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View Full Version : Initial Squeezebox2 sound impressions vs my luck and a NAD C 541



bludragon
2005-09-14, 15:50
So, finally got my squeezebox on Friday, after waiting 10 days for Dabs to get them in and one to me. Already had slimserver/softsqueeze up and going. Plugged it in, and seems I was unlucky at first. Everything worked except for the actual decoding of the audio. I connected to the server OK, could browse my music, add to the playlist and set it playing. At this point the spectrum analyzer would not show any activity, nor once I'd enabled it via the server, did the time counter increase. After making sure I wasn't doing anything stupid, I decided to post my problem on the slimdevices forum. 10 minutes later I had a suggestion from Sean Adams, of Slim Devices, which had me up and going in around 2 minutes. Turns out somehow the FPGA programming had become corrupt, and I needed to get the box to reprogram it.

Brilliant. So, 2 minutes setup time assuming you've not been unlucky enough to get one with a corrupt FPGA. For the sake of completeness, I should add that I did have another minor issue in that I couldn't enter my full length WPA key with the supplied firmware (software for the processor - different from program for the FPGA) - it wouldn't scroll along once I reached the edge of the screen. The latest firmware almost fixed this - it now scrolls along, but if seems unhappy once I enter the final character. No matter, I'm sure shortening my key by one digit won't be too insecure.

OK, so I'm up and running, I'm sat in my chair, and I'm quickly thinking that having access to every CD I own via a remote control is pretty much as revolutionary as going from cassettes to CD's. Great, brilliant, what could be better? Well, it doesn't sound half bad either, but I happen to have a pretty decent CD player, so lets see how it sounds compared to that.

Initial test system (prices are retail - I don't think I managed to pay quite this much for anything)

NAD C 541 CD player ~ 3yrs old (330) + QED silver spiral ~5yrs old (90) - 0 Ohms measured resistance

vs

Squeezebox2 (190) + home made 3m network cable interconnect - 0.2 Ohms measured resistance.

Both playing through a Musical Fidelity X-A2 ~5yrs old (500), and some B&W DM601 speakers ~6yrs old (200) biwired with some variety of QED silver speaker cable (~7/m).

Impressions:

Foo Fighters, in your honor, cd2

Play Squeezebox, play NAD, OK, the NAD is louder, going to have to try to compensate for that.

back to Squeezebox and nudge the volume control is there a difference?
NAD (nudge volume) - I think this sounds better,
Squeezebox (nudge volume so its definitely louder) - OK, the NAD has it.

To summarize, after struggling at first to make out a difference, the NAD sounds smoother / fuller with vocals vs the sqeezebox which has a sightly grainy character, and symbols seem to have more energy. There's possibly more dynamic range, with the symbols hitting you from a quieter background.

In terms of bass, the NAD does have a fatness to it, which pretty much always sounds good, but I suspect it may be adding a touch of distortion here.

OK, possibly unfair to not check out the difference to the cables, give the squeezebox the QED interconnect, the differences are still there. Compare cables on the NAD only. Its very difficult to notice a difference, exacerbate by the time it takes me to plug, unplug and restart the track, but the QED might just have a slightly smoother mid upper and more detailed, or simply louder treble.

This is all straight out the box for the squeezebox, so I left it playing for a few days, having added every cd I own to the playlist. This is where I discover that after ~ 1 day of playing it stops, and I need to go back to the network config, to get it to see my wireless network connection. DOH! Have yet to investigate this properly, but I'm on the best channel I can find, getting 70-80% signal strength.


2nd Test System

OK, 5 days on, lets have a listen through some headphones, specifically some sennheiser HD650's (~230) powered by a WNA (White noise audio) MkII headphone amp, with a few tweaks (~165 for the DIY kit). I've only recently got this setup, but it turns out it was a mistake. It makes my musical fidelity amp, and B&W speakers that once sounded excellent, now sound far too much like a cheap ghetto blaster. I really don't want to spend 2k on a full size system to match the quality offered by this headphone system.

NAD - oh wow, I really need to stop wasting my headphone system by attaching it to my pc (but that's what I got it for).
Squeezebox - OK this is good too, but the step down from the NAD is now more obvious (possibly because I know what I'm looking for), but unchanged in character from previously.
Cheap liteon divx/dvd player - far worse than either of the above. I can't even begin to describe how its worse, its too far away to make any sensible comparison.


Conclusion.

