Zeus is deceptive. It takes very little to drive them and running low wattage does NOT affect responsiveness and limit the dynamic range.
From the designer: KS Park:
"For PX-25 and A-6000, they are real single-ended, (one vs.four tubes), but there are two differences, first A-6000 is plate choke transformer drive (which need coupling capacitor) and PX-25 is a true interstage transformer coupled which is the most difficult method (no need of coupling capacitor).
In comparison, A-6000 has -6dB feedback for bass driving factor (Damping factor). Without feedback, its bass is very poor, although -6dB is very slight and natural feedback, it is not good to have negative feedback. PX-25 is real Non-negative feedback, but the bass is excellent naturally. A-6000 is better on very high frequency (because of feedback), it is so complicated and delicate. PX-25 is the most basic and authentic triode single-ended, truly unique design, only Allnic can make this amp."
If available, these amps are offered with Kron PX25 tubes. 1937 OSRAM NOS PX25 and OSRAM U52 tubes may be available at additional costs.