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Question on Connection of Mac Mini with DAC and HDD


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I have since purchasing my 2010 Mac Mini from recommendation on this site connected my DAC to the Mac Mini by USB and my external HDDs are daisy chained connected via FireWire 800 and this has performed well without issue.

 

I am facing a couple of challenges going forward and would appreciate some opinions.

 

I am approaching the need to replace my current 2TB HDD (featuring USB 2.0 and FireWire connections) with larger probably 3TB or possibly 4TB HDD (featuring USB 3.0 and Thunderbolt connections). That is my most immediate concern and need. I would at sometime consider upgrading to the newest version of a Mac Mini but that is not a necessity at this moment.

 

My interest and concerns revolve around connection to the Mac Mini and DAC. Since the new HDD do not feature FireWire I am looking at the possibility of have to use USB for both connection of the DAC and HDD to the Mac Mini. I know that the Mac Mini dynamically selects the USB BUS and with some manipulation it might be possible to have the DAC on a high speed BUS and the HDD on the other BUS but is that ideal or just the lesser of two evils?

 

Would it be of benefit to have some sort of USB to SPDIF converter to make the connection to the DAC? even with this connection you still have a connection at the Mac Mini and HDD using USB so do you gain anything? What method of connection would you recommend.

 

If in the end I opt at some point for the new Mac Mini with Thunderbolt do they allow for a "daisy chain" connection of 2 or more HDD like FireWire or is there more than one Thunderbolt port available on the Mac Mini?

 

I do like the current set up with the Mac Mini, HDDs and DAC all on my equipment rack direct connected.

"If you fly a flag of hate you are no kin to me"

Ry Cooder

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Here's an alternative solution for the HD that will work with both USB 3.0 and Firewire. It will give you the flexiability for later MacMini upgrade. I would also recommend the Audioquest firewire cables for the HD, they make a big difference.

Hard Drive:

http://www.amazon.com/G-Technology-G-DRIVE-Professional-Strength-External-0G02537/dp/B009AP6X0C/ref=sr_1_3?ie=UTF8&qid=1422461389&sr=8-3&keywords=gtech+firewire

 

 

I have since purchasing my 2010 Mac Mini from recommendation on this site connected my DAC to the Mac Mini by USB and my external HDDs are daisy chained connected via FireWire 800 and this has performed well without issue.

 

I am facing a couple of challenges going forward and would appreciate some opinions.

 

I am approaching the need to replace my current 2TB HDD (featuring USB 2.0 and FireWire connections) with larger probably 3TB or possibly 4TB HDD (featuring USB 3.0 and Thunderbolt connections). That is my most immediate concern and need. I would at sometime consider upgrading to the newest version of a Mac Mini but that is not a necessity at this moment.

 

My interest and concerns revolve around connection to the Mac Mini and DAC. Since the new HDD do not feature FireWire I am looking at the possibility of have to use USB for both connection of the DAC and HDD to the Mac Mini. I know that the Mac Mini dynamically selects the USB BUS and with some manipulation it might be possible to have the DAC on a high speed BUS and the HDD on the other BUS but is that ideal or just the lesser of two evils?

 

Would it be of benefit to have some sort of USB to SPDIF converter to make the connection to the DAC? even with this connection you still have a connection at the Mac Mini and HDD using USB so do you gain anything? What method of connection would you recommend.

 

If in the end I opt at some point for the new Mac Mini with Thunderbolt do they allow for a "daisy chain" connection of 2 or more HDD like FireWire or is there more than one Thunderbolt port available on the Mac Mini?

 

I do like the current set up with the Mac Mini, HDDs and DAC all on my equipment rack direct connected.

Link to comment
Here's an alternative solution for the HD that will work with both USB 3.0 and Firewire. It will give you the flexiability for later MacMini upgrade. I would also recommend the Audioquest firewire cables for the HD, they make a big difference.

Hard Drive:

http://www.amazon.com/G-Technology-G-DRIVE-Professional-Strength-External-0G02537/dp/B009AP6X0C/ref=sr_1_3?ie=UTF8&qid=1422461389&sr=8-3&keywords=gtech+firewire

 

The only differences between that and what I have is the 3.0 USB versus my current 2.0 and the 4TB versus my 2TB. while it solves my need currently for the larger HDD and keeps my current connection functional I would have to change out HDD again should I upgrade to a new Mac Mini because of the lack of FireWire on the Mac. I guess I'm trying to future proof myself and maybe I cannot. I have seen this brand at the Apple Store. What's your experience on reliability and build quality?

