Speaker Suggestions for 300b SET Amp

Johnk ;
"Or one is just SETing themselves up for failure."

Great line !
And advice . 

The fatal weakness of so called circutron otl push pull power amp design is that the power grounding have to go through both legs‘ cathodes, thus power path mingle with the signal path, introducing distortion and noises.
Furthermore, after some experiment,  i found circutron push pull otl amps have very low damping factor, it produced worst sound when driving my quad 57 among all otl design amps.
Atmosphere uses circutron design, so it has very high distortion and is terrible for driving difficult loads such as quad 57s.
Transform coupled tube amplifiers on the other hand uses inductance to their advantages when driving difficult loads.

I am using an Audion 300b (7watts) with Spatial Audio M4s in a very large room.  Fantastic sounding speaker, very stylish and amazing bass with no strain (never past 10oclock on volume) and these are not the triode version, which is more SET friendly. Spatials have a 60 day trial period. They do take a long while to  Breakin. Replaced Maggies and equal to them in what Maggie’s do best and far superior in the areas that Maggie’s suffer. Of course I wasn’t using 7watts with the Maggie’s.

The fatal weakness of so called circutron otl push pull power amp design is that the power grounding have to go through both legs‘ cathodes, thus power path mingle with the signal path, introducing distortion and noises.
Furthermore, after some experiment,  i found circutron push pull otl amps have very low damping factor, it produced worst sound when driving my quad 57 among all otl design amps.
Atmosphere uses circutron design, so it has very high distortion and is terrible for driving difficult loads such as quad 57s.
Transform coupled tube amplifiers on the other hand uses inductance to their advantages when driving difficult loads.

Obviously this person has not used our amps with Quads. We have a lot of Quad customers. The opening statement is false; you can literally run the amp with no filter caps and it will sound pretty decent. So the first paragraph is outright false.

The damping factor has entirely to do with the number and type of tubes involved, how they are driven, the power supply voltages and bias points, and finally how much negative feedback is employed, if any. We don't use any, and this resulting in an output impedance that is 1/2 that of other OTL output circuits running open loop. I regard the 2nd paragraph as highly misleading as it is apparent that whatever amp he used (if indeed he did use an OTL at all), it was not one of ours.

Our customers with Quads say its a match made in heaven. The 3rd paragraph is false but may be based on the premise of a homemade amp of some sort.

We get about 0.5% THD at full power with most of our designs- a bit lower with the larger amps, with about 0.04% or less IMD; not bad for zero feedback! Care must be taken to not accidentally ground the speaker terminals via the test equipment, else the distortion skyrockets. This is a **very** easy mistake to make. If byang12 really did try to measure the distortion of a circlotron OTL, its very likely he made this mistake. I've seen several respected magazines do it as well and I've done it myself.

Coherent Speakers from Canada. Give Frank Fazzalari a call or email....his speakers are amazing and I am using them with 300b and 2a3 ...sound is delicious and involving.