Power Transformer size influence on preamp sound. - Page 3 - 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 4th January 2013, 02:58 PM   #21
diyAudio Member
 
Triodethom's Avatar
 
Join Date: Dec 2009
Location: Newnan GA
Quote:
Originally Posted by Cobra2 View Post
Yes. There is a difference. I have in several projects used/ended up with very oversized trafo(s). And not only me could hear the difference....
In my last riaa, I used 300VA, 50VA would been good...but did not sound as good.

Arne K
What was the rest of the power supply. A quiet but not isolated power supply would provide a lower impedence current path for the circuit with a big trans with a low secondary impedence , than a higher impedence lower current supply. the transformer is part of a whole supply and should be viewed as a system not just one part. In the above cas the larger transformer would sound better than the smaller one . The cause for this is under isolated circuit . It just a mater of how you want to address the use of the positive feedback loop we also call a power supply.
  Reply With Quote
Old 4th January 2013, 03:06 PM   #22
GoatGuy is offline GoatGuy  United States
diyAudio Member
 
Join Date: Dec 2012
Location: SF Bay Area
Oh, for the love of potato chips ... (more tangible than god) ...

PUHLLLEEZE folks... no matter what you think, you can not "hear" the difference in a *******' pre-amplifier that consumes less than 5 watts, when driven by a 25, 50, 100 or 200 VA primary transformer, competent bridge rectifier, RC/LC multistage pre-filtration, tight low impedance regulation, cascaded RC post-reg filtering ... and current-balanced preamp design (which balances every positive excursion with a complimentary negative excursion in mirror stage, thus evening out current-draw to near-flat levels).

You cannot. Indeed: Take the transformer OUT of the preamp, and have a couple of terminals whereby you can simply swap transformers with an A/B/C/D switch. Have someone beside yourself switch between them, say 50 times. Or a hundred. Quite simply, you will not be able to make any correlation between size-of-transformer and the performance of the pre-amp, no matter what you think. IF for some reason, you do, and using the "blind" testing, you find others do... then the only probable answer is ... you do not have a competent regulator-and-filter circuit on the INSIDE of the chassis. Period.

It makes so much more sense to put extra design effort into the DESIGN of the power supply, its regulation, and all the ancillary systems, rather than just specifying "more iron", in order to have more "weight" and "apparent value" in a box.

GoatGuy
  Reply With Quote
Old 4th January 2013, 03:33 PM   #23
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
I have more than a hundred transformers lying around. It is easy for me to plug and play certain transformer to see how they sound. Oh yes, they sound different. I believe that VA (over) rating is not that critical. Quality of the transformer matters most. Those EI with metal casing around windings sound good. Those with paper between winding layers also sound very good (but too big for its VA rating). Of course, R-core is the best that I have compared. And I can compare between R-core of different brands... but VA rating is different... When talking about BOZ preamp (biased at 40mA), my 1A per channel R-core is not enough. The one with bigger VA rating is better.
  Reply With Quote
Old 4th January 2013, 03:38 PM   #24
JMFahey is offline JMFahey  Argentina
diyAudio Member
 
JMFahey's Avatar
 
Join Date: Mar 2009
Location: Buenos Aires - Argentina
I love diyaudio
  Reply With Quote
Old 4th January 2013, 03:43 PM   #25
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
Quote:
Originally Posted by Jay View Post
I have more than a hundred transformers lying around. It is easy for me to plug and play certain transformer to see how they sound. Oh yes, they sound different. I believe that VA (over) rating is not that critical. Quality of the transformer matters most. Those EI with metal casing around windings sound good. Those with paper between winding layers also sound very good (but too big for its VA rating). Of course, R-core is the best that I have compared. And I can compare between R-core of different brands... but VA rating is different... When talking about BOZ preamp (biased at 40mA), my 1A per channel R-core is not enough. The one with bigger VA rating is better.
Could have written the above myself. Minus the BOZ part, as i don't have one.

Yet, some people cannot hear and others choose not to listen. Of course we all know there cannot be an audible difference between competently designed amplifiers, dacs and preamps. Why should power supplies be any different. Trouble is no one can tell you how exactly to design "competently".

OP could have simply tried a few transformers, but creating polemics is so much more fun
  Reply With Quote
Old 4th January 2013, 03:44 PM   #26
GoatGuy is offline GoatGuy  United States
diyAudio Member
 
Join Date: Dec 2012
Location: SF Bay Area
Jay, please. Words like "I have hundreds" and can plug them in... is just wonderful, but my good fellow - it sidelines the real point, doesn't it? IF there is some "sonic signature" of a power transformer, then it implies that the regulator is crap... (or, that the transformer output is far too close to the regulator output).

