Build a dedicated Audio PC

[Sligolad]

Are you talking resistance across the contacts John or impedance due to some magnetic effect from the coil nearby?
Research I have done has not highlighted any issue going this route as long as you have good quality relay contacts.
Just to be clear the coils are powered separately from a high power SMPS on my audio PC and the relay contacts just manage the switching of the DC Linear supplies direct to Mobo and cards on the Mobo.

The one take away for me going this route is that the improvement seems to cancel out most software changes recently which has me a little confounded.
I have been changing between JPlay Mini, different versions of MQN and I am really struggling to hear differences.
I changed OS drives between CF SATA drive to SATA SSD drive with various implementations of server 2012 stripped down and could not find improvements.
Played with Memory timings, voltages and multipliers in Bios and still no real improvements.

I guess the proof of good or bad with this approach will be a comparison some night but until then the only downside for me is that it shows up some music I previously though OK to listen to have now become difficult to listen to......but music which has been well recorded sounds amazing on either JPlay or MQN and even something as simple as Lister in Total Commander for Wav files.

I agree with Nigel that taking the linear voltages direct to the board and the board components is better than passing through any Dc to Dc convertor.
Cheers, Pearse.

[nige2000]

Are you talking resistance across the contacts John or impedance due to some magnetic effect from the coil nearby?
Research I have done has not highlighted any issue going this route as long as you have good quality relay contacts.
Just to be clear the coils are powered separately from a high power SMPS on my audio PC and the relay contacts just manage the switching of the DC Linear supplies direct to Mobo and cards on the Mobo.

The one take away for me going this route is that the improvement seems to cancel out most software changes recently which has me a little confounded.
I have been changing between JPlay Mini, different versions of MQN and I am really struggling to hear differences.
I changed OS drives between CF SATA drive to SATA SSD drive with various implementations of server 2012 stripped down and could not find improvements.
Played with Memory timings, voltages and multipliers in Bios and still no real improvements.

I guess the proof of good or bad with this approach will be a comparison some night but until then the only downside for me is that it shows up some music I previously though OK to listen to have now become difficult to listen to......but music which has been well recorded sounds amazing on either JPlay or MQN and even something as simple as Lister in Total Commander for Wav files.

I agree with Nigel that taking the linear voltages direct to the board and the board components is better than passing through any Dc to Dc convertor.
Cheers, Pearse.

weird i tested using mqn 2.71 v2/raw/raw background, still could find the differences between them

[Sligolad]

Must be showing my age Nige but I have lost the ability to hear differences between them recently.
Beginning to think something fundamental has shifted recently....either in my head or in my audio PC :-))

[tony]

Must be showing my age Nige but I have lost the ability to hear differences between them recently.
Beginning to think something fundamental has shifted recently....either in my head or in my audio PC :-))

I think the wine consumption might be the problem. I have resisted any further changes happily using a few versions of MQn and looking forward to testing the new Jplay beta. Try some of the mellower MQn's Pearse and just crank off the tweaking. R2 2012. Do you have Usb on battery? Maybe you need to take the PV1 back out of the box?

[jkeny]

Pearse, a low resistance is a good indicator that the resistance at high frequencies (+Mhz) will also be low but no guarantee. It's doubtful that the specs will specify the resistance at these frequencies so a bit of a guess. I'm not even sure that this is going to be a significant factor in audibility - it's just that this is the theory & I've experienced it (I believe) with a battery management pcb affecting the sound.

Don't get me wrong, I'm not saying not to use relays, just a note that there may be differences between low impedance ones & high impedance ones.

But from what both you & Nige are reporting, it seems to be a big upgrade in sound

[Sligolad]

I think the wine consumption might be the problem. I have resisted any further changes happily using a few versions of MQn and looking forward to testing the new Jplay beta. Try some of the mellower MQn's Pearse and just crank off the tweaking. R2 2012. Do you have Usb on battery? Maybe you need to take the PV1 back out of the box?

Wish it was the wine Tony but it has been the first dry Friday in a while....maybe my night out last Sunday at Primal Scream in the Olympia did the damage....only kidding, a great night out but way too much beer!!

My tweaking comes to an end finally next week, I have a Paul Pang SATA cable on the way for an internal SSD drive for the music and a Paul Pang USB cable for audio PC to Meitner and that should be as far as I can go.
Every 5v line on the PC is off the Linear supply with only the external usb music drive through the iUSB power unit but that should be replaced next week.
Definitely no need for the Sub as there is no shortage of bass when needed, had a sublime evening listening to an album by Archie Shepp called True Ballads. A great recording which sounds awesome through the Zuma.

[nige2000]

took a couple of hours this morning to check the preliminary results of yesterdays testing

all testing was done in the usual hazardous fashion
so i could a-b test on the fly and disconnect/reconnect each battery rail over and over and over and one for the road etc

dont look at the pics if your squeamish, this was build for testing nothing more
and no smart ass comments about blowing up stuff (of which i am an expert)

12 volt comes in via relay from either linear or battery which i can swap on the fly

3.3 volt cell can be isolated via switch and powered by pico(which was powered by smps for testing)



this is my botched 5v supply atm of which i can switch between smps and battery



As a whole the bypass dc converter system reveals more bass and more detail

each voltage has played a part in improving SQ 3.3v, 5v, 12v (its not in equal amounts but each has a substantial chunk of the sq improvement so im not going there)
even the 12v rail which there is nearly no current draw 0.06 amp (probably nothing to do with the current so)

Dc converter bypass=good

Now battery vs linear:
(ive tried all combinations but each has a similar effect on SQ)

Bass is less with battery,
bass is tighter with battery
bass feels more true with battery
detail is more with battery
battery is more revealing seams like theres more layers to the music

To trickle charge battery from pico is a problem, as if pico is recieving power from battery it thinks the pc is on and wont boot

sequence is
turn pc power button, then turn on 3.3, 5 12v within the next 3 sec, relays will do this for you

[jkeny]

Great work, Nige - must get to hear it sometime.

My suggestion for your final config
- Use 3 or 4 pole switch instead of multiple relays - try these NKK switches with max 10milliohm contact resistance http://ie.mouser.com/ProductDetail/NKK- ... wI2AA2%2fK
- You could also put a switch between battery & Pico

[nige2000]

Great work, Nige - must get to hear it sometime.

My suggestion for your final config
- Use 3 or 4 pole switch instead of multiple relays - try these NKK switches with max 10milliohm contact resistance http://ie.mouser.com/ProductDetail/NKK- ... wI2AA2%2fK
- You could also put a switch between battery & Pico

im sure it will be at a meet at some stage

Switches i can see it now


be like an aircraft cockpit if i get the sequence wrong there will be smoke

was hoping for something a little more foolproof

[jkeny]

Great work, Nige - must get to hear it sometime.

My suggestion for your final config
- Use 3 or 4 pole switch instead of multiple relays - try these NKK switches with max 10milliohm contact resistance http://ie.mouser.com/ProductDetail/NKK- ... wI2AA2%2fK
- You could also put a switch between battery & Pico

im sure it will be at a meet at some stage

Switches i can see it now


be like an aircraft cockpit if i get the sequence wrong there will be smoke

was hoping for something a little more foolproof

Haha - it's retro :)

No, I mean 3 pole or 4 pole switches i.e one toggle turns on/off 3 or 4 circuits! The correct terminology for them is 3 pole, single throw or 3PST or 4PST - have a look on good ol' wiki http://en.wikipedia.org/wiki/Switch