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DIY Stompboxes => Digital & DSP => Topic started by: zachlovescoffee on August 04, 2021, 01:11:59 PM

Title: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 04, 2021, 01:11:59 PM
Hello team DIYSB,

I have an EHX QTron+ in the black box with the boost knob that I picked up recently. I'm having a real difficult time getting the envelope to trigger. The only way to get a decent or usable sound is with the Peak nearly maxed out and the Gain nearly maxed out in any of the filter settings. It's kind of annoying.

I've tried using lower gain and peak settings but putting a clean boost or low gain O/D in front of it and that helps a little. I've got an Eric Johnson Strat and the pickups are anywhere between 5.3-6.3Hz DC resistance and playing in the middle position to bring all pickups in to push the signal.

Is there something I'm missing? It seems kind of useless to have a Peak (Q) and gain setting that only make the pedal work at max settings. Any advice would be welcome.
Title: Re: QTron+ (w/ boost) Issues
Post by: ElectricDruid on August 05, 2021, 07:53:15 AM
Welcome Zach!

It sounds broken rather than just "operator error" to me. A Strat is about as standard a guitar as there is, so any pedal should work fine with a Strat without too much mucking about.

I haven't got any experience with the QTron+ though, so perhaps others can step in.
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 05, 2021, 11:46:56 AM
Thanks ED! If anyone has any idea how I could troubleshoot to confirm and maybe repair. I'm quite handy with a soldering iron. Warmly, Zach
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 05, 2021, 03:04:08 PM
I just sent it to EHX to repair. The seller on Reverb is giving me all kinds of excuses: "envelope filter pedals are tricky, sometimes they work, sometimes they don't". Nah dude -- they either work or they don't. I shouldn't have the max the peak and gain just to get it to produce a usable sound at bedroom volumes. EHX will have it back to me within 3 weeks from delivery. The cost to repair is $25 with return shipping included. That's not too damn bad for a $200 pedal.

Will update you if it's fixed :)
Title: Re: QTron+ (w/ boost) Issues
Post by: ElectricDruid on August 05, 2021, 04:58:02 PM
That does sound like an excellent deal, to be honest. $25 isn't even a hour of a tech's time, and they're throwing the shipping in too, so they reckon they can get a lot of these repairs out of the door pretty fast. They probably can. Most are something simple. Whether yours is...well, now that's their problem!


Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 19, 2021, 06:58:07 PM
I head back from EHX directly and they said they cannot find anything wrong with the pedal. They asked me for more info. I sent these videos I uploaded from YouTube. Judge for yourself if something seems off on this pedal.

https://youtu.be/zzyRld5oB4s

https://youtube.com/shorts/dbcht3dT1J8
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 20, 2021, 10:00:56 AM
After EHX reviewed the videos and attempted the same settings they said the pedal is fine. They are saying that itís my EJ strat pickups and that they are on the lower end of output. I guess that is a possibility since they are modeled after the 1954 strat pickups.

Their suggestion was to dime the volume on the guitar, which would allow me to lower the gain on the pedal. I guess Iíll give it a shot and see how it works. This means Iíll have to add a volume pedal in my loop so I donít blow the walls out of my office.
Title: Re: QTron+ (w/ boost) Issues
Post by: ElectricDruid on August 20, 2021, 06:54:42 PM
If they're right, you should be able to fix it by putting a simple boost pedal in front of the QTron. Not too much boost, since you don't want to hit overdrive territory and start to lose the dynamics through clipping, but a good loud signal with plenty of dynamics would definitely help. If that *doesn't* work, they don't know what they're talking about and there's definitely something up with the pedal.

Still, I'm a bit surprised. Isn't it possible to turn up the sensitivity on the pedal somehow? Who designed this sh!t?!? Jeez! I've seen plenty of better stuff around here! ;)

Title: Re: QTron+ (w/ boost) Issues
Post by: idy on August 20, 2021, 09:31:15 PM
Isn't the "boost" setting exactly for this? To beef up a weaker input? And make the filter wake up? And having a gain control that you can turn all the way up, also for weak pickups. The "exact settings they show in the manual" is a general place to get an idea of its sounds with an "average" guitar.

