In Reply to: RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS posted by Chip647 on March 30, 2015 at 18:15:26:
Hi Chip,You obviously have never even HEARD the circuit you disparage, properly executed - that's OK, I forgive you.
NO, you can not Direct Couple the SUN amp with 290-0-290 VAC as the high voltage secondary. I ain't a one-trick pony either.
---------------------------------------------
So, you wanna pick my brain. Fine !
What that SUN SV 2A3 stereo amp DEARLY needs is - TWO things :
(1) A better power supply B+ filter, on several "levels" :
Change the stock B+ filter from a "super crude" C/L/C filter, ( with a NASTY "C" 47 uF ( ooochh, phooey ) ringing input filter and its stock L ( FAR too HIGH in DCR for a 2A3 ).
The SUN needs to use a refined-sounding L1/C1/L2/C2 B+ filter with modern film Cs and two Ls, both Ls small ( under 2 pounds). Ls each measuring under 10 Ohms in DCR... " ultra high fidelity ".
(2) The 2A3 is likely running stock at close to 100% of its 15 Watts plate dissipation, 250 VDC P-K at 60 ( too high ) milliamperes.
Use a more conservative 2A3 plate dissipation, closer to a "Golden Ratio" 62% proportion, The 2A3 will no longer be thermally stressed, and sound stressed. (As always IS the case, the way 90% of the people mis-run 2A3s.)
Hell, number (2)'s easy, changing the stock amp's self bias Rks to two Mills MRA-12s, in each channel.
With a SUN SV 2A3 however, both number (1) and (2) need to be done in conjunction with each other, to get within 5% of the new "optimized" B+ op points. I have figured out HOW to reasonably do that, as the result of many simulations.
Other than the above two changes, the rest of the amp is fine, "for a three stage amp". I have conservatively worked this modification out over the last few weeks. Just need to double check with someone - what the stock SUN amp measures, in four or five places at idle.
Jeff Medwin
Edits: 03/30/15 03/30/15 03/30/15
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Follow Ups
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 19:29:11 03/30/15 (58)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - hennfarm 23:51:51 04/19/15 (1)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 09:57:57 04/21/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - FenderLover 07:43:39 04/01/15 (45)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 09:08:13 04/01/15 (44)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - elblanco 10:58:33 04/01/15 (36)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Caucasian Blackplate 17:02:25 04/01/15 (35)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - rage 02:47:20 04/11/15 (19)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - rage 03:12:45 04/11/15 (18)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - rage 03:15:08 04/11/15 (17)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Al Noakes 06:18:42 04/13/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Tre' 08:00:07 04/12/15 (1)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - rage 14:41:08 04/14/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - dave slagle 21:06:24 04/11/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 10:08:07 04/11/15 (12)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - elblanco 21:44:58 04/11/15 (11)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - rage 13:28:27 04/17/15 (10)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 16:38:27 04/21/15 (9)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - used-hifi 10:06:30 02/06/17 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - dave slagle 13:31:39 04/22/15 (7)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - rage 09:08:54 04/26/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 15:49:12 04/25/15 (5)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - dave slagle 07:55:25 04/28/15 (4)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - rage 01:49:34 05/06/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Mr_Steady 17:07:01 04/29/15 (2)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Tre' 18:26:12 04/29/15 (1)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Mr_Steady 18:54:02 04/29/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 18:51:24 04/01/15 (2)
- whoa!..what just happened - elblanco 06:17:49 04/02/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Caucasian Blackplate 19:43:16 04/01/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - elblanco 18:17:07 04/01/15 (11)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Caucasian Blackplate 19:45:42 04/01/15 (10)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Al Noakes 10:42:50 04/02/15 (9)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Caucasian Blackplate 11:49:42 04/03/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 11:08:49 04/02/15 (7)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Al Noakes 13:57:08 04/02/15 (6)
- RE: 40 mile drive ... - deathtube 667 06:39:41 04/16/15 (2)
- RE: 40 mile drive ... - Al Noakes 07:06:50 04/16/15 (1)
- RE: perhaps RMAF ... - deathtube 667 08:02:46 04/25/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 14:22:51 04/02/15 (2)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Al Noakes 16:04:05 04/02/15 (1)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 17:15:17 04/02/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - FenderLover 09:35:04 04/01/15 (6)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 09:52:46 04/01/15 (5)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Paul Joppa 18:49:52 04/02/15 (4)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 07:59:22 04/03/15 (3)
- De gustibus non est disputandum (nt) - Paul Joppa 10:24:39 04/03/15 (2)
- RE: De gustibus non est disputandum (nt) - Tre' 10:41:24 04/03/15 (0)
- RE: De gustibus non est disputandum (nt) - drlowmu 10:39:49 04/03/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Wojciech 05:56:06 03/31/15 (9)
- he's on the right path.... - PakProtector 17:26:09 04/01/15 (0)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 07:17:42 03/31/15 (7)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Caucasian Blackplate 10:16:58 03/31/15 (6)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 10:24:16 03/31/15 (5)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - Caucasian Blackplate 10:40:10 03/31/15 (4)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 14:05:27 03/31/15 (3)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - elblanco 15:10:58 03/31/15 (2)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 10:01:07 04/01/15 (1)
- RE: SUN SV 2A3 stereo SE amp .... MEASUREMENTS - drlowmu 10:05:20 04/01/15 (0)