[BradJudy]

I was browsing DIY audio sites and found that Hagerman Tech has a 'half kit' (like Tangent and the META42) for a power supply (http://www.hagtech.com/bugle.html#powersupply). It's meant for their phono pre-amp, but provides 15 VDC using a toroidal transformer on a nice PCB. It seems like a perfect match for someone wanting to make a wall powered META42 without a wall wart.

$25 for the board and $33 in parts from Digikey. Not bad if it's a good power supply.

 

[Rodelius]

You can also take a look at this one.
I built the half + side of it for a PSU powered Meta42. No noise, no hum, no nothing. An excellent PSU!
I have used a small encapsulated 6VA transformer and a cheap protoboard.
Don't have the amp here at work, but will post a picture next saturday if it could serve as an example. Could also post the ExpressPCB schematics I made for having sure that everything was right.

I have checked the Hagerman's... Looks nice and neat, but 10000uF+ per side seems to be a heckuva lot of capacitance for such a small application like the Meta 42 doesn't it? Are you gonna put C2 and C3 on the Meta board?

On the other side -and I'm not criticising the Hagerman's approach at all- the Zero Distortion PSU seems to have some extra degree of filtering (e.g rectifier noise) and its voltage adjustable, so you will be able to make it work with any OpAmp you choose. Parts costs will probably be the same for both units. If you go with the Hagerman you will probably get a nice looking PSU, unless you take the time to make a printed circuit...

Regards,
Rodelius

 

[BradJudy]

I'm not looking to make myself another META42. I already have a wall powered one using a simple PS design I got from someone on this forum. I just wanted to throw that out there for people looking for a PS. As you said, it's a bit overkill for this application, but it's a good fit for someone who's at the right technical level to build a META42, but doesn't want a wall wart.

 

[Rodelius]

Oops... sorry... As the subject of your post was a question and your member information says you're a junior member... I thought you were looking for opinions.

Rodelius

 

[BradJudy]

Perfectly understandable. Maybe I'll edit that title to something more appropriate.

Just for giggles, here's my Meta42:

 

[Rodelius]

Nice work BradJudy!

BTW... What regulator have you used? Doesn't it get hot being so close to the transformer?

 

[PeterR]

Looks like a SE power supply - why no dual supply?

 

[guzzler]

no need for a META since it splits the supply on the board itself...

g

 

[PeterR]

Quote:

Originally posted by guzzler no need for a META since it splits the supply on the board itself... g

Sure it does, but it doesn't look like this amp is going to be powered by batteries. So why not ditch the virtual ground circuitry and go for a dual PS? The effort would be minimal...

 

[guzzler]

not really and advantage at all, seeing as the TLE splits the rails dead in two, whereas a dual supply needs to be tweaked to provide equal +/- levels; you at least double the cost of the PSU by making it dual; and finally it takes up more space...

g

 

[Rodelius]

IMHO a dual PSU probably brings some extra measured performace, but I tested my Meta 42 with a lab-grade dual PSU at several voltages and could not tell the difference with the single PSU I built.

 

[BradJudy]

Rodelius: thanks for the compliment. I don't recall the regulator off-hand, but I'll check this evening. It has never had a problem getting warm (the input is very close to the output, so there isn't much to burn off), but I've never used it for more than a couple of hours straight. I never even bothered putting a sink on once I had tried it and found it didn't get hot.

PeterR: It wasn't really a design decision on my behalf - I asked a couple people about PSUs and someone gave me a design they were happy with and was easy to build. I'm really just a builder, not a designer - hence why I found the Hagerman PSU kit interesting.

 

[PeterR]

Quote:

Originally posted by guzzler not really and advantage at all, seeing as the TLE splits the rails dead in two, whereas a dual supply needs to be tweaked to provide equal +/- levels; you at least double the cost of the PSU by making it dual; and finally it takes up more space... g

Not much tweaking necessary. Cost? Most expensive part is the transformer, which you don't double up, so it wouldn't be much more expensive (if at all, if you factor in that you don't need the rail splitter and the buffer)...

 

[xtreme4099]

cool express pcb .... yeah that would be nice...

 

[MERTON]

Quote:

Originally posted by BradJudy Perfectly understandable. Maybe I'll edit that title to something more appropriate. Just for giggles, here's my Meta42:

waht's that big ass blue thing on the left? mine didnt' have taht