Adequacy of power supply in Mac

[Encore]

Dear Chris and CA Forum members,

 

This is one great forum – what a relief to have found a site where people behave like grownups.

 

For my EmmLabs DAC2, I’m deciding between trying to build a Mac-based system with a Lynx-card, or to go for a Linn Sneaky or Majik DS.

 

Currently, I’m feeding the Emm with a Sq.box Duet with a Bolder Cables power supply. The latter helps a lot, even with my supposedly jitter immune DAC. In fact, I use the Toslink connection – this gives better sound than the COAX. My take on this is that the DAC really is immune to the higher jitter levels of the optical connection but benefits from the electrical isolation from the probably less than stellar electronics of the SB.

 

So my first question is: When the SB benefits so much from an improved power supply, won’t a Mac G5 or Mac Pro with a Lynx Card also improve from a better power supply? Or in other words – is the standard power supply of the Mac towers adequate? Can they be improved?

 

My second question is: Has anybody compared the digital out of the Sneaky vs. the Majik?

 

I previously borrowed a Sneaky, and found its digital out to be WAY better than that of my Sq.box Duet (although that was before I had the Bolder power supply, and it was with my then Accustic Arts DAC I MK4), so I know that the Sneaky is already quite capable. BTW, what kept me from buying the Sneaky back then was the lousy GUI, but that seems to have been fixed.

 

In the last couple of years, my system has seen a steady improvement of its digital source. Frankly, before that I didn’t take digital seriously, partly because of ignorance, but I still find my almost 20-year old (an still un-rebuilt!) Audio Note Japan IO PU the reference to beat, at least in the outer grooves. It’s just a tad more natural and coherent. I hope that changes once I’m able to feed the Emm proper hirez. But with the Emm, I’ve found for the first time a digital source that is at least comparable to my vinyl rig in terms of sound stage scale and impact. In fact, just going from 16 bit to 24 bit helps a lot. The John Butt recording for Linn of Messiah is a good case. The 24 bit version (with my SB I don’t benefit from the 88 kHz) gives a lot better sense of the recording hall, and it is as if a veil has been removed compared to the 16-bit rip from CD. The difference is subtle in “hifi terms”, but important for the musicality of the reproduction.

 

Sorry, I’m digressing. Also, forgive me if my questions have already been discussed in other threads. I did a search but I couldn’t seem to find the exact same issues discussed. I tried posting the question about the Linn DS’s on the Linn forum, but apparently nobody has done the comparison.

 

Best regards,

 

Jens

 

[The Computer Audiophile]

Hi Jens - Thanks for the nice comments about the people around here. CA is a laid back site where people work on enjoying our wonderful hobby. As soon as the typical nonsense starts good people start heading for the exits and when nonsense is not allowed the trolls tend to stay away. Calling us grownups is giving some of us too much credit :~)

 

Anyway,

 

" is the standard power supply of the Mac towers adequate? Can they be improved?"

 

Using the term "adequate" in a discussion with audiophiles is dangerous. Since when do we settle for adequate :~) There is certainly a difference between power supplies in all computers. I believe the Mac Pro PSU measures OK but not as good as the silent PSU in the Zalman TNN300 case. Computer PSUs are an area where vast improvements can be made, but nobody really seems to be addressing this one.

 

I haven't compared the two Linn systems unfortunately. I really like the Linn concept though.

 

[Encore]

Thanks, Chris. I did get the impression that computer power-supply mods wasn't something big. Is it something you have on the horizon to experiment with?

 

Anyway, for now it's basically down whether I want the option of AES/EBU og coax connectivity. As far as I know, there's also a Lynx card which provides optical output and which is used in connection with AES card.

 

Best

Jens

 

[dht4me]

Are you guys kidding me.

The PS in the Mac Pro is probalby the best PS I have ever seen in a computer. I have seen, replaced and measured them. They are so far beyond what is an a PC box that It is not even funny.

It was a while ago but I was extremely impressed by the units.

I have a pic somewhere and Ill try to find it.

