SET vs OTL

Martykl, one thing about SETs that makes them quite different from OTLs is the way their distortion signature interacts with the human ear/brain system. SETs tend to have very low distortion at low power, but on transients, where the power occurs, the distortion can be quite a lot higher (10% at full power is quite common).

Thus there is high distortion on transients, and while normally the odd-ordered harmonics are kept at vanishingly low levels, at high power they have an effect. Of course, they are masked by the presence of even-ordered harmonics, but despite that the brain reacts to their presence anyway.

That reaction is a sense that the amplifier somehow is a lot more dynamic and can play louder than it should be able to given its actual power output. You commented about that quality in describing your amplifier above.

OTOH if the amplifier actually has the power to make real spls, and if the distortion is kept low, then the result is that the system is can be more relaxed- that the volume you pick is not based on perceived 'loudness'. IMO, a good system will not have a sense of volume or loudness- it should act that way real music does in that regard.

Atma,

I know what you mean. I also wonder if the steep impedence spike of the VSMs (@ app 1Khz) is audible via SET and contributes to the sense of dynamics from the SET/VSM combo. Nevertheless, the cumulative effect of pairing this speaker with these amps was very, very satisfying in many (not every) way(s).

While I wouldn't particularly agree with your description of the dynamic behavior of a "good" system, I will acknowledge your point. There were times when the dynamics felt a bit more "juiced" than strictly natural, but with most of my recordings, I'd call this quality more realistic sounding. There were recordings, however, which would substantiate your view.

When I described OTLs as more "revealing" earlier in this post, that's partly what I was getting at. Shortcomings in speakers and source material was usually more evident via OTL. I know some folks find this the holy grail of this hobby, but I don't.

Marty

Marty, I understand what you are saying. I want the amp to play what is good in a recording, and with the poor recordings, not get upset by artifacts in the recordings. In other words, forgiving? -but without giving up anything to resolution. Its a fine line to tread.

Bobby P. has been making certain over the years that Merlins are tube and particularly OTL friendly. OTLs and Merlins are a very common and successful combination!

Atma,

Couldn't have said it any better. I guess I found those early iterations of both the S-30 and the VSM SE slightly less "forgiving" than I'd prefer. Not "ruthless", or even "unkind", but maybe a touch "strict"?

Marty

PS I think my S-30 was one of the very first you guys manufactured. I was wondering which current Atmasphere model you typically pair with current VSMs? After this thread, I'm (uh-oh) starting to get that urge to expand the amp collection (again!). Let's see, we got 45s, 50s, 2a3s, OTLs,....

Hi Marty, most people with VSMs usually go with the M-60. They have enough power to really make the speaker sing.