[El_Doug]

Following Tangent's guide nearly 100%, let's say I wanted to run the amp strictly off of the wall, never planning to use a battery (and thus skipping any circuitry for switching). I realize I would need a linear, regulated ac/dc brick. However, regulated ones are few and far between, large, and expensive.

Could I use an unregulated linear power brick, say rated at 12v, in combination with a circuit like this in order to put out a constant 12v? is there a better regulation option I should consider, either DIY or available for purchase?

 

[Juaquin]

Tangent has a nice regulator circuit called TREAD. Small and cheap. Tangent Regulator, Adjustable, plus Diode bridge

 

[El_Doug]

ive never run DC through a rectifier before - i assume nothing ill will come of this, except wasting a few 1-cent pats?

 

[DKJones96]

What about using a switching power supply? I have a large regulated power supply I use for testing because I can vary voltages on it but when it comes to normal use I always use switching type supplies because they are cheap, quiet, and common.

 

[Pars]

Most switching supplies aren't very quiet electrically, but of course you can try it. A good place for linear regulated wallwarts at decent pricing is jameco. Look at their Reliapro line: Welcome to Jameco Electronics! Great Products, Low Prices.

 

[Juaquin]

Quote:

Originally Posted by El_Doug /img/forum/go_quote.gif ive never run DC through a rectifier before - i assume nothing ill will come of this, except wasting a few 1-cent pats?

Yeah, the tread can be used to regulate a non-regulated DC power supply - you just remove one of the caps and a resistor (tangent has instructions). It may be overkill though when it might be just as easy to just find a regulated wall wart.

 

[fuzz1111]

To be honest unregulated wallwarts is all I've used with several cmoy-based amps I've built, I've used them all as headphone amps and preamps without issue. Actually I lie - I once had sub 10hz signals coming out of a system I was using a cmoy as a preamp to, though that involved a big car amp with floating earth inputs, powered from a carbattery and 13.8v 40amp switchmode powersupply in parallel, a laptop as the source, using god knows what as its powersupply, a wire running from car amp power ground to laptop signal ground to stop ground loops, and poor cmoy in the middle with its wallwart - so god knows what the culprit was there.

Just make sure the wallwart is isolated, and using one with way more current than you need will mean voltage won't move too much (I mostly use the 12V 1A ones that come with home routers and switches).

I would also use more rail capacitance than tangent uses - atleast use 470uf caps instead of 220uf, change the resistors to 3.3k while you are at it, actually if you are always going to use a wallwart and power usage isnt an issue, you could do what I did for my A47-based amp and use 4 3300k resistors and 2 1000uf caps per rail - though if you use caps that big or bigger you should also use a 10uf cap per rail to bypass them.

 

[fordgtlover]

Quote:

Originally Posted by El_Doug /img/forum/go_quote.gif ive never run DC through a rectifier before - i assume nothing ill will come of this, except wasting a few 1-cent pats?

You don't run DC through the rectifier. If you already have DC, the TREAD needs to only do voltage regulation.

See this page. It states the following in regards to the (B1) rectifier,
If the TREAD’s power source is a DC supply (for instance, an unregulated wall wart), this part is not necessary. If you leave it out, however, you will have to hook the power supply up to bypass the bridge position; the simplest way to do this is to hook the power source to the C5 pads, which is also not needed in this situation. You can still add the bridge if you want; it just drops the voltage a bit, which is harmless in most instances, but unnecessary.