Alesis 9v power supply problem

peter miller

peter miller

New member
My alesis power supply for the nanoverb is a noisey sucker .Could I use a boss supply and reverse the polarity.
I had a generic power supply once on my effects peddles when I got the boss one the noise dissapeared.My guess is it might work on the nanoverb if i reverse the polarity
 
nononononono

look very carefully at your alesis supply. Im not so sure, but does it say 'output 9V AC' on it? Because *most* power supplies are DC, but alesis has this NASTY habit of using AC. And they are INCOMPATIBLE. so check it out.

oxoxox
 
Hey I checked it out and both the boss and alesis packs say 9V AC does this mean I have a go or what.One thing I'm not sure on is are the alesis inputs standard or reverse polarity like boss. 'cause it doesn't say on the product or power supply anywhere..thanks ,
 
shit, if they both got AC outputs, you should be money. Does it say the polarity on your alesis ps? cus if it doesn't, then you should probly just write alesis and ask..

good luck!

xoxo
 
im almost postive the nanoverb is 9v AC.
which kinda sucks cause you wont really be able to use a DC power supply with it. maybe you have a faulty cord or are getting ground loops or something. just another aspect to look into.
 
If it is an AC supply, then polarity is not an issue. That only matters for DC. If its causing a problem, throw it away and get a new one. they're cheap. Just make sure the current and voltage ratings are the same.

Twist
 
Thanks every body You are all my heroes...
sorry I haven't got back sooner I couldn't get through to the site for some weird reason.
DC.. AC what is the exact difference anyway
 
AC/DC

AC means Alternating Current, DC means Direct Current.

That means that with DC, the current runs only one way (from + to -), but with AC the direction of the current alternates. It goes first back, then forth then back then forth. It does this 50 or 60 times a second (depending on where in the world you live). This is the cause to all that hum you get when you record...

Now, when it comes to power supplies and noise:
The current you have in the wall as AC. Electronics run on DC. Therefore you need conversion. With cheap power supplies this is often done badly, and the DC power that comes out are noisy, it has a lot of ripples in it, remains of the AC. Some units (mainly Boss ones) rely on the current being clean, and therefore starts generating a lot of hum with a bad power supply. Therefore you need good DC power supplies.

This however is NOT the case with AC power supplies. AC units does their own conversion, and hum and ripples on the power will in general NOT generate hum on the output of these units. Therefore, switching power supply will most likely not help you in this case.
Also, the fact that you even consider reversing polarities make me very worried. If your BOSS and Alesis power supplies are AC, then there should not be any notes on the about polarity. And if there isn't any such notes, why did you think you needed to reverse the polarity?
My Tech Support instincts tell me there is something wrong here... :(

In short: Don't do it. Not yet at least. I need more info to be sure that you are not gonna burn something. :)
 
to REGEBRO

Hey Regebro ,the reason I was thinking of reversing the polarity was because on the boss gear I have(which is very quite) the centre pin in the ac jack is negative where as all the other stuff , the centre pin is positive.
The boss power pack is fused where as the alesis product is not fused which is dumb I reckon it would be very simple and smart to add a fuse in it's circutry .......
 
on the boss gear I have(which is very quite) the centre pin in the ac jack is negative where as all the other stuff , the centre pin is positive.
Click to expand...
Ah. That was exactly what I suspected. My Tech instincts are rarely wrong. :)
WARNING, WARNING, WARNING! If it has polarity it is not AC!!! AC HAS NO POLARITY!
Read my last post again, and tell me if I'm what (if any) that isn't clear. It can be a bit hard to explain these things with just text, so if there is something that is unclear I will try again.

In the mean time: Do NOT switch any plugs anywhere. Alesis does quite often use AC power, the Microverbs are all AC. The Boss power supplies you have are CLEARLY DC power supplies, or the would not be marked with plus and minus.

When power supplies are marked they are marked with input and output voltages. The input would is typically marked something like 110-120V AC 60HZ, or 220-240V AC 50HZ. The OUTPUTS are typically marked 9V DC or 9 V AC. Sometimes instead of AC or DC you have a little graph. The wave (~) means AC and the straight lines (=) means DC. Usually you get BOTH. Also, if it's DC it's usually marked with polarity.
You know, like this: + -(·- -
AC supplies doesn't have that. And if they would, It wouldn't be + and -, but rather with letters lien N or 0 for the Zero , L for Live and G for ground and stuff. Also most equipment is marked like this. My Boss stuff is all marked like that. So is my Microverbs. They all have a clear label saying "9V AC" above the power input.

Check out what your equipment is marked with, both the Miiverb in question, and all your powersupplies. Post them here, and I'll tell you what to do.
 
Wow what a can of worms I have here!
Nanoverb _____ 9VAC~

Alesis power supply_input:240V~50Hz 10W
output:9V~7VA
SAC

Boss AC Adaptor model psa-240
: PRI 240V~50HZ 8VA
___
: SEC 9V---200mA
T 500mA T25/E

And yes my boss gear has a little sticker on the back
saying use boss psa adaptor only(9VDC)

Hope this is clear.
Someone mentioned on this site to add a resistor somewhere
I've never heard of addinng a res' to stop noise but I have heard of adding a capacitor.

Thanks
 
Wow what a can of worms I have here!
Nanoverb _____ 9VAC~

Alesis power supply_input:240V~50Hz 10W
output:9V~7VA
SAC

Boss AC Adaptor model psa-240
: PRI 240V~50HZ 8VA
. ___
: SEC 9V---200mA
T 500mA T25/E

And yes my boss gear has a little sticker on the back
saying use boss psa adaptor only(9VDC)

Hope this is clear.
Someone mentioned on this site to add a resistor somewhere
I've never heard of addinng a res' to stop noise but I have heard of adding a capacitor.

Thanks
 
some how I sent the message twice
as a note the ___ above SEC actually goes above---
thats how I posted it but it came out different.
 
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