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Regulated Power Supply ?

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Posted on October 7, 2009 at 04:51:16
WALLACE
Audiophile

Posts: 24
Location: London, UK
Joined: July 31, 2008
 Any thoughts on regulating the power supply to ther output tubes ? The volts and current are low enough to use a IGBT - the base of which could be driven by a triode . .

W.
RE: Regulated Power Supply ?, posted on October 9, 2009 at 10:12:50
LinuxGuru
Audiophile

Posts: 108
Joined: November 11, 2008
 I will build one, regulated/stabilized 490V 500mA for my new project, with 6.3V/10A DC filament supply for audio tubes. I'm trying to negotiate order of custom toroidal 500VA power transformer, without major progress so far. Schematic is not proven yet, so I will post it till I'll be sure all things working properly.

RE: Regulated Power Supply ? for an OTL, posted on October 14, 2009 at 08:41:22
Ralph
Manufacturer

Posts: 1156
Location: Minnesota
Joined: April 24, 2002
Contributor
  Since: April 1, 2002
 the voltages need to be lower (150-160V at the most) and the currents higher- a lot higher, depending on the power output of the amp. In addition you might need 2 supplies, depending on the topology of the OTL.

The power supply should be resistant to arc-over events from the tubes too.

RE: Regulated Power Supply ?, posted on October 7, 2009 at 07:59:14
Lew
Audiophile

Posts: 2685
Location: Bethesda, Maryland
Joined: December 11, 2000
 In this type of amplifier in particular and in most all tube amplifiers, the general consensus seems to be that regulating the output supply is usually a net negative upgrade. In the circlotron, that thing has to swing huge amounts of current; you don't want to impede that freedom. This is one of the reasons Ralph does not even like to use inductors in the output supply filters. If you go for it, use massive overkill on the components, and tell us what you hear.

RE: Regulated Power Supply ?, posted on October 15, 2009 at 02:10:22
Satelliteman
Audiophile

Posts: 101
Location: Napier - The Art Deco City of the world
Joined: May 21, 2006
 Talking about massive Overkill ... well , I dont have anything special in my Output section other than 1kw Output supply transformers for the 110VAC rails . ( thats on my m60 DIY ) . because of the size - i use beefy Bridge rectifiers too - I didnt like the thought of a weak rectifier or one that lets go from inrush current .. CRCRC is all I use . Plenty of speed & less to go wrong . A good cleaning of the ears will blow away any enhancement that a over tricked output supply is going to do . Its all about speed & reserves ! .
Stu

RE: Regulated Power Supply ?, posted on October 8, 2009 at 10:07:06
WALLACE
Audiophile

Posts: 24
Location: London, UK
Joined: July 31, 2008
 Yep - I suppose trying it is the right answer ! But it does influence choice of transformer or at least the output voltages).

I had hours of endless fun playing with Duncan Amps PSU design - I'm a bit of a fan of choke supllies as they don't pulse the mains transformer so much - but it has to be right otherwise using a stepped load from max to min current really swings the output voltage. I've got it down to a few volts or so - and just wondered if a regulator would improve things.

Oh well - let's get out the soldering iron !

W.
`

RE: Regulated Power Supply ?, posted on October 8, 2009 at 13:44:19
Lew
Audiophile

Posts: 2685
Location: Bethesda, Maryland
Joined: December 11, 2000
 is this for an Atma-sphere or other Circlotron type OTL? I would love to hear one with a choke-loaded supply, let alone a regulated one. If you use choke load, I suggest the DCR should be as low as possible.

RE: Regulated Power Supply ?, posted on October 9, 2009 at 03:46:34
WALLACE
Audiophile

Posts: 24
Location: London, UK
Joined: July 31, 2008
 Circlotron !

I had some 0.1 H chokes made up - and brought a shed load of capacitors of eBay. I will do some photos when I get a chance but it's still very much in the component 'aquisition' stage - and thinking up a circuit design for the driver.

The plan for the regulator is to have a choke input (albeit with a smallish capacitor beforehand) for the power stage - and off the same transformer (maybe a higher voltage tapping) a capacitor input which will give me a higher voltage to just drive the triode which drives the IGBT regulator.

Just a thought at the moment though . . .and the thing's big enough as it is !

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