At last... (Audiolab) - part VII

[ChrisPa]

By patenting you are declaring your secrets. Someone else only has to get around the wording of the patent and modify your design accordingly and they have nicked your design.

By implementing your concept into a working design you are declaring your secrets. Someone else only has to copy your design without modification and they have nicked your design

Modifying a design defined in a patent inherits the creativity of that patent and doesn't 'get around' it. Only if they implement a parallel or truly alternative way of implementing the design - one which includes none of the creativity/intellectual property of the original patent - will they get round it. And if they've been that creative themselves, such that the new design includes none of the creativity from the original patent, then they deserve their new creativity to be adequately rewarded.

Whilst a patent has to describe 'an embodiment' of the new intellectual property, it very seldom gives a reader a short-cut to the black art of implementing a working product. With electronics, it's probably a combination of a real world circuit and simulation that start giving that away.

Serge's suggestion has a lot of merit, but probably only if you've got a thriving production stream which is giving you benefit from the income.

 

[russel]

Back in the 1970s, I worked for a company that didn't patent anything. All their inventions were published in Wireless World or the RTS Journal so that nobody else could patent the idea. They figured that there was no way they could fight Sony or JVC on a patent infringement, so by publishing they were as well protected, and anyway, so many modern inventions have a finite and fairly short lifetime before they're obsolete, so by the time another manufacturer had caught on, they'd moved on. It worked for them.

S.

There is a more formal method of doing that now. I know of one company today that stopped patenting because it was expensive and the lifetime of the inventions was so short.

Research disclosure website

 

[TimR]

I'l also take a look at TimR's unit ands see if its possible to add Clock-Lock interface.

Hi John, still waiting for a PM with your address when you get a spare minute.
Thanks again,
Tim

 

[TimR]

I could take a look - I had not considered it... but we could have the same arrangement as MDAC...

John

So you're saying there's still a chance I might not need that MDAC

 

[miki166]

Hi John, I am very happy with 8200CD. I have one problem with Kenwood dp5090 cd as a transport (sharp-sony drive) 8200cd sync perfectly while does not recognize old philips CD850 mkII (philips cdm4 drive). Any advice?
Thanks in advance.
Regards from Serbia
Miki

 

[sq225917]

RTFM. Bandwidth receiver

 

[ChrisPa]

The MDAC has a Sync Link interface both over Optical, 64Fs, 96Fs, 128Fs, 192Fs, 256Fs or 384Fs - Coax is WordClock Out only.

I'm not sure how you would Sync to the SB - I don’t have one... Nor have I held one in my hands.

The idea behind Clock Syncing is to lock the DAC's Clock to the Data Source - thus allowing the DPLL BW of the ESS to reduce to its lowest setting - thus least intrusive ASRC.

In simple terms, unlike other implementations of ASRC, the ESS leaves the vast majority of Audio samples "Bit Perfect" and only very occasionally say every second will it insert an additional sample (say 1 out of 84 Million) to correct for Time domain energy errors.

"Conventional" Sample rate converters modify EVERY sample - the real beauty of the ESS ASRC is to leave the vast majority of Audio samples untouched - in fact only adding "Correction" pulses...

Locking the MDAC to the Data source - minimises the need to insert these "Correction samples" – and also removes any “Audio related” Modulation – I.e. removes any correlated jitter patterns (and thus Correlated correction pulses).

The Clock Lock interface will work with older CD transports I mentioned earlier + its really intended for our future Transport / Streamer.

We have full control of its function (Clock Rate) via software – so we can increase it functionality via a later software update – i.e. add direct support for units such as the SB (if it has a Clock In interface).

John

John - some questions to increase my understanding:

- the Fs outputs are to provide a master clock to the digital source (rather than a word clock) ?
- how does the dac know what clock rate to provide; how does the dac know the sample rate required by the source?
- is the word clock/Fs set per input?
- what about connecting the clock output to several devices simultaneously? Eg. Cd transport & SB - not expecting to drive them simultaneously in any sensible way, but that does lead on to the question of what happens to the source devices if, for example the CD wants an Fs of 256, but the SB wants an Fs of 128 or a word clock

With regards a clock input modification to a SB, I'm sure there a lots of people who'd be interested in that (one here). An interesting implementation would be if it were possible to allow it to be relatively readily changed between external clock and internal clock

 

[Jo Sharp]

Are you referring to the MDAC? The optical does function to 192kHz, its just most optical sources and Cheap Plastic Fiber are so bad that its not a reliable connection - so rather then having to constantly field customer complaints that the MDAC’s Optical connection does not work at 192kHz (due to no fault of our own) - we have just rated them to 96kHz.

USB is limited due to the USB1.1 hardware Spec. Our hardware is designed using the TAS1020B which is a USB 1.1 device (A maxim of 12Mbps, which is just a tad too slow for 192kHz Audio Streaming).

John

The manual states it has a USB2 port...is that an error?

Can files be played direct from a USB memory stick using a suitable adaptor cable to attach it? Apparently that gives the best playback with the Naim DAC as there can be no source jitter.

Jo

 

[Plutox]

The manual states it has a USB2 port...is that an error?

USB2 (the standard port that has now been around over 10 years) is not the same thing as USB Audio Class 2.

