USB Power Question For The Technically Inclined

[Bob Boyer]

Here's one I'm curious about with my new Mac Mini, which doesn't have enough USB ports. I guess they assume you won't use external hard drives or wired keyboards/mics, etc. So I've purchased a USB dock, which has two additional USB-C ports and two standard USB ports. Due to the fact that I can't run bluetooth devices (mouse and keyboard) on my personal and my work computers when they're on simultaneously, I've been running a wired keyboard and mouse to my home computer, the Mac Mini. I use my wireless keyboard and mouse on my work computer. I'd go bluetooth on both computers if they wouldn't get confused over which keyboard or mouse goes with which computer when they are both on at the same time. And that still wouldn't solve all of the peripheral connection issues on either computer.

So I've got the dock to expand my Mac Mini's connectivity. I also expanded by using the monitor's USB Jacks. At the moment, I plug the mouse, keyboard and printer cable into the back of the monitor and run a standard USB cable from the monitor to the dock. The dock takes up one of four USB-C ports on the Mini. I use the remaining three USB-C ports to connect my external drives, which are all USB powered only. The remaining USB port on the dock goes to my DAC, which is a USB powered device only. The signal gets to it using a 25 foot USB cable.

Here's where I noticed when experimenting with hookups on the Mini that the dock didn't have enough juice to power my Glyph hard drives. Hence, all external drives (two Glyphs and an Apple Superdrive) are connected directly to the other three USB-C ports on the computer.

So my question after all that context is if powering the Pro-Ject DAC from a dock that doesn't pass enough signal to a hard drive is going to cut down on the quality of the signal stream. The DAC works fine and sounds okay (it's interim until I decide to get an RME unit) but I'm curious, since bits aren't necessarily bits, as someone here remarked to me recently, if the reduced power from the dock (let alone the cable length) might be impacting the signal negatively. I doubt the Pro-Ject would resolve the differences but the RME might.

Thoughts?

 

[BlazeES]

USB power is a delicate business. Key thing about Macs: Thunderbolt ports have the juice to get into doing fancy things with quality peripherals. What you want to do is get a firm grasp of the specs across the entire 'chain'. Once you know the power ratings of the delivery system, you need to augment the entire 'system' with USB cables that are designed to deliver both the 'bits' and the power. Thunderbolt cables and/or USB4 rated ones is something you absolutely need to get right; especially with longer cable runs.

Which dock are you using Bob?

 

[rtp_burnsville]

Not a Mac person so can't help on that front. They do make powered USB hubs which should help on the power requirements. The Raspberry Pi community recently introduced a USB hub which can be powered for around $25.00. Have not tried it but sounds like it should work. A 25 foot USB cable sounds a bit long, you could be getting into transmission line effects. The USB specs use to be around 6 ft but that may have changed in recent years.

Robert

 

[Bob Boyer]

USB power is a delicate business. Key thing about Macs: Thunderbolt ports have the juice to get into doing fancy things with quality peripherals. What you want to do is get a firm grasp of the specs across the entire 'chain'. Once you know the power ratings of the delivery system, you need to augment the entire 'system' with USB cables that are designed to deliver both the 'bits' and the power. Thunderbolt cables and/or USB4 rated ones is something you absolutely need to get right; especially with longer cable runs.

Which dock are you using Bob?

Pretty sure it's this Hyper HyperDrive Next 6 Port travel dock, Tony. Don't have the receipt in front of my but I'm guessing based on price - and it was in stock as is this one:

https://www.bestbuy.com/site/hyper-...dows-pc-midnight-blue/6547715.p?skuId=6547715

I know I didn't spend $100 on it; I had to buy 3 Apple USB to USB-C adapters for my legacy drives on my work MacAir.

 

[74sdta]

To further what BlazeES stated, you need to know what each port on the Mini is good for. Some share power between ports and if one over consumes, the others become dead (sounds like you already discovered this).

I will throw this out as another option - battery power the DAC;
I have a desktop DAC and it sits one rack shelf above my music server (old laptop running Daphile) but I power it from this power bank - https://www.anker.com/products/a1277

It is quick charging and will run for multiple extended listening sessions

 

[Bob Boyer]

That would be a great solution but the USB-C connector also has to pass the audio signal - doesn't look like that one will. unless I'm reading to incorrectly. That said, I think I'll invest in an AC powered USB-C hub - I'm looking at a few that appear to pass sufficient power and signal but they're not cheap. Nor do they have a lot of USB-C ports.

 

[Chris Cables]

Just a thought Bob, but once you start using powered USB hubs to pass any audio/data intended for a DAC/amp etc. you introduce more risks of noise infiltration.
It's one of the reasons why I stay the hell away from making USB cables for audiophiles as you just don't know how bad or good their source/receiver components and/or hub device are going to be.

