Music Server Computer transport - Hop On!

[jkeny]

There's always a gopher jumping out of the woods, isn't there

Thanks Brian, keep us informed, please.

[audionut]

why convert from usb to spdif??

Something like Doede's 1543 mk II which converts usb to I2s to feed the dac chips works well. You can't use your existing SPDIF DAC, but the mk II is so inexpensive, it can be tried with out financial hardship. I implemented the Mark II with Jung Super Regulators for the power supplies. The effort was well worth the results.

[GTHICM]

The efforts here to tease out the best quality from a 100 USD device are very interesting. The question I would ask is if one is trying to get spdif out to a dac, such as Brian's great sounding Satch, wouldn't it be far simpler, easier, less expensive and practical to just buy the new version of the Squeezebox, if you want the higher sampling rate, or the Duet if you do not? It seems to me that the spdif output of the stock Squeezebox is low in jitter, but there are of course lots of options to improve it. Plus, it can be wired to the server or use a wireless connection.

[janneman]

Question to you guys:

I have a QNAP 109 II NAS with Squeezecenter pre-installed, feeding a couple of Duet receivers. Works fine, but now there's a new version of Squeezecenter out and I'd like to upgrade. But I have no idea how to upgrade any software that is actually on the NAS. I can get to the NAS throught it's IP and the port number (9001 on my system) but that only gets me the Squeezecenter GUI.
Anybody know how to do that?

jd

[jkeny]

Originally Posted by GTHICM

The efforts here to tease out the best quality from a 100 USD device are very interesting. The question I would ask is if one is trying to get spdif out to a dac, such as Brian's great sounding Satch, wouldn't it be far simpler, easier, less expensive and practical to just buy the new version of the Squeezebox, if you want the higher sampling rate, or the Duet if you do not? It seems to me that the spdif output of the stock Squeezebox is low in jitter, but there are of course lots of options to improve it. Plus, it can be wired to the server or use a wireless connection.

I agree with you GTHICM, to some extent & I'm looking at the SB Touch as a future purchase for me mainly because they have put some effort into the SPDIF & clocks (running 2 clocks on a low jitter mux to switch speeds) - only issue is that over here it's >$300 & not $60 - 80 as is the Musiland (god bless the Chinese ). The other advantages of the SB Touch, in my opinion:
- runs off ethernet, wired or wireless so galvanic ground isolation probably covered
- no need for a PC in the listening room
- remote control via iPhone or iTouch (could probably do this with PC & Musiland too)
- possibly the user interface but don't know about this yet?

So I'll be looking at how the iTouch pans out

[ChuckT]

If u guys do so much tweaking, u might consider bypass the USB/spdif and PC and use a media server instead and use the spdif output - no USB conversion. Put in a 1TB hdd and you can have a huge library of music. My 500gB is almost full:-)
eg.
various TVIX module
HOME > Products > Product Info > TVIX HD M-6500
or
http://www.dragontechcorp.com/downlo...0hd_panels.gif

There are many others.
I use the TVIX and I found spdif output are excellent.

Or do the ultimate and tap the I2S from the inside.

Music server with TDA1541 (I2S direct)

[bcherry]

The replacement transformers have arrived. I'm just waiting for some SMD parts and then we will:
- leave the RCA output with our resistors and 75ohm cable untouched
- install the transformer on the second out and connect (with some SMD parts) that to a 2nd RCA output. This will allow us to switch between the current output (which is already significantly better than stock) and the output with the upgraded transformer.

Thanks for the comments; I'm very interested in the other ways mentioned and will get one of those devices to compare.

Some have asked why we are doing THIS instead of THAT.
This is a vendor's forum. The idea was to see how far we can go with what we have on the shelf using the commonly and cheaply available Musiland (which gives us 24/192) and a computer transport.
To recap:
The Musiland needed a good clock, power supply, and the right cable. These things removed much of the performance bottleneck.
In addition the chipset likes and is able to swing more voltage so we made the circuit changes for that, but the transformers (already marginal) were unable to keep up. So we used resistors and this has taken us to the current level of performance.
Now we have the upgraded transformers and will try the next phase described.

Regarding some of the other ways to get digital music playback I received this interesting email:


"Brian,

I had a look at several of these Media Streamers. Reviews of many can be found at the MPC Club website, they are worth reading for the comments on the music side of things.

I do not wish to comment on the SPDIF output implementations in these machines, but yes, they work and bitperfect if the volume control is left at full.

All these machines have a most basic software and interface section for the Music part.

Worse, none to the best of my knowledge handle music playback in "gapless" mode, absolutely essential if live or classical albums are ripped into seperate tracks (or indeed such items the recent "Love" Album made from The Beatles back catalog or something like DSOTM by Pink Floyd.

The only way around this would be to rip such albums as complete images, in that case these players lack the support for .cue files that allow individual track access in these whole CD Images.

This basically precludes their use for music playback if one listens to anything where gaps inserted between tracks are unacceptable."

[jkeny]

Brian, why don't you go to BNC instead of RCA outputs while you're at it (real 75ohm is possible).

The media servers all use PLL synthesised clocks - not the most jitter free implementation!

[GTHICM]

Another ready made alternative that may offer increased options for interface to different dacs, including i2s, is the Empirical Audio Off Ramp converter. Although it would appear to be more expensive than the Musiland upgrade path, although it is not clear to me that it really is, given the cost of all the additional components and parts for the upgrade, it seems a ready made solution.

Here is the link for further information:

Off Ramp Converter > Products : Empirical Audio

[bcherry]

Originally Posted by jkeny

Brian, why don't you go to BNC instead of RCA outputs while you're at it (real 75ohm is possible).

The media servers all use PLL synthesised clocks - not the most jitter free implementation!

You are right and we will. But at this point it would introduce another variable whereas we just want to spotlight the difference between Rout and TXout.

In fact today we installed the upgraded transformer into 75ohms and had a preliminary listening A/B between Rout and TXout. I'll write more later after we do something more extended but briefly:

There were 4 of us and 3 didn't know which was which, Rout or TXout. We listened to one track, about 8 passes. After the first pass 2 of 4 listeners choose Rout as better detail and bass, 2 listeners choose not to comment.

By the third pass the tide changed to favour the TXout and by the last pass it was unanimous the TXout was best. It took a few passes to identify that the extra detail was really a kind of aggressiveness and the bass was somewhat exaggerated.

All agreed the TXout had more real detail and more tuneful bass. Dynamics were about the same. The listeners liked the word 'natural' to describe the TXout. Next week I'll check out some bass heavy tracks to find out if the lows are rolling off at all. I'll then install a TX in second output with a little different loading. Once we get a winner there then I'll do the BNC connection.