MDAC first listen (part II)
- Thread starter mark.king
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JohnW
pfm member
While in "AV Bypass" you will be able to separately select the Digital routing - so you can route any Digital input to your AV processor,
John
JohnW
pfm member
The Freq. variation is indicative of either poor on board clocking within the Sono's - but more likely its "Data Flow Control" as the Sono's is not the system "Clock master" - and its Clock frequency has to track the source clock - Hopefully the MDAC can attenuate the Jitter products. It's related to the Sono's design architecture and cannot be changed.
What do you use the Audiolab pre-amplifier for? You could connect the Audiolab to the AV pass input. The latest development of the PSU will also allow Gain control (volume control) option of the Analogue input(s).
I'll PM you the Java App.
John
Ah Ah, so we'll now have a Q-DAC option (M-DAC + PSU + Stepped attenuator)... Brilliant!
For an extra £100, I'm very interested as this would allow me to remove my analog preamp (I understand that the PSU has in effect two switchable analog inputs: a balanced one and an unbalanced one)
For an extra £100, I'm very interested as this would allow me to remove my analog preamp (I understand that the PSU has in effect two switchable analog inputs: a balanced one and an unbalanced one)
JohnW
pfm member
John mentioned them a while back in the original CDQ thread. As far as I know;
Mono blocs with balanced input and 'cross' output. And I assume current delivery will be 'adequate'
Possibly class A too, but that's a guess. I hope they will be in the same sexy silver finish as my Mdac.
Matching casework (Footprint & Finish (Silver and Black) compatible) with the MDAC.
The power amplifiers are Stereo units but can be configured for "Bi-Amp" mode or Bridge mode - so you can start off with a single unit and upgrade later for more power or Bi-Amp.
They will be rated to about 120W per channel / 200W+ Bridged - with plenty of current!
The design topology is totally unique - I'll try and refrain from releasing more details until closer to the launch date
John
JohnW
pfm member
well yes - blame Tim!
Yes, the Balanced input can also be configured for a single-end operation with a special cable - in fact this would result in the highest quality RCA input.
John
Now John u got me interested again but I hope there's true differential design maximizing balance out from mdac, monoblk that could handle 2ohm load stable which will kick some 8200mb axx
but I hope there's true differential design maximizing balance out from mdac, monoblk that could handle 2ohm load stable which will kick some 8200mb axx Matching casework (Footprint & Finish (Silver and Black) compatible) with the MDAC.
The power amplifiers are Stereo units but can be configured for "Bi-Amp" mode or Bridge mode - so you can start off with a single unit and upgrade later for more power or Bi-Amp.
They will be rated to about 120W per channel / 200W+ Bridged - with plenty of current!
The design topology is totally unique - I'll try and refrain from releasing more details until closer to the launch date
John
desp_erado
MDAC fan
Hi John,
Thanks for the reply - the Audiolab pre-amp is literally used for switching between the M-DAC and the pre-out from my Yamaha surround processor (which has its own volume control). It sounds like the new PSU's AV pass input will mean I no longer need to use the Audiolab's pre-amp! My Audiolab 8000LX has pre-in connections, but can't remember if it's one of the models that needs an internal jumper changing too to enable power amp mode. I'll investigate in the meantime.
I look forward to the PM, many thanks. Also let me know when you need my details for the PSU.
Cheers,
Ben
desp_erado
Matching casework (Footprint & Finish (Silver and Black) compatible) with the MDAC.
The power amplifiers are Stereo units but can be configured for "Bi-Amp" mode or Bridge mode - so you can start off with a single unit and upgrade later for more power or Bi-Amp.
They will be rated to about 120W per channel / 200W+ Bridged - with plenty of current!
The design topology is totally unique - I'll try and refrain from releasing more details until closer to the launch date
John
Excellent news John.
Could you put me on the pre-pre order list?
Most obliged.
By next xmas I hope to have both an active speaker/CDQ/cross upgrade set up in one room and a non active Mdac/psu/bridged mono's/trios in the other.
If you are going to the trouble of reed relays for volume control, how much extra effort would be involved to provide, say, three independent analogue inputs and the ability (reed relays) to select between them?
The necessary XLR sockets could be fitted to replace blanking plates covering pre-cut holes. Slightly more expensive metalwork, but lots of flexibility for those who desire such...
John - how is this physically possible?
desp_erado
MDAC fan
Thanks John, I've PMed it to you.
I've just been experimenting too! I plugged the M-DAC into my 8000LX's power-in RCAs, but nothing came out. It must mean there's an internal mod needed as I suspected. On searching for this, your name came up on another thread! Can you remember what needed to be done? It does sound like it's not easily reversible though too? (Although, I guess I could just connect the pre outs to the power ins on the back to get the amp back to what it was).
Cheers,
Ben
JohnW
pfm member
I'm wondering if the contact on the USB connector that mounts onto the MDAC PCB has broken-off, or more likely during production they have not pushed the pins of the connector into the PCB holes, rather then protruding though the PCB for soldering, it might have miss aligned with the hole, and just folded over on top of the PCB - rather then though the PCB...
