MDAC first listen (part XV)
- Thread starter hluga
- Start date
- Status
JohnW
pfm member
I braved it and applied power.
John - exactly what number would you like the rails to be? Set to 15V atm.
Not tried playing music yet.. It's late, I am tired and it needs voltages double and triple checking under load. But I am pleased to see the Mdac spring to life, and no magic smoke escaped.
Hi Sam,
Sorry I've been away from the Computer - working on BDAC paper....
Use a Volt Meter to test the rail voltages - the MDAC's internal voltage reading is a little inaccurate once the diodes have been bypassed (the diode drop is compensated by the software).
With a Voltage Meter + / - 15 Volts DC input is good
I noted on your unit with A06/A06 software that sometimes you had to cycle the Digital filters on power-up otherwise you have no audio...
If the Voltages are correct then leave the MDAC to run-in... (Run in the new Caps),
Looking forward to your listening tests...
Just remember to insure that you have the same software / filters on both units during your listening season..
John
JohnW
pfm member
Morning John and all, I turned on my M-DAC this morning and started to play via USB from my Audiolab 8000DT (same as I do pretty much every day) and was presented with the dreaded crackling coming from the left channel
I have never experienced this before and was quite alarmed as I had the wick turned up considerably from the day before, fresh underwear was very nearly required!
I immediately stopped playback and turned down the volume then tried playback again, the crackling was still present on every track I until I got to Kate Bush Hounds of Love Vinyl Rip, does the M-DAC like Kate or was it the fact that the rip was 24/96 that 'fixed' the issue? everything else played back fine afterwards
and Sam, your DC PSU looks fantastic I am a beautiful shade of green, enjoy!
Martin
Hi Martin,
What's your MDAC software version?
If its not the later A08/A08 then there's a very slight chance of the occasional left channel crackle- - in most cases it will be very rare indeed.
I'm on the very original A0.90 and have NEVER experienced the crackle - but then I only use 44.1KHz /16 (CD)...
John
MartinDurham
pfm Member
Hey John, version 0.90 here too as I prefer the sound, the crackle happened on 16/44.1 material but switching to 24/96 cleared it, at least I know what to do if it happens in future
Martin
Steven Toy
Accuphase newbie
I can't believe John missed Puss-in-Boots on page 41
I know you're a busy man John but if you get the chance could you check my posts on page 44 of this thread, I had a faulty M-DAC unit the other week with the 'No Comms' messages and have just received a replacement unit which also seems to be faulty, this time the remote control doesn't seem to work.
http://www.youtube.com/watch?v=ZdPBUTFJ3yA
Any ideas on how I can fix this without having to send the unit back once again, or would you advise I make another RMA?
Kind Regards,
James P
Links to the posts:
http://www.pinkfishmedia.net/forum/showpost.php?p=1860791&postcount=646
http://www.pinkfishmedia.net/forum/showpost.php?p=1860867&postcount=653
http://www.youtube.com/watch?v=ZdPBUTFJ3yA
Any ideas on how I can fix this without having to send the unit back once again, or would you advise I make another RMA?
Kind Regards,
James P
Links to the posts:
http://www.pinkfishmedia.net/forum/showpost.php?p=1860791&postcount=646
http://www.pinkfishmedia.net/forum/showpost.php?p=1860867&postcount=653
sam_cat
C'est Crounchifique!
John - Problems.. :-(
All rails on the diy psu are 15V (+/- 0.1v), and the minus ones are minus 15v, Mdac reports digital rail as 14.3v..
Sound coming out of right channel only and sounds weak/distorted. No sound from left channel unless volume turned up.
Have reflashed firmware update to original 0.9, no difference. Checked using headphones and get the same issues.
Any ideas?
Thanks,
Sam
All rails on the diy psu are 15V (+/- 0.1v), and the minus ones are minus 15v, Mdac reports digital rail as 14.3v..
Sound coming out of right channel only and sounds weak/distorted. No sound from left channel unless volume turned up.
Have reflashed firmware update to original 0.9, no difference. Checked using headphones and get the same issues.
Any ideas?
Thanks,
Sam
JohnW
pfm member
Best guess is that you have miss-wired the 9W Mini Din... which might also result in DC on the audio outputs...
sam_cat
C'est Crounchifique!
Okay, still having troubles and am sure its something I have done so just want to run through exactly what has been done.
I used the cable from my MDac psu, so no mini-din wiring needed.. As my mdac is DC modified it was of no use anymore. Followed exactly those colour codes (and double checked a moment ago).
Checked output from my regulators and they are now exactly +/- 15v as appropriate.
Black wire is not connected, taped off. No stray wires etc and all solder joints look good (got a good light and magnifying glass on them)
My only thought is the 0v connections.. I have 3 different 0v pads (due to the 5 seperate windings and 3 rectifier boards), checked with a meter there is NO continuity between the 0v pads.. Currently all 0v wires go to the same 0v pad.. If you tell me which colours are 0v for which other wires I can put them all to the correct 0v pads, or maybe I would be better off joining the 0v pads together?
Thanks,
Sam
JohnW
pfm member
Hi James,
Which dealer did you buy the MDAC from? did the unit appear freshly sealed? While statistically possible you could have a second duff MDAC in a row, its very very unlucky.
Where the units B-Grade stock?
You could try the MDAC in a different room, just in case something is blocking the IR transmission - also is the Mini Din power cable correctly inserted, with no bent pins?
While the handset can be seen to be transmitting it cannot be guaranteed that its transmitting the correct codes - so it could be the handset or the MDAC itself...
Try twisting the power cable on the rear very gently...
JohnW
pfm member
Hi Sam, yes, all the 0V on the PSU should be connected together...
In the lead there are 2 black wires - one that's join onto the outer shield wiring - this should be connected to 0V the other is a "Real" black wire that was unconnected in the original AC PSU, keep this one unconnected...
If no luck, PM me your contact number and I'll give you a call...
sam_cat
C'est Crounchifique!
Only one black wire, and a 'silver' wire that was not insulated.. Silver wire showed continuity to the shield/outer casing of the mini-din. Black wire is taped out the way.
Will link all the 0v points together now and see if that helps.
Sam
JohnW
pfm member
Hi Sam, also connect the Silver wire to 0V
jamjar784
Heavy Up
John i've got a question concerning burn in. Is it feasible using headphones or is it better to connect to a switched on amp ?
Moreover how many years does it needs
br /
Previous advice IIRC was that the MDAC only needs to be powered up to allow the caps to bed in. Expect some variation in SQ for a few days before settling down to 'excellent'
sam_cat
C'est Crounchifique!
Linking the 0V points fixed it. Rechecked and tweaked all voltages back to +/-15V (Now +/- 0.01v) as they shifted by linking the 0V pads.
Silver wire was already connected to 0v.
Playing music now (through headphones,which is not my normal listening method) and it sounds perfectly fine. :-D
Quick 'shoot out' this weekend against Dads standard Mdac with a standard psu and his own dc psu.
Thanks for the assistance!
Silver wire was already connected to 0v.
Playing music now (through headphones,which is not my normal listening method) and it sounds perfectly fine.
:-D Quick 'shoot out' this weekend against Dads standard Mdac with a standard psu and his own dc psu.
Thanks for the assistance!
- Status