Amp power

[cosmomurphy]

Howdy yall, I have a question concerning the wiring of a power source to an amp. I'm a beginner, so forgive me if my question is simplistic. The amp in question is the DTA-2
Dayton Audio DTA-2 Class T Digital Audio Amplifier Module 300-385
I'm building a portable sound system with it, and I want to be able to have the option of powering it using batteries as well as a Dc input. I drew up a simple schematic for how I'm planning to wire it, and I'm wondering if this will work or if I'm missing something. My plan is to wire the +\- terminals of the DC input to the corresponding terminals on the battery holder and then wire that to the +\- terminals on the T-AMP. Will this work? If not, I was wondering if you could suggest an alternative method on how to do this.
Thanks in advance
Best regards-
Cosmo


--------------------------------------------------
| | |
| - | - | -
DC input 8AA battery T AMP
Jack Holder |
| + | + | +
| | |
--------------------------------------------------

[sofaspud]

I think the board stripped the spaces from your ASCII art. But what you need is a diode to prevent DC from flowing into your battery. A Schottky type such as the 1N5821 will drop your battery supply ~0.3 volts. Basic circuit shown below.

[JoelS]

yes agreed about the diode. another good reason to use a diode when using battery power is to prevent your circuit being destroyed if you happen to connect the battery backwards by mistake.

Also, with battery power you have to consider the current required by the circuit and the source impedance of batteries. the link you posted says the DTA-2 is 15W per channel. I doubt AA batteries will be able to deliver enough power (current) for this, and if it works at all the batteries will probably run down completely in less than 1 hour. (maybe longer at low volume) try D cells.

batteries are not a regulated voltage source, be careful not to over power your circuit and be aware that an amplifier will be more easily distorted as the battery voltage drops.

-Joel

[dangus]

Battery life may be tolerable. A 15 watt amp playing music near clipping is only drawing that much power for the brief waveform peaks; average power could be less than a watt. 2000 mAH NiMH cells would give pretty good runtime.

[cosmomurphy]

Thanks for the help yall, I have a questions about your concerns over battery life however, the dta-1 Dayton Audio DTA-1 Class T Digital AC/DC Amplifier 15 Watts Per Channel - Parts Express 300-380 runs off of 8 AA batteries, and i've gotten it to run for at least 6 to 7 hours before it starts clipping because of low power. I figured since the DTA-2 is the same circuit, I could just connect a battery carrier(along with the dc input), and it would run the same. Am I wrong in assuming this?
Thanks

[dangus]

I don't see why not.

Rechargeables have a more constant voltage, and I ~think~ lower impedance than alkalines. Consider sealed-lead-acid ("gel cells") instead of NiMH. They're heavy, but I think the capacity/dollar ratio is better. It would take 30 2000 mAH NiMH to get near a 12V 7AH battery (which the local battery warehouse sells for $28). By the way, it's slightly possible you might find a usable battery in the recycling bin outside such a battery warehouse. Some applications use pairs or triples, and when one of those batteries fails, all are usually replaced at once. And, in my experience often just one cell of a battery fails; I've exposed the links between cells and soldered on a wire to make a 10V or 8V battery from a bad 12V one.

[cosmomurphy]

Alright, so I got another question. If I get a closed circuit DC jack, and wire the battery pack to it, do I still need to use a schottky diode? The section on this page about DC jacks seems to describe what I'm trying to do
How to Wire Panel Components
but I want to make sure before I wire it and mess something up.