Same goes for audio over ethernet, there's too much risk in it for me that their gear will just be crap and noisy then condemn the cable for causing or not solving their existing noise issues.
tbh, anyone thinking of buying an 'audiophile' network cable needs a lesson or two in how good bog standard ≥cat5e cable actually is for passing analogue audio signals. They use twisted pair conductor geometry (CMRR), they're usually well-shielded and are as cheap as chips!

 

[Bob Boyer]

Agreed, Chris. I wish there was a way to bring the music closer to the DAC; as much as I dislike running a long USB cable, I'm even less enamored of any wireless setup. As I've noted, there's too much interference between two computers, mice, and keyboards on one desk as it is. There's just so little space in this room to place a computer close to the equipment.

Just a thought Bob, but once you start using powered USB hubs to pass any audio/data intended for a DAC/amp etc. you introduce more risks of noise infiltration. It's one of the reasons why I stay the hell away from making USB cables for audiophiles as you just don't know how bad or good their source/receiver components and/or hub device are going to be.

Same goes for audio over ethernet, there's too much risk in it for me that their gear will just be crap and noisy then condemn the cable for causing or not solving their existing noise issues....

Which leads to another question. Might it be better to locate the DAC close to the computer and make a 25' run of audio cables to the preamp? I have enough cable to do that as well, though I might need to talk to you about an upgrade as part of the purchase of a new DAC. Whatever I run needs to be able to stand up to foot traffic underneath the rug. (See attached panoramic.)

 

[J!m]

I would run 25' of balanced cable if you can, Bob. But that seems a better option, plus you keep the "digital hash" away from the analogue equipment. Even switching power supplies (like most things have these days) on the same AC circuit as the gear is audible.

 

[BlazeES]

Sent you a PM Bob.

 

[Chris Cables]

Agreed, Chris. I wish there was a way to bring the music closer to the DAC; as much as I dislike running a long USB cable, I'm even less enamored of any wireless setup. As I've noted, there's too much interference between two computers, mice, and keyboards on one desk as it is. There's just so little space in this room to place a computer close to the equipment.




Which leads to another question. Might it be better to locate the DAC close to the computer and make a 25' run of audio cables to the preamp? I have enough cable to do that as well, though I might need to talk to you about an upgrade as part of the purchase of a new DAC. Whatever I run needs to be able to stand up to foot traffic underneath the rug. (See attached panoramic.)

View attachment 85435

Swings and roundabouts Bob. I'd do a bit of experimenting before investing time/expense in a potentially expensive cable solution. A cheap (shielded) power+data spec USB cable. Somebody must be selling those somewhere!

Long runs of cables are susceptible from internal and external EMI/RFI noise, so isolation is the key. The best idea imo would be to have your DAC located nearer to the pre-amp. Not handy for switching unless it has a remote control (?) but better for mitigating noise issues if you can source a suitable USB cable. I take it there's no other power option for the DAC except via USB?

Routing cable in front of that door is the obvious caveat to either setup as both cable types will be subjected to repeat-cycle foot traffic. You could get a cable-step of course but theyre mostly pretty ugly and inconvenient.
Any option to go the other way around the room, avoiding the door?

If you do decide to implement analogue cables under the carpet then I'd recommend Belden 8412. It's the strongest, most durable mic cable bar NONE. I actually stopped using it for a cable model I used to make as it had a propensity to rip my fingers apart when working with it! I can only take so much abuse!
I used to joke that if there was ever a nuclear armageddon the only things left on the planet would be cockroaches...and Belden 8412 cable




This was the last order of cables I made with Belden 8412. My fingers needed a week off work after this!

 

[George S.]

I use the Monoprice Monolith USB cables.
Lot's of other options on that site.
https://www.monoprice.com/product?p_id=33464

 

[Bob Boyer]

Sent you a PM Bob.

Yes, thanks. Just got on to reply a few minutes ago. Been a hectic day.

 

[Bob Boyer]

Swings and roundabouts Bob. I'd do a bit of experimenting before investing time/expense in a potentially expensive cable solution. A cheap (shielded) power+data spec USB cable. Somebody must be selling those somewhere!

Long runs of cables are susceptible from internal and external EMI/RFI noise, so isolation is the key. The best idea imo would be to have your DAC located nearer to the pre-amp. Not handy for switching unless it has a remote control (?) but better for mitigating noise issues if you can source a suitable USB cable. I take it there's no other power option for the DAC except via USB?

Routing cable in front of that door is the obvious caveat to either setup as both cable types will be subjected to repeat-cycle foot traffic. You could get a cable-step of course but theyre mostly pretty ugly and inconvenient.
Any option to go the other way around the room, avoiding the door?

