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

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

Regulator for tube pre
Regulator for tube pre
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 13th March 2007, 01:49 AM   #1
senderj is offline senderj  Hong Kong
diyAudio Member
Join Date: Feb 2006
Location: Hong Kong
Default Regulator for tube pre

I want to build a pre-amp with 12AX7 X2 and 2AU7 X2. I find this regulator that come along with the pre schematic. But it did not indicate the current load of each output of the tranformer. It may be a piece of cake of experienced, but not for a newbie like me. Can anybody help me figure out the current required? Thanks.

NB. the 12V output at the left side is for the output delay.
Attached Images
File Type: jpg psu.jpg (29.2 KB, 427 views)
  Reply With Quote
Old 13th March 2007, 02:01 AM   #2
SY is offline SY  United States
On Hiatus
SY's Avatar
Join Date: Oct 2002
Location: Chicagoland
Regulator for tube pre
I can't say precisely without the actual preamp schematic, but if it's like the other 99% out there using those tubes, for the high voltage, figure 1mA for each 12AX7 section, 4-5mA for each 12AU7 section. Each tube has two sections in its envelope. I'll leave the totaling to you.

Heaters run 0.15A total per tube.
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 13th March 2007, 09:26 AM   #3
viagraless is offline viagraless  Viet Nam
diyAudio Member
viagraless's Avatar
Join Date: Mar 2007

Because you did not post the schema, so not easy to tell you exactly current needed. However i could guest basing on quantity of tubes which may not more than 45mA for both chanel, therefore if i were you, i will choose the transformer:


Some time could supply the "hot" things
  Reply With Quote
Old 13th March 2007, 10:22 AM   #4
ulibub is offline ulibub  France
diyAudio Member
Join Date: Nov 2006
Location: Lorraine

I would replace the bipolar transistor by a mosfet. I recommend using the type IRFI 840 G. Base resistor changes into a gate resistor at the same position, but you can take a value largely above 100 kOhm - I went as high as to 4.7 Mohms. Put a condenser parallel to the zener diodes. Depending on the time constant of the gate resistor - condenser array, you do not only get a perfect ripple rejection, but also a slow switch-on characteristic of the output voltage. Put a 470 ohms resistor directly in front of the gate pin to prevent any self-oscillations - like a grid stopper on a tube grid. Use a 47 uF capacitor between output and ground.

This mosfet stands 500 V and 4.6 A, 40 W max. dissipation. It is in a fully isolated package which stands up to 2.5 kV, so you even don't need a silicone or mica tab for mounting on heatsinks (or chassis). I use this layout also in the power supplies of my 6C33CB Circlotron amp with peak currents up to 500 mA. Works perfectly.


  Reply With Quote
Old 13th March 2007, 11:17 AM   #5
viagraless is offline viagraless  Viet Nam
diyAudio Member
viagraless's Avatar
Join Date: Mar 2007
Sorry for my typping error, i mean 280V/70mA are OKie.

By the way, in my opinion, the good choke more than 10Henry with 01 Oil Cap and 01 Polypropylene are very better than any solid regulator circuit, the sound will be more naturally.

Some time could supply the "hot" things
  Reply With Quote


Regulator for tube preHide 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Perfect tube regulator CarlyBoy Tubes / Valves 30 28th July 2016 04:14 PM
PSU Tube regulator piero7 Power Supplies 2 16th June 2009 08:48 AM
For Tube:350-750v Regulator uhcmos Swap Meet 3 1st November 2008 10:36 AM
Tube God TH-1 Amp Regulator PCB ???? Zero Cool Tubes / Valves 7 30th March 2006 10:47 PM
Tube Regulator Jay Tubes / Valves 51 5th April 2003 04:07 PM

New To Site? Need Help?

All times are GMT. The time now is 09:07 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio