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what is mono dual power supply in a preamp

110.22.30.200
Posted on July 6, 2016 at 00:27:17
Heifetz
Audiophile

Posts: 245
Location: Melbourne, Australia
Joined: April 3, 2013
 Greetings,
I'd really appreciate if someone could tell me what 'mono dual power supply' means in reference to a preamplifier.
​Is there an alternative to this and which one better ?
Thx so much for any comments.
Bob

"You have to leave something to your imagination"

 

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That refers to a stereo preamp, posted on July 6, 2016 at 07:03:20
E-Stat
Audiophile

Posts: 37559
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 whose power supply consists of separate transformers and circuits for each channel. One might argue whether or not such might also need to reside in separate boxes.

Click here for an example - Audio Research REF10. Click the fourth thumbnail under the main pic for a view. Likewise, the audio circuitry (third thumbnail) is dual mono as well. In this case, there are actually a total of four supplies (and transformers) - two for the digital control circuitry and two for the audio signal.

Is there an alternative to this and which one better ?

The alternative is to employ a shared power supply which is far and away the more common approach.

Which is better? Arguably, one gets better isolation with separate supplies as you find using mono amplifiers which necessarily have separate supplies as well.

 

RE: what is mono dual power supply in a preamp, posted on July 6, 2016 at 08:46:32
Palustris
Audiophile

Posts: 2408
Location: Cape Cod
Joined: September 12, 2008
 "I'd really appreciate if someone could tell me what 'mono dual power supply' means in reference to a preamplifier."

It means the marketing department was working overtime to come up with an unnecessary "feature" for the brochure.

 

RE: what is mono dual power supply in a preamp, posted on July 6, 2016 at 09:48:40
Awe-d-o-file
Dealer

Posts: 21037
Location: 50 miles west of DC
Joined: January 10, 2004
 What? You may disagree with the performance outcome of dual mono design and separate power supplies but you have done a disservice to this board with your post. Estats post is accurate yours is bs.

ET


ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

RE: what is mono dual power supply in a preamp, posted on July 6, 2016 at 13:51:02
Heifetz
Audiophile

Posts: 245
Location: Melbourne, Australia
Joined: April 3, 2013
 Thank you E-Stat and Awe-d-o-file for your comments.
Now I get it.
I am looking at a particular preamp- TS Lim Diva JP200 .
I'll post a new topic to enquire if anyone has knowledge of this particular preamp.
Thx so much, Bob
"You have to leave something to your imagination"

 

FWIW, posted on July 6, 2016 at 15:29:20
E-Stat
Audiophile

Posts: 37559
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 The original Jadis JP200 was a four chassis affair.

Two mono preamps with separate power supplies.

 

RE: what is mono dual power supply in a preamp, posted on July 6, 2016 at 15:31:20
Palustris
Audiophile

Posts: 2408
Location: Cape Cod
Joined: September 12, 2008
 Nonsense: just because you don't understand the issue doesn't mean that I have done a disservice.

 

RE: what is mono dual power supply in a preamp, posted on July 6, 2016 at 16:39:33
Tweaker456
 Complete BS. All things being equal I can't imagine a situation where separate power supplies would not sound better. Don't listen to Palustris BS. Yeah, everyone goes to the trouble and expense to put in separate supplies at great expense just to rip off their customers. I'm no big fan of many manufacturers but when they do something right it should be recognized. Tweaker

 

RE: what is mono dual power supply in a preamp, posted on July 7, 2016 at 13:06:57
Awe-d-o-file
Dealer

Posts: 21037
Location: 50 miles west of DC
Joined: January 10, 2004
 I dont understand? Youre a fool.

ET
ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

RE: what is mono dual power supply in a preamp, posted on July 7, 2016 at 13:15:18
Awe-d-o-file
Dealer

Posts: 21037
Location: 50 miles west of DC
Joined: January 10, 2004
 Thanks, its a pretty simple concept. Some may do it well others may not but to what that fool said is ridiculous.

ET
ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

RE: what is mono dual power supply in a preamp, posted on July 7, 2016 at 15:33:57
Palustris
Audiophile

Posts: 2408
Location: Cape Cod
Joined: September 12, 2008
 Thanks for your post; you clearly don't mind embarrassing yourself in public despite your overwhelming ignorance.

I stand by my statement that a dual mono supply in a preamp will be detrimental to the sound and, further, that the only reason for a marketing department to make such a statement is out of desperation to come up with something different. Having worked in both marketing and engineering I fully understand the pressure and the need to employ some means to differentiate a product from the competition. That's just the nature of the business.

That said, it just so happens that I have spent some time in the last few months actually testing different power supply configurations both dual mono and stereo for a preamplifier, DAC, or as the frontend for an amplifier. I built three power supplies; two mono and one stereo and I employed them in preamps and as the voltage stages of amplifiers. The supplies were architecturally the same: CLC with low reactance and low resistance parts; power transformers with abundant current capabilities; Wima DC Link capacitors exclusively; and a low reactance low resistance choke in the pi filter. The three power supplies have very low internal impedance and the same stable voltage output with ample current capabilities.

I employed my three power supplies using the same vacuum tube preamp stage and the same voltage amplifier in a power amp either as dual mono or as a stereo. While both mono and stereo supplies sounded truly excellent, extended listening with certain well recorded music revealed a slight difference between them. The stereo supply had an edge in coherence and a noticeably more stable and precise stereo image. This surprised me as I truly expected both the stereo and mono supplies to sound the same. As I have already stated, the three power supplies were identical with respect to architecture and components, the only difference was each will have had slightly different internal impedance and output voltage a result of standard deviation of the parts employed in the supplies.

If we abandon our preconceived notions and audiophool dogma and consider what might be happening, it becomes clear that slight changes in power supply voltage can manifest themselves in a tube amplification stage as slight differences in transconductance, plate resistance, and gain. This phenomenon is clearly shown in the tube manual. So, I believe what is happening is that despite the attempt to make the two mono supplies identical, it is impossible to make them entirely so since they are composed of two sets of transformers, capacitors, inductors and resistances. These slight changes manifest themselves, as I stated above as a slight blurring of the placement of instruments in the soundscape. They move slightly, blur, and are not as pinpoint accurate. The stereo supply does not suffer from the same defect because both stereo channels are fed off of the same supply: the voltage and internal impedance is identical for both channels.

So, Mr. Awedeophool, I challenge you to do your own testing; build your own power supplies; listen for changes in sound. Report back to us your findings. If you are fair-minded you will retract your characterization of me as a "fool" and apologize to the board for your ignorance.




 

RE: what is mono dual power supply in a preamp, posted on July 8, 2016 at 05:58:27
Awe-d-o-file
Dealer

Posts: 21037
Location: 50 miles west of DC
Joined: January 10, 2004
 You can post your opinion all you want. You should have done that first instead of your stupid statement in your first reply. So dual mono is only about the ps to you? Whatever..... I will be apologizing right after you do.

ET
ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

RE: what is mono dual power supply in a preamp, posted on July 20, 2016 at 05:26:49
JURB
Audiophile

Posts: 2056
Location: North Ohio
Joined: May 29, 2016
 Bottom line, it doesn't matter if you know how to design. How to deal with grounds currents and all that.

Totally separate supplies are alot better in power amps. There it can make a real difference that is measurable. Preamps don't pull any real power, so there is no reason for it.

Well, solid state preamps. If you are talking tubes maybe there is some advantage.

 

RE: what is mono dual power supply in a preamp, posted on July 21, 2016 at 07:35:43
Tweaker456
 Well it is true, better sounding is not necessary.

 

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