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MDAC First Listen (part 00101111)

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Then try it with a five Calex Psu.

Speaking of which if you could identify the wiring on the 10 pin connector CN1 on the main board please as the service manual is non too clear.

Thank you.
 
JohnW said:
Basically the test where conducted to gain further insight into a theory of operation that’s applicable to both FDAC and MDAC, and if anything is relevant to the Detox (WRT further improving its performance).
Click to expand...

Thanks, John. So Renata is fully involved and you have the bruises to prove it!
Wrt that article on RF intermod, but for the ubiquity of mp3 audio it might have been properly dealt with 25 years ago. Strange how things turn out.
 
jadidih101 said:
Hi John,

Does this mean the 'optimal' position might be different depending on USB source or other factors? Or will it be 11-12 O'clock for everyone.
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The 11-12 O'clock position is for the "Unique" circuit modifications to MDAC - its not the Detox settings.

With the Detox I just listen at full level, ATM Time is so critical I need to get the paperwork to China for production then I'll have more time to listen at lower levels... If anything drastic comes from the listening then we can just forward a simple component BOM change for the production units.

jadidih101 said:
Also, have you tried Detox with a non-modified MDAC to see if the result/improvement is the same?
Click to expand...

Yes first test where with a standard MDAC - I happened to have RTRT's Toy MDAC for repair and tried it and was really pleasantly surprised how much better it sounded :) but the Detox had the same effect on sound quality with both units.
 
davidjt said:
Thanks, John. So Renata is fully involved and you have the bruises to prove it!
Wrt that article on RF intermod, but for the ubiquity of mp3 audio it might have been properly dealt with 25 years ago. Strange how things turn out.
Click to expand...

Paul Miller stop performing the RF tests as so may units measured so badly, and few manufactures had any inclination how to tackle the issues - HiFi is such a Mickey Mouse industry.
 
misterdog said:
Then try it with a five Calex Psu.

Speaking of which if you could identify the wiring on the 10 pin connector CN1 on the main board please as the service manual is non too clear.

Thank you.
Click to expand...

Paul, I'll have to draw it up on Paper and post here - I'll try this evening, I'm still updating the Detox PCB and have come down with some kind of bug thats knocked me out these past few days...
 
misterdog said:
Then try it with a five Calex Psu.

Speaking of which if you could identify the wiring on the 10 pin connector CN1 on the main board please as the service manual is non too clear.

Thank you.
Click to expand...

Perhaps I'm missing something, but why 5? Wouldn't 4 do ?
 
4 digital rails and one for analogue is how the original AC supply is configured, though it may not work out that way for optimal results with 5 x + - 0 supplies available.

Hypothetically,

1 for the Dac chip.
1 for the clock.
1 for 'other' digital.

1 for analogue left channel.
1 for " right channel.
 
Hello John - reading on the last posts and things are looking/sounding exciting for the FDAC :cool:

I have an FDAC question for you - in an earlier post you referred to using the on board DSP to add delay - will it be possible to delay the mains a few 10s of mSec behind the sub?

I ask because my sub has quite high group delay and so I have it placed much closer to my listening position than my mains to compensate a bit. If I can delay the mains, I can place the sub more freely.

Re the MDAC - I'm more than happy for you to keep a hold of it for as long as its useful to you.

Of course if that means you can leave installed the 'supercharger pcb' when you're completely finished, then I'm even more for it :D
 
JohnW said:
Paul, I'll have to draw it up on Paper and post here - I'll try this evening, I'm still updating the Detox PCB and have come down with some kind of bug thats knocked me out these past few days...
Click to expand...

So basically this needs to be modified for five rail DC input on CN1?

MDAC%20PSU%20PCB%20REV03a.jpg
 
Indeed, I intend cutting the umbilical between CN 1 and CN2 and routing the cable out of the case (luckily I have included extra height in the ply case mainly for additional cooling).

All 10 cables are colour coded, black, to make life more interesting.
Using 1 Calex each as per Johns post No 288, this leaves me to find a supply for the remote r/c pin 9. So maybe 6 Calex's :eek:
But I only have 5 arriving ?
Is 15V DC the optimum voltage here ?.

Anyway should be an interesting experiment.
The reason for this apparent madness is that I considered the improvement of the dual Calex to be greater than twice that of the single.
 
fusion5 said:
So basically this needs to be modified for five rail DC input on CN1?

MDAC%20PSU%20PCB%20REV03a.jpg
Click to expand...

You need to connect to CN2 (well the main power cable to the MDAC PCB) - but not you loose the Power switch, so you need to switch the MDAC via the PSU / AC socket.
 
misterdog said:
this leaves me to find a supply for the remote r/c pin 9. So maybe 6 Calex's :eek:
Click to expand...

The RC pin is not a PSU rail but "Remote Control" BUS signal - its to communicate with an external HQ PSU etc. Leave Unconnected.

15V DC is good.
 
JohnW said:
You need to connect to CN2 (well the main power cable to the MDAC PCB) - but not you loose the Power switch, so you need to switch the MDAC via the PSU / AC socket.
Click to expand...

Meaning I don't need the powerboard at all?
 
CN2 is the connector on the PSU PCB, so does power want to be supplied to the umbilical
(10 cable harness) leaving both CN1 and CN2 connected ?
 
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