Mac Mini version of a CAPS music server - Step by Step

[alfe]

How have you (or anyone else ) measured this? In an anechoic chamber?

 

It is hard to fine ambients with at 30 dB linear or less.

 

You think I should invest in an anechoic chamber just to check if the claim is real?¨-)

The only thing I can say ,even sticking my ear to the fan I can't hear it.

[EuroDriver]

The fan itself running on 5v has a acoustic sound level of 10 db and inaudible 30 cm away, but the electric / magnetic disturbance was very noticeable with the noisier amp and cheaper speakers

[fmak]

You think I should invest in an anechoic chamber just to check if the claim is real?¨-)

The only thing I can say ,even sticking my ear to the fan I can't hear it.

 

All I am saying is that acoustics nonsense should not be quoted and spread in the audio community.

 

If your ambient noise level is 40 dB flat, and your fan is 34 dB flat, then you may not hear it. 6.7 dB without qualification is nonsense.

 

When you can't hear it, this does not mean that it does not affect sound quality via electrical and vibrational means.

[alfe]

All I am saying is that acoustics nonsense should not be quoted and spread in the audio community.

 

If your ambient noise level is 40 dB flat, and your fan is 34 dB flat, then you may not hear it. 6.7 dB without qualification is nonsense.

 

 

When you can't hear it, this does not mean that it does not affect sound quality via electrical and vibrational means.

 

 

I have an external linear PS with a Sotm fan filter.

Anti-vibration feet for the carrying box.

And magnetic shield foil around the box.

[fmak]

I have an external linear PS with a Sotm fan filter.

Anti-vibration feet for the carrying box.

And magnetic shield foil around the box.

 

This has nothing to do with fans being 6.7dB quiet, which is the subject of discussion.

[alfe]

This has nothing to do with fans being 6.7dB quiet, which is the subject of discussion.

 

Hit the ground man, I don't care about dB it's quiet dot.

[Alexis777]

I have now completed almost all the path indicated by tranz well (thank you).

Now my mini sounds really awesome ... too bad that I made the changes just now !!!

I have also done several comparative tests on the individual steps, and I have to completely confirm the mods made ​​by tranz.

For example, by removing the infrared sensor (in addition to the wi fi and bluetooth, also removed), also turns off the LED power.

Too bad, because the LED is convenient! But the differences are evident in listening wtihout are tooo positive!

The biggest difference perhaps was to be powered separately the ssd card (with a second Keces 116). Wow. My MSB + Analog Power Base (along with my Tad R1 and Viva + Tenor amps) has never sounded so good!

 

Now I wonder what I can do to improve still, waiting to figure out how to make the card with a separate high performance usb card, which is not there yet for OSX. :-(

 

For example: The special cables SATA PP or JCAT or other similar products: ... has anyone tried if they work better than regular sata computer cabling? Similar effect to changing usb cables? ( I am actually very happy with the new MIT Matrix USB, aftre testing a lot of others, inclusive Total Dac cable)

The special card SSD for internal OS from PP? worth a try?

Suggestions for other tweaks ...?

 

Thank you very much... for all suggestions,

exiting to squeeze even the last bit from the digital source...

[Superdad]

I have now completed almost all the path indicated by tranz well (thank you).

...

Suggestions for other tweaks ...?

 

Thank you very much... for all suggestions,

exiting to squeeze even the last bit from the digital source...

 

Alexis: Glad to know you are having such success.

How are you powering the Mac mini fan? If you still have the stock fan hooked up to the motherboard, then about the biggest difference you can make is getting rid of the fairly high-current (500mA) 25KHz pulses between the fan and the motherboard which are a byproduct of the 4-wire PWM fan controller circuit.

 

As far as I know, there are only three ways to do this:

1) Power the fan at a fixed speed by running it from an external LPS (about 3V results in typical 1800RPM);

 

2) Build a funky-looking housing with big fan to set the Mac mini on with its bottom off, and power that fan with a linear PS. You may need more airflow than the stock mini fan because it will not be mated to the computer's cowling the way the stock fan is. Also, the EMI from some of the bigger computer fans is larger than from the Mac mini's small one--though an external fan will be further away.

