I have been playing with CD transports for a while now, culminating with the really excellent CDPRO2, but with the advent of PC based music, and related media players like the Squeezebox, CDPs slowly lose out in favour.

And with media players, once you modify them ala Crazy DIYers, the gain in performance puts many esteemed CD transports to shame. What more, these media players are really cheap! I don’t have to tell you how expensive it is to procure a CDPRO based transport. Go google yourself.

However, as much as I enjoyed my highly modified Squeezebox, CDPRO2 based transport still trumps. There just seems to be a glass ceiling where we are still trying to break.

But then when I heard of SD card players, I got interested. This got the makings of an ultimate digital source.

What’s so great about it? Purportedly no moving parts, hence better reliability; less jitter, hence better sonics etc.

I consider prototyping one myself but the engineering efforts takes time but fortunately our Chinese brothers in Shenzhen QLS Hifi offers a built up WAV player for not a lot of moolah.

On the other hand, this WAV player ONLY plays 16-bit 44.1kHz WAV files. So no MP3, no FLACs, no 24-bit gizmo etc. No, nope, None, Nilch, Nada.

So what’s so great about this WAV player? You just got to listen to it.

Easy. Just play music through it.

Feeding it WAV files and playing off stock, the first few hours was good but not great but after some hours of running in…. Wooooooooooowwwwwww!!!!!!

I was speechless.

I was stunned.

I was… dumb strucked.

Here is this humble looking fella (stock standard!), trouncing my highly modified Squeezebox with upgraded external Paul Hynes power supply.

And putting the CDPRO2 transport to shame.

What more does one want?

Being a greedy bastard, I opened it up and looked for modding potential.

There are Sanyo Oscons all around. Not exactly SA grade but still no slouch. There is a 7805V pre regulator followed by 3 LM1117 regulators. One for the DSP chip (this guy does all the hard work, reading off the SD card, updating the display and sending out I2S signal), one for the oscillator clocking this chip and another for the I2S-SPDIF generator. Impressive!

The pic below however, isn’t stock standard anymore as itchy-fingered me just have to work on it. I swapped the pre pre-regulator cap with another Oscon and removed the SPDIF RCA and Toslink sockets. I replaced the SPDIF RCA with a BNC socket. This should be the way to go!

Also, I replaced the output pulse transformer (there’s already one inside) with a Newava make.

Note that there is I2S output available on this player. On another player, I tapped this out and fed to an I2S-EIAJ convertor to feed directly to mojo (which accepts EIAJ readily). This my bro, beats the SPDIF interface! But it took me a while to hear the difference while Gabriel (who has much better ears than me) detected the improvement right away. So if you can’t hear any improvement, get a pair of better ears!

All in all, I’m so happy with this little guy, I use it as my reference these days. Yeah, the Squeezebox has a nice display and offers loads of convenience but the SD player gives the best sonics.

Sounds familiar? It’s like the CDP offers lots of convenience but the turntable gives best sonics.

So what do I make out of it? This SD card WAV player is like a Digital Turntable.

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Squeeze me!

I’m having too much fun!

Oh yeah baby! SSSSSQUEZEEEEEE MMEEEEE!!!!!

Sorry folks, I have been having too much fun lately. So much so that I haven’t bothered with my own job. Have been playing too much with this device, have forego sleep/food/sex and have even called in sick!

So I MUST tell you about this little device that has given me sooooooo much fun! (No, no, no, it’s not a little blue pill)

Well, word has it that it all began in 2001, when a bunch of guys got together and made this “thingie”.

4 generations later, in 2006…

What? Never heard of the Squeezebox? Well, I certainly couldn’t do a better review than Mark Lanctot here. http://www.abxzone.com/abx_reviews/fraoch2/article_p1.html

Go ahead, read the page. The link opens up in a new window.

Take your time, I’ll wait here.

Done? All 6 pages? That’s fast! Now you know why I’m having so much fun?

