Squeezebox power supply, transport mechanisms, etc.

rblnr

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I use the digital out on a couple of Squeezebox Touch units into good DACs that minimize jitter. The Touch itself measures well (low jitter), and has been shown to pass the signal bit perfect(ly). Some people believe that exchanging the SBs switching power supply for a linear one actually improves sound using the digital out. These power supplies are as much or more that the Touch itself. Does anyone believe these claims? If so, why? And what are people's experiences with different transports feeding a good, jitter reducing DAC -- any differences noted?

I'm interested too in people's experiences with USB DACs such as the Wavelength and Ayre that use asynchronous transfer that allows the DAC to control the data flow of the computer. And lastly, software solutions such as Amarra -- any improvement?

In sum, I like the Squeezebox system, particularly now that it will pass 24/96 digitally. Also the touch screen is very handy for family and guests. BUT, are there better non-disk transport options?
 

Bigfish8

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Apr 20, 2010
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I use the digital out on a couple of Squeezebox Touch units into good DACs that minimize jitter. The Touch itself measures well (low jitter), and has been shown to pass the signal bit perfect(ly). Some people believe that exchanging the SBs switching power supply for a linear one actually improves sound using the digital out. These power supplies are as much or more that the Touch itself. Does anyone believe these claims? If so, why? And what are people's experiences with different transports feeding a good, jitter reducing DAC -- any differences noted?

I'm interested too in people's experiences with USB DACs such as the Wavelength and Ayre that use asynchronous transfer that allows the DAC to control the data flow of the computer. And lastly, software solutions such as Amarra -- any improvement?

In sum, I like the Squeezebox system, particularly now that it will pass 24/96 digitally. Also the touch screen is very handy for family and guests. BUT, are there better non-disk transport options?

I own a Squeezebox 3 that I had modded by Bolder Cable Company (http://www.boldercables.com/servlet/StoreFront) to improve the analog quality. While it was in for the mods I had Wayne Mod an Elpac Power Supply which by the way also works for the Touch (I recently purchased one). Yes, converting to a linear power supply from the noisy switching power supply will improve the sound quality. I would contact Wayne of Bolder to determine if he can recommend a place to purchase an Elpac and have him mod it. I think mine modded 3 years ago was around $150.00.

Concerning the subject of USB DACS - I just converted from using a Touch and feeding it digitally to DAC to a Mac Mini/Tranquility DAC. It is the most analog sounding digital I have ever heard. The Tranquility does not play HiRez but Eric Hider of db Audio Labs told me he expects to introduce a hirez DAC within the next few weeks. Prior to the Touch I was using a ModWright Modified Transporter (which does HiRez) and while the Transporter was better than the Touch the Mac Mini/Tranquility is another step-up in music quality.

If you decide to venture into Computer Audio with a USB DAC I seriously recommend you consider a Mac Mini as your music server and use an external fire wire drive for your music files. If you are in the Raleigh area I would be glad for you to listen to my system.

Ken
 

rblnr

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I own a Squeezebox 3 that I had modded by Bolder Cable Company (http://www.boldercables.com/servlet/StoreFront) to improve the analog quality. While it was in for the mods I had Wayne Mod an Elpac Power Supply which by the way also works for the Touch (I recently purchased one). Yes, converting to a linear power supply from the noisy switching power supply will improve the sound quality. I would contact Wayne of Bolder to determine if he can recommend a place to purchase an Elpac and have him mod it. I think mine modded 3 years ago was around $150.00.

Concerning the subject of USB DACS - I just converted from using a Touch and feeding it digitally to DAC to a Mac Mini/Tranquility DAC. It is the most analog sounding digital I have ever heard. The Tranquility does not play HiRez but Eric Hider of db Audio Labs told me he expects to introduce a hirez DAC within the next few weeks. Prior to the Touch I was using a ModWright Modified Transporter (which does HiRez) and while the Transporter was better than the Touch the Mac Mini/Tranquility is another step-up in music quality.

If you decide to venture into Computer Audio with a USB DAC I seriously recommend you consider a Mac Mini as your music server and use an external fire wire drive for your music files. If you are in the Raleigh area I would be glad for you to listen to my system.

Ken

Thanks for the info. Does Bolder claim that the Elpac would improve the digital out as well?

My house is very Apple-centric, and if I was to do a USB DAC, a Mac Mini would definitely be the server. Very handy too to use an iPhone as the the remote. BTW, they just came out w/a new Mini that has an HDMI out.

My hesitation is/was about a USB DAC is that I'm comfortably setup w/the Squeezebox model of one server for the whole house. The notion of a computer (or NAS) as a source in a each room seems clumsy from a music import standpoint (multiple HDs music has to be copied to), an operational standpoint, and cost as well. But for my main room, if a total of $2200 or so (700 for the Mini/1500 Tranquility) get me something great and SOTA, I'm willing and interested.
 

