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Positive Feedback ISSUE 68
july/august 2013


Our readers respond…we respond right back!

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Andy Schaub, in his nice review of Audirvana Plus (May-June), which agrees with many of my experiences, writes in his summing up:

"it does sound like a very good, very high end CD player if not a bit better than that."

Perhaps it depends on how high end you can afford to go with your CD player, but for me, working with good but not state of the art CD, it's not just "a bit better". To remove the variable of the CD player DAC, my comparisons have been made with two somewhat elderly, but none-the-less respected transports, the Meridian 500 and the Linn Ikemi used as a transport, both into an Audiolab M-DAC. To my ears these have the traditional curtains in front of them, some of which are pulled away when I use my Mac Mini as input, even with just iTunes. Audirvana Plus, especially with some of the beta 1.4.9 variants (see the long CA threads on this) removes even more curtains, and in my experience computer music can be well ahead of these CD transports, not just a bit better, when compared on the same DAC.

However, I do not get this difference if I run the Mini off a normal Apple brick supply; here I think the transports win. Until I looked at power supplies I spent a long time wondering why anybody would use a computer other than for convenience. For me the change began when I put in a very cheap linear supply- that began to even out the comparison, but I was unprepared for the total transformation produced by a small Paul Hynes power supply (SR3); this is what turned things around completely. (Details at

At this stage I realised that designers of high end CD players put a lot of effort into providing the best internal power supplies they can. It's a bit unfair to compare a Mini, on a cheap and very noisy supply, with a player with really good power supplies. If you want to do comparisons with CD players, I suggest you give the Mac/Audirvana a decent supply first.

Bob Lloyd

Cambridge, England

That's a very interesting comment. I'm about to put money that I inherited from my aunt into an Audio Note DAC 4.1x Balanced Signature, built specifically for me, and go "low res" via Audirvana Plus to get a more musical sounding digital music server based on some empirical analysis (i.e., listening) I did with a borrowed Audio Note DAC 5 Signature; but that still fails to address the limitations of the power supply in the Mac mini, which I know are an issue. The problem is, there are a number of solutions out there and I honestly don't know which one to get.

Thanks very much,


The Higher End

About the "expectation of privacy" and those emails to Positive Feedback Online

Ye Olde Editor

We do like hearing from you, our readers. It adds a great deal fun to what we do, encourages our editors and writers, provides information we may have missed, and correction that we may need. This is all to the good.

Your communication with us these days is almost always via the highly rational path of email. And we do read it, responding to the constructive correspondence—which is most of it, really—as quickly as possible. (The destructive stuff is routed directly to the bit bucket. Didn't yo' mama teach you better than that?!) Dave Clark and I are generally pretty rapid in getting back to you if a response is needed from us, or in re-directing inquiries to the appropriate person at PFO if it needs to go to an editor or writer.

By the way: please understand that the writers and editors at PFO are helpful folks, eager to assist their fellow audio/music lovers, or they wouldn't be doing what they're doing. Nevertheless, PFO is not an audio consulting service. Please do not clog the gears with complex requests for assistance with the sourcing of audio gear in your personal setting. Remember too that PFO is not, and has never been, an audio ombudsman. If you are having problems with a particular vendor, company, or dealer, please avail yourself of the normal channels for such resolution; no audio publication has the time or resources to take on such a responsibility for consumers. Enough said.

With an increasing flow of emails to Positive Feedback Online, and upon evidence of some recent confusion on the part of our email correspondents, it's become necessary to re-state the ground rules by which we operate here. So gather round the campfire, friends…

Any time an email, or an exchange of emails, is both constructive and of potential wider interest, we exercise the reserved right to publish it in "Reverberations," the letters section of PFO. This is, after all, a publication, a "journal for the audio arts." We are seeking to further educate and entertain our readership in our common love for fine audio, and contributions in the form of emails/letters from our readers are one way that we accomplish this goal. When you write to any of us… our essayists and reviewers included… we assume that you are aware of our nature as a publication, and that you write to us in the light of that knowledge.

This means that—unless you request confidentiality explicitly in your email or letter—there is no expectation of privacy here at Positive Feedback Online.

To put it another way: Any email or letter sent to this journal will be considered fair game for publication, unless you state in the document itself that the contents are private/confidential.

So… our default is PUBLISH.

The reverse is also true: the editors do reserve the right not to publish an email or letter. We are not obligated to publish your letter or comments simply because they are submitted. And hostile, negative, sarcastic, destructive emails or letters are never published.

So…sometimes we DON'T PUBLISH.

Finally, our subtitle for "Reverberations"—"Our readers respond—we respond right back!" is not a guarantee that we will always respond to an email or letter that is published. Often we do; sometimes we don't… usually when we don't, it's a case of res ipsa loquitur.

So finally… sometimes we PUBLISH WITHOUT RESPONSE.

I think that makes things clear. Having said all of this in the name of clarity, keep those cards and letters coming in!

All the best,

David W. Robinson