Help me build a DCDC (5V to 7.2V) boost circuit

I have portable tape decks that have lost their very-hard-to-find power supplies. Plus they were bulky and doubled as chargers (via a 3rd connector) which I don't need. I basically want to power them off of USB 5V power from my desk without having to build a wall wort. I can also power them from my car which has USB.

Before I get started, let me say that I'm proficient with soldering and wire work but I haven't built a real circuit since college over 10 years ago.

Here's what I need to build and I'd like to build it as small as possible (its going to live on my desk).

USB 5V input (I think USB2 is rated at 0.9A max but some Apple supples go up to 2.1A)
DC 7.2V output 0.6A max

So basically I need a compact circuit that is small enough to heat wrap with cable and connectors at both ends that takes USB 5V input and outputs 7.2V to a proprietary connector which I will deal with.

Check ebay for boost converters, there is probably one that you can use.

Ah thanks. This looks perfect:


http://bit.ly/1hbnnwi

So I'm seeing a lot of circuits for sale and they mostly differ in the IC used.


LM2577 - 52khz
LM2596 - 150khz
XL6009 - 400khz


Not so sure about efficiency for 5v => 7.2v for those ICs and how much the rest of the circuit affects that.

if you wang to built it real small. you'll need to built a pcb your own,and its not that easy, i'll suggest you buy a kit