Tube PS question: Acceptable ripple - 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 13th November 2010, 09:22 AM   #1
diyAudio Member
 
Join Date: Aug 2010
Location: Chicago
Default Tube PS question: Acceptable ripple

I've been working on a 6D22S-rectified PS (for a 6C33C PP) in PSUDII for a couple of weeks, and have managed to get the voltage ripple down to ~1.6mV, but not lower (at least not without voltage and current warnings). Is this generally considered "acceptable", or should I continue working on it? I've been beating my head against a wall trying to get it flat - then realized that it would be a good idea to ask here before putting any more time into this...

This is my first attempt at designing a PS from scratch; I'd like to get it right.

Thanks, folks.
__________________
Joe
  Reply With Quote
Old 13th November 2010, 09:55 AM   #2
diyAudio Member
 
Join Date: Aug 2009
Location: Sacramento
Hello Guiseppe,
Tell us more!
What do you have going; capacitor, resistor, choke? Go too far past a Pi filter and start adding much resistance you get better ripple rejection at the expense of greater total impedance. Your power supply starts getting soft and acts like an unknown plate resistor.
DT
All just for Fun!
  Reply With Quote
Old 13th November 2010, 11:36 AM   #3
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Giuseppe, to determine what is the necessary ripply, you start with two variables: what is the required signal-to-noise at the output and what is the power supply noise rejection of the signal circuit. Then you can work backward to determine power supply noise.
__________________
And while they may not be as strong as apes, don't lock eyes with 'em, don't do it. Puts 'em on edge. They might go into berzerker mode; come at you like a whirling dervish, all fists and elbows.
  Reply With Quote
Old 13th November 2010, 12:25 PM   #4
diyAudio Member
 
Join Date: Sep 2010
Location: Melbourne
Ripple is better expressed relative to supply voltage then it can be related to the supply rejection of the amplifier that it is powering. Assuming a 400V supply the ripple is -108 db With an amplifier of 60db or better supply rejection I would be quite happy with a full load ripple of -40db as this would give 100db or better signal to ripple at full power. Your application may differ so it pays to define your goals everything is a compromise.
  Reply With Quote
Old 14th November 2010, 12:00 AM   #5
diyAudio Member
 
Join Date: Aug 2010
Location: Chicago
DT:
Schem attached. Couple of notes: R1 is a NTC thermistor (R at 25șC=200Ω; R at Current=5.001Ω; max current 500mA); I'd prefer to have it on the 0V leg (per advice received here), but PSUD won't allow it. Choke is a Hammond 193N (3H, 500mA). The power trafo is 350V/500mA. The PS will be supplying one 6C33C at 200-225V, 400mA max.

Not sure if this is gonna work or not. I'm concerned about the max current at the choke. Any thoughts?

Sy: Still working on the amplifier design. At this point, all I know is 6N1P-EV input/6N6P drivers/6C33C-B outputs in PP.
I started playing with PSUD, and couldn't let it go...

Thanks for the responses. Everything I've read says work backwards from the OPT - I need to listen, and get the amp designed.

Guess I'm putting the cart before the horse... but PSUD is fun to work with.
Attached Images
File Type: jpg 6D22S PS 3Hchoke.jpg (49.3 KB, 182 views)
__________________
Joe
  Reply With Quote
Old 14th November 2010, 12:21 AM   #6
diyAudio Member
 
Join Date: Sep 2009
Try switching C1 to around 40uF and let us know the results.
  Reply With Quote
Old 14th November 2010, 12:40 AM   #7
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Quote:
Originally Posted by Guiseppe View Post
At this point, all I know is 6N1P-EV input/6N6P drivers/6C33C-B outputs in PP.
I started playing with PSUD, and couldn't let it go...

Thanks for the responses. Everything I've read says work backwards from the OPT - I need to listen, and get the amp designed.
Well, this will be much easier than you think. It's a power amp, so voltage levels are pretty high. It's push-pull so there's ripple cancellation there, too. I think it will be difficult to screw this up.

The main things to be concerned about are keeping the ripple current reasonably low (don't use a monster cap at the input of the filter) and the way you actually do the grounding (don't induce ripple currents into the grounds). Past that, it's pretty simple. Don't get carried away!
__________________
And while they may not be as strong as apes, don't lock eyes with 'em, don't do it. Puts 'em on edge. They might go into berzerker mode; come at you like a whirling dervish, all fists and elbows.
  Reply With Quote
Old 14th November 2010, 12:42 AM   #8
diyAudio Member
 
Join Date: Aug 2010
Location: Chicago
Quote:
Originally Posted by quikie22 View Post
Try switching C1 to around 40uF and let us know the results.
IFRM hits 1.8A. Max for that bridge is 1.0A, so this is not good.

Ripple IS reduced to ~0.3mV, though...
__________________
Joe

Last edited by Guiseppe; 14th November 2010 at 12:46 AM.
  Reply With Quote
Old 14th November 2010, 12:53 AM   #9
diyAudio Member
 
Join Date: Aug 2010
Location: Chicago
Sy:

Thank you, sir.

Quote:
...don't use a monster cap at the input of the filter...
I take it C1 at 0.47uF does NOT qualify as a Monster Cap?

Quick question: Can I use the thermistor in the R1 position shown on my schem, or should I move it to the 0V leg? Does it really make any difference? I haven't tried to run the circuit without R1 - need to see what happens with that gone...
__________________
Joe
  Reply With Quote
Old 14th November 2010, 02:29 AM   #10
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Why not put the thermistor in the primary?
__________________
And while they may not be as strong as apes, don't lock eyes with 'em, don't do it. Puts 'em on edge. They might go into berzerker mode; come at you like a whirling dervish, all fists and elbows.
  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
Acceptable Ripple Current for Aleph 2 hifileslie Pass Labs 3 9th August 2009 11:35 PM
Question regarding PS ripple in guitar amps - TubeLab? LowRedMoon Tubes / Valves 8 30th April 2008 02:03 PM
Charlize PS ripple Greyskale Class D 2 4th December 2007 11:48 PM
acceptable amount of ripple for AlephX PS nobody special Pass Labs 4 27th February 2003 09:56 PM
Acceptable Aleph Ripple? dshortt9 Pass Labs 1 15th July 2002 10:56 PM


New To Site? Need Help?

All times are GMT. The time now is 07:27 AM.


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