But I know the annoyance, having spent years with meatball clones that didn't trigger w/o a booster...that was a matter of swapping a chip...
Title: Re: QTron+ (w/ boost) Issues
Post by: ElectricDruid on August 21, 2021, 06:52:23 PM
Isn't the "boost" setting exactly for this? To beef up a weaker input? And make the filter wake up? And having a gain control that you can turn all the way up, also for weak pickups. The "exact settings they show in the manual" is a general place to get an idea of its sounds with an "average" guitar.

Totally agree. Isn't a Strat with '50s / '60s style pickups pretty much the definition of the electric guitar?! If they weren't designing for that what the hell were they designing for?!?
 
Whack the boost up and it should be fine. If it isn't, something's wrong. If EHX claim that's ok, then what's wrong is their sense of what constitutes a sound guitar pedal, so somethings still wrong. ;)

Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 21, 2021, 09:08:40 PM
I know! This is what Iím concerned about. You can see in the second video I have a clean boost going into the pedal and itís just causing the amp to distort. Not triggering the filter at all.

We shall see!
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 21, 2021, 09:20:56 PM
Isn't the "boost" setting exactly for this? To beef up a weaker input? And make the filter wake up? And having a gain control that you can turn all the way up, also for weak pickups.

The boost is post filter. It boosts the signal out of the pedal as I understand it. The gain boosts the signal into the pedal. I have to basically max it out and max out the peak to get a usable sound. Any of the videos you see online of say John Mayerís settings or even the EHX demo videos, I get nothing from the pedal. No filter at all. So maybe I donít have the volume high enough or maybe my pickups are too weak.
Title: Re: QTron+ (w/ boost) Issues
Post by: idy on August 21, 2021, 11:47:20 PM
The manual says:

Boost Switch (Normal/Boost)- Normal mode passes the input signal through the filter at its original level. Boost mode increases the signal gain to the filter according to the gain control setting.

It doesn't clarify if that boosted signal is also going to the side chain/trigger. Can't imagine it not doing that....

The manual also tells that the gain knob functions differently when boost is engaged, it becomes a volume control...

All this aside, it sound like you would probably be happier trying out some other triggered filter pedals. There are other fish in the ocean. Even other EH pedals like Riddle: QBalls, very consistent, easy to use. It doesn't sound like EH is going to "fix" your issue, but once you have it back it seems like there may be some point to re-reading the manual and trying the suggestions.
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 22, 2021, 06:58:15 AM
This is going to be a major face palm moment if boost mode + gain/vol solves the issue for me in my current set up.
Title: Re: QTron+ (w/ boost) Issues
Post by: idy on August 22, 2021, 11:53:33 AM
Welcome to trouble shooting!
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 24, 2021, 04:36:29 PM
Welcome to trouble shooting!

At this point I now have to conclude that it is my guitar. I am noticing that I don't get *any* meaningful volume from the guitar unless the volume is at 9 or 10. Anything below that and the amp doesn't even register a signal. Even if I have my TC Spark Mini on at 12 o'clock. The pick up height appears to be appropriately set, it's about half way between the bottom of the strings and the top of the pickup or ~ 6mm.

Any thoughts?
Title: Re: QTron+ (w/ boost) Issues
Post by: idy on August 24, 2021, 08:18:40 PM
First compare it, same amp, same cable, no effects to a "know good" guitar. Make sure it is the guitar. You don't want to change the pickups and find you have a bad cable! You want to eliminate the cheap and easy problems before you go shopping.

6mm seems a bit much...I just had my first experience with "stratitis": pickup too close, horrible dull sound no sustain, impossible to intone especially 6th string, pulled pickups back to about 4 mm (open string, much less when I fret up high) and viola, a clear and proper sound with the ability to set intonation. So try closer and pull back when you get horrible dull mush.

After that, with a Strat, it is a matter of loosening strings, removing pick guard and getting into the harness, the "electronics" (three pots and switch) and the pickups themselves. No volume until 9 or 10 might be changed by taper of pot; a linear taper takes a long time to get to that useful range, the audio sweeps up there faster.

And then you might try things like snipping some wires and wiring a pickup (and bridge ground) directly to a jack, no pots, no switches. And find out what a PU does by itself.
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 25, 2021, 08:45:25 AM
These are great troubleshooting steps. I will definitely check them out as soon as I have time today. I have an EHX POG2 on its way to me as well so I have a lot of modding projects on my hands soon.

