Which Front End?

[catastrofe]

Okay, so I've been lurking, researching, and buying some equipment in preparation for my server build. So far, I've purchased a Drobo/Droboshare for use as a NAS, and a pre-owned Esoteric D-05 for my D/A conversion. I've also been installing a wired network in my home, so I'll have the best connection between my listening room and the Drobo.

 

Now I need to decide on a "front-end". The D-05 accepts coax, Toslink, and AES (but in a stereo configuaration, which I've never seen before) digital inputs.

 

I've been leaning towards a Mac based on ease of use and sound quality. A Mac Pro may be out of my budget, so I'm looking at a Mini, an IMac, or a Macbook. I'm assuming I'll need to go Toslink from the Mac to the DAC. Is there a sonic advantage of one Mac over the others? Should I be concerned that I'm limited to 24/96 unless I go Mac Pro/Lynx?

 

Or, should I consider a PC build with a Lynx card? The thought of frying my tweeters concerns me but I'm not sure if this only happens when changing settings in Windows. Whatever route I take, the unit must be silent as it will be in my listening room.

 

Thanks,

 

Bob

 

[tmfidelis]

NOT IN ORDER OF PREFERENCE:

 

1. Mac G5 with Lynx AES16 PCI card.

2. Mac pro with Lynx AES16 PCIe card.

3. PC with Lynx AES16 PCI card with carefully attention to OS configuration to greatly increase the system stability.

4. Firewire devices still under evaluation.

 

A. A computer may be installed in a "hush box" to reduce or eliminate fan and hard disc drive noise. SSDs may be used to eliminate drive noise if accessing files from a NAS system.

 

B. The decision is very important as it may dictate the overall system capabilities and will influence decisions downstream. It's somewhat like selecting a Sure SM57 microphone to record chorale music. It may take much work and adjustments to get the recording to sound good but may never be as good as having started with a Neumann U67.

 

Regards,

 

[audioengr]

Use a laptop like Macbook or a headless Mac Mini with either USB to your DAC or Toslink to a reclocker and then to the DAC. Then, control this with an iPod touch or IPhone. This is the most convenient system. Wired for the audio local to the rack and wireless for control from the listening position. Supports 24/96.

 

If you dont have a USB DAC, then add a USB to S/PDIF converter with a good USB cable.

 

Steve N.

Empirical Audio

 

[catastrofe]

Thanks guys.

 

Steve, my DAC doesn't have USB, but I'm not averse to a converter if there's a sonic benefit. Do the Macs provide 24/96 out on USB as they do with optical? If so, is their USB implementation on par with optical?

 

Thanks,

 

Bob

 

[The Computer Audiophile]

Hi Bob - I did a little research on your DAC and it looks like you have the makings of a very good sounding system. That DAC can handle up to 24/192 material and it would be a shame not to take advantage of this potential. The HRx albums from RR are 24/176.4 and the Esoteric would work very nicely with these albums. The AES inputs support dual wire, but I don't believe it is a requirement. Plus, a really great part of your DAC is the ability to send word clock out. So, I recommend using a Windows PC with Lynx AES16 PCI card. Use the Esoteric to send word clock to the Lynx card. Then you'd have once source of master clocking. This has huge potential to improve your sound. I've listened to some different configurations with different word clocks including a Pacific Microsonics Model Two in the mix, and word clock can be a very nice improvement. I believe the next component in my system will be an external clock since the Berkeley Alpha DAC doesn't send word clock out.

 

One note: If you use the Esoteric word clock output and Lynx card be sure to turn Synchro-Lock off. When and if you get to this point I'll be glad to help. It's really not hard.

 

[Mike Smith]

Is there such an animal as a stand alone reclocker that is geared for those who already have a USB DAC?

 

[catastrofe]

Chris, thanks.

 

A few more questions. . .

Is there a reason you suggest PC/Lynx rather than Mac/Lynx?

I think you recommend the AES16 over the AES16e express version. . .is that correct? Why?

Assuming the non-express version is the way to go, there are 3 versions available; card without cables, card with 2-4' XLR cables, and card with SRC and 2 cables. Which would I purchase?

