TDA1541A DAC + SqueezeBox

Tony Moore · Post by **Tony Moore** » Fri Jul 04, 2008 9:56 am

Hi All,

I just thought I'd post an update on how my SqueezeBox3 + DAC experiments are coming along...

As many of you probably know, a couple of years ago I built the CDPro2M drive into the freaky case shown in my Avatar above. Then soon after built my Pedja Rogic based TDA1541A DAC into a "similar" looking case. (the larger box)

Not long after that though I was "introduced" to the wonders of the SqueezeBox (thanks Neal. :rolleyes:;)) and so my CD player has never really been able to compete, except when using the I2S based interface rather than s/pdif. Since the SB3 is probably an inherently better "transport" than any CD mech I have always wondered just how good it might sound if I could use the I2S from the SB3 instead of the s/pdif. Well, since the SB3 uses a slightly different I2S format to the TDA1541A it is not possible to simply connect them together. That was a couple of years ago.

However at the last Owfest NickG, Andrew and I got to talking about what might be achieved using a device called a CPLD (complex programmable logic device) to do the SB3 -> TDA1541A conversion...Moving on...with help from Nick and Andrew on the programming side I have managed to get the SB3 to drive the TDA1541A via I2S as hoped. The sound _is_ actually far better than using the s/pdif connection! One main drawback is that the I2S signal paths can only be very short before too much signal degradation sets in. Hence I have now built the SB3, it's ALW power supply, CPLD board and all reclocking into the DAC case. It's a work in progress at the moment and I'll post further photos when it's complete but here's how it stands at the moment.

The SB3 can be seen mounted to the left, the X shaped board is the Xilinx CPLD evaluation board, the actual CPLD is that large square IC in the middle. The Tent XO clock is underneath the X Board and to the right is my sync reclocking circuit. The ALW regulator on the back is for the SB3. The actual DAC pcb and Hawk output buffer board are waaay down underneath, out of view now! As you can see, there's no way to view the SB3 display but I don't much care about that. In fact if anyone knows how to power it off then I'd love to hear it!

There's quite a bit of wiring left to complete but at least now I know it'll all fit! At some point in the future this may all change again but at least I'll have something that looks like a proper piece of hifi gear and not a lashup of batteries, cables and wires that Liz reckons looks like some mad scientist's nightmare.

Cheers,
Tony

simon · Post by **simon** » Fri Jul 04, 2008 10:24 am

Well done on squeezing (no pun intended!) all that in to the case, no mean feat. I heard Nick's DAC with CPLD board a couple of weeks ago and was very impressed - looking forward to hearing yours at the next fest.

Tony Moore · Post by **Tony Moore** » Fri Jul 04, 2008 11:39 am

Hi Simon,

Yes, I'm also very keen to hear Nick's DAC as he's moved in a different direction to me, concentrating on the differential mode. Since I already had the Pedja DAC and Hawk buffer I've gone for a (possibly temporary) middle step. I do hope to be able to compare DACs though and make a decision on whether to go along that route also at some point in the future.

Cheers,
Tony

simon · Post by **simon** » Fri Jul 04, 2008 1:16 pm

Did you hear the DACathon at Owston last time Tony? Very interesting but perhaps a rather sharp example of our tendancy towards anorakness...

pre65 · Post by **pre65** » Fri Jul 04, 2008 1:31 pm

Hi-i missed most of the DAC test at Owston.

How did Als DAC fare in the running ?

Someone likened my Shek DAC to the Berisford but i'm looking for something better.

simon · Post by **simon** » Fri Jul 04, 2008 1:53 pm

Al's DAC went down very well Phil, it was some peeps favourite IIRC. I think there's a fair bit of discussion about the DACs somewhere here, probably on the Owston thread?

Ali Tait · Post by **Ali Tait** » Fri Jul 04, 2008 3:36 pm

All the DAC's sounded good,but with the unfortunate upshot that the Beresford suffered by comparison(to me anyway as I had one!) and I remember Al's as one of the best sounding.I've come into possession of an Audio-Note Dac Zero,which is far superior to my ears.

Ali Tait · Post by **Ali Tait** » Fri Jul 04, 2008 3:38 pm

To the Beresford I mean!

Post by **Nick** » Fri Jul 04, 2008 4:14 pm

come into possession of an Audio-Note Dac Zero,which is far superior to my ears.

I must talk you into letting me hear that some time Ali...

Tony Moore · Post by **Tony Moore** » Sun Jul 06, 2008 12:02 pm

Completed!

And with the Xilinx CPLD board removed:

I just have to re-program the CPLD for the new pin assignments and then do initial power up tests!

Cheers,
Tony

Andrew · Post by **Andrew** » Sun Jul 06, 2008 12:21 pm

Smashin' Tony.

Ali Tait · Post by **Ali Tait** » Sun Jul 06, 2008 4:06 pm

Seconded! Look forward to hearing it Tony.Nick,I could bring it round and collect Paul's trannies at the same time if you like.Won't be for a few weeks though.Will let you know.Mo is interested in hearing it with the SB so perhaps he could come along and we could make a day of it?

Post by **Nick** » Sun Jul 06, 2008 4:16 pm

Ali: Fine, let mw know

Tony: That looks great, I still have to try and tidy up the mass of wires thats my DAC, I bought a new bit of MDF this morning for it though. I have replaced the spdif receiver that was part of the DDDAC with a home brew around a CS8416, doesn't sound as good, but I expected that, as the current receiver has no jitter suppression. So the next step (after getting it on a single board) is to build a XTAL controlled PLL similar to the Tent Labs one to provide a 11Mhz reclocking signal.

audio-talk

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