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9V Ac Adapter(s) only work on half my 9V pedals.

Spybeach007
June 13th, 2010, 02:58 AM
I will make this simple as possible:

Gator "tote board" 9v 1700mA = all my pedals work.
Batteries only = all pedals work.

4 different 9v ac adapters tried out: 750mA, 780 mA, 1000mA, 1300mA(came with new jamman stereo) = half my pedals work - half don't.

Checked wall outlets one is perfect other is open ground, both work the same on this. When pedals do not work I can hear a hum/buzz from walwarts. No noise when a pedal works.

Pedals that DO NOT work with AC adapters: Boss rv-5, Danelectro Spring reverrb, Ibanez Fuzz, DOD tremolo, Digitech digidelay, Boss OD sd-2, Boss NS-2

Pedals that WORK with AC adapters: Danelectro danecho, Digitech Jamman Stereo, Digitech grunge, Korg pitchblack, ART tube mic pre-amp, Boosta Grande'.

The pedals that do not want to work with walwart (except pedalboard) all do different things - none make any sound. RV-5 lights up even with no input cord, others dont light, others stay lit, Boss NS-2 lit dimly etc..no consistency except they all work with the Gator board.

My understanding(been told over and over) was, mA can be over pedal specified amount and be OK.
Somehow I think mA has to be closer to the target zone on this for pedal to work correctly. Most of these pedals do not list mA on them. Danecho lists 300 mA MAX yet works on 1.3 mA adapter. Jamman lists 1.3 amps and works on all, even the lower mA ones. ( It may be something else also besides mA - that was the only variable I could think of since they are all 9v and I do not see ohms or watts on these things if there is any.
I swear I am not doing drugs today and this is really happening :confused:

Thanks in advance for reading list - any insight is appreciated,
Jim

fly135
June 14th, 2010, 01:54 PM
I have a DigiDelay that works fine on an adapter. The adapter should have a MA rating higher than the pedal or sum of pedals. Yes a lower rating will work just like low speed rated tires work on a high speed car. You just don't know the point of failure.

The Jamman is 9VAC, so I suspect you are using the wrong kind of power supply. The PS for the Jamman is not supposed to work with your other pedals and vice versa. Check your specs. A standard pedal board power supply is predominantly 9VDC negative center pin.

Spybeach007
June 14th, 2010, 02:23 PM
I have a DigiDelay that works fine on an adapter. The adapter should have a MA rating higher than the pedal or sum of pedals. Yes a lower rating will work just like low speed rated tires work on a high speed car. You just don't know the point of failure.

The Jamman is 9VAC, so I suspect you are using the wrong kind of power supply. The PS for the Jamman is not supposed to work with your other pedals and vice versa. Check your specs. A standard pedal board power supply is predominantly 9VDC negative center pin.

The jamman PS is 9V and so are the other ac adapters.
I'm sure that a distortion pedal is also not over mA.
My adapters are all neg center.

fly135
June 14th, 2010, 05:03 PM
The Jamman Stereo is 9V AC unless the manual is wrong. There is no such thing as a neg center AC pedal

jefrs
June 14th, 2010, 05:30 PM
My RV-5 works well with most 9V adaptors. I run the lot off one SoundLab Pedal-Power 450 (GS025MA) 9VDC 450mA each socket. This is not a wallwart but a large metal box 6-socket mains adaptor (beefy total 2.7A), I actually run 8 large units off it by daisy chaining.

The other multi adaptor is a 10-way 'DC-9X' 100mA each socket, again no problems driving the lot, except I dislike the 12VDCx1A wallwart plug part.

Wall-warts get hot and imo are a bad design move since their primary invariably gets left connected live to the mains, and they are usually built in a shoddy manner.

The thing to look for in multi-adaptors is isolated supplies i.e. they do not have a common ground rail. They can draw more than the stated for each socket up to the total share for the box.