Only guessing here as we don't know for sure its the issue...
Hmmmm, i did what you said John & tightly taped the metal connection of a USB cable to the metal part of my MDac's RCA output, plugged the other end of the USB cable into my PC, and then i couldn't get the USB connection to fail no matter what i did.
I tried everything that previously caused problems, CD player, old sub cranked to the top, hoover, even multiple toilet flushes lol!
In the past if the USB connection started behaving for a short while & i couldn't trip it up i'd check the USB buffer level & when i used any of the problematic appliances the buffer level would dramatically dip indicating there was still an underlying issue
Getting the USB buffer on the display now i can't get it to dip...
Then i tried the CD player one last time & guess what the USB connection went 'inactive'
BUT this time it didn't seize playback on the PC, every single time in the past when the USB connection seized, it made the media player playback on the PC seize aswell, like clockwork.
Just now the hoover managed to trip it up, but not like ever before - the USB still showed as 'Ready' and the dB meter was showing sound, but with no sound coming out the speakers. (reset -all ok)
So now it seems the USB connection on the MDac can still be affected but not playback on the PC.
Bare in mind this is very intermittent now, i can switch the CD player on/off 20 times & have it affect the USB connection maybe once.
Is it safe to leave this extra 'grounding' USB cable between the MDac & PC as it definitely seems to have made everything much more stable, if not then its a very very strong coincidence.
Also, any tips on securing the USB cable a bit better? ill at least switch to electrical tape
JohnW
pfm member
Hi Ben,
Only guessing here, but here goes:-
If you take a close look at this internal picture of a 8000LX:-
Just left of the Black heatsink you will see positions for "REAL" jumper links that are not fitted - I cannot read the PCB text, but I believe it indicates the position of links if / when they are fitted.
I'm guessing that first you have to remove the following "jumper links" which look like resistors, but I suspect are in-fact links (I've circled them in red):
Once you remove the "Links" I've highlighted in Red - you then might need to add new links indicated on the PCB in Yellow text just to the right of the removed links - between the heatsink.
If you could send a High Res picture of this area of the PCB (So I can read the text), then I can give you clearer modification details.
I've never seen a 8000LX, so just going on "designers" instinct.
John
JohnW
pfm member
Hmmmm, i did what you said John & tightly taped the metal connection of a USB cable to the metal part of my MDac's RCA output, plugged the other end of the USB cable into my PC, and then i couldn't get the USB connection to fail no matter what i did.
I tried everything that previously caused problems, CD player, old sub cranked to the top, hoover, even multiple toilet flushes lol!
In the past if the USB connection started behaving for a short while & i couldn't trip it up i'd check the USB buffer level & when i used any of the problematic appliances the buffer level would dramatically dip indicating there was still an underlying issue
Getting the USB buffer on the display now i can't get it to dip...
Then i tried the CD player one last time & guess what the USB connection went 'inactive'
BUT this time it didn't seize playback on the PC, every single time in the past when the USB connection seized, it made the media player playback on the PC seize aswell, like clockwork.
Same story with the hoover, it can trip up the USB at the MDac's end intermittently, even make it show as 'Ready' and the dB meter showing sound, but with no sound coming out the speakers.
So now it seems the USB connection on the MDac can still be affected but not playback on the PC.
Bare in mind this is very intermittent now, i can switch the CD player on/off 20 times & have it affect the USB connection maybe once.
Is it safe to leave this extra 'grounding' USB cable between the MDac & PC as it definitely seems to have made everything much more stable, if not then its a very very strong coincidence.
Also, any tips on securing the USB cable a bit better? ill at least switch to electrical tape
Oh yes - well that's it then - the DC ground is missing from your USB connector on the MDAC PCB... It can still be effected by the "RF" arching produced by power-cycling the CD player power switch in close proximity to the MDAC (as the USB connection is not correctly terminated).
Its safe to use with the extra USB Ground strap - its just a Botch (not what you expect to have to do when you purchase a new unit)!!! I have my head bowed down here in shame... We resorted to "Blue Peter" methods of sticky tape and flushing the toilet to diagnose the issue
Hopefully the UK will receive its next batch of MDAC's very soon.
John
Ah don't be shameful, even with little niggles like this you can be very proud of your work, im smiling ear to ear listening to music through the MDac right now and that's what matters most
To be honest if this hadn't made my setup sound so much better id've probably switched back to my old DAC & got a refund, the fact i've stuck with it just prooves it's worth
I do keep scaring myself though, i keep hitting 'source' instead of the volume control on the remote lol
I spoke to the shop i purchased from today about the right channel cutting out & they said they will swap me a new unit when they have stock.
I wonder if the problems are related in anyway?
Thanks a ton for the help John
To be honest if this hadn't made my setup sound so much better id've probably switched back to my old DAC & got a refund, the fact i've stuck with it just prooves it's worth
I do keep scaring myself though, i keep hitting 'source' instead of the volume control on the remote lol
I spoke to the shop i purchased from today about the right channel cutting out & they said they will swap me a new unit when they have stock.
I wonder if the problems are related in anyway?
Thanks a ton for the help John
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