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

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Voltage regulator prefixes and capacitor source questions
Voltage regulator prefixes and capacitor source questions
Voltage regulator prefixes and capacitor source questions 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 23rd March 2016, 02:58 PM   #1
bblument is offline bblument  United States
diyAudio Member
 
Join Date: Dec 2012
Location: Near Syracuse, NY
Voltage regulator prefixes and capacitor source questions
Default Voltage regulator prefixes and capacitor source questions

I've been a kit builder for decades (Dynakit, Hafler, Heath, and Audio Concepts) and hae managed to successfully design and build a few sets of speakers from scratch using Vance Dickason's LSCB. However, I don't have much actual electrical theory knowledge. I can read basic schematics.

I've had an Audio Alchemy Dac-in-the-Box lying around for years with a burnt out power supply. I couldn't find a replacement PS for it except for Alchemy's big buck "upgrades," and those were out of the question. Yesterday, with the help of a great guy at a local electronic supply place, we designed a regulated power supply for it, and I successfully built it from scratch. Felt great to resurrect a dead piece of gear; the DITB sounds better than ever.

Which brings me to my questions. I came across the attached article by Kalman Rubinson suggesting some cheap easy improvements for the DITB and power supply that I was thinking of trying, but he's suggesting using "AN78XX" and "AN79XX" regulators, but all I can find on Digikey or Mouser are LM prefixes. I used an LM7912 and an MC7812 to regulate my PS. What do the prefixes mean? Are they important?

Second, the article mentions using specific Nichicon Muse and Panasonic PP or V series caps. I can't seem to find those on Mouser or Digikey either, but I confess I'm overwhelmed with all of the data. Their word search boxes invariably return "No results," and if I drill down using their regular menus, I get so many options that I'm not sure which one is the specific cap mentioned.

I KNOW these are probably pretty stupid questions, but I could use some help. Thanks in advance to anyone who can spare a few minutes for me..

Best wishes,

Barry
  Reply With Quote
Old 23rd March 2016, 03:32 PM   #2
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
diyAudio Member
 
JonSnell Electronic's Avatar
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
The prefix is related to the manufacturer, MC = Motorola, LM = TI etc. The suffix relates to accuracy and type of case, SMD etc.
__________________
Support for Fender, Marshall and all Valve Equipment; Audio Innovations, Audiorama FU29, Quad and Leak. www.jonsnell.co.uk
  Reply With Quote
Old 23rd March 2016, 03:38 PM   #3
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Voltage regulator prefixes and capacitor source questions
Go to DK's site and search by manufacturer. Nicchicon audio capacitor comes up right away.

Audio Capacitors - Nichicon | DigiKey

ELNA "silk" are very good audio electrolytics for the money.
  Reply With Quote
Old 23rd March 2016, 04:34 PM   #4
bblument is offline bblument  United States
diyAudio Member
 
Join Date: Dec 2012
Location: Near Syracuse, NY
Voltage regulator prefixes and capacitor source questions
Jack and Jon,

Thank you both for your replies. With your help, I've managed to find some AN (Panasonic!) regulators on the digikey site, but they don't stock them. PLUS, all of them are listed as "AN7XLXX" rather than "AN7XXX," which I gather means they're only acceptable for up to 100ma output, correct? Does it matter when used as Kalman suggested in the DITB mod? BTW.. I realize I forgot to attach it to my first post; I've attached it this time.

I did find the page w/ all of the Nichicon caps; thanks for the link. I WAS able to locate the right ones on that page, I believe. Thanks, also, for the suggestion of the Elna Silmics. If I'm looking at the correct equivalent Elna caps, they cost a LOT more than the Nichicon FG or KZ series caps. Here's the link to the page I'm looking at..

Aluminum Capacitors | Capacitors | DigiKey

Elna is $2.52 for a 330uf 50v while a Nichicon KZ is $0.73 or FG is $0.53? I thought the Elnas were a high quality yet budget alternative to the "Muse" caps. Here's the Nichicon page, just in case I'm looking at the wrong thing.

Aluminum Capacitors | Capacitors | DigiKey

Not that it really matters; I only need a few of them and the money isn't significant. I just want to make sure I get the right stuff and don't ruin my DAC.

Thanks again, very much, for your help.

Barry
Attached Files
File Type: pdf DITBMOD(1).pdf (129.1 KB, 19 views)

Last edited by bblument; 23rd March 2016 at 04:42 PM.
  Reply With Quote
Old 23rd March 2016, 04:48 PM   #5
indianajo is online now indianajo  United States
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
The 78xx and 79xx regulators were invented by Fairchild. Why not use those? There prefix BTW was microA, greek mu being a character not even available to computers except through some weird alt sequence. Besides LM which is now TI, the other first line IC manufacturer is ST which use to be RCA but is now French something.
Electrolytic capacitors, I use the long service life grade, not pricey "audio grade" which have sucker written all over the specs. I haven't bought any bad sounding ones using that as the figure of merit. Panasonic, Nichicon, Rubicon all make great e-caps, also some short life ones for people looking to save $.20 If those are out of stock I've used United Chemicon CDE and mulitcomp (farnell house brand) but don't expect them to last as long. the last three have a looser specified end of life test (read datasheet) than the first three.
In non-electrolytic caps, polyprophylene is probably worth a 40% premium versus mylar or polyester film . In restoring old circuits, paper caps really do sound different than polyester. Those might be worth an "audio" premium". Mylar made my PAS2 excessively trebly.
In resistors, metal film really does hiss less than carbon comp especially 100kohm up. I redone my dynakits with them. But radio circuits might require low inductance carbon comp, they are still available.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 23rd March 2016 at 05:05 PM.
  Reply With Quote
Old 23rd March 2016, 07:17 PM   #6
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Voltage regulator prefixes and capacitor source questions
Hey Hoosier -- I think you're conservative in putting polypropylene ahead of polyester (mylar).