To add to the above, be prepared for these lifestyle changes!

I burn less calories these days. No more having to get up and change the CD. Repetitive Stress Syndrome and your thumb will be acquainted soon. Channel surfing? How about music surfing? Kashmir to Carmina Burana to Black Magic Woman in seconds! No more straining your eyes, with your head leaning sideways scanning your CD racks for a particular CD! Read BBC news, CNET blogs and check how well your stocks are doing while listening to music. Who said men can’t multi-task?

A week later with the Squeezebox, I impressed even myself! My wife is impressed I could multi-task better than any guy she knows. My friends are impressed I have up-to-date news/info at my finger tips. My doctor is impressed I no longer have neck aches (and my over-developed thumb). My tailor is impressed i need new pants now to fit my expanding waistline. My neighbours are so impressed they want their own Squeezebox to tap into my music collecton!

As you can see, this is soooooooo much fun! Everybody together now: SSSSSQUEZEEEEEE MMEEEEE!!!!!

DIY Paradise is the Malaysian reseller for the Squeezebox. Malaysian customers, place your order here! http://store.diyparadise.com.

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Computer Audio is Soooooo Much Fun!

Boy, I have been having so much fun with computer audio, or do you prefer the term “PC Audio”? Playing music through a PC is addictive. We’ll look at the hardware side first before going to the software end.

I admit I have been late to this “PC audio party” but as they say “better late than never”! And I’m glad I joined the party! The sonics has so much potential compared to conventional CD playback and most folks believe this is mainly due to much reduced jitter when playing through PC. You see, with conventional CD playback, we almost can’t escape from using digital output (SPDIF) format. The Achilles’ heel of SPDIF has to be the way the critical Bit Clock is recovered from it.

This is the work of the digital receiver (like CS8412, CS8414 etc) and we are limited by how well it recovers this clock signal. CS8412 for example has jitter specifications of Bit Clock of 200ps. Not very impressive! Monica’s asynchronous reclocking (as shown the light by Kunosoki san more than 20 years ago) ameliorates this but it’s no way a solution either.

With computer audio, let’s say this together. “To hell with SPDIF!” Ha ha!

Back to hardware, the Squeezebox is a little computer gadget that appeals to geeks like you and me. It streams (wired or wirelessly) audio files stored on your PC to your hifi system. Of course, if you do it wirelessly, you could have your noisy PC in one room and your hifi set in another. Wonderful!

To be honest with you, I know nuts about playing music through a computer but ever since I got a Squeezebox, have to start a crash course on it!

Fancy having a dig at DIYing your own Squeezebox? Well Ole Schüsseler here shows you how to do it with his Linux based Audio Appliance.

So what if you don’t want a player like the Squeezebox and prefer to play from your PC? Sure, no problem! Back then you’ll need at least, a good quality soundcard, but nowadays, there are USB DACs to consider. Yup, takes USB data and converts to analog signals.

The Wonderful World of USB DACs
You see, operating systems (at least for Windows and Macs) are smart enough to know that when they detect a USB DAC, all audio signal will be routed through there. Of course, you could control not to do this as well, but unless your soundcard has better sonics, it’s good to consider USB DACs.

USB DACs like Texas Instrument’s PCM2706 (used in My USB Convertor) not only functions as a USB DAC but also as a headphone amp, USB-SPDIF convertor as well as USB-I2S convertor. The last function is the most interesting as once converted to I2S, we could hook up many DAC chips directly. DAC chips like TDA1543, TDA1541… etc. Like this:

If you want to try this yourself with my USB Convertor,

Pinout of I2S on my USB Convertor pin 1 is GND pin 2 is Word Select leave pin 3 blank pin 4 i Bit Clock pin 5 is Data

I guess you know which pins to connect to which pins right? Told you it’s very easy! Power your DAC chip separately though. Don’t be cheap and use the USB’s 5V supply. If you do so, don’t complain if it doesn’t sound good ok?

