MDAC First Listen (part 00101111)

[LarsS]

Sheesh calm down everyone. ...

Indeed, calm and relax are the words.

My previous out of the blue/guesswork project forecasts were far too pessimistic, and still they all failed. Caused by loss of insight/influence and a high degree of longing/wanting for the FDAC (making my plans to positive).

Anyway, this is my latest iteration of project forecast (all considered) for the Detox and FDAC (Analogue board, MiniDSP, BB Computer, Digital board, Chassies, Software, Filters, Testing ... aso).

Detox = Christmas 2016
FDAC = Midsummers Eve 2017

I'm good with these dates considering what we'll get.

So, as ti33er eloquently put it - calm down ... ;-)

 

[iansr]

Well - once I've completed the Documentation and design update - its in the hands of China production progress... lets see (he says with a little fear), 2-3 months before they arrive at your door with shipping etc.

I'll have say 10 pcs of T0 production units within 1 to 2 months once I've issued all relevant documentation and I'll ship these to PFM members for early evaluation...

As soon as I've completed the documentation and I no longer need the prototype Detox here - I'll send it over to Jem if time allows for its first "public" evaluation - hopefully Jem can arrange a local (Oxon) PFM listening session.. but lets see

John
Re beta testing, there are at least 3 prospective FDAC owners here in Yorkshire
and we could easily arrange joint listening sessions . . . . 😉

 

[sq225917]

Don't worry Ian, I'm holding two pairs of Renata's boots ransom until we get first Detox and Fdac samples...



I really should post them on...

 

[LarsS]

Don't worry Ian, I'm holding two pairs of Renata's boots ransom until we get first Detox and Fdac samples...



I really should post them on...

Just note you need to get them studded as it'll be Winter/Cold/Icey when Detox arrive ... ;-)

 

[davidjt]

JohnW,

It strikes me that as I have a slightly over-sized case for my new MDAC psus, I might as well reduce the clutter here by supplying the Detox from the same unit. What voltages and plug type do I need to provide, please?
Many thanks

 

[radamel]

Remember - the only sure things are death and taxes.

Hehehe!

And that's according to Ben Franklin because some people I know might just only agree with the death part...

 

[JohnW]

JohnW,

It strikes me that as I have a slightly over-sized case for my new MDAC psus, I might as well reduce the clutter here by supplying the Detox from the same unit. What voltages and plug type do I need to provide, please?
Many thanks

David,

You need a power cable like this:-

http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=281958591361

With 9V @ say 500mA (for the MDAC).

The centre "Hole" is Positive, with the outer collar being negative.

 

[Bob L]

David,

You need a power cable like this:-

http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=281958591361

With 9V @ say 500mA (for the MDAC).

The centre "Hole" is Positive, with the outer collar being negative.

Sorry to butt in, but a) John, should that be "9v( for the Detox)?
b) David, are you thinking of using the spare half of your "Digital" Calex? I wondered about doing that for my Regens, but the voltage is too high, and I also think there may be a danger of shorting out the Calex with different grounds in the MDAC and Detox/Regen in the input line. Maybe I worry too much?

Bob

 

[davidjt]

David,

You need a power cable like this:-

http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=281958591361

With 9V @ say 500mA (for the MDAC).

The centre "Hole" is Positive, with the outer collar being negative.

Thanks John. I was thinking of a few tens of mA.
With the Calex marginal at only 400mA each, dropping the voltage from one of them is obviously not an option. Oh well! Nice idea while it lasted. Maybe I'll be able to tuck the supplied psu inside the larger case, given sufficient ventilation.

I reckon the improvement from separating the analogue and digital supplies is about the same as that from the Regen. So when the Detox arrives, will I really need an FDAC?

 

[JohnW]

David,

As the MDAC /FDAC require no power from the Detox 300mA, even 250mA will be OK...

But the Ground needs to be isolated on the PSU otherwise you loose the benefit of Detox's isolated USB output.

 

[JohnW]

Sorry to butt in, but a) John, should that be "9v( for the Detox)?
b) David, are you thinking of using the spare half of your "Digital" Calex? I wondered about doing that for my Regens, but the voltage is too high, and I also think there may be a danger of shorting out the Calex with different grounds in the MDAC and Detox/Regen in the input line. Maybe I worry too much?

Bob

Bob,

Yes 9V is perfect for the Detox - if your operating into the MDAC / FDAC which dont load the internal DETOX PSU then 12V is OK (power dissipation).

Yes, insure that the grounds are isolated on the DETOX power rails otherwise (PSU Ground not shared with the MDAC / FDAC) otherwise you loose the benefit of the electrically isolated USB output.

 

[JohnW]

Yesterday day I spent time listening to the Detox I connected a second subwoofer to the system via the RCA outputs of the MDAC - with the main amplifiers connected via XLR (purchased from PFM's "Furyous", thank you ).

As the RCA and XLR's outputs are shared technically its a bad idea to have "unbalance" loading on the MDAC's output stage - but what surprised me was how badly the sound quality was effected with the treble detail becoming very recessed and collapsed sound stage.