 

3) Install the UpTone Audio Mac mini DC-conversion/Linear Fan Controller Kit (MMK; $135). It replaces the PWM DC pulses with smooth, variable DC--still using the tachometer line and remaining under automatic control of the computer and OS X based on thermal sensors and cooling requirements.

In my system it is almost as good as with the fan disconnected entirely. I say almost because the fan still has a slight EMI field, but that can be taken care of with application of some **3M EMI Absorber AB5100S strips on the underside of the fan housing.

Getting rid of the PWM pulses makes a really significant SQ difference.

 

Please excuse the plug. I really don't make much money at all on the MMK kits. I only profit if people buy my John Swenson circuit, dual-output, choke-filtered linear PS.

 

Regards,

--Alex C.

[tranz]

Alexis: Glad to know you are having such success.

How are you powering the Mac mini fan? If you still have the stock fan hooked up to the motherboard, then about the biggest difference you can make is getting rid of the fairly high-current (500mA) 25KHz pulses between the fan and the motherboard which are a byproduct of the 4-wire PWM fan controller circuit.

 

As far as I know, there are only three ways to do this:

1) Power the fan at a fixed speed by running it from an external LPS (about 3V results in typical 1800RPM);

 

2) Build a funky-looking housing with big fan to set the Mac mini on with its bottom off, and power that fan with a linear PS. You may need more airflow than the stock mini fan because it will not be mated to the computer's cowling the way the stock fan is. Also, the EMI from some of the bigger computer fans is larger than from the Mac mini's small one--though an external fan will be further away.

 

3) Install the UpTone Audio Mac mini DC-conversion/Linear Fan Controller Kit (MMK; $135). It replaces the PWM DC pulses with smooth, variable DC--still using the tachometer line and remaining under automatic control of the computer and OS X based on thermal sensors and cooling requirements.

In my system it is almost as good as with the fan disconnected entirely. I say almost because the fan still has a slight EMI field, but that can be taken care of with application of some **3M EMI Absorber AB5100S strips on the underside of the fan housing.

Getting rid of the PWM pulses makes a really significant SQ difference.

 

Please excuse the plug. I really don't make much money at all on the MMK kits. I only profit if people buy my John Swenson circuit, dual-output, choke-filtered linear PS.

 

Regards,

--Alex C.

 

Don't forget the best option:

 

4. No fan at all

[tranz]

Hi Alexis777,

 

Thanks for sharing. Glad to read some of it has helped.

 

My hope is in a LAN input to the DAC solution in order to bypass the USB kludge as the next big improvement. Since you have an MSB you might want to wait and see what they come up with.

 

Cheers

[Superdad]

Don't forget the best option:

 

4. No fan at all

 

Well sure Tranz. But not too many people want their Mac mini to look like yours!

 

 

If you still have your EMI meter and your Mac mini fan hanging about, can you test for us the effect of the 3M AB5100S on it? (I'd ask John Swenson to do so with his more sophisticated equipment but he is tied up on a big project these days.) I did include a big square of it in with our Mac mini DC-conversion/Linear Fan Controller Kit that went to someone in Australia, but I myself have been too busy to try it. Was thinking about putting a cut circle of on the side of the mini's fan shroud that faces the motherboard.

 

Ciao,

--Alex

[jfaaz]

I have never noticed any noise from my late 2012 fusion drive Mac Mini, other than the fan running when the system is copying lots of data fast. I do not have any Mac Mini noise coming from the headphone out or power supply. Am I missing something here?

[tranz]

Well sure Tranz. But not too many people want their Mac mini to look like yours!

 

[ATTACH=CONFIG]14454[/ATTACH]

 

If you still have your EMI meter and your Mac mini fan hanging about, can you test for us the effect of the 3M AB5100S on it? (I'd ask John Swenson to do so with his more sophisticated equipment but he is tied up on a big project these days.) I did include a big square of it in with our Mac mini DC-conversion/Linear Fan Controller Kit that went to someone in Australia, but I myself have been too busy to try it. Was thinking about putting a cut circle of on the side of the mini's fan shroud that faces the motherboard.

