In Reply to: RE: 1-meg grid resistor: not a problem as long as one stays in class-A posted by Al Noakes on May 27, 2009 at 03:37:52:
Sure, if you drive it harder it will eventually transition into AB --this is to be expected. Nonetheless, it will stay within class-A approx 90% or more of the time with normal usage.BTW: I've tried the 12B4A split-load with the EL84. Surprisingly, it was a pretty lack-lustre in sonic results. Bottom line: the split-load inverter just was not found to be sonically comparable to the long-tailed pair fro driving the EL84. In fact, it's much more than a subtle audible improvement with the long-tailed pair.
As far as CCS implementation: I'm not entirely sold on CCS usage. I suspect they can introduce more low-level harmonic artifacts than is generally assumed. And BTW: 32mA is much more current than you really need for clean triode-connection operation at the 5-watt level. It sounds much better with 24/25 mA.
As for the "too much gain" concerns: carefully re-read my previous posts here. There is a sound reason I included the 12AU7 input stage which has nothing to do with the additional (yes, unneeded) gain the stage provides.
You seem to be quite interested in this circuit. I'm curious, Why not suspend your disbelief, try it out, and then judge for yourself? Then you can get back with me and we can discuss your impressions.
Cheers,
-T.M.
Edits: 05/29/09 05/29/09 05/29/09
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Follow Ups
- Class-A most of the the time, and also... - Thom_M 09:50:52 05/27/09 (21)
- RE: Class-A most of the the time, and also... - Al Noakes 11:03:23 05/27/09 (20)
- I suppose if your memory serves you, to your complete satisfaction.... - Thom_M 12:17:45 05/27/09 (19)
- RE: I suppose if your memory serves you, to your complete satisfaction.... - Al Noakes 13:28:04 05/27/09 (18)
- It would seem to me... - Thom_M 14:08:39 05/27/09 (17)
- RE: It would seem to me... - Al Noakes 05:53:49 05/28/09 (16)
- Al: "I have over a hundred EL84 in my stash , mainly Mullards..." - Thom_M 16:45:18 05/28/09 (15)
- so you like EL84, eh? - PakProtector 17:15:33 05/28/09 (14)
- FYI: I'd never slander the 2A3 , or the DHT approach in general... - Thom_M 21:51:36 05/28/09 (13)
- but you did... - PakProtector 03:16:26 05/29/09 (12)
- One more time... - Thom_M 11:01:27 05/29/09 (1)
- Good - PakProtector 11:04:14 05/29/09 (0)
- RE: but you did... - Al Noakes 05:03:20 05/29/09 (9)
- damn Al, then you will need these. - dave slagle 00:16:25 05/30/09 (5)
- RE: damn Al, then you will need these. - Al Noakes 01:05:41 05/30/09 (4)
- and of course.... - dave slagle 18:31:46 05/30/09 (0)
- Oh yeah. - dave slagle 17:09:46 05/30/09 (0)
- RE: damn Al, then you will need these. - dave slagle 17:06:41 05/30/09 (0)
- RE: damn Al, then you will need these. - PakProtector 08:42:46 05/30/09 (0)
- RE: but you did... - PakProtector 06:06:42 05/29/09 (2)
- RE: but you did... - Al Noakes 06:19:43 05/29/09 (1)
- RE: but you did... - PakProtector 07:48:48 05/29/09 (0)