[JiggaD369]

Hey guys,
 
I'm looking for a DIY 12V PSU to replace my crappy wallwart (12V, 1.25A) that I received with my Kramer 6410N. I thought about using a laptop 12V PSU but then maybe that might not serve the purpose well. And I've been waiting to get into DIY so I thought why not take up a small project like a PSU? 
 
I have some parts available such as a Hammond 182L12 (50VA and Secondary Voltages:2 x 12V). I know this transformer is way way over what I need but I have it laying around and don't need it anyways. 
 
I'm assuming I need a single (+12v) not a dual (+-12V), correct? Sorry I'm still learning.
 
Some that I ran across:
 
The Placid from Twiste Pear
 
http://cgi.ebay.com/Variable-Voltage-Regulator-1-5-30V-up-5A-Bare-PCB-/320630257561?pt=LH_DefaultDomain_0&hash=item4aa70d7799#ht_1498wt_909
 
http://cgi.ebay.com/All-FET-low-noise-super-shunt-regulator-PCB-Borbely-/320619074637?pt=LH_DefaultDomain_0&hash=item4aa662d44d#ht_2645wt_1026
 
http://cgi.ebay.com/Low-noise-High-Current-dual-power-supply-LT1083CP-kit-/220722396483?pt=LH_DefaultDomain_0&hash=item3364147d43#ht_6728wt_1026

 

[FallenAngel]

What is the intended application?  If it's for the 6410N, I wouldn't bother

 

[JiggaD369]

Hey fallen (again ),
 
It is for the 6410N but the wallwart feels so da*n light and cheap that I think it can def. use a upgrade. And since I have the transformer laying around since no one wants to buy, I can put it to some use. 

 

[Yoga Flame]

Quote:

Hey guys,
 
I'm looking for a DIY 12V PSU to replace my crappy wallwart (12V, 1.25A) that I received with my Kramer 6410N. I thought about using a laptop 12V PSU but then maybe that might not serve the purpose well. And I've been waiting to get into DIY so I thought why not take up a small project like a PSU? 
 

 
Welcome to the wonderful world of DIY! And yeah, the laptop PSU is most likely a switch mode one. Probably too noisy and not recommended for audio.
 
Quote:

I'm assuming I need a single (+12v) not a dual (+-12V), correct? Sorry I'm still learning.
 

 
If the included wallwart has two wires in the cable, and terminates with a normal looking DC barrel plug, then it's a single supply. If there are four pins in the plug, then it's dual.
 
I am not too familiar with the PSUs you listed. But I agree with FallenAngel that the Placid might be an overkill for the Kramer DAC. Maybe try a sigma25 (σ25) with a big heatsink. Relatively simple to put together for a first project and doesn't cost a lot. And definitely performs much better than a wallwart.
 
As with any PSU, make sure you know what your are doing when dealing with wall AC power.

 

[JiggaD369]

Hey Yoga,

Tahnks for the input!

I've read the manual for the Placid and it's def. a good learning read!

But is the Hammond 182l12 feasable for a small dac or will it blow it up?

 

[Yoga Flame]

Your 12V transformer should work fine with the secondaries wired in parallel. Even if it has a high max current output, it will only supply as much as is needed by the DAC.
 
I forgot to mention in my earlier post that the sigma25 is from AMB.

 

[JiggaD369]

Hi Yoga,
 
Yeah I just got home and checked the wires and it is 2 wire run so it's a single ended PSU I assume.
 
So you would def. recommend the AMD PSUs over the Placid?

 

[Yoga Flame]

I would. Though not because one is superior to the other.
 
The Placid is a shunt regulator. I'm not too familiar with those, except that they are better suited for low current applications. And your stock wallwart has a 1.25A rating, which isn't terribly low. Also, you'll need to know in some good detail what levels of current the DAC will draw. I.e. will it fluctuate a lot, or mostly draw x mA, or whatever. And then configure the shunt regulator accordingly. With the Twisted Pear DACs, they know exactly what the power requirements of their DACs are, so no problem using the Placid there. I dunno, maybe your Kramer came with sufficient documentation to figure out what you need.
 
(These are just things I have read about shunt regulators, and have not attempted this myself.)
 
The AMB sigma25 is a simpler design based around a 7812 IC. It's good for up to 1.5A, and as long as you use a large enough heat sink you won't have to worry about much else. So I figure this would be better in that respect, especially since this is your first DIY project. It's similar to the power regulation section on your LC amp (from your sig). 

 

[JiggaD369]

Yoga,
 
Yes the manual for the Kramer does state that it requires "POWER SOURCE: 12V DC/1.25A, 150mA" so I'm guessing it draws 150mA but the wallwart is rated upto1.25A?
 
I've been reading the AMB website about the sigma25. The parts list is very short so putting it together seems like a nice first project. But one think I cant't seem to figure out is the heatsink issue. You state that I need a big heatsink but their PCB is not configure for a big heatsink. 

 

 

[Yoga Flame]

Oh, 150mA. That's not much at all then. No need for a big heat sink in that case. You might even get away with no heat sink at all, but I'd use something like the one pictured anyway to be on the safe side. But hypothetically if you were to use a big heatsink, you would mount the heatsink onto the board first, and then solder the LM7812 to fit vertically instead of bending 90 degrees.
 
The sigma25 in the picture is a bit non-standard, just in case you didn't already know. You will need to populate the D1 position for it to work with a transformer. It's just jumpered in the pic.

 

[JiggaD369]

Hi yoga,
 
Yeah I just googled for a pic. of sigma25 and that's what came up.
 
But is there a reason why the sigma is a better option as compared to the placid? Pic. below for comparison.
 

 

[Yoga Flame]

It's "better" in terms of cost and simplicity. And maybe with noise levels already below the threshold of the Kramer.
 
If you're up to it and want something with even better specs, then go for the Placid. I guess 150mA should be no problem. There's also the AMB sigma11. Tangent's YJPS is another top tier supply too, if you can find someone who still has a board to spare.
 
I'm just a relatively new DIYer with no engineering background. So maybe someone more experienced can chime in with a more in depth comparison.

 

[JiggaD369]

Yoga,
 
So you say sigma25 would be my best bet? No audible difference between any of the ones you listed?
 
I'm just dipping my feet into DIY also but I was planning to build the power supply onto a breadboard to really get my soldering skills up.

 

[Yoga Flame]

First define "best". Then it will be easier to get an answer.
 
As for whether there will be any audible difference, that's beyond my ability or experience. I haven't tried the Kramer 6410N before. I'm basing my opinion off someone's comment in your Kramer thread (yes, I'm following that one; seems like an awesome deal at that price) about the DAC's specs being "below CD quality".
 
Now on the other hand, if the poor specs are a direct result of the stock PSU, then using a super high end PSU should help a lot. But that's a big "if" that I don't know the answer to.
 
In any case, the sigma25 is a nice "DIY 12V PSU for a noob" project.

 

[JiggaD369]

Sorry for the ambiguation but I meant what would be the most optimal solution for learning and performance purposes. 
 
I think sigma25 seems like the easiest one to assemble without a PCB.