Is this a workable idea?

[n4vgm]

I am a musician and am taking up bass guitar. While I save up for a real bass amp ($300) I'm wondering if I could use a class-D kit running 25-50w powered by a 12v wall wart (I have several laying around). I also have an EQ pedal for a preamp and a cab with an 8" 50w woofer (modified hifi cab for another project). I have tried this cab connected to a 15 guitar combo amp but it just needs more power.

Running 12v would be nice as I could use a portable jump pack to power it for unplugged jams.

Any ideas will be appreciated (I did use the search first but could not find anything like this).

Thanks in advance, Bob

 

[wakibaki]

25W from a 12V supply means an input current of 2A, even if your amplifier is 100% efficient, which it won't be. You can get a class D kit from 41Hz.com (although they are in Europe) that will do 2x25W into 4 ohms, it'll be ~80% efficient, which means about 5A in, if you run both channels into 2 4ohm speakers. Unfortunately I don't think they have a bridgeable one, which would allow you to use a single 8ohm speaker. The speaker impedance is critical in terms of the power you can get at a given voltage. Most wall warts only run ~1A, so it'll run from a car or leisure battery, but probably not a wall wart. This is not the end of the world, you can charge the battery when you're not playing (if your wall wart puts out 15v+ unloaded you can use that, otherwise you'll need a charger)

If you can find a bridgeable 2x25W 12V unit, that'll be the way to go. 50W is not a lot for bass, but it's probably OK for portable. You want a speaker intended for bass guitar probably, they tend to be more efficient (louder) than hifi speakers.

Not all good news, because there's some expense involved and some potential problems. Might be better to put the cash towards a proper amp.

w

 

[n4vgm]

Well, you have summarized what I had figured out so I may just limp along rather than sink money into a temporary thing.

Thanks for the answer, I'll keep poking around.

Bob