Which amp kit w/UPS as power supply?

[critofur]

Hello,
I am considering building my first "kit amp" and I happen to have a spare UPS which I replaced when the battery inside died.

I would like to use the UPS as the power supply + case for the amp. Mostly to save money, and, because I already have this dead UPS sitting on my shelf collecting dust.

I notice the "AMP9" kit from 41hz.com can run off 12V, guessing that would be my best option then?

Another thing I was considering - if I wanted a completely noise-free power source, then later I could replace the battery that was in the UPS and then the UPS would be just a batter charger, and the battery would be the power source.

The AMP9 can be powered off of just one +12V source? If I wanted more output, would I have the option of using +/-12V instead? And, from a typical UPS, I could probably get +/-13.8V??

Should I post some pictures of inside the UPS?

I see here: http://diyaudioprojects.com/Chip/AMP6-DIY-T-Amp-Kit/ he's used just the transformer from a UPS, I was hoping to use the whole UPS, including the case as the AMP case.

edit: another thing about the AMP9 that looks good is that it's good down to 2 Ohms, I'm thinking to use it with speakers that will probably have some impedance dips down to about 3 Ohms (w/ a pair of these: http://www.partsexpress.com/pe/showd...number=299-164 wired in parallel to keep the sensitivity over 90 db)

[pacificblue]

You better ask questions about class D amplifiers in the class D forum.

You can also find some of your answers on www.41hz.com They sell three versions of Amp9. The low profile version can be used up to 14,5 V, the basic version from 12-24 V, and the tall capacitor version 27 V. That means you can upgrade basic and tall capacitor versions later without change, but need to swap capacitors to upgrade the low profile version.

The text on 41Hz seems to indicate the use of single power supply, however the pictures show connections for symmetric supply. I think you should rather ask them directly, if by 12 V they mean ±6 V or 12 V single, and by 24 V mean ±12 V or 24 V single. Maybe they designed the amp in a way that both can be used, but my impression is that you will need symmetric supply.

As long as you use the amp with the batteries, ±13.8 V (or a bit more) is fine. That is pure DC and the capacitors are rated for 35 V.
If you use the amp, while charging, that is a different matter. If 41Hz allows 27 V, then 27.6 V won't kill the capacitors, but you rather ask them directly.

[pacificblue]

BTW, the UPS voltage could be higher than 13.8 V. I remember something like charging with 1.6 or 1.7 V per 1.2 V nominal battery voltage from my formation days.