Squeezebox concept is brilliant. Going from cassette to cd meant you could pick your track with ease. This is the next step. No more hunting around for that album I might have left in the kitchen, no more long interruptions, when I feel like listening to a few tracks off different albums. No more always listening to the same stuff because that's what's out. Hardware configurability seems excellent - the firmware for the cpu can be updated, as can the algorithms that run on the FPGA. Currently the software seems good, but not idiot proof - mostly due to the wireless network setup.

Sound quality is very good, and probably (without having tested it against one) matches the sound of a dedicated cd player in the region of 150.

The worst bit - ripping all the cds you own. Make sure you do this properly to start with. Set up EAC with FLAC, then do a couple of cds, and test them with the software to make sure the artist, album name, etc is to your liking. Only then take the time to work your way through your entire collection. Keep the log files, so if any of your cds have any problems reading, you'll at least know which one's aren't quite bit perfect. Ideally then back up the whole lot onto another hdd in another machine.

The future:

I'm going to upgrade the external psu.
I might modify the box itself - possiblly adding a couple of super reg's to upgrade the internal psu's.

I really really want to try it with a Cyrus DAC-X (1000), or an all digital TACT amp (2200), and a nice pair of floorstanders (700-1000), but might have to wait until my numbers come up for that!

One day I'll finally finish that DAC concept I started 6 yrs ago at university, and try it with that.

Can I have one for my car please? No really, I want one, and I'll pay double.

bludragon
2005-09-14, 15:53
Also posted this on headfi. Hope it is of some use/interest.

Sithuk
2005-09-15, 00:49
Blu,

Excellent post mate.

I'm currently speccing a SB2 system to buy. I currently own no hi-fi kit at all. From the mass of posts I've read it seems that you need an external dac / headphone amp to get the best from your HD650s. I am looking into the following:

Squeezebox 2 (190ish)

HD600 (100ish second hand)

Supermacro 3 headphone amplifier (150ish second hand) http://www.fixup.net/products/macro/

Headroom micro dac (150 new) - it's a new design that can't be found 2nd hand yet.
http://www.headphone.com/products/headphone-amps/headroom-amps/the-micro-line/headroom-micro-dac.php


With this setup I should get the most from the HD600s though it should be noted that the Emmiline SR-71 headphone amp is rated a better amp, and it is only 25 more 2nd hand, however it doesn't have crossfeed which I value greatly for the older recordings like the Beatles which I like.

I will not be getting the external DAC until a few month after initial purchase but I hope to notice a difference on the HD600s.

Fifer
2005-09-15, 02:00
I agree, good review. FWIW, I too am using the SB2 with HD650s and a tweaked WNA Mk2; it's a winning combination. I suspect that a decent linear PSU to replace the supplied switching jobby would be a cheap but significant upgrade option. I just haven't got round to looking for something suitable yet.

Sithuk, if you can solder or know someone who can, I'd recommend the 160 WNA Mk2 kit. It is fantastic value for money. The Mk1 left my Musical Fidelity X-Can V2 for dead and the Mk2 was another significant improvement over the Mk 1. It works extremely well with the HD6XXs.

JulianL
2005-09-15, 10:17
Nice post. I don't want to hijack this thread but, since you had a long wait from Dabs and got your SB2 at exactly the same time as me, I suspect you have one of exactly the same batch that I just got. Unfortunately my SB2 seems to be partially dead on arrival, I can get absolutely no output from either the optical or the coax digital outputs. Did your tests include any tests with the digital output(s)? I'm just curious as to whether this is a one-off issue with my device or a batch problem.

- Julian

bludragon
2005-09-15, 11:20
Thanks for the feedback. Don't have much time tonight, but I could try the hd650's via the headphone out on the squeezebox if you want Sithuk.
One thing worth mentioning about the HD600/650's is that they don't keep out much background noise, something to beware of if you have a pc in your listening room - obviously the squeezebox solves this problem.

JulianL, do the analogue outs work ok? I haven't tested my digital outs, but I have noticed the optical glowing. If I can find the right adaptor I should be able to test them with my pc. Certainly I'd like to make sure mine are working for the future!

JulianL
2005-09-15, 11:33
Thanks for the reply bludragon. Yes, my analogue outputs do work. Right now I am using the SB2 with my Meridian DSP5000 speakers by feeding the SB2 analogue outputs into a 14.95 analogue to digital converter that I happened to have in a cupboard. Needless to say I'm not in a position to contribute any meaningful observations on sound quatlity, this must be about the most extreme example of a weak link in a system!

My optical output is also glowing but no meaningful data seems to be coming out. I'm really hoping that it might be something similar to your problems, i.e. a corruption in the firmware or FPGA so that I can fix it in the comfort of my home rather than needing to return it.

