14 Aug
2014
14 Aug
'14
3:17 p.m.
The expense and weight of the output transformer is
not at issue with current OTL (Output Transformer-Less) designs, but rather distortions
introduced by the output transformer through core loss, hysteresis, etc. I've seen
modern designs that use a pile of hard-to-find Russian military tubes to achieve an output
impedance of about 2.5 ohms.
Yes, the distortion problem is also an issue, but I think the expense
is a bigger one. All newly made quality audio output transformers are
very expensive these days, and ones made for the low impedance tubes
are really, really, really expensive. Most transformer shops will not
even do them, as they are very difficult to make properly.
Weight? Meh. Most audiophiles do not care much about weight. Looks are
far more important.
--
Will