Mac Mini iSense Circuit

[hytechrednek]

There is an often referenced circuit on the internet for recreating the Mac Mini iSense Circuit. I was building a linear power supply for the Mini but found the iSense Circuit did not work. Thanks to Benjamin Zwickle of Mojo Audio, he advised me on how to correct it. I thought I would share it here.

[4est]

What one is the correct schematic?

[hytechrednek]

What one is the correct schematic?

 

Bottom

[chrisfrenchie]

Hi,

in bottom schema, should'nt the input voltage be 12V ? Is it for Mac Mini after 2010 ?

Thanks

Chris

[hytechrednek]

Hi,

in bottom schema, should'nt the input voltage be 12V ? Is it for Mac Mini after 2010 ?

Thanks

Chris

No, this is for the older models with the white top. I believe the later models were all aluminum enclosures 2010 and up.

[Superdad]

Yes, that is the connector for all the tall minis (2009 and earlier). Voltage for those was always 18.5V, but they will run on on a lot less. I had a linear supply on one at 13.8V for a long time. Just watch the current rating of the adapters. Some units, like the Core Solo processor used a supply at something crazy like 165W.

 

All thing aluminum minis (2010 onward) have an internal switch mode supply which can be removed.

[chrisfrenchie]

Oh !! Thanks a lot for clarification.

Do you know what is the pinout for Mac Mini after 2010 ?

In case of power supply removal, i saw on different pictures and/or videos (clonesaudio, coreaudio etc...) that there is a connector that comes on the motherboard. I'm looking actually for the pinout of this connector, in order to make my own cable.

and until now i didn't find this pinout

 

Thanks

[chrisfrenchie]

Hi,

i continue on my investigation for the pinout of a Mac Mini 2010 power supply .

I found this : https://www.gothamsound.com/library/mod-mac-mini-dc-power.

It seems that this is a 10 pins connector, 4 pin are linked to Zero and 4 are linked to 12V, 2 are unused.

Could someone confirm it ?

 

Chris

[BobL]

Hi,

i continue on my investigation for the pinout of a Mac Mini 2010 power supply .

I found this : https://www.gothamsound.com/library/mod-mac-mini-dc-power.

It seems that this is a 10 pins connector, 4 pin are linked to Zero and 4 are linked to 12V, 2 are unused.

Could someone confirm it ?

 

Chris

 

Yes, I've done this with my 2010 machine, and it is running happily. One suggestion- you can find people who will sell you the cable itself- if you use one of these, then should you ever need assistance by Apple (Genius Bar, perhaps), you can get the old supply back in. There are many other tweaks, but replacing the Apple supply (2009 or 2010) with a good linear supply is the one change which makes a really dramatic improvement (I have Paul Hynes, but the Mojo is also very good).

[Superdad]

One suggestion- you can find people who will sell you the cable itself- if you use one of these, then should you ever need assistance by Apple (Genius Bar, perhaps), you can get the old supply back in. There are many other tweaks, but replacing the Apple supply (2009 or 2010) with a good linear supply is the one change which makes a really dramatic improvement.

 

I bought one from this fellow on eBay a couple years back (before I moved to new gen minis). He still sells them. Brand new for $6.80! I added $3 extra for faster shipping--it's coming from China. Genuine Apple. They must have bought a bunch of them from somewhere when that generation went out of production.

 

Power Cable for Apple Mac Mini Computer 110W 85W Power Adapter Output Cable | eBay

 

And yes, linear PS upgrade is a great boost for ANY Mac mini. Even made an old G4 mini sound fantastic.

[BobL]

I bought one from this fellow on eBay a couple years back (before I moved to new gen minis). He still sells them. Brand new for $6.80! I added $3 extra for faster shipping--it's coming from China. Genuine Apple. They must have bought a bunch of them from somewhere when that generation went out of production.

 

Power Cable for Apple Mac Mini Computer 110W 85W Power Adapter Output Cable | eBay

 

And yes, linear PS upgrade is a great boost for ANY Mac mini. Even made an old G4 mini sound fantastic.

 

I wish I'd found this cable a couple of years back! It cost me 3x as much to get a lead from Carnetix to cannibalise, and even then I had to make up a ground connection for it. In the event the (2009) Mini did not care whether the ground was connected or not.

 

(My comment above was about the connector cable for the internal switch mode supply in the 2010 machine, but the same principle applies.)

[dude2010]

Hi,

i continue on my investigation for the pinout of a Mac Mini 2010 power supply .

I found this : https://www.gothamsound.com/library/mod-mac-mini-dc-power.

