Drummer Cafe Forum

LOUNGE => General Board => Topic started by: BlackEvovii on July 15, 2002, 10:33 PM

Title: Tama Rhythm Watch RW100 A AC ADAPTER QUESTION
Post by: BlackEvovii on July 15, 2002, 10:33 PM
I have a metronome here that requires a 9v power supply(AC ADAPTER)

im wondering, since the tama watch requires a 9v 250mA DC source

if i go and get a 9v 850mA would that be too much for the Watch?

what about a 300mA?
Title: Re:Tama Rhythm Watch RW100 A AC ADAPTER QUESTION
Post by: Bart Elliott on July 16, 2002, 12:20 AM
My Rhythm Watch requires 9V 200mA power supply ... not 250mA.

And yes, it could possibly damage your metronome.
Boss makes a power supply that will work, if you are having problems finding one. Their power supply works for the Rhythm Watch as well as their own metronome, Dr. Beat.

Ohms Law shows us that the metronome is expected to have a load of 45 ohms (Voltage divided by Amps equals Resistance). Increasing the amps will decrease the expected load ... but the metronome doesn't change ... so there's your problem. The 9V, 300mA power supply is expecting a 30 ohm load (resistance). You would have more resistance with the Rhythm Watch ... and the extra current has to go somewhere ... such as through heat transfer which will eventually fry your metronome.

Some may say it's not enough to matter, but it WILL matter over a period of time. Follow the specs for the Rhythm Watch and purchase the correct power supply. AND MAKE SURE YOU HAVE THE CORRECT POLARITY SETTING TOO!!!  ;)