Spybeach007
June 15th, 2010, 01:43 AM
The Jamman Stereo is 9V AC unless the manual is wrong. There is no such thing as a neg center AC pedal

All guitar pedals run on negative center adapters. Inside of plug is neg..outside is positive.
Here is an example http://accessories.musiciansfriend.com/product/Dunlop-ECB003-AC-Adapter?sku=333103

I still have no idea whats wrong unless my walwarts are all shoddy.
Its true chargers all tend to be left plugged in constantly. Cell phone ones etc..

I dont use walwarts but use the gator powered pedal board..the cheapie..works great. Just was wondering why four..make that five..
9V walwarts would work on half my 9V stuff and board on all. Very baffling

Anchoret
June 15th, 2010, 02:13 AM
All guitar pedals run on negative center adapters.

NOT THE ONES THAT RUN ON ALTERNATING CURRENT. :roll:

Some digital pedals and MFXs run on 9VAC, not 9VDC.

While most stomps that run on 9VDC are positive ground, a small few are negative ground, and keyboards and MIDI controllers typically use 9VDC negative ground.

The message here is that you have to understand the power requirements of your equipment and match them to the correct adaptors, or you're going to have some expensive problems in your studio.

jefrs
June 15th, 2010, 03:08 AM
Some units like the JD-10 can run on AC or DC, either polarity and 9V to 14V or more.

fly135
June 15th, 2010, 10:29 AM
While most stomps that run on 9VDC are positive ground, a small few are negative ground, and keyboards and MIDI controllers typically use 9VDC negative ground.That includes my Rat, DOD chorus, and Double Muff.

Spybeach007
June 17th, 2010, 04:28 AM
My pedals are all Boss, digitech, danelectro...usual stuff...
9v AC neg center. Adapters are all 9v AC output.

My orig post tells that the same brands contradict themselves.

fly135
June 17th, 2010, 11:17 AM
Spy, you are still not getting a handle on this PS thing. Your pedals are not all 9V AC. Your Jamman Stereo is 9V AC. Again there is no such thing as 9V AC negative center. Negative center only applies to DC. Most of your pedals are probably 9V DC negative center.

justin.ray
June 17th, 2010, 01:27 PM
AC and DC power are VERY different and circuits designed for one may do strange and terrible things when powered by the other. Each pedal should indicate AC or DC near the power supply jack, usually like this: 9 VDC, 4 mA or 9 VAC, 4 mA with a little diagram that indicates the polarity of the pin and barrel. Having the appropriate voltage, current type, and polarity is critical.

The mA rating on the pedals indicates the rated current draw at the designated voltage.
The mA rating on the wall warts is there to indicate the rated current capacity of the transformer in the wall wart for the rated voltage. Transformers can only handle a given amount of power (voltage x amperage). Connecting a smaller load (i.e. amperage) to a power supply will not cause any problems at all, it will only result in a lower amperage on the primary (i.e. connected to the wall) side of the power supply.

Spybeach007
June 17th, 2010, 11:39 PM
Ok I get the idea..but two different digitech, danelectro not working on 9v AC output?
The problemis the pedals say nothing except "use boss adapter #..." or the likes.
The jamman says "9vAC 1300mA Power" and the danecho says "9Volt 300MA max center negative" not mentioning ac or dc..Hey ACDC! what do they use?? just kidding...
None of my other pedals say anything so I will have to hunt down specs.....BUT..why would they ALL work on my stupid gator pedal board?

The pedals that apparently dont like AC volts are : 3 boss pedals (RV5,NS2,DS2), DOD "vibrothang", Digitech digidelay, Ibanez fuzz (FZ7)

The pedals that will work on the AC volts are digitech"grunge", danecho, digitech jamman stereo, Boosta Grande' and pitch black tuner.

