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MDAC First Listen (Part 00101001)

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John, now that it is obvious that an upgrade board for the original MDAC is not going to happen, I need to know if the full width chassis will fit my rack. How deep (front to back) will it be? I have 37cm from wall to front of shelf.
(And how deep will it be with the new USB gizmo plugged directly into the back)
Regards
Clive

Clive,

The FWC is 320cm deep - the Dotex can be connected via a short USB lead without degradation.
 
IN a world in which asynch usb requires 3 cascaded sets of usb regeneration to work, I would imagine that anything less than 5k on a S/PDIF cable was madness.

:D

In answer to your earlier question, the Detox design cascades 3 USB hub devices, each with there own local PSU regulation and RF filtering & Clock tree.
 
John, I've lost track....to makeDetox more generally applicable will it include a 5V reg to power USB cards? I realise it might need a bigger linear ps when used this way.

Btw I've sent you a pm too.
 
No worries John.

I don't plan to use USB, so I assume there's no point in me joining the USB Detox project. Although it's quite possible I'm missing something. Am I?

By the way, with regard to S/PDIF cables, what's the general view... are the standard plastic Belkin type cables as good as any or is it worth a bit of an upgrade?

Bruce,

If you stream audio from a PC or device with a USB port then the ASync USB is the best connection method - if your only using SPDIF then there is no need for the USB Detox :)

If your using optical then standard plastic fibre is OK - what's your audio source?
 
John, I've lost track....to makeDetox more generally applicable will it include a 5V reg to power USB cards? I realise it might need a bigger linear ps when used this way.

Btw I've sent you a pm too.

Yes - it will be able to supply a "Clean" 5V, you might need a larger AC adaptor if you require the full 500mA.
 
I do like their style..."Improves Sound, Color Printing, Data Stability
Just kidding. This is silly. That’s like saying charging your iPhone off Wyrd makes the battery last longer. But some listeners say Wyrd improves the sound of their system. We’re not going to make any such claims. Nor are we going to recommend it for printers, external USB drives, or iPhone chargers."

Its almost worth $99 just because of their honesty.

Yes, they seem like a refreshingly decent company :)
 
:D

In answer to your earlier question, the Detox design cascades 3 USB hub devices, each with there own PSU and RF filtering & Clock tree.
That I follow, but just to clarify 1 complete detox solution= £130 and one wall socket or £390 and 3 wall sockets?
 
7 payments made - thank you :)

Jem, you will have serial number 001 :)

A nice evening project - hopefully lessons learnt can be applied to the FDAC USB port :)

Its good to take my mind of the two major projects FDAC and VFET amp.
 
The MCU we are planing to use for the FDAC Digital board has a SDcard interface, I was considering adding a SDCard reader to the FDAC so that later we might release a software update (lots of work) that could read and write to the SDcard - Mainly to be able to offer an all in one recorder / or test system.



This opens a whole bag of hurt - dear Adam here on PFM will be rolling around in discomfort!

I can see how the varying CPU process produces different RF / Jitter spectrum and this is a fact of life - what's not tolerable is that this makes its way into the Analogue domain. I myself have heard such effects myself and am not proud - it indicates design limitations with the audio system and as an audio designer I have to share the blame.

Computers will radiate all kind of nasties - they are horrid is this regards so we need to accept this as a fact of life and tackle the problem head on.

I slept on the ideas last night and really want to design this USB Detox ( :) ) interface as I'd be avoiding the elephant in the room to ignore the multitude of problems posed by connecting a computer to the audio system. I've always stressed that the RF and Jitter should be dealt with BEFORE they are allowed to enter the DAC enclosure - this holds true for the MDAC and FDAC.

The design is a quick task, the production will be interesting, but I'm really keen to "send a simple design down the production line before the FDAC PCB's" so it makes this little project even more interesting.

If there is significant interest then it will take less then a week to design the PCB.

As each USB Hub device only offers a certain "limited" level of attenuation I'll cascade 3 devices in series each with there own PSU and Clock interface, this will add extra cost - but its the correct way to design the board.

Lets to a proper job of this :)

I'll use these RF screen tins for each Cascaded attenuation stage and the Master clock circuit:-

http://www.teko.it/en/prodotti/famiglia/RF/serie/49

So the design will look something like this:-

USB input

RF Filtering

1st Hub

RF filtering

2nd Hub

RF filtering

3rd Hub

USB 2.0 480Mbps USB output (Non Isolated) + RF Filtering

USB 1.1 12Mbps galvanically isolated USB output + RF filtering

There will be two toggle switches to enable the Clock-lock interface + Spectrum decorrelation mode (Enables a random spread spectrum clock source).

Development fee GBP50 + unit sold at cost say around GBP80 payable once we start to manufacturer the PCB's.

If we have say 20 PFM'ers interested then I'll launch the project and spend an hour or 2 designing the PCB each night.

John

I think we got our wires crossed earlier :confused:

Could the USB Detox be made to use the current MDAC AC adapter and feed this through to the MDAC 'cleaned up'? So this might make the Detox cheaper, and kill the other 'bird' i.e. Swagman et al replacement PSU's at ~£350? This would make it MDAC only, but a 'killer' product :D

Thanks
 
7 payments made - thank you :)

Jem, you will have serial number 001 :)

A nice evening project - hopefully lessons learnt can be applied to the FDAC USB port :)

Its good to take my mind of the two major projects FDAC and VFET amp.
Damn have I missed 007
1 complete detox solution = £130 and one wall socket.
These graphs had better be good.
 
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