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Mac Mini PSU Upgrade


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Hello People....

 

Just done an upgrade on my Mac Mini PSU.....

Had to saw the case open though!!!!

THIS MODIFICATION WAS CARRIED OUT BY A QUALIFIED ELECTRONICS ENGINEER. DO NOT ATTEMPT THIS IF YOU KNOW NOT WHAT YOU DO.

Changed the main high voltage capacitor to a BHC 220uf 450v, changed the 2 x 1500uf output smoothing caps to a 4700uf non-polar Blackgate. Added some EMI/RFI absorption sheets, added some acoustic absorption on the output lead, fitted a Furutech IEC inlet and built the whole thing into a much larger case.

 

The Mac Mini has a separate hdd for storing my music ripped into .wav, optical spdif out into a highly modified Entech 205 dac...

 

Much better soundstage depth and width, much better low level detail, top end is very smooth and detailed and less digital harshness. Bass is more tuneful.

 

All in all a very worthwhile overall improvement....now I might have to get in the MM to see what I can do there!!!!

 

Regards[br]JC

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Hi JC,

 

this sounds very interesting, can you please provide some pictures.

 

I assume that you 'pimped' an old version of the MM. From my side I have seen some enhancement when streaming music from a ram-disk rather then a hard-drive or thru networked storage/servers.

 

Best regards

be4

 

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JC,

 

What was the output voltage?

 

Using the NP Blackgates will not really do much. A better bet if the voltage is under 10V output would be the BGN 1500uF/10V units. Or some of the organic caps which are much better for switching supplies like the Elna RFS or the UCC units.

 

Really I have been thinking of a hefty linear unit for the Mini and some of the Western Digital drives.

 

Thanks

Gordon

 

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Hmmm ...this goes back to that XXHighEnd conversation. The Microsoft techie felt that, in theory, processor use COULD cause a drain on the power supply which in turn COULD therefore affect your audio playback. Somebody tell me I've over simplified that ..

It could be measureable ... would it really be audible - if it was even measureable ?

 

Can you back up the advantages of the new power supply with any stats? I'm struggling with this one now ... (and am waiting for someone else to post some stats too)

 

M.

 

Just realised I'm typing away and not listening to any music. tut tut.

 

HTPC: AMD Athlon 4850e, 4GB, Vista, BD/HD-DVD into -> ADM9.1

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JC,

 

The BGN are not a real good idea in this area. What you need is the organic ultra low ESR's to kill all that high frequency crap. The BGN are pretty high ESR.

 

I would look at using some of the UCC APS models but I don't see any 20 or 25v available anywhere.

 

http://app.arrownac.com/aws/pg_webc/0,1086,,00.html?application=SEARCH&appid=nac&event=1020&docid=46269916S9300941N6220

 

Maybe the ELNA RFS these have low ESR like 0.1, unlike the UCC which are usually like 0.008 ESR. Do a search on DigiKey.com for ELNA RFS. I have the ESR curves for these somewhere when we did them.

 

Remember when it comes to switching supplies... more is not neccesarily better.

 

jtwrace,

 

Well batteries are good in places. I am not sure it would pay to try and make a honken large supply for the mini. The Cosecant would be fairly easy but I am not sure your going to see one of these soon. It would really require something that told the Battery pack to charge and run. That's what we do in the Crimson.

 

Thanks

Gordon

 

 

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BEEMB,

 

While the Mac Mini itself can be "unclipped" with a putty knife, the power supply for the Mini is a separate Brick that is sealed, much like an iBook or MacBook AC Adaptor. To get into these devices requires some warranty voiding semi-destructive disassembly. The reason for this is that Apple doesn't really want folks tampering with potentially lethal voltages, protecting their customers for harm and their company from liability.

 

IF a change in the PS can result in better performance, I don't know why someone wouldn't just produce something in a separate chassis and fit the same PS plug that Apple uses. Of course, I am sure that the PS connector on the back of a Mac Mini is NOT a standard part!

 

ATB,

Tom "TJ" Jankowski

 

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I assume this isn't a spoof.

 

So how does upgrading the power supply improve the computer? Especially given that a considerable load is removed from the PSU if no graphics is in use (depending on model) when the mini is used headless. What specifically improves by fiddling with a PSU which is already designed to do the job, isn't required to drive varying loads (like an amplifier PSU) and can even be isolated from subsequent components in the chain by using an optical out rather than self-powered USB?

 

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I do hope we are not heading in the direction of green marker pens and frozen CD's. If, and this is a big if, if a power supply upgrade was likely to improve things, then, as Chris has just pointed out, we would come across an external bolt-on by now.

 

 

 

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Just to clear a few things up.