Bigfish8

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Apr 20, 2010
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Thanks for the info. Does Bolder claim that the Elpac would improve the digital out as well?

My house is very Apple-centric, and if I was to do a USB DAC, a Mac Mini would definitely be the server. Very handy too to use an iPhone as the the remote. BTW, they just came out w/a new Mini that has an HDMI out.

My hesitation is/was about a USB DAC is that I'm comfortably setup w/the Squeezebox model of one server for the whole house. The notion of a computer (or NAS) as a source in a each room seems clumsy from a music import standpoint (multiple HDs music has to be copied to), an operational standpoint, and cost as well. But for my main room, if a total of $2200 or so (700 for the Mini/1500 Tranquility) get me something great and SOTA, I'm willing and interested.

There are a lot of posts on the various audio forums claiming that replacing any switching power supply with a good quality linear power supply will provide sound quality benefits. Wayne of Bolder Cable, Channel Islands Audio and Paul Haynes all make linear power supplies for Squeezebox Products. If you plan to keep a Touch in your main system I would recommend you purchase a linear power supply for that one.

If you decide to go with a Mac Mini and DAC in your main system I will recommend what I purchased which is what guys that proceeded me recommended to me:
1. Mac Mini with Snow Leopard Operating System
2. Replace the hard drive supplied in the computer with a small Solid State Drive as it will just hold the operating software.
3. You will want to have 4 GB of Ram.
4. A Fire Wire 800 (preferably) external hard drive (you do not want USB as the only USB connection on the Mac Mini will be for the DAC)
5. A good quality USB DAC - I chose the Tranquility (Eric Hider sells the DAC to Audio Circle Members for $1295)
6. A high quality USB Cable - I purchased the db Audio Labs Cable for $195.00 with the DAC purchase.

Unfortunately, the Mac Mini would be a committed purchase but you can try the Tranquility DAC and cable for 30 days with a $75.00 restocking fee. Eric Hider told me that his development team blind tested music server computers and selected the Mac Mini as the optimum choice. I asked him why and he told me it is because, especially with a SS Internal Drive, there is not a lot of gear inside the Mini to create noise or to impact the quality of the data sent to the DAC. I am not a computer guy but what he told me made sense and I can testify that my Mac Mini is extremely quiet.

Music systems are all about our individual ears, tastes and unfortunately room interferences. I have gone through my share of gear to find the sound I am now enjoying and I realize it may not be what others would love. I totally believe in the "trust your own ears policy because you are paying for it" when it comes to audio gear. By the way I am still using a desktop PC as my music server for Sqeezecenter to my Squeezebox for my outdoor system.

Good Luck,

Ken
 

rblnr

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Exchanged some email with Eric. If I go that route, would wait for the hi-res capable DAC. Would likely go w/a Mac Mini w/any USB DAC and use a FW800 external drive. As for the improvement a linear power supply can make for the digital out, I'm both skeptical and open-eared. Will have to try for myself obviously.
 

Bigfish8

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Apr 20, 2010
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Exchanged some email with Eric. If I go that route, would wait for the hi-res capable DAC. Would likely go w/a Mac Mini w/any USB DAC and use a FW800 external drive. As for the improvement a linear power supply can make for the digital out, I'm both skeptical and open-eared. Will have to try for myself obviously.

If I had HiRez Music Files I would have waited for the next generation db Audio Labs DAC but I don't and I do not find much music in HiRez that I like to hear. Also, the ModWright Transporter Experiment cost me at lot between my investment and what I was able to sell it for. The Tranquility for $1295.00 is a real bargin in comparison.

I would also add that their are folks working on developing a linear power supply, to sell, for the Mac Mini. Eric Hider told me he has blind tested a linear on the Mini and it makes an audible difference to the sound. He also told me he did not know if the problem would be commercially viable as the power supply would like cost more than the Mini.

As a thought maybe you could contact Wayne of Bolder Cable or Dusty of Channel Islands Audio to determine if they possibly have a demo power supply you could audition. Trust your own ears!

Good Luck,

Ken
 
Last edited:

amirm

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Exchanged some email with Eric. If I go that route, would wait for the hi-res capable DAC. Would likely go w/a Mac Mini w/any USB DAC and use a FW800 external drive. As for the improvement a linear power supply can make for the digital out, I'm both skeptical and open-eared. Will have to try for myself obviously.
If you like, I can explain why it could make a difference but not whether it does :).
 

rblnr

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If you like, I can explain why it could make a difference but not whether it does :).

Please do, and your point is not lost on me.
 

amirm

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A switching power supply takes the AC input signal and converts it to DC. It then switches this on and off at higher frequency than the line input (60 Hz). The much higher frequency allows the transformer to be much smaller and the device achieving much higher efficiency. This is why switching power supplies are smaller, lighter and cooler than normal linear power supplies which run at 60 Hz.

The side effect is that now we are switching high voltage signals on and off. Doing so generates a lot of noise -- both in the produced output and radiated from the device. Filters are deployed to tame these but still, there is switching noise that did not exist in a linear power supply.

