Mac Mini

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frugal-phile™
Joined 2001
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The best way is FireWire. As to USB or Toslink, it will depend more on the DAC. One of the (few) Asyncronous USB DACs would likely work best, but you are well into the price range of FireWire DACs.

(BTW, it is Mac Mini -- i've updated the thread title for you)

This is the one i'm looking at getting next

http://www.rolandus.com/products/productdetails.aspx?ObjectId=731&ParentId=114

An externally hosted image should be here but it was not working when we last tested it.


I have 1 of the cheaper USB ones (cost $75 at swap-n-shop) and it is quite decent, but still doesn't trump our better CD players, and is limited to 96k one way. The Firewire will allow simultaneous in/out at 192k, which makes digitizing records worthwhile, and will allow the playback of scarce yet, but available hi-rez downloads.

dave
 
The mac mini has an optical output in the same location as the headphone out. Both firewire and usb require additional software processing, while optical is a hardware solution.

plus optical dacs are considerably cheaper than usb or firewire. we had a "bargain dac" shootout using my macbook as a source, and the vintage entech number cruncher (about $75 to 90 used) was the winner.

I use a zero dac with a discrete jfet buffer. The headphone output is nice too.
 
frugal-phile™
Joined 2001
Paid Member
d to the g said:
The mac mini has an optical output in the same location as the headphone out. Both firewire and usb require additional software processing, while optical is a hardware solution.

What extra SW processing?

With optical... you have a SPDIF transmitter in the Mac > out

With USB ... you have USB to IS2 hardware (transmitting the USB does require use of the main CPU)
With Firewire ... you have Firewtre to IS2 hardware

(i'd specifically avoid the ones that go FireWire or USB>SPDIF)

All the same software is in play (CORE audio -- you do need to make sure the settings in Audio MIDI setup and in your player are right)

The optical might be the cheapest (and that is questionable), but he asked for best.

dave
 
I run my digital end of my audio system from a Mac mini via USB, basically I use a trends UD10 and then through to a DAC of choice via coax.

The sound is great, no issues at all.

The Trends is run off a purpose built power supply from a 6v SLA with integrated charger, totally noise free and better to my ears than the USB power supply. This I feel is a great solution and in the end pretty economical.

I am pretty convinced also that the MAC mini is the ideal tool for this, even out of the box it sounds way better than any other computer I have had, including my other macs. Basically I think there is much to be said for having the computer power supply external from the computer.
 
planet10 said:
The best way is FireWire. As to USB or Toslink, it will depend more on the DAC. One of the (few) Asyncronous USB DACs would likely work best, but you are well into the price range of FireWire DACs.

So what is the difference between Firewire and USB for this purpose? Does FW have lower latency? My understanding is that USB is better than SPDIF because SPDIF is not "reliable" (i.e. doesn't guarantee accurate data stream).

Looking at the FA-66, that would be comparable to the UA-25EX on the USB side right?

I was originally looking for simply a DAC, but actually it would be cool to have the input capabilities of something like this as well for playing around with garageband etc.

d to the g said:
we had a "bargain dac" shootout using my macbook as a source, and the vintage entech number cruncher (about $75 to 90 used) was the winner.

Is that not available any more? It looks cool.

Zero One said:
I run my digital end of my audio system from a Mac mini via USB, basically I use a trends UD10 and then through to a DAC of choice via coax.[/B]

Why not use the DAC that's built into the UD-10?
 
Why not use the DAC that's built into the UD10

No problem at all, it actually works really well, and sounds far better the computers output, though the analogue connection via the stereo minijack plug is not too great. basically it's intended for headphone use.

In the end an external DAC will sound a bit better and of course you can access different flavours of DAC, ie NOS, upsampler, etc
 
frugal-phile™
Joined 2001
Paid Member
sbwoodside said:
So what is the difference between Firewire and USB for this purpose? Does FW have lower latency? My understanding is that USB is better than SPDIF because SPDIF is not "reliable" (i.e. doesn't guarantee accurate data stream).

Firewire was designed from the start as a multi-media transport. It has dedicated hardware for handling the data transport.