It is not a spoof...I really did this. Am I mad?...Oh YES.... Am I stupid?...Undoubtedly...

I REALLY did saw the case of my Mac Mini POWER SUPPLY open. I tried to unclip it but could not. So out came the large Hacksaw...new blade at the ready and hey presto after a few hefty hackings the power supply case was off. Next up was the removal of the thin aluminium sheeting which was impeding the access to the delicate innards of the power supply. Out came the industrial sized sheet metal snips. These made extreeeeemly short work of the task. NOW the intimate innards were exposed....MMMmmmm.

 

See the cheap capacitors glinting in the pale light reflected off my large, bald, misshapen head. Watch as they are removed with the white hot Weller number 22 chisel bit. I gleefully snort the acrid fumes arising from the blackened Pcb and the molten components nearby.

 

I scurry in to the next room, my precioussssss Black Gate capacitors are stored here, away from the jealous green eyes of the poor ones. I carefully weld them into the mass of carbonised remains. The whole thing is levered into a new case, the wires are re-attached and the unit is plugged into the wall socket and the non-sawn open Mac Mini... The little rear button is caressed and it bursts into new life......My precioussssss is working, it sounds better....I am happy....

 

Gordon.

Thanks for the info and tips on caps etc....I will be having a look around for other ones to try, now the whole thing thing is easily accessable I can do measurements etc..... The plugs I am not sure about though...I think they would be the same... For your info, there are 4 wires in the DC out cable.. +, -, screen and a very thin wire poss used for some sort of sensing, shutdown etc....

 

Regards[br]JC

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Why bother putting a battery or uprated supply on a Mac Mini when a Macbook is practically the same machine with .. um a battery.

 

Dangerous things these CD colouring pens, particularly if you sniff 'em.

 

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  • 3 months later...

This is a dumb question undoubtedly, but can one just replace the external stock power cord with a power supply from someone like Paul Hynes? (or is it necessary to be replacing the internal cap's to have the optimum effect). Could also toss on a large Infinity box from Alan Maher on top which would probably also tame the noise/interference after settling in a few days.

 

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The psu is 18.5v @ 6.5a as far as I remember...but is has this extra little wire connected which probably is some sort of sense wire??? not sure.. I am sure a Paul Hynes design would be a much better job though.

 

Regards

 

JC

 

Regards[br]JC

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Having just bought a new mini as my Amarra/iTunes music server, power upgrade was high on the list. Have coordinated with Wayne at Bolder Cable, and they're customizing their Squeezebox power supply to work with the Mac Mini. Will be at 18.5v, and will also deal with that pesky mac mini "iSense" wire in the power cable required to operate.

 

this unit: http://www.boldercables.com/servlet/Detail?no=395 [or course folks can go all out with their "Ultra" model, but that exceeds the cost of the Mini]

 

this cable: http://store.mp3car.com/MacPac_Power_Cable_Kit_p/cbl-002.htm [just using from this kit what is needed]

 

 

 

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Gordon....if you are still looking I have a dead Mini PS....need to check if the plug is the same but you are welcome to it....I didnt realise it was dead when I bought it....send me postage and you can have the brick as well...

 

Roon NUC I3 w 2500 albums, microRendu to Liberty DAC, Pass DIY Amp class amp, Klipsch RP600 or to Schiit Freya + Gumby MB, Sanders ESL amps and speakers, Mjolnir KGST and Stax L700

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  • 6 months later...

So the question is will the Mac Mini sound way better with a better quality power supply?

It looks like this thread has been on idle for some time.... So does anyone have some new info???

 

Phil

Santa Fe

 

Mac Mini 2009/ Amarra/Wavelength Brick/Apogee Duet/Apogee Ensamble/Variuous home made DAC's/Home made 2A3/45/300B anps/ First Watt J2/ OB Feastrex speakers/ various PS wires etc etc.

 

Open baffle with Feastrex for the top end and 16\" AE for the bass.[br]Pass labs 30.5 drives the AE and my own 45 with Intact Audio output transformers all silver build drives the Feastrex. [br]Lynx Aurora with Antelope clock.[br]Pure Music does the crossover work. Mac mini with a SSD and a Glyph hd for the data. [br]West of the Pecos...[br]East of the Rio Grande...

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Here is the schematic for the Mac Mini Cable.

 

Open baffle with Feastrex for the top end and 16\" AE for the bass.[br]Pass labs 30.5 drives the AE and my own 45 with Intact Audio output transformers all silver build drives the Feastrex. [br]Lynx Aurora with Antelope clock.[br]Pure Music does the crossover work. Mac mini with a SSD and a Glyph hd for the data. [br]West of the Pecos...[br]East of the Rio Grande...

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