[Yoga Flame]

I am considering obtaining a linear regulated PSU for use with my Aune mini dac+amp. The Aune officially takes 12V-18V, but can go as high as 24V. Ideally, I would like it somewhere below 24V, to be on the safe side.
 
This is a used PSU I found for sale, and it has a fixed output of 24VDC:

 
So my question is, can I tweak this PSU to reduce the output voltage? The blue wheel in the picture looks like it might allow that, but I'm a total noob in things like this so I can't be sure. Is that even a wheel? The manufacturer website doesn't seem to say anything about it either (http://www.tectrol.com/products/linear/).
 
Failing the "blue wheel", are there any modifications I could make to this unit to bring the voltage down to within 18V-22V?
 
Thanks for any help or suggestions you can give.

 

[FallenAngel]

Just build a TREAD and set it at whatever voltage you want.

 

[Yoga Flame]

Thanks. I did look at the TREAD, but decided against attempting it because while I have been soldering stuff here and there, I may not be competent enough to build it right now. I don't even have a multimeter yet. Besides, the used PSUs I was considering were selling really cheaply.
 
I ended up getting this PowerVolt BVA-24BS2.4 for $10 + shipping. This one has a trim pot clearly marked as "V. ADJ" for adjusting the voltage, and had a specs sheet that said the adjustment range is 10%. 21.6V seemed like a good figure for the Aune.
 
I used cheap speaker cable to hook up the -V and +V terminals. Connected it to a light bulb first to conclusively determine which direction of the pot was to decrease the output voltage. Haha. I really should get a multimeter.
 


 
It's not much to look at, and I should probably get an enclosure for it. But it works beautifully with the Aune.

 

[francisdemarte]

Definately get a multimeter.
 
The THREAD kit from Tangent's site takes about 20 minutes to solder together. It was my first DIY project.
 
The only substitution you will need to make is one resister. R2 should be 1.2K so you can have an adjustable range of 14-24v. You can pick one up for next to nothing at Radio Shack.
 
Speaking of Radio Shack, they also sell a 15V DC linear regulated supply that works with the Aune.
 
 
 

 

[regal]

I think the powervolt is a better idea than a tread,  you would need one a big heatsink and enclosure to deliver the power needed for the aune  you would spend a lot more money building a tread.

 

[Yoga Flame]

The PowerVolt was definitely a steal at the price I got it for. Supposedly these can cost $100-$200 new. And the eBay seller I got it from was in Canada too, so no bother with customs and what not. I am very happy with this PSU, all things considered.
 
That said, according to the data sheet the PowerVolt's output ripple is "2 mV RMS maximum, 3 mV P-P", lower values being better. Not sure what exactly that means. Is the typical ripple considerably less than the max? But that does seem to be not as good as the TREAD's 0.06 mV RMS rating. (http://tangentsoft.net/elec/psu-tests/) On the other hand, the Aune does have some of its own voltage regulation built in. If it can handle the unregulated linear wall wart that it ships with, it can certainly smooth out that little bit of ripple from the PowerVolt.
 
Side note: I finally got myself a multimeter. Measured the PowerVolt and it is indeed 21V when adjusted down. Hooray for science!  I think I will try a TREAD next time, should I ever need another PSU. Even if only for the DIY experience.