If you are ooo-laa-laa over sonics of Monica, then this isn’t so simple. Monica’s TDA1545 chip uses EIAJ format instead of I2S. The main difference between both signal formats is the where upon the DATA signal is sent. I2S sends the DATA signal at the beginning of the Word Select signal but EIAJ sends at the end.

No, please don’t ask me why can’t those folks sit down and agree on one format. I have no idea. But look at SPDIF. The very few instances where all folks concerned agreed on a format but it turned out to be a lousy format. Oh well…

Anyway, I tested and built a pure USB Monica, taking in USB signal to I2S then converted to EIAJ then fed to TDA1545. Give us a few more weeks and you can jive with her soon! [USB Monica is ready!]

Squeezing more juice out of the Squeezebox
Back to the Squeezebox. I’m sure many will be wondering how does the Squeezebox compare to audiophile CD players? Well, stock player is nothing to shout about however never ever under-estimate the power of DIY! I’ll share with you 2 mods I tried here.

The very first upgrade every Squeezebox owner should do is to replace the stock power supply adaptor with a beefier unit. One capable of at least 1A (2A is better). Some folks prefer linear supplies while some prefer switching. My preference is switching power supplies but don’t let me influence you. Go try yourself. Just make sure it outputs 5V REGULATED and you’ll be fine. Oh yeah, pay attention to polarity too since we are dealing with DC voltages here.

For the adventurous diyers, the first mod is considered too easy, no fun at all. The second mod, you need to pull out your Torx T10 screwdriver and dismantle the Squeezebox unit.

This is a relatively easy tweak. Easy to understand and easy to implement if you are good with soldering surface mount components. If your soldering skills isn’t up to par, then forget it. Find someone to do this for you. Remember as with all mods, you can kiss your warranty goodbye so if you are not up to it, don’t try to be cheap here. It ain’t worth it brudder.

What we want to do here is modify the SPDIF circuitry. If you trace the digital output RCA socket, you’ll find it ends at pin 6 of chip U15. This is just a 7404 invertor chip. What we have here is that the invertor output goes through a coupling cap then 2 resistors to ground. The resistors form a voltage divider to scale down the output of the invertor from TTL logic level to SPDIF level. If you find all this Greek, don’t worry.

By right, there isn’t a lot of problems with this circuit but due to the very noisy environment of the Squeezebox (what more with a wireless card nearby), we don’t want all the noise to be carried all the way through the digital output (via SPDIF format) to your DAC and the rest of your audio chain. And the easiest way to accomplish this is to use a digital pulse transformer.

The digital pulse transformer accomplishes 4 things.
First it breaks the ground. The SPDIF signal ground is no longer the Squeezebox unit’s ground. This is possible due to usage of transformers.
Secondly, I believe the trans has better driving capability then just a the invertor and voltage divider circuitry.
Third, with a trans, we could benefit from its common mode rejection capability. Meaning, it rejects noise common to both signal and ground. Like in a noisy environment inside the Squeezebox.
Lastly, we could better match the impedance output impedance with the usage of suitable trans.

So first remove L8 and L9. Then desolder the R67 107ohm resistor. One end of R67 goes to ground while the other end is tied to R66. There’s a mistake in above diagram though. Primary (red dot, pin 1-4) has ratio of 1 while secondary (pin 5-8) has ratio of 2. So you should wire pins 5-8 facing the 7404 invertor chip and the other end (pin 1-4) facing output RCA socket. To anchor the trans, I soldered one leg (pin 8) to junction between 107 and 245ohm resistor. Thus pin 5 goes to ground. Pin 1 (red wire) goes to SPDIF output. Pin 4 – SPDIF ground. (If you are fussy, replace 245ohm resistor with 300ohm for even more accurate 75ohm output impedance.)

Now you know why I’m enjoying computer audio?

Moving on to the Software side

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