 

thanks

"If you fly a flag of hate you are no kin to me"

Ry Cooder

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Love the style. I've never heard of the brand. The connection issues current/future would be the same as above. I think what I want that would cya me is an HDD with USB 3.0, FireWire 800 and Thunderbolt connections but I don't think that exists.

 

Im trying not to buy new HDD and a new Mac Mini at the same time.

 

Thanks also

"If you fly a flag of hate you are no kin to me"

Ry Cooder

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I'm not the poster who recommended the G-Technology drive, but I have some experience with them. I currently own three of their 1TB "Mini" (2.5") drives. The controller chip in one failed within a year, and it was replaced under warranty. A second one is starting to act up. I had also bought the 2TB (3.5") version (referred to in post #2), but returned it to the Apple store. I found it to be too noisy. You could hear the platter spinning from across the room.

I think Other World Computing offers excellent products and great customer service. In my main music system, I am using their Mercury Elite Pro Dual Mini portable RAID along with my MacBook Pro. I'm quite happy with it.

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I use a somewhat different approach to storage and playback. I also use a 1 TB drive from OWC for storage. I do not keep it connected to my 2009 Mac Mini. I recently had installed a 250 GB SSD to replace the stock HDD. In order to minimize cable and usb issues I load the music files from my OWC drive on to my computer SSD then disconnect the ext drive and play the files. I use Amarra as player. Although this may seem cumbersome I like the results. I found that using the SSD improved sound quality significantly and I can store the files in other locations as needed.

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I have since purchasing my 2010 Mac Mini from recommendation on this site connected my DAC to the Mac Mini by USB and my external HDDs are daisy chained connected via FireWire 800 and this has performed well without issue.

 

I am facing a couple of challenges going forward and would appreciate some opinions.

 

I am approaching the need to replace my current 2TB HDD (featuring USB 2.0 and FireWire connections) with larger probably 3TB or possibly 4TB HDD (featuring USB 3.0 and Thunderbolt connections). That is my most immediate concern and need. I would at sometime consider upgrading to the newest version of a Mac Mini but that is not a necessity at this moment.

 

My interest and concerns revolve around connection to the Mac Mini and DAC. Since the new HDD do not feature FireWire I am looking at the possibility of have to use USB for both connection of the DAC and HDD to the Mac Mini. I know that the Mac Mini dynamically selects the USB BUS and with some manipulation it might be possible to have the DAC on a high speed BUS and the HDD on the other BUS but is that ideal or just the lesser of two evils?

 

Would it be of benefit to have some sort of USB to SPDIF converter to make the connection to the DAC? even with this connection you still have a connection at the Mac Mini and HDD using USB so do you gain anything? What method of connection would you recommend.

 

If in the end I opt at some point for the new Mac Mini with Thunderbolt do they allow for a "daisy chain" connection of 2 or more HDD like FireWire or is there more than one Thunderbolt port available on the Mac Mini?

 

I have a late 2012 Mac Mini. There is only one Tbolt port and a FW800 port. Having faced similar questions and considerations, here are some personal observations and experiences.

 

My DAC is connected via USB and i wanted to keep external storage separate from the USB hub. Initially (before Tbolt drives were as common as they are today), i went with an external FW800 drive.

 

I had a very reliable 3TB external HD from OWC via FW800.

Link to today's version:

Macsales.com - OWC Mercury Elite Pro USB 3.0/2.0, FireWire 800/400, eSATA External Hard Drives

 

This unit was great unit i exceeded storage. It was fast enough, very quiet and reliable. Highly recommended if you only need FW800 and not Tbolt. I didn't use raid or partition the drive. Backups were manual and i was concerned about a possible drive failure between backups. FWIW, the drives never failed over the course of about 2 years.

 

After i maxed the storage capability, I considered NAS or another approach.

 

I decided to go with a 6TB Tbolt external unit.

Link:

OWC 6.0TB Mercury Elite Pro Dual USB 3.0 &... in stock at OWC

 

This unit is not very expensive and can be daisy chained via Tbolt (from one HD to another; the Mac only has one Tbolt port). It has a small footprint, is relatively quiet and does not require software for raid settings (raid can be set by a turn key on the back of the HD). I'm running raid 0 for speed and max storage capability. Instead of mirroring drives, i prefer a backup on an alternate dup external HD that is only connected at the time of backup. Caution: in the event of drive failure, i only have data as of my last backup. Tbold makes this fast and easy.

