Perhaps I should put my $0.02 here from an end-user perspective.
I have owned at least seven (7) different OTL tube amps, some are big brands, some are DIYs from experienced (10+ yrs) tube amp hobbyists with extensive engineering experience.
IMHO, OTL tube amps are reliable if you understand their operation limitation first. I found that:
1) OTL tube amps do not work well under 4 ohm or less speakers. Even some transient passages at 2 or 3 ohms may blown the tubes. This is not specific to the tube type.
2) OTL tube amps are much less tolerant to wide impedance swing. The more stable the speaker's impedance, the better.
The best sound I got from OTL amps is when I use them to drive impedance-friendly monitors, with the aide of quality subwoofers covering 180Hz-250Hz and below.
Hope this helps.
I have owned at least seven (7) different OTL tube amps, some are big brands, some are DIYs from experienced (10+ yrs) tube amp hobbyists with extensive engineering experience.
IMHO, OTL tube amps are reliable if you understand their operation limitation first. I found that:
1) OTL tube amps do not work well under 4 ohm or less speakers. Even some transient passages at 2 or 3 ohms may blown the tubes. This is not specific to the tube type.
2) OTL tube amps are much less tolerant to wide impedance swing. The more stable the speaker's impedance, the better.
The best sound I got from OTL amps is when I use them to drive impedance-friendly monitors, with the aide of quality subwoofers covering 180Hz-250Hz and below.
Hope this helps.