Q-Tune DIY Tuner kit

Ok, I’m game. Other than the pretty screens, what separates it from other tuners. I want to want it, but I need more info.
 
As asked for, Feedback concerning the live feed (sorry no YouTube account so I'm commenting here instead of in the live-feed):

PRE-ORGANISATION: Like how a cooking show will have pre-chopped ingredients... pre-organising the components and having them laid out read to go so you're not fishing through component-drawers would speed things up for the overall actual live-feed/build-time.

VOLUME: I've got my laptop speakers CRANKED and barely able to hear it above ambient neighbourhood noise (sitting on front porch with doggo and breeze in the trees and neighbours windchimes are almost drowning you out.
\\

Easter-eggs: let the end-buyer-builder-user find 'em. (Neighbour just fired up their weedwacker... very difficult to hear now. (3:37)
Thanks for the feedback. This was definitely a last-minute type of stream and not really “official.” We’ll make a better one later on … our documentation is top notch though so a build video shouldn’t be needed. We’ll be posting the nice build doc within a couple weeks.

And, of course a risk of doing a live demo there was always a risk of something not quite working right out of the gate. I didn’t pay the demo gods enough and that happened. I’ll troubleshoot offline and circle back to it and post the fix once I get time to make it all work. For those who tuned in, thank you!
 
Ok, I’m game. Other than the pretty screens, what separates it from other tuners. I want to want it, but I need more info.
As a self-confessing tuner snob, here's my as-unbiased-as-I-can-be opinion:

Turbo, Peterson and Poly3 are all great, but ALL the rest fall short for various reasons. Honorable mention to Canvas, nice big screen and similar 'screen' features that Q-tune does (colors, rotation, etc), but I didn't find it as accurate as the rest and I didn't like the buffer.

Turbo Tuner: Been on my board for 15+ years. Tons of respect. But it's an old design. Side jacks aren't great. Lacks a buffer. Old style LED's.
Peterson: Outstanding tuner, but I found the buffer colored my tone. It does have sweetenings, etc. but only 1 UI option. Smallest footprint available, narrower than TT mini when considering side jacks. Fantastic mechanical design. Super accurate tuner. #respect.
Poly3: A lot of great features, and I like the buffer. Small screen. Not a lot of bells/whistles, but a solid, accurate, built-like-a-tank tuner. The fact that I put it in the league with the above two is significant.

Why is Q-tune better:
  • Top jacks AND top DC jack
  • 5 Tuner styles (something for everyone)
  • 5 standby screens
  • Top notch buffer that won't color your tone, with Monitor Mode option.
  • In-tune threshold (adjustable), none of the rest have this.
  • 4 screen rotation options and 8 color options (like Canvas)
  • And the software WILL continue to grow. Updated via USB-C.
Just my opinion.
 
Demo mistake…

Remember that component I said wasn’t going to be in the production circuit board that I jumpered? I made a very effective mute circuit by that jumper connecting signal to ground. I clipped it and everything works as planned. Thanks for humoring me w/ the prototype build. It was a bit off-the-cuff and we’ll make a better one later with the real circuit board.
 
Understood, but when there was no signal to begin with my first thought was ICs, then later the jumped jack ... I've jumpered the wrong jack before.
 
Will the code be open source? I had been checking in on the project here and there since we first crossed paths last year, but it looks like all repositories are no longer public
 
Will the code be open source? I had been checking in on the project here and there since we first crossed paths last year, but it looks like all repositories are no longer public

Hi @xconverge, great to hear from you—and I appreciate you keeping an eye on the project!

I did originally plan to make Q-Tune open source, but after some reflection, I’ve decided to keep the code closed for the time being. There are a few reasons for the shift. Most importantly, Q-Tune has matured from a fun side project into something with real polish and potential, and I want to ensure it has room to grow in a sustainable and focused way.

Open sourcing can be great, but it also comes with overhead—support expectations, fragmentation risks, and less flexibility in setting direction. For now, keeping the code private allows me to move faster, stay focused, and explore where this can go without needing to formalize everything for broader public consumption.

That said, I’m still very inspired by the DIY and open-source community, and I wouldn’t rule out releasing parts of it or circling back to open source later on. Just not quite yet.

Hope that makes sense.
 
That seems like a lot of gain. And there's the DC offset on a 5v single supply R2R opamp with a single clipper. Without asking you to reveal trade secrets, are you detecting the guitar signal as variable frequency DC, essentially? Kinda a half wave rectifier via the offset and clipping?
Interesting approach if so!
 
5) 165 mA nominal while tuning, spikes up to 170. Recommend a 180 or 200 mA source.

You could save about 20mA by using something other than the NE555 for the relay+footswitch logic. One way is with a simple microcontroller such as the ATtiny13a: you can have it go into a deep sleep state when not responding to switch presses (here's how I did it), where the power consumption should be 1mA or less. The microcontroller approach also opens you up to a more "sophisticated" footswitch-based user interface, e.g. press-and-hold, double-tap, etc.

For simple on/off, you could also use a CMOS logic chip with Schmitt-trigger inputs, like the CD40106 or 74HC14. Unless you go with surface mount, these ICs are physically large (DIP 14); but they are cheap, current-production commodity parts, and use micro amps of power. This is what I now use for most of my true-bypass builds, I'm happy to share the schematic if you're interested.
 
Hey a DIY tuner with all the features I want combined in the same unit… I am interested! Good luck ironing everything out and don’t forget to strike a deal with Musikding if possible, so us EU folks have an easier time grabbing one :)
 
You could save about 20mA by using something other than the NE555 for the relay+footswitch logic. One way is with a simple microcontroller such as the ATtiny13a: you can have it go into a deep sleep state when not responding to switch presses (here's how I did it), where the power consumption should be 1mA or less. The microcontroller approach also opens you up to a more "sophisticated" footswitch-based user interface, e.g. press-and-hold, double-tap, etc.

For simple on/off, you could also use a CMOS logic chip with Schmitt-trigger inputs, like the CD40106 or 74HC14. Unless you go with surface mount, these ICs are physically large (DIP 14); but they are cheap, current-production commodity parts, and use micro amps of power. This is what I now use for most of my true-bypass builds, I'm happy to share the schematic if you're interested.
Yes, we've been told similar things from other EE types, we've looked into it. Currently the esp32 screen we are using is GPIO limited, we don't have any more GPIOs left. So we'd have to get a GPIO extender and/or other complications. This type of thing is possible and we are interested in pursuing it, but not now, possibly down the road. SMD would give us a lot of advantages too, but then it becomes a much harder DIY.
 
Last edited:
Back
Top