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Suggest the best available cheap power supply for CAPS or Mac Mini


blownsi

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First of all I want to clearly state that my use of the word cheap is intended to remove the high end options from this discussion. I have no doubt they are all great supplies for the money is no object audiophile. I'm asking for the rest of us who can barely afford a CAPS (or Mac Mini) in the first place. To start with I am running a Topanga clone with a simple switching 12v/5a laptop style power supply (from Logic Supply ) and would like to spend say $100 or less on an improvement. Sure I will go somewhat above that but not hundreds of dollars. So far I have seen two solutions:

 

1) LiFePo4 battery pack with charger - The battery will only last a few hours and will require a rather pricey charger. Many people say that battery power is nowhere near as good as a linear PSU

 

2) Tripp Lite PR7 - Regulated supply that is supposedly noisy to the ear and noisy in the actual power line. Is it actually better than the switching supply?

 

I'm sure there is something from the used market medical field which would work but I have no idea what. I've also heard that there are some laptop style supplies that are linear (Xbox 360 HD-DVD) but I have no idea if they are any better than the stock either.

 

What else has been tried? Any other options?

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Eloise

---

...in my opinion / experience...

While I agree "Everything may matter" working out what actually affects the sound is a trickier thing.

And I agree "Trust your ears" but equally don't allow them to fool you - trust them with a bit of skepticism.

keep your mind open... But mind your brain doesn't fall out.

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Yeah, it looks very nice, but seems a bit shy on amps for a Mac Mini :(

 

Depends upon the model year, processor, and drives in your mini, as well as what applications and even which OS you are running (recently discovered that Yosemite is a bit of a power pig). My stripped down 2012 i7 with 16GB consumes about 0.85A at idle, 3.9A during startup, and about 3.5A during heavy DSP (HQ Player) or running HD video off the web.

I am able to directly quote this because I made a test cable to go between my 6.4A JS-2 and my mini (DC plugs at both ends, a break in the positive lead in the middle with plugs to stick into my multimeter).

 

So the 65VA supply Dave linked to--with 4.16A rating when preconfigured for 12V--will probably run your mini fine. At least with its R-core transformer you can be confident it will be close to dead silent mechanically. That's much more than can be said for most of the bench/lab/CB units being sold for cheap.

 

Hope that helps.

--Alex C.

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Hope that helps.

 

Alex, Yes, it helps a lot ! I have been looking at various LPSU's for powering my 2 Regen's (now that the Green has returned home from it's demo tour), and possibily for the Mini. If the 65VA box can power my 2010, I could use it immediatly for Regens, then, once the UTA mystery power reg hits the streets, move it over to the Mini with a MMK kit.

 

I'll have to try out my Kill-a-Watt to see the Mini's current draw* (if I can position it to be able to see that pis-ant LCD screen). Could be a sweet, affordable, solution for me, and a fun Fall project !!

 

Thanks :)

 

 

* Hard to shut down my system and go without amazing music these days through...

 

 

That's much more than can be said for most of the bench/lab/CB units being sold for cheap.

 

'Lab Grade' doesn't seem to stand for much any more :)

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Depends upon the model year, processor, and drives in your mini, as well as what applications and even which OS you are running (recently discovered that Yosemite is a bit of a power pig). My stripped down 2012 i7 with 16GB consumes about 0.85A at idle, 3.9A during startup, and about 3.5A during heavy DSP (HQ Player) or running HD video off the web.

I am able to directly quote this because I made a test cable to go between my 6.4A JS-2 and my mini (DC plugs at both ends, a break in the positive lead in the middle with plugs to stick into my multimeter).

 

So the 65VA supply Dave linked to--with 4.16A rating when preconfigured for 12V--will probably run your mini fine. At least with its R-core transformer you can be confident it will be close to dead silent mechanically. That's much more than can be said for most of the bench/lab/CB units being sold for cheap.

 

Hope that helps.

--Alex C.

 

Thank you and it does help:)

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Have heard some really good things about this AC Filter.

Manufactured by a company that is mostly in HAM radio.

