[JN]Regulated PSU tubes

Daniel Normolle monk@umich.edu
Wed, 01 Oct 2003 10:36:09 -0400

 > Karsten H°jbjerg wrote:
 >> Dear Sirs
 >> I my regulated PSU I'm using EF86 as error amplifier and EC360 as
 >> shunt. The EF86 lifted up by a 0B2, 105V and the grid 2 is supplied by
 >> 150V0C2 which is connected in series with the 0B2, 10mA through the
 >> gas tubes. Both the gas tubes is by passed by 0,1ÁF is that ok?
 >> Are there other tubes that will do the job better than the EF86?
 >> What is lift time for 0C2, 0B2 etc and how do I know that they are
 >> close to death?
 >> What is lift time for rectifiers, 5U4G, 5R4G? etc and how do I know
 >> that they are close to death?
 >> Best regards
 >> Karsten H°jbjerg
 > Scott Grammer wrote:

 > I am told that one should not directly bypass gas regulator tubes with 
capacitors due to the possibility of creating a relaxation oscillator.

Steve Bench has an excellent review of the classic series voltage
regulator design on his web site.  He says up to 0.01 uF is acceptable.

The EF86 should be a great tube in this application.  I have been
running 0B2s daily in this circuit for 3 years and have yet to see
a failure or any drift in voltage.  Allegedly, these tubes are highly

Assuming "lift-time"="time to full voltage", the 5U4G family tubes
are not very effective as slow-start devices.  I have found TV
damper diodes much better.  You can use one in series with a
solid-state (HexFred, of course) rectifier bridge to achieve a
cost-effective, slow turn-on supply.