I personally haven't heard any amp design that offers what OTL's do when matched with an optimal load. The traditional design will however exibit problems if not properly matched to a stable high impedance speaker load. The ideal being 16 ohms. Not too many dynamic speakers exibit such a load therefore the zeroformer is used. This thing DOES affect the sound of the amp. The higher the multiplier, the dryer the sound becomes losing some of the characteristic OTL "sound", in my mind a compromise. The plus side with this device is maintaining the clarity at the frequency extremes.
The Berning zh270 really isn't a true OTL which by definition means nothing but wire between the plate and speaker terminal. The Berning uses a patented high frequency impedace converter which is essentially a transformer without the effects of iron, the signal is unaffected. What you get is a pure signal with the pluses of OTL's PLUS the ability to drive low impedance loads at full power. This design is also high bandwidth and doesn't have the limitations of traditional output transformers. I expect some of the more expensive modern tube designs have limited some of the problems associated in the past with transformers.
Ultrakatz's reservations about owning such a product was also a concern of mine. What happens if the designer isn't around to fix the amp if there is a problem down the road? Berning's track record for reliability of his products is legendary, he personally assembles his own amps. I guess at some point you have to take the leap of faith and not worry too much about it. Listening is believing, this amp is quite special as well as offering flexibility beyond a typical basic amplifier.
The Berning zh270 really isn't a true OTL which by definition means nothing but wire between the plate and speaker terminal. The Berning uses a patented high frequency impedace converter which is essentially a transformer without the effects of iron, the signal is unaffected. What you get is a pure signal with the pluses of OTL's PLUS the ability to drive low impedance loads at full power. This design is also high bandwidth and doesn't have the limitations of traditional output transformers. I expect some of the more expensive modern tube designs have limited some of the problems associated in the past with transformers.
Ultrakatz's reservations about owning such a product was also a concern of mine. What happens if the designer isn't around to fix the amp if there is a problem down the road? Berning's track record for reliability of his products is legendary, he personally assembles his own amps. I guess at some point you have to take the leap of faith and not worry too much about it. Listening is believing, this amp is quite special as well as offering flexibility beyond a typical basic amplifier.