 

Array Solutions - NQN AC Filters

 

Should not hurt the wallet too much at $106 a piece.

I have a few ordered and will be able to share my experience in a few weeks.

Custom Win10 Transport | Mutec MC-3+ Smart Clock USB | Lampizator Amber | Acoustic Portrait Thiyaga | ATC SCM20SL

 

 

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To my knowledge, SBooster does not produce a 12V power supply with sufficient current to power a Mac mini or CAPS. One really needs to be looking for a supply capable of at least 4 amps, with 5-6A being more suitable.

 

Sorry, you could be right. I use my 5V SBooster for an USB device only ...

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Thanks jabbr. Really looking forward to when these reach over here. Supposedly used by some of the armed forces for their gear. Very effective in RF rejection.

Custom Win10 Transport | Mutec MC-3+ Smart Clock USB | Lampizator Amber | Acoustic Portrait Thiyaga | ATC SCM20SL

 

 

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As there were some laboratory PSUs suggested: A while ago I tried a vintage Systron Donner PHR 20-10 (in its time, probably late 70's or early 80's, it was a very good supply incl. a sense loop) for my 2009 MacMini. It can deliver 10A and voltage can be adjusted up to 20V, thus it seemed to be perfect to find out about the difference between LPSU and original Apple SMPS at a reasonable price:

 

http://www.ebay.de/itm/Laborstromversorgung-200W-0-20V-Spannung-nach-Wunsch-/231064781150?nma=true&si=pRWh6tfVGDNkGq1TK5P9aI5Fv5Q%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

 

The seller had checked it before shipping and it actually has very little ripple and is very stable even at high current loads.

Nevertheless, I could not tell much of a difference in my system between the LPSU and the SMPS.

 

I'm not an expert but I could think of several reasons to cause this:

1) LPSU is old and has degraded over the years – anyway the testing showed that it delivers clean and mostly noise-free power and can keep a selected voltage firm under high current loads, so this point is somewhat implausible

2) My hearing / my system is too weak – at least I was able to detect some improvements over some time, the latest being Regen and Supra USB cable, so also somewhat implausible

3) There is something different with laboratory supplies and "audio-grade" supplies – but what? The Systron Donner has a very large and heavy transformer (which is very quiet!) and also a very large capacitor. The audio supplies I have seen so far generally have a large number of small capacitors adding to a (relatively) large capacity as well. Might that be a key point?

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3) There is something different with laboratory supplies and "audio-grade" supplies – but what? The Systron Donner has a very large and heavy transformer (which is very quiet!) and also a very large capacitor. The audio supplies I have seen so far generally have a large number of small capacitors adding to a (relatively) large capacity as well. Might that be a key point?

 

For use running a computer the transient behavior of the supply is very important. A computer is not a continuous current load, but varies all over the place and changes very quickly.

 

A lot of supplies can give out a lot of current at low noise, but if the load changes rapidly they cannot keep up and the voltage sags or rises for a short period of time as the supply tries to keep up with the rapidly changing load. It takes the right amount of capacitance before and after the regulator to produce a supply that can handle transient loads well.

 

A fairly large number of supplies have an interesting property, they can handle very short transients well, but if the transient lasts for a while the output voltage sags and then slowly ramps back up. This means the output cap and regulator work fast, but the raw supply feeding them is too slow to keep them fed when given a longer lasting current increase.

 

Its hard to tell how a specific supply is going to behave with different transient loads. This is never part of the "specs" for the supply, especially since it is not a single number, but a whole sequence of graphs. The fact that there is no official test for this also makes it very difficult for supply manufacturers to let you know how their supplies behave, even if they wanted to let you know.

 

The designers of "audiophile" power supplies take these issues into account when they design the supplies, whether the designers of the inexpensive supplies available in various places do as well, who knows. They may, they may not. You might get lucky and find a supply that has good transient load response, or not. It's very hard to tell just by looking at the pictures.

 

These supplies with R-core transformers may mean the designer is trying to make a better than average supply so MIGHT be an indicator that you have a better than average chance of getting a design that does have good transient response. But it does not guarantee it.

 

John S.

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