 

Thanks again,

 

Bob

 

 

[tmfidelis]

Hey Bob and Chris:

 

Here's and interesting configuration for Bob - A proper Mac G5, Lynx AES16 PCI card and down the road, SoundBlade that may include Amarra.

 

Regards,

 

 

 

[Mike in MD]

Hi Chris,

 

I (and, I am sure, others) would be interested in reading your thoughts on external clocks: what's available, and how they would connect into the system. I did not see anything on the CASH list.

 

Thanks,

Mike

 

 

 

 

[The Computer Audiophile]

Hi Mike - Good question. Right now the external clock that I really like is the Antelope Audio Isochrone OCX. It's available from many places online as well as a dealer network that could likely answer many more questions than myself. Here's how this clock would connect to one of my music servers. The Antelope Audio Isochrone OCX sends the clock signal to my Lynx AES16 PCI card. This Lynx card sends the digital audio output of my music server to my Alpha DAC. This is a very basic description, but the details are pretty easy. If you pick up a master clock I, and others here on CA, will certainly help you out if there are problems.

 

 

 

Right now the Antelope Audio Isochrone OCX is on sale for $995. Here is a link:

 

http://www.sweetwater.com/store/detail/OCX/

 

 

[Mike in MD]

Chris,

From your reply, I am guessing that a DAC does not have an internal clock, but takes its time signal from the actual arrival of the incoming words that are sent by the Lynx PCI card. I had thought that the DAC had a clock, too.

So the Antelope will control the Lynx which will control the Alpha DAC (should be another animal name). The oven-controlled oscillator on the Antelope should be a big improvement over the Lynx's open PCI card environment.

It appears that I would have to manually switch the frequency of the Antelope when I changed music formats in Media Monkey, for example from 24/88.2 to 24/96

 

Thanks,

Mike

 

[The Computer Audiophile]

Hi Mike - You're close but a little off. DACs have internal clocks, but often benefit from an external clock or they benefit from using the internal clock as a master clock if they have a word clock output.

 

Example -> Antelope send clock signal to the Lynx which allows you to skip the Lynx crystal and supply a better clock source to the Lynx. The Lynx does not send clock to the DAC since the DAC already has a clock. A really neat solution is to use a DAC with word clock output to send to the Lynx card. This system means you only have one master clock in the system.

 

I'm certainly no expert on external clocking and may have caused more confusion here. Hopefully others with better knowledge of these clocks will jump in this conversation.

 

You are 100% correct about the requirement of manually changing the sample rate on the external clock. This is the one pain in the butt with external clocks at the moment. Most clocks are built for pro audio where people set the clock at one sample rate for a complete project and don't need to change it frequently.

 

 

 

 

[catastrofe]

Chris,

 

I think I answered a couple of these questions by searching the site. Can you confirm my understanding?:

 

You recommend a PC/Lynx solution because the Mac only accepts PCIe which doesn't sound as good as standard PCI. That also answers my second question.

 

I'm still not sure if you recommend the SRC version of the Lynx or the standard. . .

 

Assuming I go this route, is there some type of guide available that provides all the "tweaks" needed to get the best audio quality? And, with this type of setup, which ripping/playback software would you recommend (EAC and MediaMonkey?)?

 

Thanks,

 

Bob

 

[Mike in MD]

Chris,

 

So the best solution would be to have the Antelope feed a master clock signal to both the Lynx and the Alpha DAC. But the Alpha DAC does not accept an external clock.

We can start a petition to be sent to Berkeley Audio to add this feature. For $5k we should be able to get a master clock input.

 

And I am also interested in Bob's question on how to optimize the ripping/storage strategy with EAC and MediaMonkey.

 

Mike

 

[cfmsp]

 

Chris,

yes, I'm confused on this matter of externals clocks in general, esp. with the Lynx PCI card.

 

As I understand it, it is best to place (and use) a clock in the DAC.

As I'm looking to simplify the process as much as possible, Im not sure I understand the value of using an external clock to drive the Lynx card.

 

On top of that, IF one is reclocking the Lynx card, what exactly is is that the Lynx card is doing that a straight cable won't do.

