Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tube for a shunt voltage regulator
Tube for a shunt voltage regulator
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
Thread Tools Search this Thread
Old 25th October 2006, 06:07 PM   #11
Wavebourn is offline Wavebourn  United States
Designer & Technologist
diyAudio Member
Wavebourn's Avatar
Join Date: Sep 2006
Location: Pleasant Hill, CA
Tube for a shunt voltage regulator
...or take one FET, one Zener, and one resistor. No FET and resistor needed if the current is in the range of specs for a zener. Or take a P-channel FET and mount it directly on a chassis to eliminate heatsink.
Nothing in the universe is perfect. The ideal things are the ones that are most optimal. Optimization criteria, what matters. When I hear "No Compromise Design", I want to take a sledgehammer and test how impact-proof it is.
  Reply With Quote
Old 25th October 2006, 09:12 PM   #12
Geek is offline Geek
diyAudio Member
Geek's Avatar
Join Date: Sep 2004
Originally posted by SY

As long as the voltage is below 250-275V. Otherwise, it won't work.
Right. In that case, tie the screen to something lower. Anode can go anywhere (almost).
  Reply With Quote
Old 26th October 2006, 01:08 AM   #13
JohnAtwood is offline JohnAtwood  United States
diyAudio Member
JohnAtwood's Avatar
Join Date: May 2006
Location: Rural Nevada
Default Simple tube shunt regulator

I've been using tube-type shunt regulators for several years, and have had good sonic results with them. The basic circuit is a high-transconductance pentode (typically a video amplifier tube) using its own gain to regulate. A filtered negative reference voltage is used. The regulation is not high, but if it is only used for one stage, never shared between channels, the results are good. With a little tweaking, the impedance vs frequency can be made essentially flat.

I've built this circuit with 6CL6, 6AG7, PL83, and the pentode section of a 6CX8. It would have better regulation with super-high transconductance tubes such as the 12GN7 or 7788, but I am somewhat allergic to frame-grid tubes in my circuits.

Here is a somewhat simplified version of the 2A3 amplifier circuit that I wrote about in Vacuum Tube Valley issue number 15. It is the one with RF-powered filaments. It is also one of the best-sounding amps I've built.

Simplified 2A3 amp

The top part of the schematic is a basic three-stage SE amplifier using a 5879, 2E24, and 2A3 (all pentodes triode connected). The 2.5V filament supply for the 2A3 is returned to ground through a current-sensing resistor. The 12AU7 is a cathode follower that is used to filter any hum or noise out of the -150V source. It also helps isolate this reference voltage between the two channels of the stereo amp. The 2.2K 10W resistor feeding the shunt regulator sets the gain of the regulator. If a higher voltage is available, a larger dropping resistor can be used, thus increasing the gain. I've tried using a choke here, but have run into stability problems. The 0.22uF cap across the 365K resistor allows the regulator to have full gain across the audio band. The 6CL6 screen is bypassed by a big capacitor. If you want even better stability at DC, a VR-tube could be used here.

- John Atwood
  Reply With Quote
Old 26th October 2006, 02:55 AM   #14
gingertube is offline gingertube  Australia
diyAudio Member
Join Date: Oct 2004
Location: Adelaide South Oz
I finish a 4 week stint in Cairns as support engineer on the Navy's Laser Airborne Depth Sounder today and fly home to Adelaide tomorrow. As far as I know I'm about the only guy in Adelaide who has the full Vaccuum Tube Valley collection so if you want to reference John's article give me a buzz Saturday or after (82693539).
I also recall that there was a series of articles on the TubeCad webpages about suitabilty of various tubes in voltage regulator circuits. They may have been talking about series regulators rather than shunt (don't recall) BUT any tube suitable as a series regulator device is also suitable as a shunt regulator device. Do a search on that web site.
  Reply With Quote
Old 26th October 2006, 04:19 AM   #15
ray_moth is offline ray_moth  Indonesia
diyAudio Moderator Emeritus
ray_moth's Avatar
Join Date: Jan 2004
Location: Jakarta
Here is the article on pass tubes
  Reply With Quote


Tube for a shunt voltage regulatorHide 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

Forum Jump

New To Site? Need Help?

All times are GMT. The time now is 06:53 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio