At last... (Audiolab) - part VII

[sam_cat]

I wont be buying the upgraded PSU, I will make my own using a handful of STR's and a few other tricks... But then I am happy building my own equipment.

Sam

 

[Space is the Place]

For me, minimum connectivity functionality and features would come first, then SQ, then 'nice to have but not essential' connectivity functionality and features.

Are you really saying that you will NOT be buying the upgraded PSU?

Not at £300 i wont no.

 

[finesensations]

Not at £300 i wont no.

I admire your willpower.

Not even if JohnW offers it on a 'return if you don't like it for no quibble refund' basis?

 

[Space is the Place]

It's £300! Surely the Dac on its own has enough capacitance to jump start Frankenstein!

 

[finesensations]

It's £300! Surely the Dac on its own has enough capacitance to jump start Frankenstein!

You're asking the wrong person.

Best to ask JohnW any questions regarding the upgraded PSU.

 

[sprint]

Not at £300 i wont no.

A £300 psu will have a prime cost of something in the region of £50/60 the rest is just mark up's and profit margins.

 

[dtd]

Not even if JohnW offers it on a 'return if you don't like it for no quibble refund' basis?

Give JohnW a break!

 

[JohnW]

I admire your willpower.

Not even if JohnW offers it on a 'return if you don't like it for no quibble refund' basis?

Even I dont know if its going to make a big enough difference to justify "£300", I hope it well as we are just about to open the tooling for the casework.

From past experance, I'm sure it WELL make a difference - it will just be a question of how much difference...

Still, the PSU will also have the AV bypass and 12V Triggers...

John

 

[Markus S]

A £300 psu will have a prime cost of something in the region of £50/60 the rest is just mark up's and profit margins.

True, but with Audiolab's numbers of products made and parts sources, you'd probably end up paying about 150-200 £ on parts to re-manufacture the Audiolab product.

 

[JohnW]

TimR,

Your Squeezebox Touch (SBT) arrived today – I’ve not powered it up yet as I instantly dived into it internals.

Nicely designed - from first looks we will be able to do something, but I need to confirm a few things first before I can decide which route to take. At first glance it does not appear that the SDPDIF output is re-latched to the “Clean Audio Master Clock”, so this could explain your comments on the SPDIF quality.

The questions I need to answer first :-

1. Are the SPDIF Output sampling rate channel status flags correctly set by the SBT? (If they are then interfacing with the MDAC will be easier, as the MDAC can just read the channel status Info embedded within the SPDIF to set the Output Clock-Lock FS rate accordingly.

2. Space is going to be an issue inside the SBT to add our clock-lock board (and a second optical Clock-in connector) – it’s going to be fun.

3. Hopefully the SBT will not get its knickers in a twist as we change its Audio Sampling rate "On the Fly" in response to a change in (hopefully) the SPDIF Channel Statues info...

Going to be fun, I wish I had a better equipped lab here in CZ (my lab will be shipped back from China in the coming months (hopefully)) – otherwise I'd have this done in no time...

John

 

[bottleneck]

If anybody is interested in one of the devices JW has spoken about, which removes the power line from the USB input (preferable on audiolab dac, cdq etc when using USB input)..

Send me a PM.

I have bought one, but it doesnt do anything on the Young Dac, which terminates the power rail apparently anyway.

 

[arthur]

A £300 psu will have a prime cost of something in the region of £50/60 the rest is just mark up's and profit margins.

Wow!! I wonder if any other consumer stuff is like that???

 

[JohnW]

Hi Tim,

After doing so more measurements on the SBT I'm not sure if Clock-Locking worth the effort and here's why:-

The SPDIF output Jitter of the SBT streaming 44.1 kHz via Coax:-

Around 1nS RMS (Really Noisy Measurement)
Around 17nS Peak (Really Noisy Measurement)

But after the first 2 stages of Jitter Attenuation by the MDAC (Measured at the MDAC's Re-clocked Digital output):-

10pS RMS (Noise Floor of my Rohde & Schwarz UPD here in CZ)

80pS Peak (Noise Floor of my Rohde & Schwarz UPD here in CZ)

The MDAC's Jitter Attenuation circuits have reduced the SBT's Jitter to a point that I wonder if it’s worth going to any more effort. I'd expect MDAC's Jitter results are better, as it would appear that I'm just measuring the UPD's Noise floor.

Don't forget that after the first two stages of MDAC's Jitter Attenuation - comes the final stage of Jitter attenuation, the ESS's ASRC (The MDAC has 3 cascaded Stages of Jitter Attenuation)...

We need to get you an MDAC, so you can see if you’re happy with the MDAC / SBT combo.

The MDAC's reclocked Jitter levels are so low, that I had to confirm the R&S UPD was indeed locking to the MDAC's Digital output.

I hope I’ve not made an error in measurement – I have nothing to double check the measurement results against.

I did measure a CD player to confirm the UPD’s not had a mental breakdown or something, and results looked as expected, so I really do think the UPD’s ok…

John

P.s. the "Rohde & Schwarz UPD" is a Digital / Analogue measurement Analyser

 

[JohnW]

If anybody is interested in one of the devices JW has spoken about, which removes the power line from the USB input (preferable on audiolab dac, cdq etc when using USB input)..

Send me a PM.

I have bought one, but it doesnt do anything on the Young Dac, which terminates the power rail apparently anyway.

What device is it? a USB isolator or an external USB PSU?

 

[TimR]

TimR,

Your Squeezebox Touch (SBT) arrived today – I’ve not powered it up yet as I instantly dived into it internals....

Blimey John, you didn't waste much time did you! Sounds like you're having fun, but I hope this isn't causing you too much of a distraction from your other, much more important work. Please don't rush anything on my account, I've got an SB3 that's filling in nicely here while the SBT is with you.

I must admit, when I first scanned through your last post I got the shock of my life... I thought you were asking me some technical questions before I realised you were just thinking out loud. Phew!

Re: the space issue, I for one am not going to be overly fussed if you have to leave some "guts" hanging out the back, I'm just extremely grateful for all your help.

Thanks again

 

[JohnW]

TimR,

IF my measurement results are correct, then its no surprise that you where not happy with the sound of the SBT / CDQ combo. In fact I’d be surprised if you where!!! 17nS RMS is Massive (and nasty).

The CD player I measured to confirm the UPD had not fallen over measured a “more normal” 150pS or so…

The CDQ only has a single stage of Jitter attenuation (the ESS's ARSC).

If nothing else, you can use the MDAC as a Jitter Attenuator!!

 

[JohnW]

Apart from the Jitter results, this Squeezebox Touch is Brilliant – why would anyone spend more on a streamer??? – I really so no reason for us to do our own!, the Touch is so cheap – nice UI etc…

I love it – OH Tim, sorry to tell you, that Squeezebox Touch you sent me to CZ sadly got lost in the post…

 

[Neil Gilbert]

I am also interested in the mdac

I have an oppo 95 connected via analogue out to a tag av32r processor
I realise the dac in the oppo is very good but I want to improve other sources spotify/Napster
Is there likely to be much improvement given the relative low quality of spotify/Napster
Can it be slotted into my setup for 5:1 even if I set the volume manually prior to the av bypass option

Anyone? I guess you are all stereo only.

I plan to use this between a squeezebox Touch and the Tag

 

[Markus S]

I'm sure this will have been answered before, but does the MDAC have balanced outputs?

 

[JohnW]

I'm sure this will have been answered before, but does the MDAC have balanced outputs?

Yes