 

Hope this helps, best regards,

Chris

Amarra 3.0.3/iTunes-->AQVOX USB PS-->Acromag USB Isolator-->Ayre QB-9-->Ayre K-5xeMP-->W4S SX-500-->Tyler Acoustics Linbrook Super Towers-->SVS SB12-Plus (L&R). Cables: Nordost, Transparent, LessLoss, Analysis Plus & Pangea. Dedicated line with isolated power conditioning per component: PS Audio & Furman. Late 2012 Mac Mini 2.6GHz Quad-Core i7 (16 GB, 1TB Fusion, 6TB ext via Tbolt). External drives enclosure http://www.computeraudiophile.com/f7-disk-storage-music-library-storage/silent-enclosure-external-hard-drives-7178/

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Hope you don't mind, but I'm going to paste in a post I just made in another thread about external HD for Macs as much of it is pertinent--at least with regards the links and comments on SQ.

 

BTW, I too advise against the G-Technology drives (noisy!!) and have had many years of success with OWC Mercury Elite Pros. But whatever you do mwheelerk, please DO NOT use a directly attached USB drive of any kind in a system with a USB DAC! Worst sound of all interface choices will result.

Do you have another Mac you can hang storage on an share with your DAC-attached mini? That will give you best SQ and eliminate differences between interfaces.

 

Anyway…. the other post I made:

 

Well it just so happens that I have done a LOT of controlled testing on the subject and posted results and rationales in three threads I started. Take a look at them in order:

 

http://www.computeraudiophile.com/f8-general-forum/my-deep-dive-media-storage-interfaces-musical-differences-heard-between-chipsets-firewire-400-800-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-sata-flash-drives-sd-cards-and-network-shares-warning-may-cause-seizures-dbt-crowd-and-flat-earth-naysayers-18108/

 

 

http://www.computeraudiophile.com/f8-general-forum/attention-current-mac-mini-users-boot-mavericks-sd-card-load-ramdisk-dismount-your-internal-sata-drives-and-pour-drink-musicians-walking-out-your-speakers-18159/

 

 

http://www.computeraudiophile.com/f8-general-forum/uh-oh-i-beat-my-sd-card-trick%3B-bypass-your-ethernet-switch-and-make-your-external-drives-sound-close-ram-disk-using-apple-thunderbolt-ethernet-adaptor-and-second-network-connection-18475/

 

 

Bottom line is that you are hearing the active interfaces connected to your computer, not the disk drives themselves. This will seem odd, but the best sounding, directly connected drive enclosure (at least for SATA and capacity, without going back to an ATA interface) will be a FW400. Even if your computer has only an FW800 port, use an 6>9 adapter at the back of the computer or buy a 6>9 cable (preferably with the power wire cut; USB | FireWire - Angled - Short - Custom - Cables - 877-522-3779 offers those as a service).

The enclosure you want is: OWC Mercury Elite Pro Oxford 934 FireWire & USB... in stock at OWC It is just USB2.0 and FW400. Only $45 with no drive. They also sell that model with a 2TB drive for $148 (OWC 2.0TB Mercury Elite Pro High Performance 7200RPM 64MB... at OWC). Don't get the ones with USB3.0, FW800, or anything else--they won't sound as good. Trust me on this. That is a great sounding enclosure--and at $45 you have nothing to lose. Sure it is slower than FW800, but that is not what matters.

 

To beat the above, you will have to ditch directly attached storage, make an SD card to boot from, dismount/eject your internal SATA drives, and put you library on a shared, Ethernet attached drive (ideally on another Mac directly connected via BlueJeans/Belden Cat6a--bypassing your network switch).

Or use the USB2.0 port of that OWC drive I just had you buy, plug it into an Airport Extreme, and cable your computer (again the unbeatable and affordable BlueJeans/Belden Cat6a) directly to the Airport Extreme. A few of my clients do this with good results.

 

Thunderbolt is nothing special as it is mostly just a multiplexing of many interfaces (DisplayPort, Ethernet, FW, USB), each of which get handed back to various controller chips on the motherboard. More speed, more signals, more noise. The only internal storage interface I think highly of--no not SATA(!)--for SQ is the new PCIe Flash option in the 2014 Mac mini.

