casio keyboard and guitar effects

[cuacua]

HEllo! i'm new to this forum, and it's great! anyways I have a small problem, i hope somebody can help me out. Every time, (well i only tried it twice) I try to use my guitar zoom 707 effect with  my small casio keyboard (i don't know the model, it has like 30 keys) - both connected to electric current with a , mmmm, in spanish its adaptador, those things that regulate the voltage (the zoom is 9 volts, and the keyboard 7.5), hte adaptador burns!!!! i'm really scared something could happen to either the effect or the keyboard, and also really curious why this could happen. The sound out put goes through a 30 watt peavey guitar amp... oh by the way does anybody know if i could fuck up my amp because of the weird frequencies? thankyou very much to those who read , and anyone who might answer. 

[nochtanseenspecht]

the solution is simple : use 2 adapters, 9volt for the 707 and 7,5 for the casio 
btw, the zoom 707 uses quite a lot of current (mA) so it is better to give it it's own
adapter anyway, something like 800 mA will suit. this way it will work.
and be carefull with the polarity on your casio, some older casio's don't have a diode at
the dc inlet...
good luck !

[Circuitbenders]

i'd imagine if the zoom is using anything near 800ma then the adapter you are using is just massively overloaded if its trying to run both machines. The MA rating printed on an adapter is the maximum milliamps it is capable of supplying. If whatever you are running from it is trying to draw more than the stated maximum output then the adapter will be overloaded and it'll usually just burn out.

[cuacua]

yep, i was using to adaptators... one for each, it would be to insane to use one for the both things... but htey got burnt anyways, its a mystery...

[Block]

my guess would be that one of the adapters is faulty and not giving 0v for the 0v rail or +ve and -ve are mixed up on the jack out from the keyboard.

In both cases when you plug them in and connect them you are creating a short circuit with current flowing from one ground line to the other via the guitar lead.
Short circuits = warm wires/adapters.