Bleeder Resistor for Choke Input Supply - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 18th June 2012, 03:59 PM   #1
Magz is offline Magz  United States
diyAudio Member
 
Join Date: Oct 2009
Location: New Jersey, USA
Default Bleeder Resistor for Choke Input Supply

Hello All,

I'm building an LCLC supply for a preamp, and wondering about the necessity of a bleeder resistor. The circuit has gas regulators drawing 45mA total in shunt from the HT to drop the voltage down to 225V, so once they strike, there is no need for a bleeder, as the minimum current for the 17H input choke is easily satisified. The voltage will climb higher before they strike, but all the circuit components are rated for far more voltage than the circuit can obtain in cap input.

The glow tubes act as their own indicators if there is a problem - no glow, then I know to shut down. Safe, right?

I'd rather not waste all that power and generate unnecessary heat if it's not necessary.
  Reply With Quote
Old 18th June 2012, 04:20 PM   #2
diyAudio Member
 
Vinylsavor's Avatar
 
Join Date: Feb 2002
Location: Lindau
Hi!

The bleeder provides some safety. If the gas tubes don't ignite for any reason or tubes are not plugged in, the bleeder will ensure that the caps are discharged when you turn off. Some caps can hold their charge for days!

If sub critical current is drawn from the PSU, the output voltage will be up to 50% higher. Ensure your caps have a high enough voltage rating for that so nothing gets damaged just in case.

If you do not want to place bleeders which draw the critical current, at least install some with a higher resistance which will dissipate less power, but still ensure discharge of the caps in any case.

Best regards

Thomas
__________________
http://vinylsavor.blogspot.com/
  Reply With Quote
Old 18th June 2012, 05:15 PM   #3
Magz is offline Magz  United States
diyAudio Member
 
Join Date: Oct 2009
Location: New Jersey, USA
Thanks Thomas,

Yes, I was planning to install high value bleeders to drain the caps, just not to draw the critical current. 200k should discharge the caps within 90 seconds without drawing very much current.
  Reply With Quote
Old 18th June 2012, 05:59 PM   #4
diyAudio Member
 
Osvaldo de Banfield's Avatar
 
Join Date: Dec 2011
Location: Barrio Garay,Almirante Brown, Buenos Aires, Argentina
Be sure to no put any condenser directly in parallel to the VR, otherwise an RC relaxation oscillator you will do.
__________________
LW1DSE
  Reply With Quote
Old 18th June 2012, 06:34 PM   #5
Magz is offline Magz  United States
diyAudio Member
 
Join Date: Oct 2009
Location: New Jersey, USA
Quote:
Originally Posted by Osvaldo de Banfield View Post
Be sure to no put any condenser directly in parallel to the VR, otherwise an RC relaxation oscillator you will do.
Yes, I've already breadboarded and listened to the preamp portion of the circuit using a different, CLCLC power supply, and using a 0.1uF Multicap PPMFX to shunt noise to ground around the VR tubes. VR tubes are fed from a cascode CCS. Worked like a charm with no oscillation detectable on my scope.
  Reply With Quote
Old 19th June 2012, 03:30 PM   #6
rongon is offline rongon  United States
diyAudio Member
 
rongon's Avatar
 
Join Date: Jul 2009
Location: Across the river from Rip's big old tree...
When you install a voltage divider from B+ to lift the heaters 40V to 60V above ground, doesn't that act as a bleeder resistor? Provides a discharge path through the two resistors to ground... No?

If so, there's killing two birds with one stone.

--
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
choke input power supply vitalstates Tubes / Valves 10 24th February 2012 01:03 PM
Best place to place bleeder resistor in a power supply? G Tubes / Valves 13 4th August 2004 09:26 AM
Resistor-Input vs. Choke-Input vs. Cap.Multip. Blitz Pass Labs 13 26th September 2003 04:59 AM
bleeder resistor for ZenV4 power supply; and ancllary matters Zapped Pass Labs 13 24th September 2003 04:02 AM
Choke input Power Supply NickC Solid State 4 6th November 2002 07:41 PM


New To Site? Need Help?

All times are GMT. The time now is 02:48 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2