jeffp:

Technically John looks to be corect about the 7/9 Volt thingie...

'Rechargeable 9V PP3' s are actually only 7.2/8.2 volts... for NiCd/NiMH, - the '9V PP3' would technically be a carbon-zinc or alkaline non-rechargeable.

Which means for us ignoramuses, that the circut may not work correctly if it cannot run down to the lower voltage - defintiely a good chance of s lower level output and perhaps more distortion at the every least.

We have exactly the same things in Australia.