 

While you are at it, you may want to consider yanking the switching PS out of your mini and installing my DC-conversion/Linear Fan Controller Kit (any users reviews of Uptone Power Supply and mac kit?). I hardy make anything on the kit; I make something if you get the UpTone/Swenson JS-2 LPS to go with it. But you can go cheaper. :)

 

Regards,

 

--Alex C.

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Hope you don't mind, but I'm going to paste in a post I just made in another thread about external HD for Macs as much of it is pertinent--at least with regards the links and comments on SQ.

 

BTW, I too advise against the G-Technology drives (noisy!!) and have had many years of success with OWC Mercury Elite Pros. But whatever you do mwheelerk, please DO NOT use a directly attached USB drive of any kind in a system with a USB DAC! Worst sound of all interface choices will result.

Do you have another Mac you can hang storage on an share with your DAC-attached mini? That will give you best SQ and eliminate differences between interfaces.

 

Anyway…. the other post I made:

 

Well it just so happens that I have done a LOT of controlled testing on the subject and posted results and rationales in three threads I started. Take a look at them in order:

 

http://www.computeraudiophile.com/f8-general-forum/my-deep-dive-media-storage-interfaces-musical-differences-heard-between-chipsets-firewire-400-800-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-sata-flash-drives-sd-cards-and-network-shares-warning-may-cause-seizures-dbt-crowd-and-flat-earth-naysayers-18108/

 

 

http://www.computeraudiophile.com/f8-general-forum/attention-current-mac-mini-users-boot-mavericks-sd-card-load-ramdisk-dismount-your-internal-sata-drives-and-pour-drink-musicians-walking-out-your-speakers-18159/

 

 

http://www.computeraudiophile.com/f8-general-forum/uh-oh-i-beat-my-sd-card-trick%3B-bypass-your-ethernet-switch-and-make-your-external-drives-sound-close-ram-disk-using-apple-thunderbolt-ethernet-adaptor-and-second-network-connection-18475/

 

 

Bottom line is that you are hearing the active interfaces connected to your computer, not the disk drives themselves. This will seem odd, but the best sounding, directly connected drive enclosure (at least for SATA and capacity, without going back to an ATA interface) will be a FW400. Even if your computer has only an FW800 port, use an 6>9 adapter at the back of the computer or buy a 6>9 cable (preferably with the power wire cut; USB | FireWire - Angled - Short - Custom - Cables - 877-522-3779 offers those as a service).

The enclosure you want is: OWC Mercury Elite Pro Oxford 934 FireWire & USB... in stock at OWC It is just USB2.0 and FW400. Only $45 with no drive. They also sell that model with a 2TB drive for $148 (OWC 2.0TB Mercury Elite Pro High Performance 7200RPM 64MB... at OWC). Don't get the ones with USB3.0, FW800, or anything else--they won't sound as good. Trust me on this. That is a great sounding enclosure--and at $45 you have nothing to lose. Sure it is slower than FW800, but that is not what matters.

 

To beat the above, you will have to ditch directly attached storage, make an SD card to boot from, dismount/eject your internal SATA drives, and put you library on a shared, Ethernet attached drive (ideally on another Mac directly connected via BlueJeans/Belden Cat6a--bypassing your network switch).

Or use the USB2.0 port of that OWC drive I just had you buy, plug it into an Airport Extreme, and cable your computer (again the unbeatable and affordable BlueJeans/Belden Cat6a) directly to the Airport Extreme. A few of my clients do this with good results.

 

Thunderbolt is nothing special as it is mostly just a multiplexing of many interfaces (DisplayPort, Ethernet, FW, USB), each of which get handed back to various controller chips on the motherboard. More speed, more signals, more noise. The only internal storage interface I think highly of--no not SATA(!)--for SQ is the new PCIe Flash option in the 2014 Mac mini.

 

While you are at it, you may want to consider yanking the switching PS out of your mini and installing my DC-conversion/Linear Fan Controller Kit (any users reviews of Uptone Power Supply and mac kit?). I hardy make anything on the kit; I make something if you get the UpTone/Swenson JS-2 LPS to go with it. But you can go cheaper. :)

 

Regards,

 

--Alex C.

 

Hi Alex,

 

I never thought using a USB drive along with a USB dac would hurt SQ. I just bought a new 4TB usb enclosure.

 

I also have available that I could use a Drobo Gen2 which is FW (not sure if it's 400 or 800).

 

Do you think I'd notice a SQ difference between the two and should I spend the time and transfer 3.75gb of music files?

 

Thanks for any help.

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Do you think I'd notice a SQ difference between the two and should I spend the time and transfer 3.75gb of music files?

