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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

Showing 1 response by pryso

pryso
1,909 posts
 
bsimpson, in case you may still be following your thread.

I've owned a pair of AtmaSphere monoblocs and spent time with a few different Joule Electras.  From that experience I can offer two considerations.

First is the appropriate match with speakers.  That is a question of both power and load impedance.  Proper mating with lower than 8 ohms can be problematic.

Second is the issue with heat.  More output tubes may be required per channel to drive lower loads with OTLs.  My AtmaSpheres had 10 outputs per channel to produce 100 watts which I attempted with 4 ohm speakers.  They put out more heat than similarly rated transformer coupled tube amps.  But with less demanding (i.e. complex) music at reasonable levels they were magical.

That was all some years ago and now I look forward to auditioning the ZOTL 40s that lancelock recommends. 
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