whynot Posted March 5, 2008 Share Posted March 5, 2008 Help. I have a Planet Waves tuner that the manual quotes needs an adaptor with a power rating of 9V, 300mA. Working through the garage I've found 2 old BT adaptors, one 15V 200mA, the other 15V 600mA. Will one of these be safe to use with the tuner or could I be doing some serious damage ? Thanks all. Quote Link to comment Share on other sites More sharing options...
RayFW Posted March 5, 2008 Share Posted March 5, 2008 You may well fry your tuner with one of those. You'll get a decent 9V adaptor off ebay for around a tenner. Quote Link to comment Share on other sites More sharing options...
BOD2 Posted March 5, 2008 Share Posted March 5, 2008 Neither of them will do. Rules for matching an AC-DC adaptor 1. Make sure the voltage is correct (i.e. 9 Volts). It MUST be this voltage. 2. Make sure the currentr capacity is sufficient (i.e. mAmps). The rating on the pedal will state how much current the device needs (in this case 300 mAmps). The rating on the adpator states how much the adaptor can suppy ( 200 mAmps). You can match a higher capacity adaptor with a lower capacity pedal (the pedal only draws what it needs) but NOT the other way around. 3. Make sure the polarity of the connector is correct. The pedal uses DC volts - this has a positive and negative contact on the plug. The plug can be "centre positive" or "centre negative". A small diagram on pedal and adaptor should say what each device is. Make sure they are the same. [attachment=6228:wartdetail.jpg] Typical rating on a power supply (centre-positive) [attachment=6229:powerplug_negative.jpg] Symbol for centre-negative In this case, both 15V supplies are the wrong voltage for your 9V tuner and would almost certainly damage it ! Quote Link to comment Share on other sites More sharing options...
whynot Posted March 6, 2008 Author Share Posted March 6, 2008 Thanks guys. Very helpful. I should know all this stuff after years of playing. Quote Link to comment Share on other sites More sharing options...
BOD2 Posted March 9, 2008 Share Posted March 9, 2008 [quote name='synaesthesia' post='153901' date='Mar 9 2008, 01:46 PM']Safe advice but not necessarily completely true. unless you have a regulated transformer, a 9V unregulated one will most certainly fluctuate quite a bit in output voltage, - send the output of a few unregulated ones to a multimeter and you 'll see. Also most chips 'see' a range of voltages, as opposed working only with a specific voltage. Chances are highly likely that the tuner chip will see up to 18V, but chances are also likely the 15V supply may fluctuate to higher voltages if unregulated.[/quote] Yeah you're right but the problem is you don't know the voltage tolerance that the device has as it's never usually stated. Your last statement is always the best advice [quote name='synaesthesia' post='153901' date='Mar 9 2008, 01:46 PM']For the uninitiated, get a regulated power supply for your device at the designated voltage and current spec, watch the polarity of your connections.[/quote] Stick to this advice and you won't go far wrong. Quote Link to comment Share on other sites More sharing options...
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