otl vs push/pull


Can anyone share their impressions of a p/p sound vs a OTL amp sound. My speakers can handle an otl amp, coincident partial eclipse. It's been suggested I take a look at an otl amp as it would be a significant upgrade over my Cary sli-80. I do not have any dealers in my area, so I can not audition an OTL.
Thanks
Mike
128x128brm1
OTL means output transformerless. PP means push/pull. These are not mutually exclusive terms as far as I know. The Atmasphere amps are both. Does anyone make a single ended OTL?
I've owned many amps of all variety and with the proper speaker an OTL can be as good as it gets IMO

I don't think the modern designs have any problems blowing speakers.
Correct, only the really old Futterman type OTL amps had trouble damaging speakers.

Although some would argue that Berning amps aren't true OTLs(I'm not getting into that old debate), I believe they are S.E., and they portray most of the traits of other great OTLs like the Joule Electras & Atma-Spheres.

Matching w/speakers that have a high impedance (ideally >8ohms) throughout the frequency range is critical with any OTL amp. Cheers,

Spencer
FWIW Israel did a lot of the formative work on his speaker line with a set of M-60s. We have a set of his Total Victories which the M-60s drive with ease.

But to the point of OTL vs P-P, for the most part, OTLs **are** push-pull. The elimination of the output transformer eliminates the hysteresis loss that all push-pull output transformers exhibit. Hysteresis loss is the phenomena of an output transformer where it takes a little extra energy to reverse the magnetic field in the transformer as the signal goes from positive to negative or from negative to positive.

Normally this is not a problem at moderate or higher powers, but low level detail does suffer. The reason is that the extra energy needed to change the polarity of the signal comes from the signal itself.

OTLs traditionally have more bandwidth that transformer-coupled amplifiers, and so on the right speaker (such as a Coincident) will have deeper bass with more impact, and obviously faster and more extended highs. If done right, those highs will not be brighter- just faster and more extended. There is a difference there, one that I regard as the difference between stereo and music.

There has been a lot of comment about how OTLs prefer higher impedance speakers, and while this is generally true, most OTLs of moderate power will easily handle most 8 ohm speakers. However, I should point out that while many believe that the ability to drive 4 ohms and less is a hallmark of quality, the facts of the matter are that no matter what kind of amp you have (tube, solid state, class D), if **sound quality** is your goal, then that goal and your amplifier investment dollar will be best served by a speaker that is 8 ohms or more (16 ohms is very nice), than by 4 ohms, all other things being equal. If **sound pressure** is your goal, and you have a transistor amp, then 4 ohms is preferred.

Most (not all) OTLs and tube amplifiers will make more power into higher impedances (our MA-2 and MA-3 actually make slightly less). But in most cases, driving higher impedance means (transformer-coupled or not) that distortion will be reduced and bandwidth (top and bottom) will be increased. Any time you reduce distortion, you increase detail as distortion masks detail, and the amp will sound smoother.

Except for the power issue, transistor amps will otherwise behave similarly- more detail and smoother, when driving higher impedances.