A higher voltage rating is preferable to lower voltage, but you don't have to go overboard.

Not to beat the horse too much, but the Linear Low Dropout LT1963A/LT3015 regs sounded much better (to the ears of the NJ Audio Society panel) than the LM317/337. They are much more expensive, however.
  Reply With Quote
Old 23rd March 2016, 09:56 PM   #7
Enzo is offline Enzo  United States
diyAudio Member
 
Join Date: Sep 2004
Location: Lansing, Michigan
LM317 is an adjustable Vreg, the OP is looking at 7812 and 7912.

You can pick an LM7812 or MC7812 or most any other brand, and they will all be more or less the same. Don't go nuts looking for the exact brand.

7812 is rated to at least 1 amp. 78M12 is rated to at least 500ma. The little LM78L12 is rated to 100ma. You chose the one with the current rating you need.
  Reply With Quote
Old 26th March 2016, 08:11 AM   #8
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
Quote:
Originally Posted by jackinnj View Post
.......
Not to beat the horse too much, but the Linear Low Dropout LT1963A/LT3015 regs sounded much better (to the ears of the NJ Audio Society panel) than the LM317/337. They are much more expensive, however.
May I ask a couple of questions about your regulator test in Linear Audio Vol. 4 ?

1) You described the test being carried out using HP/Tektronics power supply as power source at 25V. However, LT1963A data sheet mentions maximum input voltage at 20V. So did you actually lower the input voltage for the LT1963A, or did you use some form of pre-reg upstream ?

2) In your listening test, in which the LT1963A/3015 excelled over the LM317/337, were you also using the HP/Tektronics PS as voltage source, or were you using transformers and rectifiers (as in a normal audio equipment) instead ?

3) Could you share data about the noise spectrum and output impedance of the power source upstream of the regulators in the listening test ?

Many thanks in advance.


Best regards,
Patrick
__________________
xen-audio.com
  Reply With Quote
Old 26th March 2016, 09:19 AM   #9
Jay is offline Jay  Indonesia
Banned
 
Join Date: Feb 2003
Location: Jakarta
Quote:
Originally Posted by bblument View Post
Second, the article mentions using specific Nichicon Muse and Panasonic PP or V series caps.
If there is "input cap", replacing with a bipolar (BP) one is good, unless you have used non-electrolytic for that.

So the upgrade is about using a better opamp? What is the cost of the upgrade including the opamp? Yes, not many opamps can work with +/-5V but LM4565 can but is "expensive", depends on your upgrade budget.

BTW, if supply voltage is determined by 7805/7905, upgrade can usually be done by only replacing the chip with 7806/7906 or the 8V version, depends on the circuit.

Quote:
Originally Posted by indianajo View Post
The 78xx and 79xx regulators were invented by Fairchild. Why not use those?
AN is considered by many as better sounding. I myself don't use any of them, except for the small current one (TO-92).

Quote:
Originally Posted by jackinnj View Post
but the Linear Low Dropout LT1963A/LT3015 regs sounded much better (to the ears of the NJ Audio Society panel) than the LM317/337.
I don't doubt that. I'm just curious how they determine "sounding better". LM317/337 is very noisy, hence it is worse if noise is the criteria...

I have always considered LM317/337 a "not complete" design. They are very noisy, but do something "right" to the sound (I guess Zout?)...

78/79XX is not acceptable to me (to power the analog section) but LM317/337 is okay when used 2 or 3 in series. For analog, I have used 2 in series where the first one is it's discrete version.

Last edited by Jay; 26th March 2016 at 09:23 AM.
  Reply With Quote
Old 26th March 2016, 03:23 PM   #10
davidsrsb is offline davidsrsb  Malaysia
diyAudio Member
 
Join Date: Dec 2005
Location: Kuala Lumpur
The low drop regulators all have to be tuned for stability according to load current by selecting suitable output capacitors. They are not "universal" as the 78xx series are, so "sounding better" may well be marginal stability in action
  Reply With Quote

Reply


Voltage regulator prefixes and capacitor source questionsHide 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
Subwoofer AMP Questions-Single source vs speaker source SweetDoug Subwoofers 0 25th November 2014 11:29 PM
on chip negative voltage regulator with positive supply voltage gvsrkprasad Power Supplies 3 20th February 2013 03:19 PM
Shunt Regulator variations (Parallel voltage regulator variations) for SS Pre-Amp tiefbassuebertr Solid State 2 15th December 2012 11:09 AM
Using constant current source as voltage regulator Phisci Power Supplies 10 4th August 2012 07:46 AM
Component Prefixes liz Parts 4 2nd October 2003 06:29 PM


New To Site? Need Help?

All times are GMT. The time now is 01:27 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki