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Progress in 2009 on my (& hopefully your) computer audio playback


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Right now I'm listening to great music on the best playback system I've owned, and a lot of credit for that goes to this group. Thanks to all!


Perhaps others will be encouraged to share their 'tweaked' computer-based playback system here - as a symbol of progress made in 2009 - as we close out the decade. :)



For software, I'm listening to JUST released Amarra 1.2, which touts improved sound quality, although I've no problems listening via iTunes. :)


Computer is an early 2005 2.3 Ghz DP Apple Powermac G5 running OSX 10.4.11 (aka Tiger). I'm in the midst of downgrading the video card, due to excessive noise and heat generated from the current card - ATI x800xt.


Hard disk is an OCZ Vertex Turbo 60 Gb SSD (despite that I don't think the Turbo is cost effective - prefer the Agility Series).


The SSD has 3 partitions, for maintaining a clean install of OSX to restore other partitions. This is a clean install of Tiger/Amarra on SSD with no additional software, other than audio apps like Wave Editor, XLD (for ripping), etc.


EDIT: Some of the sound improvement could be due to not only clean install of OS X & Amarra (as has been discussed on Audio Circle), but also the fact that I copied all of my files to a newly initialized/partitioned hard drive, and therefore no defragmentation (as has been anecdotally reported to be an issue on AA).


I've not yet played around with renice scripts, but plan to soon.


Data is stored in Apple's AIFF format on partitioned, non-journaled HFS+ 1Tb Western Digital My Book Studio II - accessed via USB for playback. No Wifi connection is in use by G5 - it connects to internet & local network via Ethernet cable.


Computer is controlled remotely by Apple VNC Server (aka Apple Remote Desktop in Tiger) from a Macbook Air. EDIT: Given that Apple VNC Server is a big user of the computer, using 'renice' scripts would seem to eliminate possible sound degradation from same.


DAC is Metric Halo ULN-2, the 2D model with improved clock, powered by (perhaps unnecessary) custom power supply made by Gordon Rankin. EDIT: I plan to try Vinni's Black Lightning battery power in 2010, altho some have posited that the DC-to-DC converter in the MH DACs would seem to render any potential AC issue moot, other than possible pollution of AC circuit from switching power supply.


Audio is streamed 'asynchronously' to the DAC via Gold-X Firewire 400 cable - via 4pin to 6pin adapter to eliminate the power leg of Firewire. EDIT: I'll try out upgraded Firewire cables in 2010, now that the rest of the system is coming along nicely.


Volume is controlled digitally by Metric Halo's MIO software (running on G5) and/or dithered Amarra volume control.


DAC connects directly to First Watt J2 amplifier via balanced ASI Livelines - via Neutrik TRS->XLR adapters (at DAC connection). Custom TRS -> XLR adapters are in progress.

EDIT: this is a potential area of degradation - using adapters with such a revealing cable. I found this out quickly with an upgrade from one adapter to another.


I own a Dehavilland Ultraverve 6SN7-based tube preamp which is not in use at this time. EDIT: May move to First Watt B1 Buffered Preamp in 2010.


Speakers are Audio Physics Virgos, connected via Analysis Plus something-or-other cables. Cables to be upgraded soon to ASI Livelines. EDIT: Speakers will be upgraded to Devore 9s at some point in the future.


AC circuit is tuned by Alan Maher Reference Power Conditioners, and other various AM products, e.g. PE VI, Reference II, Quantum Reference Power Cables, Infinity CBFs, and soon-to-be Quantum V2.



I also have a Wavelength Proton DAC, connected to a Mac Mini via Kimber v2 Silver USB cable ($75), and (soon-to-be) connected by ASI Livelines (RCA model) directly to the J2, with the Proton's analog volume being controlled digitally by the OS X built-in volume control.



And finally, I & others can stream any music conveniently - via Airtunes or Airfoil - from any computer in the 'hood directly to an Apple TV, which is connected via Wireworld Supernova 5+ glass Toslink cable to the ULN-2's ADAT input.



This time last year, I had only the Metric Halo ULN-2, Gold-X Firewire cable, the Ultraverve, the Apple TV and the Virgos in my system. :)


Here's to hoping that we all improve our digital audio playback in 2010 and beyond.


And thanks again to all who helped make it happen, not the least of all if Chris for hosting us here.










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Clay, I'd be interested to hear how you learned of Maher's products and why you consider his designs more credible than those of other power conditioner companies. The following quotes from his Philosophy web page seem scientifically nonsensical:


"I developed a re-clocking circuit to re-tune the harmonic structure of odd harmonics riding above the 50/60Hz sine wave, now widely known as PE technology. The circuit is designed to fill in the harmonics dips and lower peak harmonics in order to create a ruler-flat frequency response up to a particular cut frequency."


"Krell and Theta fine-tune their power supplies to a standard frequency to define their signature sound, but it also eliminates power supply harmonic cross-talk when all components are plugged into the same electrical hub. When power supplies are tuned to multiple different frequencies, you get multiple different odd harmonics distorting the circuit. The end result is one distortion modulates into another distortion, creating a third multiple, and this goes on forever - making it a never ending battle to clean up the noise. Taking all that into account, we developed specialized circuits with multi-frequency networks to combat modulated distortion and eliminate cross-talk distortion. The basic harmonic networks all communicate at the same frequency to eliminate cross-talk distortion and maintain our signature sound in all applications."


(I hope you aren't offended by my skepticism. I'm open to being enlightened.)


HQPlayer (on 3.8 GHz 8-core i7 iMac 2020) > NAA (on 2012 Mac Mini i7) > RME ADI-2 v2 > Benchmark AHB-2 > Thiel 3.7

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"Clay, I'd be interested to hear how you learned of Maher's products and why you consider his designs more credible than those of other power conditioner companies."


I first heard of Alan Maher from posts here on CA - by Silverlight I believe. Reading the AM thread on Audio Circle, I noticed several other names of respected posters here who apparently also use Alan's products. I say apparently, as I did not correspond with them personally as I did with Geoff (silverlight).


I can't say that I consider his designs more credible than others, although I believe his designs are credible. I didn't do my usual (amount of) research on products before purchase. As you'll perhaps agree, AC products are the single most environment specific audio product, even more so than speakers. Geoff's environment seemed similar to mine - great potential for problems in an apartment building in NYC, inability to install additional/dedicated circuits, etc - so I thought his recommendation was worth considering strongly.


Secondly, I don't get the point of regenerators. For that trouble / expense, I'd probably just switch to battery.


Thirdly, I'd never been a fan of the firms providing the traditional products - Monster, PS Audio, etc - for various and sundry reasons, so I was ripe for a solution that is, let's say, a bit out there. Although Bybee technology is rather well known, I didn't know that at the time. Previously I used the word 'voodoo' in reference to Alan's products, until Barrows looked into and pronounced it respectable (my word, not his). :)


So, I guess you could say no particular reason, just a passel of little ones. I noted a 15% return fee, which meant I could try it out and return it for most of my money back if it didn't work out.


Suffice it to say, it worked out fabulously for me. I've just received a second batch of gear, which I'll install shortly. There is a very long break-in (or settling) time, and the sound is noticeably worse after initial install, thus the lack of haste on installation.


Of all the changes I've made in my system, this one had the most impact!


I think of this stuff as tuning my AC circuit, not filtering it.



"(I hope you aren't offended by my skepticism. I'm open to being enlightened.)"


Not at all, I'm still skeptical myself, just less so than with the other AC product manufacturers. ;)







PS, my girlfriend just came running in and said - was that Katell singing in the background, I never heard that before, did you change something? She can't stop dancing & singing.


The answer: Yes I did, I installed the SSD and the ASI Livelines, the latter of which was more significant, BTW.




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Nice system Clay. Good to see you've assembled a very nice computer music server. And have a couple of respected DAC's to play with too. And you must be liking Maher's products. I was considering his products too but decided to take a different route.


I believe clean AC is really important to an audio system. I've auditioned a couple of isolation transformer types and like what they do. They really do clean up AC but you have to watch that you don't use a smaller transformer and limit current for amps. After the auditions I came to the conclusion that balanced power is a very approach to reducing noise without putting "things" in to the circuits. I have an electrician coming by to install a dedicated 240 volt 20 amp balanced circuit in to my listening room. And today I purchased a Torus 20 amp balanced 240 volt in, 120 volt out isolation transformer. I'm expecting some really amazing things with this type of AC. It will be one of the best things I did for my audio pleasures in 2009.


Maybe it will be as good as the room treatment I added this year. IMO and experience the most profound thing you can do to make your audio system sound enjoyable is to deal with room acoustics. Starting with uncompromising speaker placement in the room. This is more important than acoustic room products. Once the speakers are placed properly, its time to add room treatment. Whether its a shared family space or a dedicated room. There are some very spousal friendly acoustic products available today and IMO there are no longer any excuses left for the serious audiophile/music lover. Just add some bass traps in the corners of the room and you'll be amazed at the detail you've been missing.


As for music servers in 2009. Well, I didn't get mine done this year. But I did buy 2 Mac Mini's today and one of them will be my server. The DAC is still TBD. I'm thinking very seriously of the MH ULN2. I've been looking at and researching DACs for months now and the ULN2 looks like such a good buy. The only DAC's I can audition locally that interest me are the Bryston and Ayre. I might give them a listen first. But I might just buy the ULN2 unheard anyway and take my chances. It won't be hard to sell if I don't like it. They are very rare on the used market. Whatever I do for a DAC, it will something to reflect back on in 2010. And if all goes well, maybe I won't be doing much of anything at all in 2011 because there won't be anything that needs to be addressed.




Dedicated 240V balanced power, Torus RM20-BAL. Mac Mini/Ayre QB-9. LSA Group Signature integrated. Eminent Tech LFT8B speakers. Real Trap and GIK bass traps.

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Thanks for your response, Bryan.


Good to see that you're closing in on a solution.


Thanks for the reminder for room treatment - another one of those highly environmental specific solutions, like AC.


Keep us posted on the 'balanced' power improvements.







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  • 2 weeks later...

Hi Clay,


Thanks for describing your system. It sounds like you have put a lot of thought into building what I imagine is a very nice sounding system. I would enjoy hearing your system.


Could you describe the sound differences you hear between the Proton and the ULN-2? I owned the Cosecant, and thought it a very nice sounding DAC, although quite a bit different from my present DAC.


Also, I see you mention that the add-on power supply might be unnecessary with the ULN-2; do you hear differences between the stock supply and Gordon's supply?


I actually own a DIY B1 buffer with a linear dual power supply, Bent Audio remote volume controlling a Gold Point attenuator, built with Black Gate caps and a high quality switch for three inputs. It sounds very nice. However, I noted that you are running a balanced connection from the DAC to the amplifier. Maybe it is because I am running long interconnects to the amps (15+ feet), but I note a certain softening of the upper midrange, and generic coloring of the high frequencies whenever I run an unbalanced run between the balanced DAC and amps. Anyway, if you want to try the B1, maybe we could arrange a temporary trade of your Dehavilland and my B1.


I am also very interested in finding the best possible transport for a firewire DAC. I used to run the Fit-PC Slim with linear power supply to the Cosecant, and it sounded quite a bit better than other computers and laptops I've tried feeding the USB DAC. Unfortunately, I don't know of a similar cleanly powered PC that has firewire capabilities. I am having good luck with an older AMD 64 chip and Abit motherboard, with a number of the CMP software tweaks applied if running XP. It also sounds very good under Linux and MPD.


Good luck in the coming year,



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Thanks for your post, from what I know about your system, I'd enjoy it as well. As I posted elsewhere, I thought my eventual upgrade path form the MH ULN-2 was to an Orpheus, until Metric Halo released the ULN-8.


Re the Proton vs ULN-2, in a word the ULN-2 is mo' bettah. When I sent the ULN-2 back to the shop to fix the 48/96 oscillator, I throughly enjoyed the Proton, and didn't notice a big dropoff necessarily, but upon reinserting the ULN-2 later, I realized the difference was greater than I had believed. Both are quite great sounding for the price, and I consider both to be perhaps the two biggest bargains in DACs right now, but the ULN-2 does retail for twice the Proton. Better extension, more detail & nuance, more 'you are there', esp in spatial info, would be the three most obvious things to note.


I did hear a difference when I fir installed the custom PS, but that was before I had any, and I do mean any, AC circuit conditioning/tuning. I've not really tested it since, as I already have the linear supply. The theory supporting the 'maybe not required' thought is that the DC-DC converter in the '2 should obviate the need for upgraded PS, but perhaps the switching supply was putting noise back into the circuit such that other gear was affected and the custom PS therefore might have impacted the sound for the better in any event. Cleaner, more extended bass, as well as smoother high end were the things I noted at the time of install.


I'd be very interested in trying out your B1. I do I wish nelson made it in a balanced version. What part of the country are you in? I'm in Manhattan.


re the best way to feed Firewire, I think in the long run, it'll be Linux, but I'm too lazy to sort that out right now, perhaps sometime this year.


I just ordered up some parts to see what I can do with an Apple Cube - a retro, low profile (low AC, low noise, quiet) computer - although I do want to 'accelerate' the processor. Since you can't really build a Mac from parts, I'm retro-grading. :)


thanks for your post.


PM me about your thoughts on the temporary swap. I've got new tubes recently, but it's just sitting here since I'm going hot-rod mode right now, straight from ULN-2 to the J2.









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FWIW I wasn't that excited by the B1; albeit a DIY version that I made a few years ago (its a pretty old design). If you are going direct DAC to power amp then why bother?


