Hi. My name is Dan, and I'm a noob

[J M Fahey]

Hi. Those 19V are no load voltage.
You'll get to 12V (hopefully) with full 1500mA load.
That's why it pays to overspec everything a bit.

[dmartn149]

so it's not going to kill my amp?

[J M Fahey]

If it were a stiff 19.7V PSU, maybe.
Real life test: hook it to your TDA2003 board (without preamp) , no signal or shorted input, speaker connected, and measure what you really get.
As the datasheet states, it can stand 28V *no signal* but it should not "work" with more than 18V.
In a nutshell: I doubt you will have more than 18V there with any sound coming from that speaker, definitely less than that when cranking your favorite guitar licks through it
As usual, only measurements will tell.
PS: I'd buy a few TDA2003, simply because of its low cost and the real possibility of having a mob of friends asking for similar amps.

[dmartn149]

I tried the 12v ww with the input open, and shorted, and still measured over 18v both ways. I found a 9v , 300ma ww in my "pyle-o-junk" that gives 12v with no load, but it motorboats, and hums too. I haven't tried the isolating methods yet, as I don't have the caps and resistors on hand.

[dmartn149]

could I run my 12v 1500ma wallwart through this to get clean, stable 12v?
http://www.instructables.com/id/Make_a_simple_12_volt_power_supply/

[J M Fahey]

Yes, you can.
Bolt that 7812 on a heatsink, at least a piece of aluminum, and the first time you use it, touch it now and then to check it does not overheat.
Practical rule: if you feel it hot, yet you can stand touching it, it's OK; if you can't bear it over a few seconde (or even worse, if your skin sizzles or grills), then it's *too* hot.
Make an external power supply so you can power this ampand any future project freely.

[dmartn149]

I noticed after I posted that that circuit uses an ac transformer. Could I delete the diodes and use a dc wall wart instead?

[J M Fahey]

I don't understand you.
A DC wall-wart does have diodes and filter capacitors within.
When you wire a power jack for it, you send its positive and negative pins to the corresponding points in your PCB.
Adding a 2200 or 4700 uFx25V from positive to ground will lower hum and provide cleaner sound.

[dmartn149]

I guess I just wanted confirmation that I don't need the four 1N4001 diodes used in this circuit
http://www.instructables.com/id/Make_a_simple_12_volt_power_supply/
because they are for rectification, which is already done in the dc ww.

[J M Fahey]

You do not need the:
* 4 x 1N4001 diodes
* 14V - 35V transformer
* 240V input
because all that is included into your wall wart

[dmartn149]

I built the regulated power supply, and temporarily wired it up to the amp. No more motorboating! Now the gain control on the Gem doesn't seem to be working. I'll check into that when I get more time. Thanks for all the help and guidance. I'll probably be asking more questions when I decide to add some kind of tone control.
Thanks again, Dan

[J M Fahey]

OK, now you know what to do with that "International House of Pizza" membership card I signed on your behalf. (hint, hint) 8|