The theory around why this may impact a digital source (as opposed to a DAC) is that such switching noise can impact the timing of digital clock being produced together with the audio samples. Downstream devices, unless they run in "asynch mode" as you mentioned, rely on this clock to decide when to covet their digital samples to analog audio values. It is totally counterintuitive that CD audio running at just 44,100 sample per second would require high accuracy. But it does. If we want to reproduce 16 bit values perfect at 20 Khz for example, the clock accuracy must be 0.25 billionth of a second! Yes that is a quarter of a billionth of a second. Now, we don't usually care about fully reproducing such accuracy as the ear likely is not that sensitive in that region but at theory level, we have an incredibly difficult challenge with the timing of audio samples always being "analog" in a digital system. The net is that we have a super sensitive signal that has to have incredible accuracy and it is readily impacted by many factor including power supply noise.

The variations called jitter, are caused by many factors. If you look at devices using linear power supplies and look at their clock jitter spectrum, we often find a spike at 60 Hz telling us that the power supply frequency does leak into the clock timing. Here is an old example: http://www.stereophile.com/features/368/index6.html

"The Pioneer CD-65, seen in figs.25 and 26, had higher jitter than the best transports, but lower jitter than the JVC XLZ-1010. We can see a jitter spike at 60Hz, no doubt due to power-supply noise."

See the bold line spiking at 60 Hz:



At 60 Hz though, the frequency is very low and not where the hear is sensitive. But a switching power supply runs at many KHz frequency so it can cause jitter at that rate. The way jitter works is that you get the sum and difference signals between the original clock and what is interfering with it. Result is that depending on the clock frequency of the switching power supply and what is in the original audio signal, we could get distortion which is now in the mid-range and audible frequency.

Of course, there are million different power supplies and we don't know what level of jitter they cause and at what frequency. That is why I said there is no definitive explanation here unless someone measured jitter before an after. Unfortunately jitter measurement costs $20K+ and the companies making the mods don't have the money to buy such an expensive gear.
 

rblnr

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Amir, much thanks for the concise explanation of the direct connection between power supplies and timing errors across the frequency spectrum. As you point out, w/o measurements to back up the efficacy of a particular power supply, we're left w/testimonials and the option to buy and hope to hear. And I'm pretty skeptical of most testimonials on such stuff because of the want to hear and the phenomenon where different = better. If I can find a well regarded linear power supply w/o spending much, I'll hook up two Touch units into the same DAC and see if I notice anything.

Though I think I got most of it, wouldn't mind getting a bit more explanation of this:

It is totally counterintuitive that CD audio running at just 44,100 sample per second would require high accuracy.
 

puh

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I use the digital out on a couple of Squeezebox Touch units into good DACs that minimize jitter. The Touch itself measures well (low jitter), and has been shown to pass the signal bit perfect(ly). Some people believe that exchanging the SBs switching power supply for a linear one actually improves sound using the digital out. These power supplies are as much or more that the Touch itself. Does anyone believe these claims? If so, why? And what are people's experiences with different transports feeding a good, jitter reducing DAC -- any differences noted?

A cheap and easy way to test if your squeezebox sounds different/better with a less noisy power supply would be to run it on batteries. Four AA metal-hydride in series would give you about 4.8 to 5.0 volt. Since the SB touch uses no more than 600 mA you should be good for at least two hours of playing time. This has to be the ultimate low noise power source. If batteries does not make your squeezebox touch sound better then it might not be worth spending hundreds of dollars on a power supply. Cannot test this myself since I do not own a SB touch at the moment. However I'm considering getting one. So I would be very interested in any findings concerning the power supply.
 

rblnr

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A bit OT, but has anyone here done the hack that allows the Touch to output signal through the USB port? I have the instructions from the slimdevices forum, but as I'm not particularly programming adept, looking for any and all tips and advice.
 

DonH50

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garylkoh

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A cheap and easy way to test if your squeezebox sounds different/better with a less noisy power supply would be to run it on batteries. Four AA metal-hydride in series would give you about 4.8 to 5.0 volt. Since the SB touch uses no more than 600 mA you should be good for at least two hours of playing time. This has to be the ultimate low noise power source. If batteries does not make your squeezebox touch sound better then it might not be worth spending hundreds of dollars on a power supply. Cannot test this myself since I do not own a SB touch at the moment. However I'm considering getting one. So I would be very interested in any findings concerning the power supply.

Be careful with batteries as a substitute power supply because it has been shown that different types of batteries exhibit different noise. I don't have the link, but I'm sure some Googling or Bing-ing will find it. Many years ago, I had a battery powered phono stage, and it was recommended NOT to use nickel cadmium rechargables or alkaline but to use the old heavy-duty zinc ones. It has something to do with the "spitty" chemical reactions. I haven't had anything battery powered for a long time, so I don't know if the modern metal-hydride batteries would be better or worse in this respect.
 

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