 

Well if you mean transferring and then disconnecting the USB drive, then yes, in a decent system this should be very apparent. Less congestion, more coherence overall.

 

The only connections I have to my music Mac mini (2012 i7, 16GB) are: DC cable to linear PS; USB cable to DAC, Ethernet cable to other Mac. And my Ethernet method (as detailed in the 3rd link above) yields SQ equivalent to SD card (which is the quietest, simplest interface)--which I attribute to Ethernet and SD card sharing the same Broadcom controller chip in the minis.

RAM disk is still the SQ "gold standard," but it is very inconvenient. Internal SATA drive (which in my case I dismount/eject all part ions of) ranks above externals, but below SD card/Ethernet for SQ.

And I have never found SSDs to be a sonic advantage. Again, it is all about the active interfaces.

 

Hope that helps. YMMV ;)

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Yes, I'd disconnect the 4TB USB and use the Drobo Gen2 FW800 instead. I'll try it out over this weekend.

I also have a Mac mini (2012 i7, 16GB) but everything else is stock and it's just used as a music server.

 

I also have a QNap NAS, but I've never gotten use to how it works and have disconnected it as all my life I've only used Macs and I find it not quite how I was hoping.

 

Thanks for the help.

 

Well if you mean transferring and then disconnecting the USB drive, then yes, in a decent system this should be very apparent. Less congestion, more coherence overall.

 

The only connections I have to my music Mac mini (2012 i7, 16GB) are: DC cable to linear PS; USB cable to DAC, Ethernet cable to other Mac. And my Ethernet method (as detailed in the 3rd link above) yields SQ equivalent to SD card (which is the quietest, simplest interface)--which I attribute to Ethernet and SD card sharing the same Broadcom controller chip in the minis.

RAM disk is still the SQ "gold standard," but it is very inconvenient. Internal SATA drive (which in my case I dismount/eject all part ions of) ranks above externals, but below SD card/Ethernet for SQ.

And I have never found SSDs to be a sonic advantage. Again, it is all about the active interfaces.

 

Hope that helps. YMMV ;)

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I am fond of OWC products Chris, but those big ones have a fan. Fan sound varies from unit to unit and yours may be quiet, but I prefer just to daisy-chain several fanless, single drive enclosures.

 

Hi Alex,

 

Understood and agreed on the fan noise issue. I'd like to take this opportunity to say hi and good to meet you here at CA. And, wow, you have an incredible system/room! I haven't posted in long time as we moved (locally, less than 20 blocks) and then embarked on a gut reno (not easy or fast in nyc).

 

Indeed, most external drives with fans are noisy...and too loud for me. For many years in the past, i used Glyph external drives and, while reliable, they were super noisy (love Glyph as a company, but they were just too loud for me at home). I tried to remedy the noise issue in many ways...finally arrived at a near-silent enclosure linked in my sig. Sorry, the post/link is old and my build-pics are no longer available.

 

I still use the "silent" enclosure with my new drives. Noise is no longer an issue thanks to the sound dampening enclosure. As you pointed out, fanless would certainly be more quiet. I wonder if fanless might impact drive longevity? Have no experience or testing there.

 

I see you prefer FW400 vs some other connections. I haven't tested this personally. When you compared FW400 vs other connections (FW800 or other), did you isolate power for each HD in all of the tests? Just wondering if there are other factors that may have resulted in FW400 being your preference? For example, i noticed an improvement after building/assembling the silent enclosure with it's own power conditioner (I'm using PS Audio and Furman stuff). Isolating the power for DC/wall wart power adapters away from DAC and Pre seems to make a difference for me and others have shared thoughts on this in the past. Personally, i try to isolate each piece of equipment (as you did, i had the the contractor install a dedicated line with a separate panel for my system).

 

Concept/question: does noise travel forward through the FW/USB/Tbolt cable from the external HD into the computer and then into the audio chain? Or, does noise travel backwards (in reverse) from the HD's PS into the system?

 

Any personal testing or experience with this? Respectfully, this is not a trick question or otherwise motivated to stir something up. Sincerely interested in your experience and point of view.

