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Old 24th October 2010, 06:42 PM   #661
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Quote:
Originally Posted by nicoch46 View Post
I checked the pre out using a multimeter and observed a little bit of residual DC :
can be a fake reading...try misure dc current.
I haved problem with pumping cone changing psu coke with hight resistence in my tube amp,ie the clc frequency of psu ....
I use Salas HV after a LC circuit. Choke is 430R/5H. As well there are 200H plate chokes between the HV supply and plates. Would this setup create any anomalies like this?

Last edited by coolzero; 24th October 2010 at 06:49 PM.
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Old 24th October 2010, 07:58 PM   #662
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remove the choke and try....simple
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Old 25th October 2010, 03:03 AM   #663
regal is offline regal  United States
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With non regulated power supplies you will have residual DC if your mains oscillate at a low low frequency (wander +-5V from the wall), best solution short of a regulated supply is to decreace the value of your coupling cap.
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Old 25th October 2010, 04:29 AM   #664
Salas is offline Salas  Greece
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Pumping in passive filtering is a classic problem that arises in such schemes. When the charging cycle hits some unfortunate phase condition of the client circuit, or there is fluctuation. Passives don't have a reference Vo fixing mechanism. Don't be afraid of tonally synergistic regs. Its a far better and most economic solution. (With 5k6 MJE's load for those who wonder about a specific one ).
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Old 29th October 2010, 06:50 PM   #665
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Thanks guys..removing chokes got rid of the fluctuation. But I am missing some of the details now with CCS which replaces the plate chokes . If I want to continue with passives will there be any harm to my other equipments?

Salas..one question for you. After I remove the chokes and replaced it with CCS load, your SSHV supply start behaving differently. Earlier it allows to change the voltage between a wide range but now this got narrowed and it seems the SSHV is putting more current in to the tube than expected. It lost control over current and voltage both. Can you think of anything why the SSHV is behaving like this? Haven't done any other change than removing the passives.
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Old 29th October 2010, 07:13 PM   #666
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Not the psu choke 430R/5H ?
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Old 29th October 2010, 07:13 PM   #667
Salas is offline Salas  Greece
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The active load can be oscillating the reg and itself.
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Old 29th October 2010, 07:34 PM   #668
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Quote:
Originally Posted by nicoch46 View Post
Not the psu choke 430R/5H ?
That as well. Nothing much of a change though.
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Old 29th October 2010, 07:35 PM   #669
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Originally Posted by Salas View Post
The active load can be oscillating the reg and itself.
Any workaround to fix this?
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Old 29th October 2010, 07:47 PM   #670
Salas is offline Salas  Greece
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Does the CCS have a local bypass lytic where it gets its B+?
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