I disconnected the sub-woofers - and just had the cable connected to the RCA output of the MDAC and left unconnected at the Subwoofer end - so the MDAC was just "driving" the cable and still the sound was markedly effected so its really a big no to use both the XLR's and RCA outputs at the same time on the MDAC

I discussed this yesterday with Jarek and we will add a simple DAC to the HDMI card which can be used (but not limited to) to drive subwoofers.

We can also not populate the HDMI section so we just have a secondary DAC channel option for the FDAC.

 

[EIffel]

I discussed this yesterday with Jarek and we will add a simple DAC to the HDMI card which can be used (but not limited to) to drive subwoofers.

Thank you! This sounds like the perfect answer to a concern I had raised a while ago as I am interested in both a SACD/DSD playback solution and driving a subwoofer.

 

[davidjt]

b) David, are you thinking of using the spare half of your "Digital" Calex? I wondered about doing that for my Regens, but the voltage is too high, and I also think there may be a danger of shorting out the Calex with different grounds in the MDAC and Detox/Regen in the input line. Maybe I worry too much?

Bob

That was the idea, but there's no way I'll risk overloading the Calex. (I had a Trio/Kenwood valved receiver warming up on the desk years ago - the firework display when a big cap in the psu failed (I think) and the mains transformer burnt out was both scary and very messy. The set was a write-off.)
I don't have a Regen at the moment - if I did, and planned to keep it, I would hook up a tiny fan-speed controller I have lying around and see if I could safely get +5V from that: a few extra mV wouldn't be a problem.

But having opted for a second Detox it hardly seems worth the trouble.

 

[jadidih101]

.......

I discussed this yesterday with Jarek and we will add a simple DAC to the HDMI card which can be used (but not limited to) to drive subwoofers.

We can also not populate the HDMI section so we just have a secondary DAC channel option for the FDAC.

So does this mean a single FDAC can be configured as digital crossover for low freq and mid+high freq?

And what do you mean by not populating the HDMI? Which HDMI section? The one for the Linux screen output?

 

[JohnW]

So does this mean a single FDAC can be configured as digital crossover for low freq and mid+high freq?

Yes, with the optional DAC / HDMI card a single FDAC can have 4 independent audio outputs - and over time once the software for the DSP's is available you can have a digital Xover which outputs to the x4 audio channels without the need of the Slave FDAC.

Obviously the secondary DAC path will not be the same quality as the Main outputs, but for Sub-woofers its perfectly usable.

I discussed it with Jarek & we will use the mobile version of the ESS9018 on the DAC card.

And what do you mean by not populating the HDMI? Which HDMI section? The one for the Linux screen output?

Nothing to do with the FDAC's HDMI system display output but the optional HDMI Audio extraction card that allows native DSD / HiRes Audio extraction from DVD / BluRay / SACD players via the HDMI link.

To maximize our engineering resources we will design the Digital Input Card (DIC) so that it design is "triple purpose" it can be populated with or without the DAC / HDMI sections:-

1. HDMI Audio extraction & two Channel secondary DAC outputs

2. HDMI Audio extraction

3. Two channel secondary DAC outputs

 

[EIffel]

With two more DAC channels (2+2+2), this has the potential to become a 5.1 AV decoding solution... Now that is scope creep

Given that the extension board is not on the critical path, I don't think anyone should object to make sure it is part of the plan.

 

[iansr]

Yes, with the optional DAC / HDMI card a single FDAC can have 4 independent audio outputs - and over time once the software for the DSP's is available you can have a digital Xover which outputs to the x4 audio channels without the need of the Slave FDAC.

Obviously the secondary DAC path will not be the same quality as the Main outputs, but for Sub-woofers its perfectly usable.

I discussed it with Jarek & we will use the mobile version of the ESS9018 on the DAC card.



Nothing to do with the FDAC's HDMI system display output but the optional HDMI Audio extraction card that allows native DSD / HiRes Audio extraction from DVD / BluRay / SACD players via the HDMI link.

To maximize our engineering resources we will design the Digital Input Card (DIC) so that it design is "triple purpose" it can be populated with or without the DAC / HDMI sections:-

1. HDMI Audio extraction & two Channel secondary DAC outputs

2. HDMI Audio extraction

3. Two channel secondary DAC outputs

John
This is very good news as I agree that for bass frequencies the lower quality output will be just fine; this means that with just one slave unit you will be able to implement a 6 channel active crossover.
Alternatively could you do the same by using an MDAC for 2 of the 6 channels (the treble frequencies would be the obvious choice) ?

 

[jadidih101]

....
To maximize our engineering resources we will design the Digital Input Card (DIC) so that it design is "triple purpose" it can be populated with or without the DAC / HDMI sections:-

1. HDMI Audio extraction & two Channel secondary DAC outputs

2. HDMI Audio extraction

3. Two channel secondary DAC outputs

That would be great. I can put HDMI extract in one FDAC and Sub outputs in the second FDAC.

Just one thing, the name, 'DIC'? really?

How about Digital Expansion Card, 'DEC'. Should remove any misinterpretation

 

[dadab12]

Any updates on the MDAC? it seems like it will never be finished -_-