 

Best regards,

Chris

Amarra 3.0.3/iTunes-->AQVOX USB PS-->Acromag USB Isolator-->Ayre QB-9-->Ayre K-5xeMP-->W4S SX-500-->Tyler Acoustics Linbrook Super Towers-->SVS SB12-Plus (L&R). Cables: Nordost, Transparent, LessLoss, Analysis Plus & Pangea. Dedicated line with isolated power conditioning per component: PS Audio & Furman. Late 2012 Mac Mini 2.6GHz Quad-Core i7 (16 GB, 1TB Fusion, 6TB ext via Tbolt). External drives enclosure http://www.computeraudiophile.com/f7-disk-storage-music-library-storage/silent-enclosure-external-hard-drives-7178/

Link to comment
I have a late 2012 Mac Mini. There is only one Tbolt port and a FW800 port. Having faced similar questions and considerations, here are some personal observations and experiences.

 

My DAC is connected via USB and i wanted to keep external storage separate from the USB hub. Initially (before Tbolt drives were as common as they are today), i went with an external FW800 drive.

 

I had a very reliable 3TB external HD from OWC via FW800.

Link to today's version:

Macsales.com - OWC Mercury Elite Pro USB 3.0/2.0, FireWire 800/400, eSATA External Hard Drives

 

This unit was great unit i exceeded storage. It was fast enough, very quiet and reliable. Highly recommended if you only need FW800 and not Tbolt. I didn't use raid or partition the drive. Backups were manual and i was concerned about a possible drive failure between backups. FWIW, the drives never failed over the course of about 2 years.

 

After i maxed the storage capability, I considered NAS or another approach.

 

I decided to go with a 6TB Tbolt external unit.

Link:

OWC 6.0TB Mercury Elite Pro Dual USB 3.0 &... in stock at OWC

 

This unit is not very expensive and can be daisy chained via Tbolt (from one HD to another; the Mac only has one Tbolt port). It has a small footprint, is relatively quiet and does not require software for raid settings (raid can be set by a turn key on the back of the HD). I'm running raid 0 for speed and max storage capability. Instead of mirroring drives, i prefer a backup on an alternate dup external HD that is only connected at the time of backup. Caution: in the event of drive failure, i only have data as of my last backup. Tbold makes this fast and easy.

 

Hope this helps, best regards,

Chris

Was not certain you could daisy chain thunderbolt and that is good to learn.

"If you fly a flag of hate you are no kin to me"

Ry Cooder

Link to comment
Hi Alex,

 

Understood and agreed on the fan noise issue. I'd like to take this opportunity to say hi and good to meet you here at CA. And, wow, you have an incredible system/room! I haven't posted in long time as we moved (locally, less than 20 blocks) and then embarked on a gut reno (not easy or fast in nyc).

 

Indeed, most external drives with fans are noisy...and too loud for me. For many years in the past, i used Glyph external drives and, while reliable, they were super noisy (love Glyph as a company, but they were just too loud for me at home). I tried to remedy the noise issue in many ways...finally arrived at a near-silent enclosure linked in my sig. Sorry, the post/link is old and my build-pics are no longer available.

 

I still use the "silent" enclosure with my new drives. Noise is no longer an issue thanks to the sound dampening enclosure. As you pointed out, fanless would certainly be more quiet. I wonder if fanless might impact drive longevity? Have no experience or testing there.

 

I see you prefer FW400 vs some other connections. I haven't tested this personally. When you compared FW400 vs other connections (FW800 or other), did you isolate power for each HD in all of the tests? Just wondering if there are other factors that may have resulted in FW400 being your preference? For example, i noticed an improvement after building/assembling the silent enclosure with it's own power conditioner (I'm using PS Audio and Furman stuff). Isolating the power for DC/wall wart power adapters away from DAC and Pre seems to make a difference for me and others have shared thoughts on this in the past. Personally, i try to isolate each piece of equipment (as you did, i had the the contractor install a dedicated line with a separate panel for my system).

 

Concept/question: does noise travel forward through the FW/USB/Tbolt cable from the external HD into the computer and then into the audio chain? Or, does noise travel backwards (in reverse) from the HD's PS into the system?

 

Any personal testing or experience with this? Respectfully, this is not a trick question or otherwise motivated to stir something up. Sincerely interested in your experience and point of view.

 

Best regards,

Chris

 

Hi Chris, nice to meet you too!