 

Conceptually, I can 'get' that GIGO theory suggests that the less re-timing being done by the DAC, the better it might sound, BUT it still sounds very specious to me.

 

That comment goes doubly for DACs of the world class variety - Minerva / Berkeley. Why would reclocking an incoming signal (multiple times?) improve the sound - i.e., first the Lynx card, then an external clocker, and then a Minerva/Berkeley?

 

I'm not asking skeptically, I'm very curious and can't seem to get it.

 

thanks

Clay

 

 

[audiozorro]

Is this true for all external clocks - that you have to manually change the sample rate on the external clock? If so, are there any external reclockers that provide a remote control for changing the clock sample rate?

 

Is it better to set the external clock to match the external DAC – for instance in the case of the Benchmark DAC1 that upsamples everything to 110kHz, set the external clock to 110kHz?

 

This thread mentions the Antelope Audio Isochrone OCX, others mention the Apogee Big Ben or the Empirical Audio Pace Car reclockers. How does one select te best clock for a DAC without painstakingly trying each one?

 

Are some external clocks better for some sampling rates than others? Too many questions for me is probably a good indication that selecting a good and probably expensive master clock is above my comfort level.

 

[Mike in MD]

Maybe we should move Clocks to a new thread ??

 

Mike

 

 

[audioengr]

"Steve, my DAC doesn't have USB, but I'm not averse to a converter if there's a sonic benefit. Do the Macs provide 24/96 out on USB as they do with optical? If so, is their USB implementation on par with optical?"

 

You dont need USB unless you are some distance from your computer. You can run Toslink cable to a reclocker and then S/PDIF or AES cable to your DAC. Macs output 24/96 from the Toslink. I have a number of customers doing this including the editor of Positive-Feedback, Dave Clark:

http://www.positive-feedback.com/Issue39/ramblings_computer.htm

 

Steve N.

Empirical Audio

 

[audioengr]

"Is there such an animal as a stand alone reclocker that is geared for those who already have a USB DAC?"

 

Yes, but it will not use the USB input on the DAC. It will connect to the S/PDIF input. the Pace-Car 2 reclocker can do this. The source can be: USB converter, Squeezebox, Sonos, Duet, Transporter, Lynx AES16, Apple TV and others.

 

This sounds counterproductive, but it will outperform the existing USB input. I've tried it on several USB DAC's.

 

Steve N.

Empirical Audio

 

[audioengr]

Chris wrote:

"DACs have internal clocks, but often benefit from an external clock or they benefit from using the internal clock as a master clock if they have a word clock output."

 

Not entirely true. Most modern DAC's have internal clocks ONLY for asynchronous upsampling, which is an inexpensive way to get a reduction in jitter (albeit you have to live with the quality of the hardware upsampler). Only a few high-end DAC's have internal master clocks with clock outputs. If you use these, you are at the mercy of that clock quality.

 

Having an external clock input on a DAC at first sounds really good, and it is the optimum implementation. The problem is: how good is the clock that they used? Is it musical?

 

This is why I developed a DAC without clock and I provide an I2S interface directly to the D/A chip. This way, you can change devices and external clocks to get the most musical one. This places the low-jitter clock right at the D/A chip where it is optimum, but does not lock you into a particular clock.

 

Here is an example of clock musicality: I provide both Ultraclock (list $800) and Superclock (list $300) option for all of my products, as well as a low-jitter monolithic clock (2psec period jitter). The Monolithic clock is very detailed, and if you never heard the Superclock you would probably stay with the monolithic. However, the Superclock adds a lifelike "vivid" quality to the music that makes it much more enjoyable. I believe it is the spectra of the jitter that makes it more listenable, not so much the amplitude. The Ultraclock is more that twice as expensive and does provide more detail than the Superclock, but I feel that it is not as musical, so I dont push it. It may be better in one system than another though. The quality of the D/A clock is so critical that selecting a DAC with an internal clock I believe is a bad idea, at least not without several optional clock upgrades. You are married to that sound forever.

 

Steve N.