My chain is thus: 2017 Eric Johnson Fender Strat > Zach's top of the line hand made 1/4" cable > Boss TU-2 > TC Spark Mini > Mosky Golden Horse > Caline Compressor > QTron+ > Aqua Puss MkII > EHX Pot 2 > MXR Phaser EV90 > amoon Pockverb > ammoon Stereo Loop > 1969 Princeton Reverb

Will report back in if any of the steps you suggest solve the QTron+ issues. I bet it's a weird volume pot on the guitar. But, we'll see!
Title: Re: QTron+ (w/ boost) Issues
Post by: zachlovescoffee on August 25, 2021, 11:09:39 AM
Well this is an interesting development. It turns out it's three different things.


1. The first thing is my guitar cable that I built myself from a kit that either Tube Depot or Mojotone used to sell. It was super high end shielded 1/4" guitar cable, with Amphenol jacks. Very high end stuff. The cable is about 20' long.
1a. I replaced that cable with a Monster cable I haven't used in years and BAM I have significantly more output. That cable is also about 20' long.

2. The second item is the Caline Pressure tank. This thing seems to absolutely kill my guitar output and tone. When I removed it from the chain it improved.

3. The final item was some sketchy patch cables that seemed to attenuate the volume.

Having said all of this, here is how I was able to get a usable and VERY nice envelope sound that mimicked the Mu-Tron III and John Mayer/Rosie settings:

First of all, I had to rail the signal into the amp with guitar set at 8-10. Then I had to use a Clean Boost (mini Spark). I supplemented for more grind with the Mosky Golden Horse. The amp is set on 2-3 to even be able to be used, which means I'll have to use a volume pedal after the QTron+ so that as I switch back and forth between QTron for rhythm/lead I won't have to stop and re-toggle settings.




First compare it, same amp, same cable, no effects to a "know good" guitar. Make sure it is the guitar. You don't want to change the pickups and find you have a bad cable! You want to eliminate the cheap and easy problems before you go shopping.

6mm seems a bit much...I just had my first experience with "stratitis": pickup too close, horrible dull sound no sustain, impossible to intone especially 6th string, pulled pickups back to about 4 mm (open string, much less when I fret up high) and viola, a clear and proper sound with the ability to set intonation. So try closer and pull back when you get horrible dull mush.

After that, with a Strat, it is a matter of loosening strings, removing pick guard and getting into the harness, the "electronics" (three pots and switch) and the pickups themselves. No volume until 9 or 10 might be changed by taper of pot; a linear taper takes a long time to get to that useful range, the audio sweeps up there faster.

And then you might try things like snipping some wires and wiring a pickup (and bridge ground) directly to a jack, no pots, no switches. And find out what a PU does by itself.
Title: Re: QTron+ (w/ boost) Issues
Post by: idy on August 25, 2021, 11:43:22 AM
Good work!

Remember the manual: It says that with the Qtron, when the (pre)boost is engaged the gain functions as a volume control (which it is not when the boost is off.)
Title: Re: QTron+ (w/ boost) Issues
Post by: anotherjim on August 28, 2021, 04:55:01 AM
I was going to add some stuff.
Cable...
Good guitar cable has a conductive plastic layer on top of the centre hot signal wire insulation. It greatly reduces handling crackles. The conductive layer contacts the bare wire shield so is grounded - it can creep along until it touches the tip solder tag in the plug. The conductive layer isn't perfect zero resistance but it causes a partial short that can drop the volume. This fault can be missed by simple continuity testers so measure between tip & sleeve on a high resistance DMM range instead - it should read infinite resistance - no ifs or buts.
When assembling a plug on this cable, the conductive layer (often black) should be stripped off as far as you can revealing the hot wire insulation (often clear).
Strat...
The first place to look is under the jack plate, There could be conductive screening paint in the cavity or damaged wiring. Again, this can create only a partial short to ground causing volume loss. Often the jack nut comes loose & gets tightened up without a thought to what may have happened when it was spinning around!

Title: Re: QTron+ (w/ boost) Issues
Post by: pruttelherrie on September 04, 2021, 10:07:30 AM
No volume until 9 or 10 might be changed by taper of pot; a linear taper takes a long time to get to that useful range, the audio sweeps up there faster.

You raise a lot of good points but I do believe you have these backwards.
Title: Re: QTron+ (w/ boost) Issues
Post by: idy on September 04, 2021, 11:44:57 AM
My bad!