SET vs OTL

@atmasphere

Ralph, are you able to address my comparison between Graaf GM20 and Wavac EC300b in the same way? I am not yet convinced that the issues raised by @pani aren‘t valid in the same way.

For what it‘s worth I have yet to hear a balanced connection that can compete with an optimum single ended setup and I think Ken Shindo, JC Verdier and Keith Aschenbrenner would agree…

This thread is pleasantly devoid of polemics and addressing the core issues: thank you all, this is what the forum should be

Ralph, are you able to address my comparison between Graaf GM20 and Wavac EC300b in the same way? I am not yet convinced that the issues raised by @pani aren‘t valid in the same way.

From what I can see of the Graaf front end circuit, while it is balanced it must have a fairly low CMRR; this based on the lack of a constant current source. This causes the circuit to have higher offsets, lower gain and higher distortion. This in turn muddies the water as far as the distortion product goes (mostly due to the offsets generated, which cause more 2nd harmonic to be created)- you can't say its entirely cubic insofar as its non-linearities are concerned. So I can't really comment about the comparison and certainly can't contest your findings! But of course the Graaf is one of a number of OTLs out there.

Regarding the balanced connection thing, I always encourage people to look at whether the gear doing the balanced connection supports the balanced standard or not. The reason is simple: if you don't support the standard you don't accrue the benefits either! FWIW most high end audio manufacturers don't seem to support the standard. One of the more important aspects is that in balanced mode, neither the inverted or non-inverted signal references ground- they reference each other and ground is ignored. Its this bit that makes supporting the balanced standard a bit tricky- most of the time you need an output transformer to do the job. To do that right is expensive.We patented a means to get around that problem but that simply means we're the only one doing it our way, which is direct-coupled.

@atmasphere I have not heard your amps yet and also my exposure to differentially balanced amps is very limited hence I would eagerly wait to hear them out. I would be very happy if I can find the cohesion of single ended design in a powerful balanced push pull design

My exposure to OTL was only with the Tenor OTL75 which I owned for about 6 months. Lovely amplifier but surprisingly even with 75 watts it could not control my Tannoys' bottom end like a 10 watt Wavac 300b (which I owned just prior to the Tenor). The bass was loose. In my relatively small room it was an issue. The rest of the spectrum was deliciously to my taste. It still missed the cohesion of a Single ended amp though.

@pani Which Tannoys did/do you have?