#1
Hey guys.

So, cutting right to the chase. I have an old Korg AX1500g multiFX processor, bought used, and I'm having volume issues with it. Whenever I play at home, plugged into my audio interface (tascam US122, older modeL, not MKII) I have no issues whatsoever. Whenever I play in rehearsals, through actual amps, the volume drops to barely audible at random times. If I switch to another patch the volume comes back, but soon enough I get a volume drop again, which obviously means I can't gig with it and rehearsals aren't much fun when you have to tap dance every minute or so.

Now I've already checked the power supply (it's not the original Korg, it's a replacement universal adapter), and it seems to be working just fine, and is built to the required specs (DC 9V - 600mA). I've also tried a factory reset, but the problem consists. Of course first thing I did was check my cables, so no problems there. So far it's done this with 3 different amps in 3 different environments. I've also tried stripping down the patches to just the bare essentials (amp+cab only) but no change. Plus, I've also tried connecting the unit both to the input of the amp and the FX loop, no difference there either, I still get the same volume drops.

Let me mention also that I'm using it with a bass, not a guitar. But it's not an active one, so I suppose that doesn't really matter. The bass does not have any issues either, output is fine plugged straight to the amp or though other MFX units.

So, please guys, if anyone has any idea why this keeps happening or even better, a solution, chime in. Any help would be greatly appreciated! Many thanks in advance.
#2
I recently had a similar issue kind of issue with my Zoom MFX pedal which is about 10 years old - at home it was fine, in a band rehearsal it started cutting out every now and then. The lights on the pedal were still lit just no sound.

It turned out to be a problem with the solder joints on my pedal's output jack connector. When the problem happens try wobbling the jack plugs about on the input and the output of your pedal and see if the sound comes back.

I can only assume that mine got loose due to vibrations through the floor in the rehearsal room - the room had wooden floors and with the drums and the bass I guess in rehearsals my pedal got exposed to more vibrations that it would on my carpeted floor at home when I'm playing on my own at lower volumes
#3
Thanks for the answer!

I already tried that one, but I got nothing. I initially assumed it must be a loose solder at some point, but the circumstances kinda rule this one out. There are no vibrations intense enough in the rehearsal room and I suppose it would've happened at home at some point as well if that were the case. Plus, the fit is tight enough in the input/output jacks and there's not much room for wobbling, and inserting/retracting the jacks didn't do...jack!

I'm on the verge of opening up the unit and getting a good once over, see if there's any loose connections on the inside, but it being all PCB I doubt I'll be able to locate any abnormalities... I could try cleaning up the PCB in case it's just a case of too much dust/dirt on the board, but I seriously doubt that.

My thoughts were that something inside might be causing a short, but I can't really support that theory either, considering that changing patches immediately (but temporarily, apparently) brings the volume up to normal levels. I assume that if it was a short, the volume drop would persist even after patch changes. I'm at a total loss.
#4
Sorry I couldn't be much help - When the sound cuts out are all the lights still on and all the controls working?
If so that sounds less like a shorting problem and more an input /output problem

I guess other than opening it up and checking the solder joints there's not much else I can think of.
#5
I haven't really noticed what's going on at the exact time when the volume drops (since it seems to be completely random/erratic and "not time-based") but yeah, everything seems to be in order, nothing changes. All lights remain on, all controls are active, nothing out of the ordinary... I guess the short ideal was indeed a weak one.

As far as the solder joints are concerned, wouldn't a loose solder have a kind of an intermittent effect on the volume drop? I mean, it would probably be going "off" at certain intervals, since environmental factors don't seem to affect that much, and being that it's not getting moved around more than an inch or two - if at all.
#6
Yeah that's true - with the loose solder joint problem on my output jack I didn't get a volume drop, it was basically fully working sound or no sound at all.

The only other factor is that you're using a bass guitar with a pedal designed for "normal" guitars ( I couldn't think of a better description - sorry bassists!) if you connect a "normal" guitar does the volume drop still occur?

Is there anything else in your chain?
#7
Well both guitar and bass have virtually the same output level range, only difference is frequencies and that solely affects effects and preamps, there's no drastic change between the two. Apart from that, I haven't tried with a guitar (I don't have one now), but I doubt it would make any difference. And there's nothing else in my chain. I use the unit for pretty much everything and the amp virtually as a poweramp (when an amp with a FX loop is available, of course). I've worked with a similar rig in the past, just instead of the Korg I had a various units (tonelabs, boss GTs, PODs, Digitechs, pretty much everything out there) and had no problems there either.
#8
Is there an option to select the output level to line or instrument level? I had a similar issue with my G Major 2, and it turns out you have to set it differently when plugged into an amp than if you were running it into recording gear, etc. On the GM2 the setting is called "consumer" or something like that.

