Clock synchronization issue?

After a lot of experimentation lately I've come to the conclusion that there is a lower mid-range/upper bass frequency dip when using my Simaudio 650D with my Sooloos MC200. This dip doesn't occur with the other DACs I tried with the Sooloos nor does it occur on cd play through the 650D. My Sooloos dealer thinks it may be a clock synchro nation issue between the two units and is thinking that inserting some sort of re-clocking device between the two units may resolve the issue. Any thoughts or similar experiences you could share to help me out?

FYI, the Sooloos up samples the digital signal to 88.2 kHz and applies an apodising filter before outputting the digital signal. I'm not sure if the 650D also uses some sort of up sampling as well.
Just an update...I tried using an Arcam CD player as a transport, feeding the Simaudio 650D through the same S/PDIF rca input as the Sooloos. The sound was perfect - pretty much identical to using the 650D's own transport.

So, this must be an issue of compatability between Sooloos and the Simaudio 650D.

One other finding - the Sooloos/Simaudio 650D combination sounds more like the 650D's transport/dac combo when the Sooloos upsampling/apodising filter is switched off (more open sounding, although not as "rich").
You are probably experiencing either the effects of jitter or some format handling strangeness with the Sooloos. Its not a synchronization or compatibility issue. Jitter, ripping software and playback software can all have a dramatic impact on the SQ. Picking the optimum of these is critical in computer audio systems. Jitter is the most difficult thing to keep low at low frequencies. Clocks that accomplish this are very expensive.

Most all-in-one systems that I have had in my system were dissappointing either in the ripper or the playback software or both. All had higher jitter than I am used-to.

This is why I recommend a late 2009 Mac Mini with Amarra or Pure Music and XLD ripper. These all have proven track records with multiple awards.

Steve N.
Empirical Audio
Thanks Steve!

Very interesting, particularly that jitter in low frequencies can be more challenging than at other frequencies.

I predominantly use wave files ripped by Exact Audio Copy (with the program optimized for my laptop). Flac files (ripped by the Sooloos) I find don't sound quite as good.

Strange that so many of the audio reviewers use Sooloos to evaluate audio equipment if it's a limiting factor in sonic quality!

What's interesting is that the sound of the dac in the Sooloos Media Source 600 is quite warm and maybe a tad mid-bass heavy. What's also interesting is that engaging the Meridian up sampling anodizing filter before the digital output changes the sound quite a bit with my Simaudio dac - the music gets slightly rolled off in the treble and warmer in the mid-range.

Any suggestions for getting the best sound possible out of the Sooloos? I love the interface!


"Any suggestions for getting the best sound possible out of the Sooloos? I love the interface!"

If the problem is jitter, which is likely IMO, then the solution is to reclock it with a resampling reclocker like this:

You will not get bit-perfect, but it will probably sound better anyway.

If the problem is the playback software, there is not much you can do.

I would recommend using dbpoweramp with Accurate Rip enabled to rip CDs.

Steve N.
Empirical Audio
Thanks Steve. Your advice is much appreciated!

I compared the S/PDIF output of a Sooloos Ensemble with the MC200 into my Simaudio 650D dac yesterday. I got the best results with the Ensemble, which was basically on par with, if not a little better than, CD play through the 650D. Wondering why that might be - you would think that since Meridian took over the company and started to integrate their digital technology the sound would improve. Maybe the Meridian gear is designed to work best with other Meridian gear to the detriment of the sound through non-Meridian gear?
Contrary to what a lot of consumers believe, there is no "synergy" between digital components. Components are either well-designed or not. Cables are either well-designed or not.

Once you have a good digital source, all DACs will sound better with it. If it is a REALLY GOOD digital source, then most DACs will sound virtually identical. The input circuit on a particular DAC may have issues however, that holds it back. Resampling circuits are one of the things that usually breaks the SQ. Another thing that sets one DAC apart from another is the internal power systems. These are usually smaller effects compared to the digital source, unless you are taking about really cheap DACs.

Steve N.
Empirical Audio
Well, I guess the S/PDIF digital output of the Sooloos MC200 and MS600 is not optimal and that Meridian has designed their DACs to compensate. Funny, though, that we found the Arcam D33 seemed to deal with the MS600 digital output better than the more expensive Simaudo 650D though...maybe better DACs are more revealing of poor digital sources?

I honestly think that Meridian's apodizing filter colours the sound as well but if you turn it off, the quality of the digital output signal without the Meridian upsampling/apodising is poor quality.
The other thing I noticed in reading the Stereophile review of the Sooloos Source One (2008) was that the original unit they got to test had a grounding issue with the analogue outputs which resulted in an issue in the 85 Hz range. I wonder if that issue persists in the digital output of MC200 and MS600?

Your company has continued to advance with some great new products...congrats! I remember reading you wrote that NOS DACs can sometimes have poor jitter rejection...if i have an older NOS DAC (Zanden 5000 Signature) there anyway still to take one of these servers...such as the Sooloos...and: 1) relock 2) add an i2s output to be configured to go into the Zanden i2s input which i have heard is by far the best way to use this DAC?

I believe your company used to do this. Thanks for any advice!
Lloyd - To my knowledge, there is nothing off the shelf that will interface to Zanden I2S, however a S/PDIF reclocker like the Synchro-Mesh will reclock the Sooloos or other servers nicely.

S/PDIF done well is only slightly worse than I2S. My own I2S is only slightly better than my S/PDIF. In most systems with preamps, you would probably not hear a difference between S/PDIF and I2S.

It is however critically important that you use a GOOD 1.5m S/PDIF cable, such as the Ridge Street Audio Poiema. Differences in digital cables in the $50-$300 range are minimal IME. You must spend at least $500 to get a significant boost in performance.

Steve N.
Empirical Audio
Steve N.

thank you! Good to know...I have a 2nd hand Valhalla digital BNC cable...does this work for you?

Meanwhile, i may contact you about Synchro-Mesh (presume this is one of your products). Any chance for a reasonable sum, you could have it customized for i2s output to my Zanden?

Thank you!
Lloyd - I am not familiar with the Valhalla cable. Never heard anyone rave about it.

I2S output on the Synchro-Mesh may happen in the future (it will not be a mod), but it still may not be compatible with Zanden. Is it the Zanden I2S the same as Perpetual and Northstar using RJ-45 connector?

Steve N.
Empirical Audio
Hi Steve N,

thank you...I was using Cardas Neutral Ref...was surprised to find i did not like the trial Transp Ref which i use in the rest of my system...and this one-off Valhalla 2nd hand was available and it worked much better...

In any event, the Zanden uses a computer cable linkup for its i am told, one needs to know how they configured the link so it could be compatible with the source.
Lloyd - if the Zanden uses the "D" connector, it is likely not compatible with either the Perpetual/Northstar/Empirical/Stello I2S or the HDMI PSAudio/W4S/Empirical I2S.

Steve N.
Empirical Audio
Hi Steve,

I really appreciate your time. I know you're busy running a business. The Zanden uses a computer cable which looks like the ones used in networking at the a phone jack with more wires...8 i think.
Lloyd - that is RJ-45, same as my products. It might work with the Off-Ramp 4 or Off-Ramp 5. It might also require a swizzle cable to put the signals on the right wires.

Steve N.
Empirical Audio
Interesting! That is quite cool! I have done some reading on the Off-Ramp 5 from the site and reviews...i think it is computer audio only?
Lloyd - yes, computer audio only. Better than any CD transport.

Steve N.
Empirical Audio
thank you, steve!