Getting USB to do media was an after-thot and something that has been shoehorned... It requires CPU to assist in data transport.

Looking at the FA-66, that would be comparable to the UA-25EX on the USB side right?

Yes. The latter is the one i have right now... picked up used for $75.

dave
 
OK, so far this is what I'm understanding; Optical is SPDIF which is not reliable in fidelity, USB needs CPU's help to transfer data, and while I read it elsewhere, firewire is more jitter prone.

I know with the optical I avoid ground noise from the computer, does USB and/or firewire isolate the computers ground?
 
The short answer is that Firewire is probably the best (read the thread though, it's interesting). This is because the DAC clock is the master in all cases - the transport induces no jitter at all because it doesn't carry the clock. Data is sent to the audio interface when it requests it; the DAC is fully in control of the data stream. In the USB Audio Class and S/PDIF, data is sent at a constant rate and the clock is recovered from the data timing, which is where jitter becomes important.

Since the USB timing is generated indirectly from the main CPU clock (where frequency stability is not critical), and the USB frames themselves pass through a complicated path before they're transmitted, there's a ton of potential for jitter there. USB can be pressed into service to work as Firewire does, and most professional interfaces do, but not using the generic USB audio driver included with your OS.

I'm quite sure that USB doesn't guarantee data integrity (without special protocols anyway), and I don't think Firewire does either, though it may have a CRC field, I can't recall right now. It's moot for audio anyway though because there's no time for retransmission in most cases. You either ignore the corrupt sample or play it (though it would arguably be better to just replay the previous sample than a corrupt one, it's not a huge difference).

I would say Firewire = USB (DAC master)> S/PDIF > USB Audio Class.
 
phofman said:


Hi,

I have been looking for the actual implementation of USB 1ms frame clock, and so far have been able to uncover only http://www.diyaudio.com/forums/showthread.php?postid=1690264#post1690264 . This specific implementation does not use SW-driven clock.
Interesting discovery, I never really thought to look into it too deeply, but obviously it's not totally software driven or it'd never really work well. I had assumed it was driven by a CPU interrupt, which is only sort of software driven (I never said SW!). Still, it's generated from the same source as the CPU clock (and almost every other clock in the PC), and with USB's low timing requirements it's probably not treated particularly critically in the USB section of the ICH. Though you're right, I don't see how this is any worse than using the S/PDIF output which is clocked from the same source - at a guess I'd think low jitter recovery is probably considerably more difficult to achieve than in S/PDIF, however.
 
Try FireWhave from Griffin Tech.
about 30USD...
sniffed that could be of help and odrdered few months ago...
I was amased when I opened (read crashed...)
but without damaging the pcb...
*
oxford FW chip with I2S
wolfson dac
*
And next FW product is LaCie firewire speakers, also have ozford FW chip to interface
digital from firewire...
:D
 
planet10 said:
The best way is FireWire. As to USB or Toslink, it will depend more on the DAC. One of the (few) Asyncronous USB DACs would likely work best, but you are well into the price range of FireWire DACs.

(BTW, it is Mac Mini -- i've updated the thread title for you)

This is the one i'm looking at getting next

http://www.rolandus.com/products/productdetails.aspx?ObjectId=731&ParentId=114

An externally hosted image should be here but it was not working when we last tested it.


I have 1 of the cheaper USB ones (cost $75 at swap-n-shop) and it is quite decent, but still doesn't trump our better CD players, and is limited to 96k one way. The Firewire will allow simultaneous in/out at 192k, which makes digitizing records worthwhile, and will allow the playback of scarce yet, but available hi-rez downloads.

dave

I'm interested in the pro stuff as it is remarkable for being both high-quality and myth-free.

I have read some bad reviews about m-audio equipment and since there is not a big price differential between them and the roland you linked to i might buy this firewire audio interface (Much cheaper than a benchmark dac-1, which isn't mentioned often here). Is there any way to trade channels and portability for quality?

There are also the PCMXXXX + paper in snake oil caps interfaces that sell for arround $150 but i don't want to go that way.
 
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