lemmywinks Posted December 8, 2008 Share Posted December 8, 2008 I have a pedal which has a very loud hum when i use it with a 9v power supply. It's fine when i disconnect the adapter lead, but hums loudly and gets worse when the effect is on. It's an EBS multidrive. I had a look on the pinned topic and on other threads but found nothing i thought would fix it. Tried it with different basses, power packs, used the adapters with other pedals to rule them out, changed leads (it still hums loudly when the input is not connected) Any ideas? The guy who sold it didn't use it off mains and said it might be something to do with the phantom power EBS use (where you can power your pedals from an EBS amp via the jack lead). The pedal sounds ace otherwise so seems disappointing to have to return it Cheers for any info Steve Quote Link to comment Share on other sites More sharing options...
BOD2 Posted December 8, 2008 Share Posted December 8, 2008 It seems that not all 9V power supplies are equal. Some are either poorly designed, or poorly screened, or both and can introduce noise into a pedal chain. The problem then becomes knowing which ones are good and which are not. More information here [url="http://www.effectpowersupplies.com/power-supplies-8-c.asp"]http://www.effectpowersupplies.com/power-supplies-8-c.asp[/url] [url="http://www.effectpowersupplies.com/faq-2-c.asp"]http://www.effectpowersupplies.com/faq-2-c.asp[/url] Quote Link to comment Share on other sites More sharing options...
lemmywinks Posted December 8, 2008 Author Share Posted December 8, 2008 Cheers dude, i'll try it with my pedal board power supply when i get in the practice room. The hum is very loud though, not just in the background. It is unuasble in the state that it is in, that's why i think it's the pedal. I'm takin it to the guitar shop tomorrow to get looked at Quote Link to comment Share on other sites More sharing options...
BOD2 Posted December 8, 2008 Share Posted December 8, 2008 Just one other thought ... if you can, try moving the power supply around into different positions. Setup everything up so that it hums then lift up the power supply and move it around to see if the hum increases or decreases. Sometimes, other items of equipment (cables, or the amp itself) will pickup hum from a power supply and you can minimise this by careful placement of the power supply. It's worth a try. Quote Link to comment Share on other sites More sharing options...
elros Posted December 9, 2008 Share Posted December 9, 2008 Is the power adapter 9V AC or 9V DC? How much current (usually rated in A or mA) can it deliver? How much current does the pedal require? Is the polarity correct? Quote Link to comment Share on other sites More sharing options...
lemmywinks Posted December 9, 2008 Author Share Posted December 9, 2008 [quote name='elros' post='349387' date='Dec 9 2008, 09:22 AM']Is the power adapter 9V AC or 9V DC? How much current (usually rated in A or mA) can it deliver? How much current does the pedal require? Is the polarity correct?[/quote] It's a 9v AC-DC adapter and can deliver 500mA max. The pedal requires 15mA. Is this ok? The polarity is set to tip- as this is what the pedal requires Quote Link to comment Share on other sites More sharing options...
BOD2 Posted December 9, 2008 Share Posted December 9, 2008 [quote name='lemmywinks' post='349999' date='Dec 9 2008, 05:57 PM']It's a 9v AC-DC adapter and can deliver 500mA max. The pedal requires 15mA. Is this ok? The polarity is set to tip- as this is what the pedal requires[/quote] Polarity is ok. Voltage and current are ok. Is the power supply "regulated" or "unregulated" (it may not say) ? It should be "regulated" as this ensures a constant 9V output. Quote Link to comment Share on other sites More sharing options...
elros Posted December 10, 2008 Share Posted December 10, 2008 Yes: voltage, current, polarity seems OK. Does the adapter power only the EBS pedal or does it also power other things? If it only powers the EBS then I really don't know what would be wrong..... Quote Link to comment Share on other sites More sharing options...
lemmywinks Posted December 10, 2008 Author Share Posted December 10, 2008 The adapter is unregulated i think but powers my other i have to hand pedals fine (i'm only using it to check this pedal, i have a power supply in my pedalboard which is at our storage room). Tbh i think it's the pedal at fault, i'll have a word with the seller about returning it. May just be a grounding issue with the mains supply but i can't afford to spend money on it at this time of year Thanks for your replies Steve Quote Link to comment Share on other sites More sharing options...
mzivtins Posted December 10, 2008 Share Posted December 10, 2008 hi mate, this is actually my old EBS pedal. (i say old, but it was barely used) when the batteries run low the thing sounds awfull... obv you have tried it without batteries but because the pedal can run 18v etc i wouldnt use anything other than an EBS power supply like EBS say. here's the actual EBS page for it. i hope this helps you out mate, let us know! [url="http://www.bass.se/2007/multidrive.htm"]http://www.bass.se/2007/multidrive.htm[/url] Quote Link to comment Share on other sites More sharing options...
mzivtins Posted December 10, 2008 Share Posted December 10, 2008 [quote name='BOD2' post='350209' date='Dec 9 2008, 09:38 PM']Polarity is ok. Voltage and current are ok. Is the power supply "regulated" or "unregulated" (it may not say) ? It should be "regulated" as this ensures a constant 9V output.[/quote] The pedal needs a regulated (stabilized) power at 650mA... even with that tho, i would probably run it free 9v battery as mains always adds a lil more noise haha! Quote Link to comment Share on other sites More sharing options...
lemmywinks Posted December 10, 2008 Author Share Posted December 10, 2008 Yeah i always remove the batteries as i stick my pedals on a pedalboard with an 8 way supply. Although it says to use an EBS adapter it isn't neccessary, all manufacturers say this to make money. I've got a mate with one so i've asked him if i can compare. I know he runs his off a pedalboard supply with no problems. Did you have any problems with it> Anyone out there had similar problems with this pedal? Quote Link to comment Share on other sites More sharing options...
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