Re: Is a timing relay an option?

Posted by Triode_Kingdom (A) on October 11, 2006 at 16:19:49

In Reply to: Is a timing relay an option? posted by Russ57 on October 11, 2006 at 10:47:13:

Hey Russ, I think fifteen minutes is too long to wait. Even MV rectifiers wouldn't normally require that much warmup time. The more I think about this, the more I'm convinced that the best solution will be to install the CCS in the 211 cathode as Allen suggested. The DC drop across the CCS when everything is fully warmed can be set to less than 1V. If it rises to 2-3V when the amp is cold, that's perfectly acceptable. Fifteen minutes of audio that might not be quite as pristine as possible ("might" being the operative word) is better than fifteen minutes of no sound at all. Most amplifiers don't produce their best sonics until they've stabilized for 15-30 minutes anyway.

Regarding failsafes, the bias arrangement applies full -80V to the 211 if the driver tube opens, shutting it down. That's an intentional part of the design. I haven't decided yet how best to protect the 211 if the bias supply itself fails. There are quite a few options, so it's a matter of determining a method that will be both simple and effective. Any ideas on this? I guess the main scenarios are damage to the 211 from excess anode current, and damage from excess grid current. Those are two separate considerations (in other words, simply opening the cathode circuit in the event of a bias failure might not actually save the output tube). Say, do these projects ever actually end? Seems there's always some tweak or improvement just around the corner. :)

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Follow Ups Full Thread

Topic - CCS for SET Bias Stabilization - Triode_Kingdom 00:42:07 10/10/06 (19)

Re: CCS for SET Bias Stabilization - Meister 01:24:16 10/11/06 (0)

Re: CCS for SET Bias Stabilization - Dave Davenport 07:26:57 10/10/06 (1)

Re: CCS for SET Bias Stabilization - Triode_Kingdom 10:52:54 10/10/06 (0)

Re: CCS for SET Bias Stabilization - Naz 05:18:55 10/10/06 (3)

Re: CCS for SET Bias Stabilization - Triode_Kingdom 13:32:05 10/10/06 (2)

Re: CCS for SET Bias Stabilization - Naz 00:44:47 10/12/06 (1)

Re: CCS for SET Bias Stabilization - Triode_Kingdom 11:13:17 10/12/06 (0)

Apologies for the multiple posts - Allen Wright 04:12:12 10/10/06 (3)

FWIW: You can delete your own post for up to 24 hours if no one replies to it (nt) - Chris O 05:37:47 10/10/06 (2)

If the system allows access - if it was working correctly ... - Allen Wright 00:57:25 10/11/06 (1)

I had a try at deleting the two extra's that were below... - Allen Wright 01:04:41 10/11/06 (0)

Without thinking about it for long... - Allen Wright 01:42:47 10/10/06 (7)

Re: Without thinking about it for long... - Triode_Kingdom 10:33:14 10/10/06 (6)

Understood... - Allen Wright 01:17:55 10/11/06 (5)

Other techniques... - Triode_Kingdom 10:01:10 10/11/06 (4)

Is a timing relay an option? - Russ57 10:47:13 10/11/06 (3)

Re: Is a timing relay an option? - Triode_Kingdom 16:19:49 10/11/06 (2)

The DC drop across the CCS ...can be set to less than 1V. - Allen Wright 03:55:03 10/12/06 (1)

DC drop, SS Protection, etc. - Triode_Kingdom 08:42:04 10/12/06 (0)

IMO, and without spending too much time thinking about it... - Allen Wright 01:33:20 10/10/06 (0)

Follow Ups

Re: Is a timing relay an option? - Triode_Kingdom 16:19:49 10/11/06 (2)

The DC drop across the CCS ...can be set to less than 1V. - Allen Wright 03:55:03 10/12/06 (1)

DC drop, SS Protection, etc. - Triode_Kingdom 08:42:04 10/12/06 (0)

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