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Big Q-tron Problem

I

iPie

Dec 5, 2008
90
0
32
Hampshire UK
www.facebook.com
#1
Hi, I haven't posted here in a long time but I'm having some problems and hoping some of you guys here could help.

I recently purchased an EHX Q-tron (the bog-standard XO version, not the micro or the plus) from ebay. It unfortunately didn't come with a power supply but the seller generously refunded me £20 to buy an official EHX one. I decided instead to put the money toward a BBE Supa Charger as I'm sort of starting a pedal board. I also bought a t-rex voltage doubler cable and spliced a 2.5mm barrel tip to fit the Q-tron (center positive).

Now on to the actual problem.

I can't get any sort of filter sound from the damn thing! I've tried every setting under the sun, including adjusting the internal trimpot, and I've tried it with a guitar as well.

With most settings it just sounds ever so slightly different from the dry signal, and a few sound like I've clicked a wah pedal and left it in one position. The indicator light and overload light appear to be working fine, but not much else.

The power supply is giving me 24.8V and I've tried it with ~18V as well but no luck. The only thing I can think of that may be wrong is the current (not sure how to test with a multimeter) but the Q-tron only needs 100mA.

Otherwise it must be a problem somewhere in the pedal mustn't it?

Thanks in advance - I'm tearing my hair out here! :help:

EDIT: To add a little detail I forgot - I get a massive funky filtery sound if I yank the power lead out whilst it's on...
 
#4
Swift713 said:
Are you saying that it works for just a second when you pull the power plug out of the pedal? I'm wondering if you've got the polarity right.
Click to expand...

Slough Feg Bass said:
yeah, try and reverse the polarity and see if that helps.
Click to expand...

I'm 99.999999% sure I have the polarity correct. Before I try reversing it, (assuming I already have it correct) will that damage the pedal?
 
#10
Bigwan said:
Try measuring the voltage when you have the supply plugged into the pedal (obviously need to open up the pedal for this).

Hope you get it sorted - big box Q-trons are awesome... but BIG!!!
Click to expand...

I'll try this when I get home! (It's actually the problem which I was referring to as big rather than the Qtron :hiding: )

DieterVDW said:
99.99999% sure it's the polarity ...
I don't think plugging in with the wrong polarity will damage the pedal, but don't take my word for it ...
Isn't the polarity indicated on the pedal?
Click to expand...

The polarity is indicated as centre +Ve which I've been using.

Bigwan said:
Looking at pics of the EHX 24v supply the sheath is -ve/tip is +ve.
Click to expand...

Yep that's the polarity I've been using.
 
#11
Sounds to me like you are using the right voltage. On my Qtron+ if I have the gain up very much at all, the filter sounds become very extreme to the point of not sounding very filtery at all. Have you started with your bass volume way down, bringing it up slowly while listening for the sweet spot?
 
#12
cheapbasslovin said:
Have you started with your bass volume way down, bringing it up slowly while listening for the sweet spot?
Click to expand...

Tried this...

Bigwan said:
Try measuring the voltage when you have the supply plugged into the pedal (obviously need to open up the pedal for this).
Click to expand...

And this (24.8V)...

Slough Feg Bass said:
yeah, try and reverse the polarity and see if that helps.
Click to expand...

And this...

And nothing happened :( The pedal behaves exactly the same way when I reverse the polarity. :spit:
 

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