 

[The Computer Audiophile]

HI dht4me - Maybe we should all agree on what "The Best" means when it comes to a power supply in a computer. I know many computer users consider Power PC & Cooling power supplies to be the best, but for a music server I'd never use one. The fanless Zalman PSU in the TNN300 is very good.

 

[Happy]

 

Ignore the PSU this is a red herring. The computer is a huge source of digital noise - it radiates from every clock transition on every trace on the pcb.

 

It is important to isolate the computer (any digital feed) from the analog front end electronics. Of course one should make sure that the same power is not feeding the digital source and the analog stuff.

 

I feed my computer through an off the shelf power conditioner. The Analog electronics from a Equitech Balanced Power Isolation transformer i.e. the two sides of the system are not electrically connected (from a power perspective).

 

The output of the computer is fed using a shielded AES cable into the DA (reclocked)/DAC/AMP this is the only electrical connection - this makes me immune from any jitter from the source.

 

The Antelope DA is used as the 'source of the bits' essentially isolating the computer. As long as the computer sends the correct bits at roughly the right time life is good.

 

Several CA members have privately asked me about the power distribution - several have deployed Medical Isolation transformers ($400) to great effect.

 

I really would not mess to much with the computer - this is fixing the wrong problem.

 

/Paul

 

[johniboy]

I already asked this question in a different thread but you have experience with the DA, so I will ask again:

 

In theory: Why would an Antelope DA increase sound quality? It receives an spdif signal and optionally a clock and outputs an spdif signal and a clock (my understanding). If you have a high quality dac with a good clock and receiver, how can re-clocking help? You are introducing another pair of cables, power supplies, electronics, etc into your chain!

 

In practice: How large is the effect of the reclocking in your system?

 

[Happy]

 

Technically if the BADA were to reclock 'well' then this would not be necessary.

 

I use the DA (other reclockers I'm sure would yield similar results) to isolate the source of bits from the BADA. The reclocker is the source of the bits to the DAC. Now any noise causing jitter directly/induced from any source (a computer being the worst) is isolated from the DAC. The BADA folks themselves believe this to be useful.

 

I fully expect DAC vendors in the future to differentiate on Isolation, DC Power, Async input, output preamp with the signal processing and DAC function commoditising in all but the custom DACs.

 

The DA makes an enormous difference to sound - it also stops (renders unncessary) the computer tweaking silliness that goes on.

 

Earflapping and I have been conversing privately - he has talked to the BADA folks - i would refer you to his new post on the Antelope DA thread.

 

If you want to go more into the engineering issues (that are not currently reference in the CA) then please feel free to contact me privately - or here if you feel that the answers would have wider appeal.

 

/Paul

 

[The Computer Audiophile]

Hi Paul - The DA doesn't mention that it reclocks. Do you have evidence of this from another source?

 

[Happy]

 

I'm not sure what you are asking; I haven't looked for evidence from another source. The DA documentation says that the clock is extracted from several sources and reclocked through its output clocks and that any data on the AES/SPDIF input is retransmitted through AES THRU/SPDIF THRU with the new clock. I must admit I haven't put a scope on it - I have tested other clock sources e.g. AES Black and CD Player as a slave clock. For fun; I have also fed the Lynx input clock with the extracted AES clock (from the Lynx Card) - this is a positive feedback loop and as such is unstable - I was interested to see the tracking algorithms in action.

 

/Paul

 

[The Computer Audiophile]

Hey Paul - Thanks for the info, it's exactly what I wanted to know. I'd heard some conflicting info over the last few days and wanted to clear it up.

 

Thanks!

 

[ldolse]

Sort of on this topic, I've been wondering if some of the squeezebox third party power supplies are compatible with the Alix or Intel Atom boards. Seems like the voltage is in the ballpark, but not sure if the connector is the same. I was looking at the Welborne Labs kits:

 

http://welbornelabs.com/squeeze.htm

 

 

 

 

 

[Encore]

Idolse,

 

Well, today I would have gone for a battery solution for the Sq.box instead. Cheaper, and probably better. Couldn't battery power be applicable to the cards you mention?