I'm using a pair of Pass Aleph 3s on the tweeter and mids of my Orions, they are great amps. I'm guessing the FirstWatt series is the more tuned and refined version of these old amps?


On another note I finally noticed a difference with Amarra 1.2 right at my limit of identifying differences with the system, it was so small it was like 1/10th of the difference you get from changing cables. It seemed to remove a (very) small amount of grain and improve the separation of instruments within the soundstage. But this is such a small difference and no more than the difference you could get by moving your speakers 2" closer together. In any event Amarra's inability to work with ALAC on 10.4.11 is a no go for me.


Nyal Mellor, Acoustic Frontiers LLC.

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"If you are going direct DAC to power amp then why bother?"


becuase it's a bit inconvenient, and I don't trust other household members to play music in this "hot-rod" configuration when I'm not home. :)


The problem, of course, is finding a preamp that can be inserted without degrading the sound. I was thinking that maybe a buffered pre from Nelson would do the trick.


"I'm guessing the FirstWatt series is the more tuned and refined version of these old amps?"


More true than not - although the First Watt series were a number of experimental amps with completely different characteristics, the J2 is perhaps the most 'normal' (commercially-speaking) amp of the bunch - definitely the latest thinking from Nelson, and quite a step-up from my Aleph 30, due to using newly available output devices.


"In any event Amarra's inability to work with ALAC on 10.4.11 is a no go for me."


Jon's working on this. I run Tiger as well, and test releases for him using Tiger and Snow Leopard.






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Hi Clay,


I'm curious about the issue you had with the 48/96 oscillator. How did you know it was broken? And did it affect playback? And do you know if it is a common issue like a known defect? I can't imagine it was because the ML gear is known to be bullet proof but thought I should ask. And I assume service was excellent, another thing I've heard MH is known for.


My ULN2 will be here in a day. I wanted to ask you about installation. I know there are a lot of features I won't be using since I will use it for playback only. I have not seen the user manual for it and I can't find one on the MH website. Anyway, I have some questions I was hoping you could answer to help me get through the installation. The cabling is probably not going to be an issue for me. Firewire from Mac to ULN2. And TRS/XLR to my integrated amp. I have the right cables. And power is easy. So my questions are more on the software side.


Besides installing the MIO software, is there any post install configuration I have to do to get audio from iTune to go thru the ULN2?


And are you aware of any MIO or firmware updates?





Dedicated 240V balanced power, Torus RM20-BAL. Mac Mini/Ayre QB-9. LSA Group Signature integrated. Eminent Tech LFT8B speakers. Real Trap and GIK bass traps.

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"How did you know it was broken? And did it affect playback? And do you know if it is a common issue like a known defect? "


Not a common problem, but was noticed when I tried to play 96kHz sample rate, as it wouldn't lock on at that rate.


MH service was great, although they do have to rule out non-hardware issues prior to sending unit in, which takes a bit of effort. They have to insure the problem is not an 'environmental' issue, since they can't recreate someone else's setup in their shop.


Setup is pretty simple, but can be frustrating if something doesn't go right, but this only happened to me with firmware updates (as when SL came out) and setting up Toslink. For Firewire use, you simply need to select Basic Setup from the ULN-2 templates (pulldown in MIO software) to get routing setup properly. HINT: there are Basic Setup templates for all the MH devices in the MIO software, so be sure to check the ULN-2 version.


Unlike most audiophile devices, this one does have software, software drivers AND firmware. These need to be installed on your Mac, and the firmware might need to be updated on a brand new ULN-2, if any recent updates exist. Since your device is a loaner, you shouldn't need to do the latter, in fact, I'd say don't even think about it for your test.


There is a very well done manual on the MH site, keep looking...it has a tiny PDF icon I think. There's also a manual for the MIO software. And there are videos on Youtube.


iTunes is a normal setup, select the sample rate in Audio Midi Setup (or Sound preferences panel). If the ULN-2 does not appear as an option, it's not properly connected.


Ensure that you depress the -10/+4 switch in the rear, otherwise the signal might be too hot for your preamp/amp. -10 is the consumer level, and +4 is for pros.


The only part that's a bit complicated is assigning the ADAT interface (8 channels of optical) to support Toslink, IME.





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Thanks for the tip on the template, sample rate and the gain switch, Clay. I kind of expected there was a great manual, but it sure is hard to find. I will keep looking.




Dedicated 240V balanced power, Torus RM20-BAL. Mac Mini/Ayre QB-9. LSA Group Signature integrated. Eminent Tech LFT8B speakers. Real Trap and GIK bass traps.

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