[serengetiplains]

I just now snapped apart my Mac Mini supply.  The sense resistor on this supply (late 09 model, I believe) is 2801, or 2K8.  I suspect the value of this resistor isn't critical.  It probably needs but to generate a small voltage across it, so a range of 2-6K probably works.  But j'speculate.  Maybe these things are built to exacting specifications (say it isn't so).

[serengetiplains]

The thing I like about surface mount technology is how easy it makes removing components for replacement or use elsewhere.

Into the Hynes supply it goeth.

[serengetiplains]

Ok, the iMove sense resistor now has a new home in my iHynes Mini Power Supply, iSupply for short, which is now powering my Mac the Little.

Great stuff, Paul.  I wanted to add an "as usual" there, or an "as expected," but I didn't want to dilute my thanks.   

[serengetiplains]

After a day's burn-in, the benefits of powering the Mini with the SR7 are more evident.  Low-level resolution is enhanced (easily noticeable), instruments and vocals are more cleanly separated and better focused, digital glare and edge are reduced---all over, the sound is cleaner, clearer, softer and more highly resolved.  One interesting effect is, when listening to music in the background, I now listen at levels 6dB lower.  Musical sensibility, if you will, is that much better conveyed.  I suspect this latter is due, among other things, to a cleaner reproduction of transient edges and attack, which likewise are enhanced.

I suspect I'll hear further benefits with longer burn-in.  All in all, adding the SR7 was a fine upgrade I wouldn't want to do without.

[jtwrace]

Can anyone tell me what the correct size fuse is for a Mac Mini LPS?

[mintzar]

6-8A is fine, but fuses suck. Use a breaker switch. I'll see if I can grab you a link to the breaker switch I use if you'd like. Not cheap @ $22, but won't be a bottleneck like a fuse. Plus they're safer.

[jtwrace]

6-8A is fine, but fuses suck. Use a breaker switch. I'll see if I can grab you a link to the breaker switch I use if you'd like. Not cheap @ $22, but won't be a bottleneck like a fuse. Plus they're safer.

Yes please.  That size seems a bit big though.   

I did plan on using a breaker too.

[jtwrace]

One more thing.  I would like to use a connector on the end of the Mini cable.  I just need a 4 pin XLR female chassis connector.  Right?

[Paul Hynes]

Use female chassis connectors on power supply DC outputs and male chassis connectors on equipment DC inputs. Configure your cable connectors to mate accordingly. This way there will never be voltage on an unconnected male connector and no short circuit risk.

The SR7 has a female 4 pin XLR chassis connector as standard although I can fit other higher performance connectors if required.

For those who require circuit breakers instead of fuses I usually fit ETA circuit breakers in place of the fuse holder.

[jtwrace]

Use female chassis connectors on power supply DC outputs and male chassis connectors on equipment DC inputs. Configure your cable connectors to mate accordingly. This way there will never be voltage on an unconnected male connector and no short circuit risk.

The SR7 has a female 4 pin XLR chassis connector as standard although I can fit other higher performance connectors if required.

For those who require circuit breakers instead of fuses I usually fit ETA circuit breakers in place of the fuse holder.

Thanks!

What size fuse / breaker?

[Paul Hynes]

It depends on the transformer rating, the rating of the regulator output device and the arrangements for thermal management in the regulator output stage as these factors dictate the maximum sustainable current delivery to the load. The fuse/breaker should be rated to sustain this maximum current continuously and blow/trip within a few seconds should a short circuit occur on the power supply output. Thermal circuit breakers can be quite slow to trip so choose your rating carefully.

[mintzar]

http://www.mouser.com/Search/ProductDetail.aspx?R=W23-X1A1G-7.50virtualkey65500000virtualkey655-W23-X1A1G-7.50

I think that's the one I used to use. They also have two-pole versions.

I like 4-pin XLRs for DC connectors a lot, it's just a challenge to build higher-end DC cables with them as their strain relief is too small. They come in handy for multi-voltage power supplies, it just requires a little more creativity for strain relief. For a basic 18awg DC cable you'll be very happy with the 4-pin XLR. I use powercons mainly because they're a more reliable connector with better isolation between the pins as well as easier assembly (screw compression terminals). Obviously that only works for the PS end, for the Mac Mini end there are tons of possibilities... though I recommend something that fits snugly, or better yet locks into place. Helps you avoid the 'stupid tax'.

[boblloyd]

I have a couple of queries/comments about Paul's original post, and screening. The cable connection diagram shows a direct connection to ground, but the mini white brick (2009 and earlier) has no ground connection- it looks as if Apple intend the  mini and the cable screen to float, and any grounding only happens when the mini is connected to external equipment, such as a monitor. What have DIYers done about screening/grounding?

The Carnetix cable mentioned has no screen at all- has anybody managed to use this in an audiophile setup? Incidentally, 6.8k for the sense resistor must be for some old Minis- mine (early 2009), like serengetiplains's, is 2.8k.