It seems that this is a 10 pins connector, 4 pin are linked to Zero and 4 are linked to 12V, 2 are unused.

Could someone confirm it ?

 

 

 

Chris

Fuxng sweet!! I've been looking all over for this man!!! Thanks a million!!!

 

Does anyone know if there is a span on the 12VDC? Like if 13.8VDC goes - or it will go up in smoke??

[BobL]

Fuxng sweet!! I've been looking all over for this man!!! Thanks a million!!!

 

Does anyone know if there is a span on the 12VDC? Like if 13.8VDC goes - or it will go up in smoke??

 

There is a 'span'- the 2010 is not very fussy, and I have run it at 12.6v; in correspondence with Benjamin Zwickel he wrote that he had run them up to 13v, but he didn't recommend it. I think 13.8v would be new territory; I wouldn't like to go there, but maybe somebody is braver than I am.

 

 

Just in case anybody picks up my comment above about the cable for the 2009 which Superdad mentioned - I ordered one in the hope that it would be a replacement for the original Apple cable I butchered. It's not! It fits the Mini input, but the other end terminates in solder/crimp connections; no plug!

 

The web site does actually show this now, but there is also a lot of misleading info along the lines of "you must use it with an Apple brick" - but you can't! It will however, suit anybody with their own dc supply, so long as you add the i-Sense resistor (see thread on this).

[hytechrednek]

I got an unexpected treat today. I've been building a linear power supply from scratch and wanted to get a cable that would plug into my 2009 Mac Mini. At first I planned to cut the cable from my stock power supply and use it, but decided I might keep it intact and find a mac mini power supply on eBay that was broken and just salvage the cord and connector from it. I had to settle for one of the earlier model power supplies that only produces 85 watts. The one that came with my Mini is 110 watt. Still my intention was only to salvage the cord / connector from it and my total cost for the 85 watt unit was only $5.50 which included the shipping.

 

When I got it today, I was about to cut the cable / connector off and throw the rest away, but decided to see if it actually worked with the Mac Mini. Not only does it work, but it sounds WAY BETTER than the 110 watt unit I have. It even puts to shame the home brew power supply I made! It sounds much sweeter than the other two. It really cleans up the upper frequencies. While there is more meat on the bones of the linear supply I put together, the 85 watt has a huge edge on the other two from a musical enjoyment standpoint.

 

Has anyone ever noticed this difference in the stock Apple power supplies, or do I just a a freak of nature here in this particular 85 watt supply?

[BobL]

I got an unexpected treat today. I've been building a linear power supply from scratch and wanted to get a cable that would plug into my 2009 Mac Mini. At first I planned to cut the cable from my stock power supply and use it, but decided I might keep it intact and find a mac mini power supply on eBay that was broken and just salvage the cord and connector from it. I had to settle for one of the earlier model power supplies that only produces 85 watts. The one that came with my Mini is 110 watt. Still my intention was only to salvage the cord / connector from it and my total cost for the 85 watt unit was only $5.50 which included the shipping.

 

When I got it today, I was about to cut the cable / connector off and throw the rest away, but decided to see if it actually worked with the Mac Mini. Not only does it work, but it sounds WAY BETTER than the 110 watt unit I have. It even puts to shame the home brew power supply I made! It sounds much sweeter than the other two. It really cleans up the upper frequencies. While there is more meat on the bones of the linear supply I put together, the 85 watt has a huge edge on the other two from a musical enjoyment standpoint.

 

Has anyone ever noticed this difference in the stock Apple power supplies, or do I just a a freak of nature here in this particular 85 watt supply?

 

Congratulations, you got a bargain! It's not surprising that an 85w could work; the power draw for audio is around 15w or less, though a bit more when booting up. I haven't used the 85w, but the 110w supply is so bad for audio that a supply with a different construction could easily be better. Maybe the design of the later 110w just allows more hf noise from the switching to get through.

 

However if your linear supply is not as good as the 85w, it might be worthwhile investigating why not. A lot of us have found staggering improvements, to 2009 and later Minis, by going to a good (sorry, that usually means expensive) linear supply. My own experiments started with a cheap 4a linear supply, and that wasn't much better than the 110w. It was when I put in a small Paul Hynes supply that the real transformation happened, and I have heard even more improvement from Benjamin Zwickel's Mojo, and from the larger Paul Hynes. Superdad (see above) is also about to start production of a competitor supply, and there are good reports on some of the better Chinese supplies.

[4est]

He has begun...

Superdad (see above) is also about to start production of a competitor supply, and there are good reports on some of the better Chinese supplies.