Sorry... I've done dozens of experiments, really, with a combination of transformers and different regulator designs ... and a simple computer-controlled set of relays to switch various combinations on/off in a randomized pattern that even I cannot predict. The results speak for themselves: ONLY those combinations that are underpowered for either the regulator, or for the driven circuit ... or that provide supply voltages in variance with the design spec (either above, or below) have an effect on the pre-amp and/or amplifier sonic signature. And not even once in all the testing, did the effect of over-sized transformers (with correct secondary output) have any statistical relevance at all.

Its one thing to have a belief that it'll make a difference, its another thing to understand WHAT makes the differences. Regulator design #1. Insufficiency of supply #2. Undersized transformers #3. But #1 is in the lead by orders of magnitude.

GoatGuy
  Reply With Quote
Old 4th January 2013, 04:05 PM   #27
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
Quote:
Originally Posted by GoatGuy View Post
IF there is some "sonic signature" of a power transformer, then it implies that the regulator is crap... (or, that the transformer output is far too close to the regulator output).


As a simple and easily understandable example i would use my tube pre. It is choke input after tube rectification and followed by a version of Salas high voltage shunt reg. Noise well below 1mV and about 70v dropping across the cascoded CCS. And would this render the transformer somehow invisible? Or the power cord? I wish it would.

On a side note: is anyone aware of a commercial box like a dac or a phono stage powered from a wall wart which would have astounding, earth shaking bass? In my limited experience with such devices they always appear bright and gutless but maybe there is an exception.
  Reply With Quote
Old 4th January 2013, 04:19 PM   #28
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
I'm using an Echo Audiofire 2 and have no problem making the walls flex.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 4th January 2013, 04:24 PM   #29
Cobra2 is offline Cobra2  Norway
DIY !
diyAudio Member
 
Cobra2's Avatar
 
Join Date: Apr 2002
Location: Stavanger, Norway
Send a message via Skype™ to Cobra2
Quote:
Originally Posted by Erlend Sæterdal View Post
Yes yes yes It is what I believe . How was your supply Cobra ?
External...
(C-R-C-R-C- filtered)
__________________
Don't believe everything you think...

Last edited by Cobra2; 4th January 2013 at 04:26 PM.
  Reply With Quote
Old 4th January 2013, 04:26 PM   #30
GoatGuy is offline GoatGuy  United States
diyAudio Member
 
Join Date: Dec 2012
Location: SF Bay Area
LOL / Analog_sa

The ability of humans to delude themselves is both amazing and amusing. I ran an expensive, very carefully controlled wine tasting with 24 highly opinionated (and certified) sommeliers ... where I took the time to decant all the wines, clean out the bottles with odorless distilled water, rinsed that out with a bit of the target replacement wine, suffused each bottle with argon gas, then carefully trickled back in a near-full bottle of replacement wine ... all of which were exactly the same. Indeed: it was the blend of the 24 Bordeaux that had come out of all the bottles.

For 3 hours we tasted, and put together panels of comparisons. For 3 hours, not one person commented how "close" they all tasted, or whether there were any differences at all. At the end, as was my predicted inevitable conclusion, enough information had leaked out of the brown-paper wrapped bottles about their origin, that those reputed to be at the top of the line, won. The ones not so easily recognized didn't. And one or two reputed to be skunks, lost handily.

My point wasn't to reveal the duplicity and mendacity of the sommeliers, and their brand-consciousness, but to demonstrate that we are remarkably good at fabricating data-that-isn't-there. As in power cords that are cryo-treated versus single-crystal and so on. To me, scientist, your opinion is in the amusing category... further demonstrating that we are subject to our own prejudices and prognostications.

It isn't hard to build the [1-of-5] computer-controlled choice box, Analog_SA. Try it some time! Its a great project.

GoatGuy
  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
Valve power supply - How to size transformer? SanderW Power Supplies 25 4th January 2013 04:12 PM
Influence of power amplifier output coil to frequency response PMA Solid State 22 6th May 2011 07:17 AM
Which parameter of the filtering caps do influence the sound of a gainclone??? Leolabs Chip Amps 34 15th September 2007 04:04 PM
Influence of RIAA impedance value on sound Uchi Deshi Analogue Source 8 19th April 2006 02:08 PM


New To Site? Need Help?

All times are GMT. The time now is 12:39 PM.


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