EDIT: Ahh re-read the OP and didn't catch that it comes and goes. If it were an output setting it would be constantly quiet.
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Last edited by jpatan at Nov 15, 2011,
#9
No, there's no line/amp option. It's a cheap little unit and I don't think they meant it for much more than gigging casually with. Also, the thing is, once the volume drops it does not come back up on its own - not unless I change the patch.
#10
Ok, little update. I opened up the unit, checked as thoroughly as one can check a bunch of circuits but nothing seems to be out of the ordinary. No "fried" stuff on there, no excess glue/goo, no bad solder joints, no loose cables, everything seems to be ok. There wasn't even any dust/dirt in there! The jacks seemed fine, although I couldn't really tell, they're those generic ones, mounted/soldered directly onto the board, and those connections seemed fine.

Any other ideas?
#11
I can tell you that the solder joints can be bad even if you can't see it. Fixed quite few amps with bad solder joints on the jacks and pots. If you have a soldering iron I would reflow the solder on the jacks.
#12
Hey Fly, thanks for the answer. I re-did the solders but no change.

As a small update, though, I have a few more details on the "case". There doesn't seem to be a problem with anything else in the chain, since I checked it out with different guitars, amps, cables etc. and nothing changed.

Thing is, I finally noticed that the volume drop is actually caused by the output level setting on the pedal plummeting randomly to 0.0 (or near zero, either 0.3 or 0.7, the preset intervals). And, apparently, it's also doing this at home, too. So I don't think it's some grounding issue here. Still, I have absolutely no idea what could be causing that. Don't think it's dust in those buttons, I cleaned it thoroughly last time I opened it up. Any other ideas?
#14
Same thing happens with the headphone jack. The output level drops even without any input source.
#16
I'm having a similar problem with my 15 yr old AX1500G. After being turned on for a while (anywhere from 30 min to several hours) the unit will start changing settings on me randomly. It usually affects the Amp/Drive, Modulation or Pedal. When I try to reset it just flips around again. If I turn it off for a time it will be ok but it will eventually start jumping around again.

Maybe Some kind of overheat problem?
#17
After 4 years, he's probably solved the probably or upgraded by now
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#18
Gary, You. May be right. But that doesn't mean some one out there doesn't have a pertinent answer to my question.
#19
It's a flaky digital device. The worst kind of problem to fix. I'd send it to the dumpster and move on.
#21
Quote by thamlett
Gary, You. May be right. But that doesn't mean some one out there doesn't have a pertinent answer to my question.

Then start your own thread.

This is the answer though:
Quote by fly135
It's a flaky digital device. The worst kind of problem to fix. I'd send it to the dumpster and move on.


Things have moved on a lot since the Korg was made, get yourself a Zoom G5 or Line 6 POD.
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Laney VC30
Marshall TSL602
Jet City JCA22H
.
My SoundCloud
#22
If anyone has something pertinent and constructive to say I'm willing to listen.

Gary...that's not an answer it's an opinion. Just because it's old doesn't mean it should be replaced. I have a 1963 Strat, maybe I should get one of the new ones that are junk.
#23
Quote by thamlett
If anyone has something pertinent and constructive to say I'm willing to listen.

Gary...that's not an answer it's an opinion. Just because it's old doesn't mean it should be replaced. I have a 1963 Strat, maybe I should get one of the new ones that are junk.


there is a difference between old and obsolete. I have the same processor with a similar problem.

Get something new. It doesn't take much to get a unit that sounds much better.

+1 to Gary
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#24
thamlett Hey man, I'm having the same issue with my ax1500g. I guess you've already realized by now that the problem is with the Volume Pedal switch, but for anyone looking for an answer to this thread. you'll get the exact volume between pads once you deactivate the volume control out of the effects you use... The pedal doesn't use a regular potenciometer but a light sensor. That small circuit board is what fails. Check this link in order to replace it if you get lucky and find a replacement part.

https://www.ifixit.com/Guide/Korg+Toneworks+AX1500G+Pedal+Switch+Replacement/50493#undefined

And here's the service manual.


https://www.google.com.ar/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwiegv2J29XOAhWEIZAKHWRKCN0QFggaMAA&url=http%3A%2F%2Fforum.cxem.net%2Findex.php%3Fapp%3Dcore%26module%3Dattach%26section%3Dattach%26attach_id%3D427124&usg=AFQjCNEreoTAS_Gqph7sFQq81lmGhgoZyQ&sig2=nJMKP0vRrPp_Gn939mhhTQ&bvm=bv.129759880,d.Y2I&cad=rja