Best low noise regulator? - Page 37 - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 22nd April 2009, 10:04 AM   #361
Marinos is offline Marinos  Greece
diyAudio Member
 
Marinos's Avatar
 
Join Date: Mar 2003
Location: Athens
Hi salas,

I'm sure that your SLS (Salas-Lamb-Shunt) impressed relatives and friends...
I'm finishing the layout for the quadraple shunts and because experimenting with zeners on the live circuit will be PIA, I'm wondering if there is a simple test circuit that could put together for that purpose. Any suggestions ?
__________________
Marinos
  Reply With Quote
Old 22nd April 2009, 11:44 AM   #362
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Hello to you too.

You can simply use a 20V-24V voltage source (your psu plus side will do), and just with a protection resistor you can check the exact Zener voltage of each one you have.

P.S. Hey, you have promised pics when ready. Don't forget.
Attached Images
File Type: gif zmatch.gif (1.6 KB, 1114 views)
  Reply With Quote
Old 8th May 2009, 10:52 PM   #363
mikelm is offline mikelm  England
diyAudio Member
 
Join Date: May 2003
Location: England
Send a message via Yahoo to mikelm
Hi Salas,

I have read this thread and some others where you explain your design and how it sounds and I have one question. . . .

When you explain the clear & clean sound from using your regulators I am interested to know what other measures you had taken up stream to clean up the incoming supply ?

For instance . . .

Do you use mains filters ?

Do you use Schottky diodes or similar ?

Do you use a snubber on the secondary to prevent ringing when the diodes switch off ?

Do you use any chokes to filter out HF & RF noise ?

Do you use fancy filter caps for maximum filtration ?

Have you ever tried using two of your regulators in series and if you did, did you hear an improvement ?

As you may have guessed I am trying to work out if your regulator is so effective that you do not need to take any other measures to get best possible results.

In the past I have found any measures I have taken to reduce noise have always brought audible improvements but I have not yet tried any "super regulators" but have had some very good results with C R C RL C filters and all the stuff I mentioned above.

many thanks for all of your contributions

mike mears
  Reply With Quote
Old 8th May 2009, 11:38 PM   #364
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally posted by mikelm
Have you ever tried using two of your regulators in series and if you did, did you hear an improvement ?

Try 2 LM317's in series -- one as a current source, one as a voltage regulator. C'est magnifique.
  Reply With Quote
Old 8th May 2009, 11:45 PM   #365
mikelm is offline mikelm  England
diyAudio Member
 
Join Date: May 2003
Location: England
Send a message via Yahoo to mikelm
yes - interesting idea

If this is indeed true, it would confirm my belief that much of the noise of 3 pin regulators is passed though from noise upstream, rather than generated within the chips.

wonder if this idea would considered an ultimate solution . . . at this stage I want to focus on the very best I can achieve.

thanks

mike
  Reply With Quote
Old 8th May 2009, 11:46 PM   #366
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Nothing fancy really. I use mainly UF4007, rarely better, plus a 10-33R power resistor before the main filter cap if I have some volts to spare. A guy in the Riaa thread had mains input filter and CLC after rectification but his chokes were not adequate for the current, losing almost all of their inductance, so he got correct Hammond ones and he only reported a very slight subjective difference for the better. All that in sensitive MC phono stages with rudimentary PSRR.
No mains filters or better than MUR diodes I have seen implemented and listened to. I would use a CLC just to avoid possible RF and rectification junk. My main capacitors choices are good value for money ones like Panasonic FC or BHC slit foil, or Elna For Audio. No snubbers I have tried. No two regs in series also.
The main reason I did not go far with pre filtering is that the sound was right, and I could not feel real differences between main filter capacitors ranging from 2200 to 10000uF of various good makes. So I thought it may be immune enough. I did not perceive harshness. On the other hand, Ricardo over the Riaa thread who is a dedicated tweaker, can hear the main caps and changes for the better. So from what the community shares, I would recommend a CLC and trusted caps in diy circles. Ricardo talks about Nichicon KG and Jensen 4 pole. Also soft recovery diodes that people know and trust in DIY threads. Prefer softer over faster. What I know it changes the tone of the sonics is the output capacitor and there I like Silmic II or some NOS BG NP Red if you can get. Also short and thick twisted wire between the shunt and the audio circuit that receives power, is audible, plus a 0.1uF stacked ceramic or fast PP with short legs on B+ to ground at the audio circuit, can help if there is some RF around.
  Reply With Quote
Old 8th May 2009, 11:51 PM   #367
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally posted by mikelm
. . . at this stage I want to focus on the very best I can achieve.

thanks

mike
You gotta build some tried ones and listen then. Many people are reporting good sonics with mine as well as with some others. Its not complex, put together a P2P one, tweak some parts, give it 48 hours play and then you decide. A cheap easy to make reg like this can be used in a less critical application later, if you chose some other finally. Just change a Zener if the voltage needs will differ.
  Reply With Quote
Old 9th May 2009, 12:08 AM   #368
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally posted by jackinnj



Try 2 LM317's in series -- one as a current source, one as a voltage regulator. C'est magnifique.
Nice and simple. I like the spirit.
  Reply With Quote
Old 9th May 2009, 12:15 AM   #369
mikelm is offline mikelm  England
diyAudio Member
 
Join Date: May 2003
Location: England
Send a message via Yahoo to mikelm
Salas,

Thanks for your feedback and ideas.

I will indeed try some of these ideas over the next few weeks and will report my conclusions here.

I am not expecting a drastic change because all the passive measures I mention above also create a very sweet and clear sound, but I keep an open mind and am interested to see what I notice.

For my contribution I offer this . . .

The one biggest improvement I have ever noticed on power supply design for least cost & effort is a 0.1 - 1.0uF cap in series with a 47 - 100 ohm resistor directly across each secondary coil of the transformer.

This has the effect of reducing the frequency, and damping the ringing that always happens in the transformer coils when the diodes suddenly stop the current flow. If the values are fine tuned for each transformer the ringing can be damped to nothing - but any values between those mentioned above still has an extremely good effect.

Some people just use a cap and no resistor and this does help the sound very much but it only reduces frequency of ringing and does not give any damping so with no resistor the magnitude of ringing can get worse causing some extra heat in the transformer.

I hope some of you enjoy the effect of this easy mod

cheers

mike
  Reply With Quote
Old 9th May 2009, 12:23 AM   #370
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
I use a 1uF cap in that position in my KT88 amp. I guess I have to see for RC before rectification for the shunt in my Riaa, where things are more sensitive and more audible. Thanks for that.

Also there is a dedicated thread that Ikoflexer opened about my shunt, so if you make it, its better to report there, so the info will be concentrated better for the community.

Regards
  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
Reducing regulator noise. Predator864 Power Supplies 3 23rd March 2008 07:26 PM
Regulator Output Noise Voltage Spec TerryC Parts 2 23rd January 2006 04:46 AM
wanted: suggestion for a low noise regulator circuit. Raj1 Digital Source 8 30th January 2004 06:55 PM
Ultra low noise JFET voltage regulator Kochkurov Maxim Digital Source 6 25th January 2004 11:33 AM
ForSale: LT1085CT Low noise Regulator tone Swap Meet 0 10th September 2003 06:22 AM


New To Site? Need Help?

All times are GMT. The time now is 02:07 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