If you do decide to implement analogue cables under the carpet then I'd recommend Belden 8412. It's the strongest, most durable mic cable bar NONE. I actually stopped using it for a cable model I used to make as it had a propensity to rip my fingers apart when working with it! I can only take so much abuse!
I used to joke that if there was ever a nuclear armageddon the only things left on the planet would be cockroaches...and Belden 8412 cable

View attachment 85443
View attachment 85444

This was the last order of cables I made with Belden 8412. My fingers needed a week off work after this!
View attachment 85445

Yeesh. I can only imagine. Tore up my fingers with Belden 5000 for my speaker cable. Tried to keep as much of it unterminated as possible until I kept ripping skin open. Plugs and spades all the way now...

I've been looking at reversing the room on the diagonal but I have another door to a storage room in THAT corner. I'm thinking of getting rid of the sofa that Pat talked me into (it's just too long for the space) and getting a sleeper chair or love seat to use when we need to use the space as a storm shelter. That would give me a little more room between the chair and the wall where a dedicated music computer could be set up. Mom's old iMac works like a champ and I've purposely not updated the OS so I can use it with the Tascam UH-7000 interface, which does use balanced cables, plus does digital and analog both directions and sounds better than this Pro-Ject, even if it is older. Under that setup, at least the cables wouldn't be getting stepped over/on.

 

[J!m]

Theres a lot to be said for the older D/A converters. The newer ones seem to measure better but not necessarily sound better. Particularly if your reference is analogue recordings. That old Alesis Masterlink I have for example- some guys are using them just as a converter to analogue.

Compared to live performance, modern is probably better- frequency response up to infrared...

 

[Bob Boyer]

So after a conversation with Tony, I made a few adjustments. Swapped a longer HDMI run (via a cheap 4>1 powered HDMI switch) to move the Mac Mini and drives off of the corner of the desk while still leaving the monitor on the deck. This shortened the USB run from the computer to the Pro-Ject DAC by 16 feet. With the remaining 12' USB run, it's a bit long but not as bad. Haven't noticed any particular difference but at least I've done something.

Listening to Vanessa Fernandez' 2016 rendition of Zep's music on her When The Levee Breaks album using dsf files from the computer. That's an eye-opener - female jazz vocals with excellent backing and all-analogue recording on some great, male-centric material.

 

[Bob Boyer]

Interestingly, my power issues were resolved with this move as well; I no longer need the dock, which, it turns out, was the power hog - not the SuperDrive. I've got both Glyphs, the SuperDrive, the DAC, and the peripherals connected to the monitor all working with no need for the dock. Splitting the distance was the difference.

That said, I'm also looking at an OWC Thunderbolt 5 dock that may make sure I'm getting good signal to the RME DAC I'm lusting after (https://vintageking.com/rme-adi-2-dac-fs-2-channel-da-converter).

 

[Chris Cables]

That said, I'm also looking at an OWC Thunderbolt 5 dock that may make sure I'm getting good signal to the RME DAC I'm lusting after (https://vintageking.com/rme-adi-2-dac-fs-2-channel-da-converter).

That's a decent DAC Bob, with a good spec and low distortion figures but the lack of analogue inputs and balanced headphone output/s would be a deal-breaker for me. Can you live without those features (esp if your pre-amp I/O's are fully populated?)

 

[Bob Boyer]

That's a decent DAC Bob, with a good spec and low distortion figures but the lack of analogue inputs and balanced headphone output/s would be a deal-breaker for me. Can you live without those features (esp if your pre-amp I/O's are fully populated?)

The Audible Illusions has a great headphone amp built in. Louis used it as such even after he got the Pass Labs preamp. It's not balanced, but I'll bet it sounds better than my Beyer cans. And no, I'm only using about half the preamp's inputs right now. I've really pared down to (besides the computer/DAC) just the turntable, SACD player, and the Astell & Kern DAP. I have room for a tape deck, a tuner, and another auxiliary device if I choose to add them back.

 

[Bob Boyer]

That's a decent DAC Bob, with a good spec and low distortion figures but the lack of analogue inputs and balanced headphone output/s would be a deal-breaker for me. Can you live without those features (esp if your pre-amp I/O's are fully populated?)

Also, I can get the A>D function with the RME ADI 2/4 Pro converter (https://vintageking.com/rme-adi-2-4-pro-se-2x4-ad-da-converter) for $2500 but I've pretty much digitized as much of my album collection as I'm going to, so I see no sense in going beyond a DAC at this time. If I do, I'll resurrect mom's iMac and the Tascam UH-7000 converter and find someplace to set them in the room.