Empirical Audio

 

[audioengr]

Clay wrote:

"On top of that, IF one is reclocking the Lynx card, what exactly is is that the Lynx card is doing that a straight cable won't do."

 

The lynx card is synchronizing it's clock to the incoming word-clock. This way, when the data-stream goes for the Lynx to the reclocker, whether internal or external to the DAC, it is synchronous to the local master clock in the reclocker or DAC and will not overrun or underrun the buffer. If you do not use the word-clock cable, you are not synchronous and you will get continuous ticks.

 

Steve N.

Empirical Audio

 

[audioengr]

"Is it better to set the external clock to match the external DAC – for instance in the case of the Benchmark DAC1 that upsamples everything to 110kHz, set the external clock to 110kHz?"

 

No, actually if the upsampling clock is left alone in the DAC-1 (I removed it in my mods), then it is better to give the DAC 24/96. Because the two sample-rates are unrelated, the upsampler sounds a bit better. Not my cup of tea however. No hardware upsampler is as good as SRC and Foobar 0.8.3.

 

"This thread mentions the Antelope Audio Isochrone OCX, others mention the Apogee Big Ben or the Empirical Audio Pace Car reclockers. How does one select te best clock for a DAC without painstakingly trying each one? "

 

Like everything else, you probably have to read the reviews and the customer feedbacks and then decide. The editors of both Positive-feedback and Stereo Times use the Pace-Car:

http://www.positive-feedback.com/Issue39/ramblings_computer.htm

 

"Are some external clocks better for some sampling rates than others?"

For 44.1, 88.2 and 176.4 you need one clock

For 48, 96 and 192 you need a second clock

 

This is because these two clock series are not related mathematically.

 

If you start with 49.152MHz, you can generate 48,96 and 192 clocks

If you start with 45.1584MHz, you can generate 44.1, 88.2 and 176.4 clocks

 

Another thing you need to know is that master clock and word-clock are not the same. Master clock is used to derive all of the clocks that the D/A needs. Word-clock is only one of the clocks that the D/A needs. For 44.1 sample-rate for instance, master clock is 11.2896MHz and word-clock is 44.1kHz.

 

Steve N.

Empirical Audio

 

 

[Mike in MD]

It sounds like:

 

if you want to start with a Lynx PCI, and

 

you want a high quality external clock that controls both the Lynx and the DAC, and

 

you want to be able to run ALL six frequencies: 44.1, 88.2, 176.4, 48, 96, 192 and

 

you want the bit-stream to go to a high quality DAC with a clock input (and a MUTE button to protect our precious tweeters)

 

then the puzzle pieces are not all here yet.

 

Mike

 

 

[darrenwm]

Your choice of front end will make or break your computer audio experience.

 

I would try to see if you can play with an Apple TV, Remote App, Squeezebox, Sonos, etc, etc and see which interface you like using the most. Once you've settled on this simply feed the digital output of the chosen source into your DAC and then enjoy the music.

 

Personally I have a headless Mac Mini controlled by iTouch.

 

All of this talk of "musical clocks" is surely taking the piss??

 

The word "musical" is bad enough. As far as I'm concerned it doesn't mean anything, and if it did, it would mean something different to each individual. The only benefit of that word is in highlighting potential snake oil.

 

[audioengr]

"if you want to start with a Lynx PCI, and you want a high quality external clock that controls both the Lynx and the DAC, "

 

Pace-Car 2 does this

 

"and you want to be able to run ALL six frequencies: 44.1, 88.2, 176.4, 48, 96, 192"

 

Pace-Car 2 can do this although very few customers use more than 44.1 and 96.

 

"and you want the bit-stream to go to a high quality DAC with a clock input (and a MUTE button to protect our precious tweeters) "

 

No need for a clock input. What you want is an I2S input. There are several DAC's that have this including:

 

Empirical Audio Overdrive DAC

Northstar 192 and Extremo DAC's

Audiologic

Perpetual Technolgies P-3A

The new PSAudio DAC

 

"then the puzzle pieces are not all here yet."

 

Sure they are. I have several customers doing exactly this.

 

Steve N.

Empirical Audio