I appreciate that some pedals work on this and some on that and that they all arent the same...but why would they work on a pedalboard that is straight with this power supply on it
http://accessories.musiciansfriend.com/product/Gator-GBus8US-Pedal-Board-Power-Supply?sku=546042
btw that doesnt say AC or DC output..can a pedal run on either?
Crap Im really confused now over basic power supply..and I once worked at radio shack selling walwarts to ppl LOL..tells ya not to go there for advice LOL!!
Either I got me some funky P supplies or there is some crazy answer but these are just basic stompboxes..no boutique or high voltage stuff...just boss digitech etc...can two digitech small pedals run differently? I wouldnt think so myself. I have a amp tech with a "one spot" we will see in a few days if that works on what. btw two of the supplies are new digitech and ART from actual pedals/pre-amps not just some junk I found laying around. all mine say AC output. 9v. 750-1300mA

Spybeach007
June 17th, 2010, 11:44 PM
I have a DigiDelay that works fine on an adapter. The adapter should have a MA rating higher than the pedal or sum of pedals. Yes a lower rating will work just like low speed rated tires work on a high speed car. You just don't know the point of failure.

The Jamman is 9VAC, so I suspect you are using the wrong kind of power supply. The PS for the Jamman is not supposed to work with your other pedals and vice versa. Check your specs. A standard pedal board power supply is predominantly 9VDC negative center pin.

hmm..interesting. DC?
how do the same pedals that run on that run on ac output..:confused:

Spybeach007
June 17th, 2010, 11:59 PM
pedal specs: Boss rv-5:"current draw 50ma(DC 9V)"
Boosta Grande "9vDC min 200mA "
OK so right there why does the boosta work on AC output adapter?
Thats the crux...I agree the jamman stereo says AC input..ok that is different. May need to use the adapter for that to work.
Obviousely all my other pedals are DC as they use batteries as well as PS. Jamman dont do batteries. So wouldnt the question be - why do some of these things actually work on AC input? My digitech "grunge actually says power supply used should be 9V DC and it works onan AC output walwart........?

Spybeach007
June 18th, 2010, 12:15 AM
Some units like the JD-10 can run on AC or DC, either polarity and 9V to 14V or more.

THIS may be the answer. Some ar just strange units.??

Mad Kiwi
June 18th, 2010, 12:25 AM
This pedal business has driven me mad too, i have a Ibanez TS7 that blows up any adaptor i plug in to it. 6 PSU's over 10 years i finally narrowed it down to that one pedal.

But works fine on battery .....

No help to OP but further proof of strange units.

justin.ray
June 18th, 2010, 10:52 AM
The details listed by the manufacturers are rated specifications. That doesn't mean that they can't work with any other power supply, just that they weren't designed to. For example, many overdrive and distortion pedals are rated at 9V but can be operated at higher voltages. Operating them at higher voltages will change the characteristics of the circuit, and the sound of the pedal (This should only be done if you are certain that the pedal can handle the higher voltage).

It may be (marginally) helpful to think of your pedals as circuits made up of different electrical components like resistors, capacitors, and diodes, for example. A resistor will act basically the same with DC as with AC, but capacitors and diodes will do very different things, depending on their physical characteristics. Some circuits may be able to operate just fine with either AC or DC power while applying AC to some circuits can ruin sensitive components or cause them to fail over a long period of time.

fly135
June 18th, 2010, 11:28 AM
hmm..interesting. DC?
how do the same pedals that run on that run on ac output..:confused:I only run pedals on their specified voltage and AC/DC requirement. I don't mess around.

I will give you a good reason why it works on your pedalboard P/S. It's becasue the outputs are isolated. When you put the wrong electrical requirement into a pedal it *may* still work. But it may also cause odd loads on the supply that cause other pedals to not work. If you are using separate outputs on your board supply then have isolated the problematic connections.

Any pedal that is Boss adapter spec'd uses 9VDC negative center. And that is what you should use. It's very possible that a DC would work with AC. That's because the internal circuitry may only use half the waveform and ignore the other half. I wouldn't do this because it's likely to cause noise as AC looks like highly unfiltered DC with 60HZ hum superimposed. I also wouldn't use AC because you never know what pedal will blow when plugged into it.

Spybeach007
June 24th, 2010, 02:12 AM
Thanks for the answers. I guess half my DC pedals actually work with AC but now I know not to ever use an AC adapter by accident. If I didn't learn why some of
the DC pedals are ACDC - noise making - light turning on, compatible, I at least learned it can damage them and stick with batteries or my DC board. (except Jamman it's AC)
Thanks again.