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Author Topic: converting small practice amp to battery power  (Read 13413 times)

joecool85

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Re: converting small practice amp to battery power
« Reply #15 on: November 30, 2012, 03:34:04 PM »
That sort of approach might work, but the example in the paper only provides 100ma output current.

I didn't even notice that. That is pitiful compared even to linear regulators like 78XX with no heatsink on them. Switching regulators are supposed to provide more current, since the pass transistor is fully on or off.

Maybe the authors were just going after "proof of concept" to show the establishment of voltage, and so they didn't use "beefy" external components.

In any case, going to read that thing in more detail; it's interesting.

While that is true, step up voltage ICs typically have horribly low ma ratings.  Linear regulators basically burn off the excess voltage as heat, there is a lot more going on in a step up IC.
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Enzo

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Re: converting small practice amp to battery power
« Reply #16 on: November 30, 2012, 07:16:02 PM »
Switching regulators don't provide more or less current than linears.  All the types provide the amount of current designed for.  Switchers may be more EFFICIENT, but that is a different issue.

There is nothing wrong with the circuit in the paper, it does what it is designed to do.   There are plenty of low power applications that would be perfect for.  It starts with 5v.  That generally implies some sort of computer related thing, USB perhaps.  Maybe we want to power an audio interface from our USB port.  The audio will be much happier if we can give it +/-12v rails.  And a couple op amps won;t need much current.  Perfect.   And we can make it run off the 5v in the USB, so no external power sources.

flotrain

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Re: converting small practice amp to battery power
« Reply #17 on: November 30, 2012, 11:28:56 PM »
Again, great info and thanks Matt for the safety warnings with lithium batteries... I wasn't aware of the potential danger.  I checked out the Crate "Taxi" amp on Youtube. This uses a fairly large 12V 7AH battery... you can see it here: http://www.youtube.com/watch?v=AMHqqegHWjM 

The Crate is not expensive but the sound seems to be geared toward acoustic players or semi-clean playing... couldn't find any videos or clips of screaming solos! That's what I like about the little Marshall-- it behaves like a Marshall: cleans up when you roll the guitar volume back and you can dial in some pretty convincing solo and chunky rhythm tones.

I don't need much power.. a Ruby style amp is almost enough- it gets a balanced sound with an efficient speaker and enclosure (... plays for hours on a 9volt battery! :tu:)  I think an amp around 3 to 5 watts would be plenty... then maybe I could get away with a smaller battery pack..  any suggestions?