[balou]

it is a dual secondaries supply - but +/-24v, which is to high for almost any opamp. +/-18 will work with many opamps, but it's a bit on the high side. +/-15v is the standard dual supply voltage, this will work with all opamps except some recent low voltage types. for example, the ad8066 is specified for a max +/-12v

 

[ericj]

Quote:

Originally Posted by balou /img/forum/go_quote.gif it is a dual secondaries supply - but +/-24v, which is to high for almost any opamp. +/-18 will work with many opamps, but it's a bit on the high side. +/-15v is the standard dual supply voltage, this will work with all opamps except some recent low voltage types. for example, the ad8066 is specified for a max +/-12v

ad8066 is +/-13.5v max, iirc, but the extra 3 volts actually makes it sound worse.

fwiw, you could hook up the primaries as though you were in a 230v country and get +/-12v out of the secondaries.

 

[peasleer]

Quote:

Originally Posted by balou /img/forum/go_quote.gif +/-15v is the standard dual supply voltage, this will work with all opamps except some recent low voltage types.

Updated best-attempt:

http://tinyurl.com/33yh2x

I couldn't find anything supplying +/-15v at Jameco, but honestly only looked at newark aside from it and was immediately scared of the prices

How do you know if it has dual secondaries? Is it from the transformer having values for series/parallel output?

 

[heatmizer]

Yes that has dual secondaries. Take a peek at the datasheet

 

[ezkcdude]

The dual psu board I built (you can see the details on my site), can be run off an AC wallwart or transformer. I use a wall wart, just because I'm a little afraid of working with mains. Anyway, I typically use a 12VAC wallwart and hook it up to my psu using a 2.1 mm jack. The voltage output which goes to my DAC is around +/- 13.6V, but can be anything pretty much with the LM317/337 combo. I don't remember exactly how TREAD works, but I'm guessing you can use a wallwart with that one, too.

 

[balou]

peasleer - I forgot, you also have to consider voltage drop. this will be about 3v with standard rectifiers and a standard regulator (2v drop in the lm317, 0.7v drop in the rectifier, plus drops in other components, tolerances, safety margin etc), 1v if you use an LDO regulator and a schottky rectifier with a low forward voltage. and you have this drop on both regulators
so a +/-18v transformator would be a good choice for +/-15v regulated.
the +/-12v transformer would give you +/-9v - maybe a bit on the low side for an audio grade psu

edit:

this one is only 1.75x1.125" or 4.4x2.8cm, has an encapsulated transformer onboard, 150mA output power, voltage drop of below 1v, space for two 2200uF panasonic fm caps, and is probably extremely difficult to solder

(sot23 regulators, 0805 resistors, and crammed together like mad)

 

[Soymilk]

i'm interested in this "mini dual psu"; could you give me some more details? and how powerful would it be? i'm probably looking at the specs you put up the wrong way, but 150mA output power seems kind of low (i'm building a psu for a ppav2).

 

[balou]

yes, it is kinda low, and in it's current config, it's just dual 5v. I intended it as a power supply for 'transportable' category amps, which will run either off a bunch of rechargable AAs, a 9v, or this power supply. the problem is, those SOT23 chips can't really bear high temperatures, so ultra low dropout was kind of a requirement in this design (less power loss, less heat).

 

[peasleer]

Well, I priced things out last night and my wallet disagrees with this project

I made cuts on some of the non-essential caps on the TREAD, but I still couldn't beat Tangent's kit prices for the TREADs - which doesn't factor in the cost of an enclosure, jacks, and a transformer or wallwart. I also have an Alien to build and a non-audio DIY project, so this is getting shelved from my end for now as a "to-do" item when I have more time and money to blow.

Thanks for the help everyone, I'll make a new thread with build details when I get around to it.