To answer your question about AC power used in my OWC enclosure/interface showdown:

a) My studio has its own, pretty extreme AC mains sub-system (see pics in one of my profile albums);

b) The outlets behind my gear even give me a choice as to which 120V side of the 240V AC line I connect to (L1 v. L2);

c) In addition, I have two separate 1:1 isolation transformers with special characteristics of their own that I plug my front end gear into; the DAC and preamp into one, the LPS for my computer into the other; Both the isolation transformers, the gear itself, and my power amp all "float" without any connection to AC mains ground (there is nothing worthwhile on a house ground IMHO).

d) My studio also still has several outlets that are not connected through the sub-panel, but rather they go direct back to my main house panel on separate lines (2 breakers I think); My desktop computer for work, my phones, router, Ethernet switch, etc. are all plugged into one of those.

e) When I did my test of HD interfaces, I plugged the OWC-supplied tabletop switching PS units into the other of the above "standard house outlets."

f) All the OWC drives in my test use the same DC PS, so only one drive PS was ever plugged in at a time; Thus my A/B consisted of stopping the track, quitting the player, ejecting the drive, and moving the raw drive mechanism, the FW cable and the DC cable.

 

After all my tests, when I settled on the FW400 drive interface that I liked, I then powered that drive using a linear PS. That made a nice difference too. But I was not about to go back and repeat testing of all the other interfaces! Rarely is the case that something deemed as distinctly better gets worse when improvements are made in other related areas.

 

With regards to your question of which way the "noise travels": As far as the comparison of drive interfaces goes, in large part I would say "neither." What I mean is that I believe the sonic differences between FW400, FW800, USB, TB, internal SATA, SD card, Ethernet, RAM disk, and OS optimizations have mostly to do with the differences in activity generated inside the computer--and their effect on the signal integrity of the USB signal the computer subsequently sends to the DAC (where the USB PHY chip then has to work more/less hard to extract the data from the noise that is the received voltage, thus generating spikes on the ground-plane, packet data noise, etc.--which in turn results in jitter of the master clock; Phew!)

 

So while yes, as you saw--from my OWC enclosure/interface report--I preferred the simpler enclosures that did not also have USB3.0 or eSATA, etc., and it could be that those units themselves generated more "crap" even when I used their FW800 ports. But I still think it is all about what happens as a result--inside the computer.

 

Back to power supplies: Yes, it is good idea to isolate the supplies. Most all power supplies--switchers or linears--put noise back into the AC mains and are also affected by all sorts of broadband noise coming in on the line and on the ground. I happen to be in the middle of choosing a small and cheap 7.5V DC supply to include with out forthcoming USB Regen device, and I learning firsthand that when it comes to cheap supplies, linears don't always win against switchers, and the noise/ripple specs given for them are not the relevant spec for SQ. Our device has really good low-noise regulators, so my choice seems like it is going to be based more on what other crap these things kick out or back.

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Hi Chris, nice to meet you too!

To answer your question about AC power used in my OWC enclosure/interface showdown:

a) My studio has its own, pretty extreme AC mains sub-system (see pics in one of my profile albums);

b) The outlets behind my gear even give me a choice as to which 120V side of the 240V AC line I connect to (L1 v. L2);

c) In addition, I have two separate 1:1 isolation transformers with special characteristics of their own that I plug my front end gear into; the DAC and preamp into one, the LPS for my computer into the other; Both the isolation transformers, the gear itself, and my power amp all "float" without any connection to AC mains ground (there is nothing worthwhile on a house ground IMHO).

d) My studio also still has several outlets that are not connected through the sub-panel, but rather they go direct back to my main house panel on separate lines (2 breakers I think); My desktop computer for work, my phones, router, Ethernet switch, etc. are all plugged into one of those.

e) When I did my test of HD interfaces, I plugged the OWC-supplied tabletop switching PS units into the other of the above "standard house outlets."

f) All the OWC drives in my test use the same DC PS, so only one drive PS was ever plugged in at a time; Thus my A/B consisted of stopping the track, quitting the player, ejecting the drive, and moving the raw drive mechanism, the FW cable and the DC cable.

 

After all my tests, when I settled on the FW400 drive interface that I liked, I then powered that drive using a linear PS. That made a nice difference too. But I was not about to go back and repeat testing of all the other interfaces! Rarely is the case that something deemed as distinctly better gets worse when improvements are made in other related areas.

 

With regards to your question of which way the "noise travels": As far as the comparison of drive interfaces goes, in large part I would say "neither." What I mean is that I believe the sonic differences between FW400, FW800, USB, TB, internal SATA, SD card, Ethernet, RAM disk, and OS optimizations have mostly to do with the differences in activity generated inside the computer--and their effect on the signal integrity of the USB signal the computer subsequently sends to the DAC (where the USB PHY chip then has to work more/less hard to extract the data from the noise that is the received voltage, thus generating spikes on the ground-plane, packet data noise, etc.--which in turn results in jitter of the master clock; Phew!)

