few amplifier choices in 12vdc, help!


2012-03-25 2:08 am
Hello everyone,

I need advise. I have been recreationally building unorthodox mono portable speakers over the past year. Mostly little class d 12v amplifiers and a 12v lithium battery. But now I want more volume. The sure 4x100 24v boards are amazing. They produce huge amounts of volume and still sip battery power.

But..... My designs are mono based, and small. The 24v battery situation sucks (expensive, larger, weird chargers), and I really only want 1 or two channels. (I sometimes bi amp)

I feel I could....

1) Find a medium sized class d 12vdc mono amp. say 100 watts.

2) learn even more about efficient speaker design.

3) learn more about 24v batteries so they are less troublesome.

4) learn about boost converters (good idea?)

Lets put it this way, I've been extremely real life comparison with a $90 jbl bluetooth portable speaker. Its really loud and and warm sounding, at 1/20th the size of my designs.

Any advise?

For 24v you need 2 12v batteries.In series,so its not a problem.a charger from a corldess drill thing will work since soe have 24v batteries
Its not possible to get 100w from 12v
Boost converters are quite complicated and are not begginer friendly
im pretty sure a ta2020 will work but i wont be very powerfull
You can, of course, try using a mains amplifier with pure sine wave battery inverter, but this is inefficient and depending on the inverter design, the sound may not be good.

Large car amplifiers may use switch-mode power supplies to get a higher voltage, they're very often bridged and may be class D amplifiers.

Bi-amping (or even tri-amping) is a good idea. Not only do you double up the amplifier power, but a lot of power can be wasted in a 2-speaker system with a passive crossover (in the crossover). It needs careful consideration however because the power in different ranges (treble, mid, bass) in music is not evenly distributed and woofers and tweeters often have different efficiencies which can call for some juggling to get the sound balanced. I don't know of any off-the-shelf speakers for bi-amping (just bi-wiring), you'd probably need to build them.

Using 4 (or even 2) ohm speakers also increases the amount of power you can get for a given voltage. You can also run speakers in parallel (2*8 ohm to get 4 ohm) which increases their efficiency as well as getting a power gain if your amp will tolerate it.

You could buy Vance Dickason's Loudspeaker Design Cookbook to get a bit more insight into these issues and look at Rod Elliott's site Elliott Sound Products - The Audio Pages (Main Index) which has details of many of these techniques and others.
Thanks counter culture. Thanks a wonderful response. looks like if simple and loud are my goal. 24 volt batteries are the only way. The class d or tripath amps are wonderful on battery life, but many of the powerful ones are very high voltage, so I am going to stick to the tk2050 because of its track record. I've tried a few other boards, but none performed as well as the older 2050 chip with batteries. Price is a factor too. So is where the amplifier is maxed out. I certainly can't go higher than 24v (27ish actually) (if 24 is a pain, 36 certainly will be)

Does anyone out there have another 100x100 amplifier board they like that runs well on 24vdc? I'm up for trying a new amp, perhaps cheaper than the sure $45...

theres this one, but it is a fluke:

Mini 100W 100W TDA8920BTH Class D Power Digital Amplifier Board HiFi Audio | eBay

or this

DIY Class D Stereo Amplifier Board 50W 2 TDA7492 HiFi Audio Amp Board | eBay