- Julian

pfarrell
2005-09-15, 11:51
On Thu, 2005-09-15 at 11:33 -0700, JulianL wrote:
> now I am using the SB2 with my Meridian DSP5000 speakers by feeding the
> SB2 analogue outputs into a 14.95 analogue to digital converter
>[snip]
> this must be about the most extreme example of a weak link in a system!

The folks at Boothroyd-Stuart must be having a cow over this.
A tad extreme, I'd guess so.

The very idea makes me laugh.


Good luck fixing your digital output, it is near criminal to
feed your Meridians that way.

--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

Sithuk
2005-09-15, 13:26
Blu,

I would very much appreciate your review of the SB2 headphone socket with a HD600/650 headphone. I have not been able to find one yet. Specifically I'd like to know the impacts of using a separate headphone amp and/or a separate DAC when compared to the stock SB2 socket. Can a difference be discerned?

Thanks,

Sithuk

Mr Perceptive
2005-09-15, 13:44
JulianL

When you do get it going you will get great sounds, I have an SB2 -> Meridain 568.2 in my main system and an SB1 -> Meridain D600's in my second system. Both very good, both better than SB2 analogue outputs into 568.2 (which I would expect as it A-D processes then D-A) and into the D600, (which despite they age work very well)

Best of luck in getting it sorted.

Mr Perceptive

JulianL
2005-09-15, 18:03
Wheeee.... now I'm excited!!!! Kevin P from Slim Devices support got me up and running on his first attempt at diagnosing the problem. It was a corruption in the Xilinx CPLD so reprogramming it did the trick.

I can confirm that (shock horror) feeding the digital output of the SB2 directly into my Meridian DSP5000s is a distinct improvement on feeding the analogue output into my 14.95 AtoD converter. Now is not the time (2 in the morning) to do detailed listening tests I think but I doubt that I'll be able to resist at least another hour of listening right now so it'll be a pretty late night for me tonight.

Thanks for all the words of encouragement. It's nice to know there are a few other Meridian users and supporters out there.

- Julian.

bludragon
2005-09-16, 16:28
Julian,

Glad you got it sorted, was just about to mention I tried my coax digital out into a pc and it worked fine. However, it seems we both suffered a corruption in the Xilinx CPLD, though mine was completely dead until I reprogrammed it - no playback whatsoever.

Sithuk,

I did a very quick comparison with the WNA mkII vs the direct headphone out on the squeezebox. Suffice to say the WNA does improve things. More clarity, deeper bass. It's audible, but not night and day. If I were you I'd get the squeezebox first (assuming you're set on one), and then try to audition a headphone amp with it, even if its not one you intend to buy, at least you should get an idea of the improvements on offer. I'd also recommend trying the headphones out before you get them - at least for fit and comfort if nothing else.

With regards to trying out the digital out - I've just spent around 30 min switching back and forth between the squeezebox line out, squeezebox digital out into an emu-0404 sound card, and emu-0404 on its own, and I'm not sure there's any real difference between them. Actually, I'm now thinking the 0404 driven by the squeezebox has a very slight edge. My tiredness could be inventing things though... Oh, I should mention I've bypassed the output caps on the 0404.

bjackson
2005-10-06, 09:30
I would be suprised if you got any decent output out of the SB2 into a HD600/650 load which are 300 ohms.

The standard headphone is 16-32-64 ohms, and the SB2 produces decent power into them, but I don't think it has the voltage needed to properly drive 600/650's, which are 10 x the impedance. If we assume a 3 volt RMS output to the headphones (which I think is pretty realistic at full output with music that is not always a constant 0db signal), this puts around 30mW into a 32 ohm load, but only 3mW into a 300 ohm load which really isn't that much, even for headphones.

I wouldn't even consider it personally. If nothing else make a headphone amp or get one second hand. Just my two cents.

pfarrell
2005-10-06, 09:53
On Thu, 2005-10-06 at 09:30 -0700, bjackson wrote:
> I would be suprised if you got any decent output out of the SB2 into a
> HD600/650 load which are 300 ohms.
>
> The standard headphone is 16-32-64 ohms, and the SB2 produces decent
> power into them, but I don't think it has the voltage needed to
> properly drive 600/650's, which are 10 x the impedance.

I'm pretty sure you have it backwards. A source produces voltage for the
signal, and the driven impedance determines how much current is
required. And the current times the impedance is the definition of
power.

A high impedance driver is easier to drive. It takes lots less power.

