Audiophile modified Mac mini

BobLBobL
in For sale

The Mini is an i5,with16G RAM, and is fitted with an Uptone Audio MMK fan controller. It includes a 128Gb SDXC card (see below).

 

Most computers have serious problems when operating as music servers. The main one is electrical noise from the standard SMPS power supply, and this is eliminated here by using an external Linear Power Supply (LPS). A secondary source of noise is the pulse control of the cooling fan speed, and this is eliminated by the MMK. This noise does not directly affect the sound frequencies- the signal delivery is still “bit-perfect”, but the damage is to the timing of the bits, which means that the sound stage loses ‘focus’; you can’t tell which instrument is playing where, but by removing this noise the focus comes back.




For minimum RF interference, on this Mini the WiFi and Bluetooth boards have been removed, which means that for operation via screen sharing, which is the way I have been using it, a WiFi bridge is needed; an Airport Express is included in the sale for this. 



With the addition of a suitable Linear Power Supply (LPS), this becomes a high quality digital source/streamer, particularly when using the trick discovered by Alex Crespi of Uptone Audio. In this, the OS runs on an SDHC/SDXC card, and the music is pulled from a RAMdisk: see description at:


https://audiophilestyle.com/forums/...sicians-walking-out-of-your-speakers/page/30/


This thread has lots of comments from other enthusiastic users.


The Uptone Audio JS2, for which the MMK is designed, would be the ideal LPS, but the UK agent for Uptone also has a range of less expensive LPS:

https://www.vortexbox.co.uk/shop?store-page=UpTone-c110853711



The Mini is currently running on OS El Capitan, instead of Mavericks. It could easily be upgraded as far as Catalina, but Alex Crespi warns that upgrades can degrade audio quality. El Capitan was installed to use Audirvana 3.5 in conjunction with the RAMdisk. This brought the system to the best I have heard from it, so the new Audirvana Origin might be even better.


In this Mini, a small SSD (60Gb) has replaced the original HDD- this size is perfectly adequate for running Audirvana 3.5, but in practice I always ran music from the SDXC. The main purpose of the SSD now is to act as a backup in case the SDXC should get damaged.


There have been reports that SDXC/HC operation can be slow, but this combination boots in about 40 seconds.

I have been very happy with this system, and I am only putting it up for sale because I now have a similarly modified 2014 Mini.

 

The MMK alone costs £ 142.50 new: installation instructions are provided in case you want to move it to a different Mini.

Comments

  • uglymusicuglymusic
    That's a beast!
  • BobLBobL
    uglymusic said:
    That's a beast!
    Thanks- nice to hear that somebody else is convinced about using Linear PSUs!
  • uglymusicuglymusic
    Linear PSUs generally make a big difference in hi-fi. As you may have seen elsewhere on Chews, I'm planning to try one on my RPi4 LMS server.
  • cj66cj66
    On another forum there was a virtual friend that rebuilt all the important parts of his PC with linear PSUs. He was also a great supporter of what Uptone Audio were doing.
    By all accounts his mods collectively  reaped huge improvements to both playback and ripping quality.
    I have a few of his files and they are staggeringly better than any other version I have of the same recording.
    I followed many of his modified DIY projects and have my versions of some of those at home.
    For those that follow this kind of thing on various forums, his online handle was SandyK aka Alex. Extremely generous with his knowledge and time and a sad loss to the audio/DIY community.
  • uglymusicuglymusic
    Ripping is something I've never thought about in terms of as a point of potential SQ improvement.
    Sad to hear about your friend.
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