 

Ciao,

--Alex

 

Hi Alex,

 

Not fair, you had to grab that intestinal pic...put the lid on it and it looks just like a svelte CAPS.

 

When I am back from my travels I will dig up the fan and have a look.

 

Btw - are you still using the HQ Player on the Mac, and is it stable?

 

Cheers

[tranz]

I have never noticed any noise from my late 2012 fusion drive Mac Mini, other than the fan running when the system is copying lots of data fast. I do not have any Mac Mini noise coming from the headphone out or power supply. Am I missing something here?

 

Hi jfaaz,

 

Count yourself lucky, as that means you are happy with your setup and nothing else matters.

 

The fan discussions are more to do with electrical/EMI noise of the fan.

 

All my gear is in a closet as I cannot stand any harddrive chittering, toroidal hums, bluray spinning and certainly physical fan noises.

 

Cheers

[Alexis777]

Hi Tranz and Alex,

thank you for your suggestions.

I'll think about after the next experiments.

Now, after removing the fan, I'm trying a few simple tricks for passive cooling.

if it were necessary, I would avoid adding additional fans, it just sounds so much better without ...:-)

One of these tricks consists in putting over - with thermal paste - the cooling ducts a heat sink in aluminum, dimensions 20cm to about 5, with the fins of 3 cm.

(Is an element used to cool the MOS-FET, for example)

After the first tests .. it seems to work. Not too hot, so ...

We will see.

I will post a picture to better explain the whole thing.

[tranz]

Hi Tranz and Alex,

thank you for your suggestions.

I'll think about after the next experiments.

Now, after removing the fan, I'm trying a few simple tricks for passive cooling.

if it were necessary, I would avoid adding additional fans, it just sounds so much better without ...:-)

One of these tricks consists in putting over - with thermal paste - the cooling ducts a heat sink in aluminum, dimensions 20cm to about 5, with the fins of 3 cm.

(Is an element used to cool the MOS-FET, for example)

After the first tests .. it seems to work. Not too hot, so ...

We will see.

I will post a picture to better explain the whole thing.

 

Hi Alexis777,

 

Let us know how it goes. It sounds logical.

 

By the way I cannot remember whether I had mentioned this but it really helped in my setup. If using USB output for the music stream, use a bit of plastic to tape (I now use a small bit of thin plastic sticker that is made to cover LED lights) the USB cable's Pin 1 (5v) and Pin 4 (Gnd). This is for the USB cable plugged directly into the computer.

This avoids having signal and power running right next to each other.

 

The IFI USB unit (on an LPSU) then feeds my USB-SPDIF converter via a two headed IFI Gemini cable. Again to feed a clean 5v and ground downstream, and to avoid signal and power to run next to each other. If electricians are taught to not run signal wires close and in parallel to power in the house, why would we want our music to do this.

 

And so until a better, perhaps LAN balanced I2S comes along, all this shite I find necessary to lower the noise floor in my rig.

 

Cheers

[Alexis777]

Hi tranz,

I have already the IFI I usb, but I was not so happy..

But I never tried to feed the i-usb external, but only with the supplied 9v (crappy?) sw.

I'll try now, with a second linear power supply.

Now I have a question to you:

It is better to feed the usb port of the dac directly with a 5 v LPS,

or via the i-usb, also with a 9v LPS?

Thank you.

 

In the pics you can the ultrasimple trick for passive cooling, simply adding a heathsink, 20/5cm.

the aluminum part is connected to the upper side of the refrigerant duct with two elements of copper and glued together with arctic thermal glue.

on the other side you can see an optional second copper element, but I am not sur if it necessary.

It work's!!! :-)

[tranz]

Hi tranz,

I have already the IFI I usb, but I was not so happy..

But I never tried to feed the i-usb external, but only with the supplied 9v (crappy?) sw.

I'll try now, with a second linear power supply.

Now I have a question to you:

It is better to feed the usb port of the dac directly with a 5 v LPS,

or via the i-usb, also with a 9v LPS?