The former is a physical port specification - it has more than enough speed capability for anything audio I (and presumably you) would want to do.

USB Audio Class 2 is a device specification. Audio Class 1 is limited to 24/96 but this can be overcome with the installation of alternative drivers (viz. M2Tech stuff). Once MS choose to support Audio Class 2 and issue a driver (as certain third parties have), job done.

It doesn't seem clear why MS is prevaricating on this point.

 

[ChrisPa]

Can files be played direct from a USB memory stick using a suitable adaptor cable to attach it? Apparently that gives the best playback with the Naim DAC as there can be no source jitter.

Jo

The MDAC contains no user interface to browse and access files on an external usb storage device - so the simple answer is 'no'

The async interface of the MDAC provides the same "no source jitter" specification as the Naim DAC - ie. the data clock used in the usb interface is fully defined and controlled by the DAC not the source component

 

[Jo Sharp]

Thanks for both answers!

Jo

 

[JohnW]

Hi John, I am very happy with 8200CD. I have one problem with Kenwood dp5090 cd as a transport (sharp-sony drive) 8200cd sync perfectly while does not recognize old philips CD850 mkII (philips cdm4 drive). Any advice?
Thanks in advance.
Regards from Serbia
Miki

Hi Miki,
If I understand your question correctly, the Kenwood DP5090 works with the 8200CD as a CD Transport (So the 8200CD is operating as a DAC) - while your CD850 MkII does not work with the 8200CD (in DAC Mode).

If correct, have you tried that the SPDIF output of the CD850 mkII works with other DAC's?

Have you tried both Digital inputs of the 8200CD?

John

 

[JohnW]

So you're saying there's still a chance I might not need that MDAC

Damn!!!

 

[JohnW]

John - some questions to increase my understanding:

- The Fs outputs are to provide a master clock to the digital source (rather than a word clock)?

Yes, Arcam, Deltec (DPA), Cambridge Audio, Pink triangle all uses varying multiples of Fs rates to Clock-Lock to the DAC.

- How does the Dac know what clock rate to provide; how does the Dac know the sample rate required by the source?

Currently the only Clock-Lock sources are CD based 44.1 kHz devices - so with the current software build, the Clock-Lock outputs are 44.1 kHz based.

However we can read the sampling rate Flags embedded within the SPDIF Subcode to set the correct Fs. Rate (the Source would need to send the correct Sub-Code Info, then we would configure our Clock output accordingly). A second option with our own devices is to use the external Bus Link to configure the Clock Rate.

- is the word clock/Fs set per input

As we only have one Clock output connection (either Optical OR Coax), only one Clock-locked device can be support.

- What about connecting the clock output to several devices simultaneously? Eg. CD transport & SB - not expecting to drive them simultaneously in any sensible way, but that does lead on to the question of what happens to the source devices if, for example the CD wants an Fs of 256, but the SB wants an Fs of 128 or a word clock

Answered above, only a single Clock output connection is provided.

With regards a clock input modification to a SB, I'm sure there a lots of people who'd be interested in that (one here). An interesting implementation would be if it were possible to allow it to be relatively readily changed between external clock and internal clock

It looks like we might end up designing a small Clock-Lock PCB that can be fitted to the SB, if this is the case, then we can design the SB to operate on its internal clocks if no valid Clock-Lock link is present.

John

 

[JohnW]

The manual states it has a USB2 port...is that an error?

Can files be played direct from a USB memory stick using a suitable adaptor cable to attach it? Apparently that gives the best playback with the Naim DAC as there can be no source jitter.

Jo

Hi Jo,

The USB interface conforms (electrically) to the USB 2.0 Spec, but its a USB1.1 Device - this simply means that you can use the MDAC on a USB 2.0 Bus...

John

 

[jamjar784]

The HiFi Choice November Awards issue out today gives 2011 CD player award to Audiolab 8200CD and amplifier award to 8200A.

 

[PhilCTTE]

Any recommendations on such a device, what specs should we look out for ?

John I'm assuming that you haven't had time to produce one yourselves yet?

I've noticed that some dac's have them built in and wondered if it was a design decision in the omission ?

Cheers

 

[JohnW]

Hi Phil,

For RF isolation, the USB isolator needs to be located external to the DAC's Chassie.

Also, units like the iPad cannot provide the power for isolator - thus limiting units that would work with the MDAC's USB port.

John

 

[PhilCTTE]

Thanks for reply ... Only seen a few references to usb isolation. Couple of DAC's state they've built in solutions. I guess with any cable other than optical there are opportunities for this to arise. Could be an opportunity for someone to design an off board unit which accepts all interface methods. Or is this only specific to usb.

Will be interesting to read the debates on source components over the following months.

I'm not rushing into any further purchases for a while after the MDAC , but wanted to use my 7 year old Dell Inspiron as a starting point and compare it to my Sonos Zp80. I do want move closer sound quality wise to my previous reference system (Tag Mclaren AV32R DP sync linked to DVD32R). Problem is I've been seduced, by the usability of digital streaming devices. i.e Gapless audio playlists FLAC , internet radio, and Spotify

 

[chuckster]

John,

Any thought given to incorporating an USB isolator in the upgrade PSU?

Chuck