 

So while yes, as you saw--from my OWC enclosure/interface report--I preferred the simpler enclosures that did not also have USB3.0 or eSATA, etc., and it could be that those units themselves generated more "crap" even when I used their FW800 ports. But I still think it is all about what happens as a result--inside the computer.

 

Back to power supplies: Yes, it is good idea to isolate the supplies. Most all power supplies--switchers or linears--put noise back into the AC mains and are also affected by all sorts of broadband noise coming in on the line and on the ground. I happen to be in the middle of choosing a small and cheap 7.5V DC supply to include with out forthcoming USB Regen device, and I learning firsthand that when it comes to cheap supplies, linears don't always win against switchers, and the noise/ripple specs given for them are not the relevant spec for SQ. Our device has really good low-noise regulators, so my choice seems like it is going to be based more on what other crap these things kick out or back.

 

Hi Alex,

 

Wow. Your electrician must love you! Very impressive overview of your isolation and power set-up.

 

I’d like to say thank you for taking the time to walk me through your tests and observations in such a comprehensive and organized way. I feel bad asking questions that might have been a chore to respond to. Sorry if that was the case.

 

Totally agree with you on power supplies and why isolation can be helpful. Installing a dedicated line was one of my best investments. In my case, isolation after the wall outlet wasn't crazy expensive, and it too pays dividends.

 

While I’m not prepared to slow down to FW400, I just ordered a Corning 3.5M Tbolt optical cable for electrical isolation (glad they come in more reasonable lengths these days and not just long runs over 5M or 10M). It should arrive this weekend. I’ll see if there are any improvements or audible differences. I’d like to think i already have pretty good USB isolation from Mac Mini to DAC. Even if electrical noise is leaking into my computer via the generic Tbolt cable (from OWC), hopefully it doesn't make it to my DAC. Well, i know enough to know that there’s a lot i don’t know...so let's see how it sounds.

 

Cheers,

Chris

Amarra 3.0.3/iTunes-->AQVOX USB PS-->Acromag USB Isolator-->Ayre QB-9-->Ayre K-5xeMP-->W4S SX-500-->Tyler Acoustics Linbrook Super Towers-->SVS SB12-Plus (L&R). Cables: Nordost, Transparent, LessLoss, Analysis Plus & Pangea. Dedicated line with isolated power conditioning per component: PS Audio & Furman. Late 2012 Mac Mini 2.6GHz Quad-Core i7 (16 GB, 1TB Fusion, 6TB ext via Tbolt). External drives enclosure http://www.computeraudiophile.com/f7-disk-storage-music-library-storage/silent-enclosure-external-hard-drives-7178/

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Wow. Your electrician must love you! Very impressive overview of your isolation and power set-up.

 

Thanks. Actually I did all the electrical myself.

 

Totally agree with you on power supplies and why isolation can be helpful. Installing a dedicated line was one of my best investments. In my case, isolation after the wall outlet wasn't crazy expensive, and it too pays dividends.

 

Indeed! And if had more time I could relate the steps in a procedure to help you choose the better "sounding" side of your house's incoming 120/120, and how to optimize your panel afterwards. You are welcome to phone me.

 

While I’m not prepared to slow down to FW400, I just ordered a Corning 3.5M Tbolt optical cable for electrical isolation (glad they come in more reasonable lengths these days and not just long runs over 5M or 10M). It should arrive this weekend. I’ll see if there are any improvements or audible differences. I’d like to think i already have pretty good USB isolation from Mac Mini to DAC. Even if electrical noise is leaking into my computer via the generic Tbolt cable (from OWC), hopefully it doesn't make it to my DAC. Well, i know enough to know that there’s a lot i don’t know...so let's see how it sounds.

 

Do let us know how the Corning TB cable works out. Unlike the USB version of the Corning optical, the TB version does not have any copper wires running down it for power, so the galvanic isolation is real. You'll still be generating activity at the computer's Thunderbolt port, but it still may be an improvement--we all hope!

I don't suppose that 3.5m length is enough to let you put your 6TB OWC with its fan in another room?

 

I am somewhat surprised you are still using the Acromag USB isolator. The ADuM isolator chip it uses generates a fair amount of jitter. I gather your QB-9 is not updated for 192kHz as those isolators are limited to 12Mbps.

 

Have a great weekend!

--Alex C.

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