One volt driving 16 ohms will draw 1/16th of an amp of current.
The same one volt driving 300 ohms will draw 1/300th of an amp of
current. The definition of power is R*I*I
So one volt driving 16 ohms is 1/16th of a watt
And one volt driving 300 ohms is 1/300 of a watt.

It is low impedance speakers (and/or headphones) that are harder to
drive.


--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

pfarrell
2005-10-06, 19:14
On Thu, 2005-10-06 at 12:53 -0400, Pat Farrell wrote:
> On Thu, 2005-10-06 at 09:30 -0700, bjackson wrote:
> > I would be suprised if you got any decent output out of the SB2 into a
> > HD600/650 load which are 300 ohms.
> >
> > The standard headphone is 16-32-64 ohms, and the SB2 produces decent
> > power into them, but I don't think it has the voltage needed to
> > properly drive 600/650's, which are 10 x the impedance.
>
> I'm pretty sure you have it backwards. A source produces voltage for the
> signal, and the driven impedance determines how much current is
> required. And the current times the impedance is the definition of
> power.

Errr,,, how I do I say this, my math is right, but I forgot a
fundamental concept, so what I wrote is at least insufficient.


> A high impedance driver is easier to drive. It takes lots less power.

But, and this is the part I messed up on, is that there usually is
some correlation between sound loudness and amplifier power. It is
not enough to drive the load with a voltage, it needs power.
Or as Tim says on Hometime, More Power.

So, it is easy to put one volt into a high impedance load,
that part was correct, but most of the high impedance loads still
take nearly the same power to make the same loudness. (plus
or minus the efficiency of the speaker/headphone)

As one of my smarter friends explained it to me, the source can't supply
enough volts to make the watts you want, then it will appear to be
working hard (volume control wide open) and not making much music. The
waveform may clip if the amp runs out of volts. Of course, it isn't
really working as hard because it isn't supplying the watts.

In the case of a SqueezeBox, it isn't going to put out many watts of
power. Which is why you need a amp to drive anything that isn't highly
efficient.

Sorry if my mistake confused anyone besides myself.

--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

Mark.Bennett
2005-10-07, 00:12
On Thu, 2005-10-06 at 22:14 -0400, Pat Farrell wrote:
> On Thu, 2005-10-06 at 12:53 -0400, Pat Farrell wrote:
> > On Thu, 2005-10-06 at 09:30 -0700, bjackson wrote:
> > > I would be suprised if you got any decent output out of the SB2 into a
> > > HD600/650 load which are 300 ohms.
> > >
> > > The standard headphone is 16-32-64 ohms, and the SB2 produces decent
> > > power into them, but I don't think it has the voltage needed to
> > > properly drive 600/650's, which are 10 x the impedance.
> >
> > I'm pretty sure you have it backwards. A source produces voltage for the
> > signal, and the driven impedance determines how much current is
> > required. And the current times the impedance is the definition of
> > power.
>
> Errr,,, how I do I say this, my math is right, but I forgot a
> fundamental concept, so what I wrote is at least insufficient.
>
>
> > A high impedance driver is easier to drive. It takes lots less power.
>
> But, and this is the part I messed up on, is that there usually is
> some correlation between sound loudness and amplifier power. It is
> not enough to drive the load with a voltage, it needs power.
> Or as Tim says on Hometime, More Power.
>
> So, it is easy to put one volt into a high impedance load,
> that part was correct, but most of the high impedance loads still
> take nearly the same power to make the same loudness. (plus
> or minus the efficiency of the speaker/headphone)
>
> As one of my smarter friends explained it to me, the source can't supply
> enough volts to make the watts you want, then it will appear to be
> working hard (volume control wide open) and not making much music. The
> waveform may clip if the amp runs out of volts. Of course, it isn't
> really working as hard because it isn't supplying the watts.
>
> In the case of a SqueezeBox, it isn't going to put out many watts of
> power. Which is why you need a amp to drive anything that isn't highly
> efficient.
>
> Sorry if my mistake confused anyone besides myself.

Ignoring the maths, the SB (1&2) works perfectly well with my
Sennheiser HD580's, which are also 300ohms.

The amount of power you typically need to drive headphones to
high volumes is effectively tiny, and everything I have tried
with a headphone socket has worked perfectly well with the
high impedance Sennheisers.

--
"The biggest problem encountered while trying to design a system that
was completely foolproof, was, that people tended to underestimate the
ingenuity of complete fools." (Douglas Adams)

bludragon
2005-10-08, 03:08
High impedance headphones may need more voltage to get the same volume out of them, this might mean some battery powered devices struggle a little. The SB however seems to have plenty of voltage to drive headphones.