Alternative multiFX power supplies? possible hum issue?

[lefrash]

Hi guys, I've got a zoom b9.1ut multiFX and stupidle left the power supply at a gig. Its a DC12V, 3A power pack. Now, I do have one exactly like this (for my bedroom telly) and I used it tonight at practice and there was a noticable hum from my set up. This wasnt there when plugging directly into the amp using either jack leads so I can only assume its the multiFX unit. The only thing thats changes since then was the power supply. It is the same rating as I would need (according to the zoom manual) but is there something else that the original pack may have had over the one for my telly?


The reason I ask is because I want to knw what to look out for when purchasing a replacement. (and I literalyl have no idea how it all works).


Cheers for the help

Fraser

[barkin]

FWIW the markings on my B9 psu say that it's a
' Honor Electronic Co Switching adaptor'.

I'm guessing that your TV psu is just poorly filtered/regulated/whatever. IANAE...

[xgsjx]

I had a supermarket's own brand PSU which I used on my FX. Hummed like a fridge full of wasps, bought a decent PSU & no noise.
So if you can try a different PSU, do so. It may be picking up interference.

Oh, also worth checking how many mA the PSU puts out & how many the Zoom requires. Make sure the PSU supplies more than the pedal needs.


Edit: I doubt the Zoom would need anywhere near 3A, more likely to be @ 300 mA, tops.

Edited July 29, 2013 by xgsjx

[lefrash]

Thats good to know, as I'd likely just have bought a supermarket one which from the sounds of it, wouldnt have been much better. I'l get a half decent one then.

I'l google about foir the mA rating too.


Cheers

[barkin]

Just checked my manual, and it says there that the power Requirement is 12v DC, 3A.
I'd imagine there's a bit of wriggle room factored in there, but would they specify and supply a 3A PSU if they could get away with a smaller/ cheaper one?

Could it be the 12AX7 valve pre that makes the high current PSU necessary? I don't really know - just thought I'd mention it 😊

[lefrash]

Much appreciated Barkin. Would be good to know for future too, I really like the zoom so I can imagine having it for quite a few years, and I can pretty much guarantee this wont be the last PSU I leave lying aroud! haha

[Kev]

The valve pre will mean it would certainly need at least 1A I would think, althought I would be very surprised if it needed 3A!!

Try a one spot, 1200ma IIRC so should do the trick.

[Kev]

Ah needs 12v. Look at the DC Maplins power supplies.

[lefrash]

Just to give you all a heads up, I went and purchased a 12v power supply from maplin. It was £27.99. But I have A/B'd against the one I was using temporarily and there is an instant decrease in noise. I've even noticed without even switching the zoom unit on, as soon as I plugged the old one in there was a buzz.


So in other words.... £27.99 well spent!


thanks for the advice guys.

Fraser

[barkin]

Thanks for the update - useful to know for when the inevitable happens, and my PSU gets left the same place as yours...!