What's your OTL tube amp experience and suggestion?


Are OTL amps in general much less reliable due to their nature, or due to the implementation quality, or both?

Perhaps this has been discussed a zillion times in the past.   Perhaps, however, makers have now improve on past experience?  So it could be worth re-visiting.

My past encounters with OTL tube amps are among the most negative: Wonderful (but never great) sound during the brief period that they work.  Otherwise, major fire hazard.  Overheating, red hot plates, sparks, consistently toasted fuses, burning smell, you name it.  My past OTL amps are like crying babies on an changing table - don't you ever walk away from an arm's distance.   The used market seem to reflect such as well --- way more 'as-is for parts' or 'totally refurbished' units than reliable 'used' units that rarely need service.

Beg your pardon if it's just my poor judgement that keep getting the lemons.   What's your experience, and tips to keep OTL amps up and running happily?


bsimpson
@c

The heat of an OTL is like it is with any other amp- the heat is based on the class of service rather than the number of tubes. The exception might be if you run an amplifier using 6C33s (OTL or not), which run unusually hot!

If our amps are on Standby, after a day of that you can easily grab a power tube and hang on without burns. But start the amp from stone cold take it out of Standby to full On and after a minute of operation, its too hot to touch!

If you had a solid state amp of 225 watts that run class A, you would find it making a very similar amount of heat!

Atmasphere
See pics 20 and 25 on my virtual system for the otl's.
Unfortunately AudioGon does allow me to link the pics.
so
If I put a cooking rack an inch above the amps.
The Krell FPB600 will keep an X-large Pizza toasty ready to eat.
The previous OTL's would have cooked it for me as well.  

Is anyone familiar with the Alieno Ltd. 250 OTL (from Italy)?

Is anyone familiar with the Aitos EV 903 OTL (from the Netherlands)?
I have removed the Zero's from the equation using the MA-60's. 
It just wasn't needed. 
The Atma-Sphere M-60's are the finest amp(s) I have ever owned. The tube heat is not a problem, and the power output matched with easy to drive speakers (my DIY) is awesome. 
In fact, the M-60's play as loud as my Pass Labs X350.8 amps but with better sound quality.
Highest recommendation IMHO.

ozzy
Is anyone familiar with the Alieno Ltd. 250 OTL (from Italy)?
Its not an OTL, no 300b can make 250 watts. The power is being made by semiconductors.