In Reply to: RE: red plates ... bob and weave ... posted by Tre' on September 24, 2021 at 06:59:09:
3.9K is only a calculation, and it is correct
in that published distortion figures will
be lower than 2.5K on a 2A3.
2.5K does something better: at the cost of slightly
higher distortion numbers, it delivers what a 3.9K transformer
(on a 2A3) can't: a tactile feeling-- a direct contact with music.
Only two amp stages, and DC coupling also improve that.
Remember these amps were designed to LISTEN TO, not just
to perform measurements on. There is ZERO chance that a
3.9K transformer will deliver what we have. It will be a
bit cleaner, it will measure better, and 4K has been
tried. Also, 8 ohm speakers have been driven superbly
when connected to the 16 ohm tap of the 2.5K transformer.
The real question is always-- what is the DCR of the power
supply, and are its capacitors small enough and fast enough,
and are the power supply chokes low-DCR and low-inductance
enough so that short-term dynamic peaks are well reproduced..
The 3.9K output trans will handle short-term dynamic events
in a far less convincing manner-- we have experimented with 4K..
2.15K could be better yet. 2.5K is readily available and does
what it should do, musically, so we're very happy with it.
Harmonic distortion is nice to measure and theorize
about. Real life dynamics is something that is essential
to people who enjoy dynamic, complex music.
Speakers are the ultimate challenge here. They must
work, or you go to higher power. If H.F. radiators
have too little surface area, and try to fire from a tiny area,
then all forms of harmonic distortions must be lowered
to control the sub-standard tweeter's departures from
natural dynamic handling of a listening area..
-Dennis-
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Follow Ups
- RE: red plates ... bob and weave ... - tube wrangler 09/24/2118:05:04 09/24/21 (8)
- RE: red plates ... bob and weave ... - Tre' 07:28:43 09/25/21 (3)
- 3.9k 2.9% THD - Tre' 08:39:44 09/25/21 (2)
- RE: 3.9k 2.9% THD - kobasa@xs4all.nl 09:58:51 09/25/21 (1)
- Happy, happy sound machines. nt - Tre' 11:08:12 09/25/21 (0)
- RE: red plates ... bob and weave ... - kobasa@xs4all.nl 23:13:47 09/24/21 (3)
- RE: red plates ... bob and weave ... - tube wrangler 03:20:44 09/25/21 (2)
- RE: red plates ... bob and weave ... - kobasa@xs4all.nl 04:25:26 09/25/21 (1)
- For $18,000 you would expect more distortion - GEO 12:04:57 09/25/21 (0)