Thank you.[ATTACH=CONFIG]14491[/ATTACH][ATTACH=CONFIG]14492[/ATTACH]

 

In the pics you can the ultrasimple trick for passive cooling, simply adding a heathsink, 20/5cm.

the aluminum part is connected to the upper side of the refrigerant duct with two elements of copper and glued together with arctic thermal glue.

on the other side you can see an optional second copper element, but I am not sur if it necessary.

It work's!!! :-)

 

Good stuff. Thanks for sharing. What temperature are you getting with that heatsink?

 

Regarding the IFI, if your DAC does not require the 5v, just tape the pins at the source and you are good. If the DAC does need 5v, than you still need a way to connect that. A direct lpsu connection would of course work. The IFI is just an easy means to do the mechanics along with the Gemini cable. Let me know how you would directly connect your LPSU. Logically a more direct path of the signal lines is better, without the IFI in between, as it does not clean up the D+/D-.

 

The wallwart was reasonably quiet on the DC side although not as quiet as a cheap bench lpsu. I took scope pictures of that. The bigger issue is its AC noise spitting back into your circuit and the EMI field it throws.

 

Cheers

[weedos123]

Alexis

 

You could be my saviour. In my clumsiness I pushed the fan connector socket off the logic board of my mini and so am forced to run it fanless. It will survive only for about 40 mins before overheating when playing music. There is no hd in it the OS sits on an sd card.

 

So where did you get the heat sink and great lump of copper from and what is the copper sitting on? Does it allow you to upsample and do other processor intensive things without overheating?

 

Thanks

Paul

 

 

Sent from my iPad using Tapatalk

[Alexis777]

weedos,

I found the alu-heathsink on Ebay, you need also two disc's, copper or alu, about 25mm and 10 mm heigh- a simple cut from a tube, in hardware store.

if you find a heathsink a bit 'bigger, even better (so about 20/10 cm?), so you can add a third disc on the other, right side of the cooling pipe.

Dont forget the arctic thermal glue.

Yesterday I copied from the external hd a large data quantity for more then 4 hours, and no problem occured... wow.

only a little hot... :-)

in normal audio reproduction, the heathsing becomes slightly warm..

[Alexis777]

tranz

 

I found this internal filter system for the mini..

 

YFS PS-12m Mac Mini Power Supply/ Modification

 

 

not cheap, but surely well made..

suggestions?

[tranz]

tranz

 

I found this internal filter system for the mini..

 

YFS PS-12m Mac Mini Power Supply/ Modification

 

 

not cheap, but surely well made..

suggestions?

 

Hi Alexis777,

 

Never heard of them, but that does not mean anything. Superdad also has one you might want to check out. I went the Keces route as for just over USD200 at the time it was hard to beat.

 

Cheers

[weedos123]

weedos,

I found the alu-heathsink on Ebay, you need also two disc's, copper or alu, about 25mm and 10 mm heigh- a simple cut from a tube, in hardware store.

if you find a heathsink a bit 'bigger, even better (so about 20/10 cm?), so you can add a third disc on the other, right side of the cooling pipe.

Dont forget the arctic thermal glue.

Yesterday I copied from the external hd a large data quantity for more then 4 hours, and no problem occured... wow.

only a little hot... :-)

in normal audio reproduction, the heathsing becomes slightly warm..

 

Thanks. I'll go and see what I can find

[perister]

Hi Alex,

 

All my music files are stored on a WD thunderbolt external HD powered by a linear PSU.

 

Hi Tranz

 

does it make a realt difference if you use Linear PSU for the external drive?

I have a Firewire Ext Drive, powered by the wall wart SMPSU, have you seen/heard any difference by using the LPSU?

 

many thanks

Nikos

[alfe]

Hi Alex,

 

All my music files are stored on a WD thunderbolt external HD powered by a linear PSU.

 

Hi Tranz

 

does it make a realt difference if you use Linear PSU for the external drive?

I have a Firewire Ext Drive, powered by the wall wart SMPSU, have you seen/heard any difference by using the LPSU?

 

many thanks

Nikos

 

First of all you will find her under an explanation how a hard drive works (watch the video):

 

How a Hard Drive Works | ExtremeTech

 

So now you can imagine that any power supply spike will have a negative influence on reading.

And also explain why some people hear a difference with the same file having the same checksum.