DIY power supply

[LaceSensor]

Can't the same thing be said for pretty much any pedal now? It's kinda the spirit of DIY to want to build it yourself. Besides that, for me, it's another learning experience.

I hadn't seen the Fame units before, so I googled it. I found this link http://freestompboxes.org/viewtopic.php?f=16&t=15737.

The photos don't really make me want to get one. More to the point, it doesn't do what I need. I don't want 12V outputs. Using 12VAC rectified to around 16VDC and then regulated down to 9V is inefficient. It doesn't have 15V and 18V outputs, which I do want. The commercial power supplies that do have what I want are up over (US)$200. The bench supply I built was closer to (US)$30.

ok I can agree on the functionality aspect but making a PSU is quite hazardous compared to a tubescreamer, hence my choice to just buy one.
Building a fully isolated one with all the features you want it might just be better to buy a commercial one was all I was thinking.

[RobA]

...
ok I can agree on the functionality aspect but making a PSU is quite hazardous compared to a tubescreamer, hence my choice to just buy one.
Building a fully isolated one with all the features you want it might just be better to buy a commercial one was all I was thinking.

I agree completely if we are talking about using a mains input power level. But, there are a couple of different paths that are possible that use a low voltage input and those are interesting. Now, if I can only figure out which transformers are the right type to use to isolate the taps, I think we can come up with a nice and reasonably priced DIY friendly board. The problem is that I'm finding that I'm going to need to learn a whole lot more about transformers than I really wanted to know to be sure the design is correct and safe. Oh well. Anyone have a good source of info on transformers thats aren't aimed at kV levels.

[croquet hoop]

I think we have a good base with the Team Tesla! schematic... now the design could be more efficient, and I'm not sure where to find the Recom converters (Mouser does not stock them), but maybe the design can be adapted while keeping the basic idea.

[RobA]

Not only do they not stock them, they charge $7.07 per each when they do have them in stock.

But, I don't understand the point of the design to begin with. Why start with a 5VDC input and use a switching upconverter to boost the level and add more noise? Using multiple clocked converters has issues as well. Using the common mode chokes may well help with this, but I still don't get the point.  It would be much more straight forward to just start with a 1.5A 12VDC power supply and then use the regulators and common mode chokes to regulate and filter. The only thing I can come up with is that the 5V is because it is a universal USB charger power level. But, that doesn't really seem like much use for this purpose.

Edit: Of course, I could be reading the data sheet wrong and completely missing the point. I'd be happy to hear that too .

[croquet hoop]

But, I don't understand the point of the design to begin with. Why start with a 5VDC input and use a switching upconverter to boost the level and add more noise? [...] The only thing I can come up with is that the 5V is because it is a universal USB charger power level. But, that doesn't really seem like much use for this purpose.

From what I read, it's pretty much the point: 5V chargers are common, and powering pedals from a USB port is fun and can be convenient. I won't dispute that, although I agree with your objections—I find it more logical to start with 12-19v and regulate down voltage.

[RobA]

Looking around Mouser, there are other very similar DC-DC converters to the one that is specified that are in stock. The cheapest I see are around (US)$5 per converter. It's going to get pretty expensive to build a multi tap supply if you want to isolate every tap. But, I do think it would be possible with the parts that Mouser does have.

[RobA]

...
From what I read, it's pretty much the point: 5V chargers are common, and powering pedals from a USB port is fun and can be convenient. I won't dispute that, although I agree with your objections—I find it more logical to start with 12-19v and regulate down voltage.

I can see that. I'm not sure of what is happening in the DC-DC converter yet, but they are isolated according to the spec sheets. So, that would be part of the reason too. Especially if they provide total isolation so you can invert the polarity and such without causing shorts. Still, they are expensive.

[selfdestroyer]

Also there is the AMZ Power boards. Looks like this member made one

http://www.madbeanpedals.com/forum/index.php?topic=5430.0

[croquet hoop]

I can see that. I'm not sure of what is happening in the DC-DC converter yet, but they are isolated according to the spec sheets. So, that would be part of the reason too. Especially if they provide total isolation so you can invert the polarity and such without causing shorts. Still, they are expensive.

They are, but if it's what it takes to get an isolated & regulated power supply without messing with AC mains, I find it to be an acceptable tradeoff (and I can't see it being more expensive than any equivalent psu commercially available anyway). Of course, there may be better designs, and I am curious about possible improvements of the idea.

[croquet hoop]

Bump. In spite of the shortcomings of the design, I've just ordered what's needed to make a small Team Tesla with two isolated outs to give it a try and see how it performs. I'll let you know how it turns out.

[RobA]

I'll definitely be interested to hear how this turns out. If an isolated DC-DC solution can be made to work well, it could be really useful when used with some of the Li-Po battery packs that are available now. 

[chromesphere]

Although the tonepad power regulator isnt isolated like the one suggested by Lacesensor, it costs the whole part of about $10 to make (in a 1590a), so it actually is cheaper in this, well...unfair, comparison.

Check that one out if you want a super simple and safe power supply to build.  If you havent seen it, heres a couple of videos i uploaded recently:

Demo:
http://www.youtube.com/watch?v=ROZvdRb01d4&feature=c4-overview&list=UUGhzS1GbX-yxyBrUJtnUMoA

Build report:
http://www.youtube.com/watch?v=KTb2FZDkvD8&feature=c4-overview&list=UUGhzS1GbX-yxyBrUJtnUMoA

Paul