Q-Tune build — Feral Feline vs The Universe

Feral Feline

Feral Feline

Well-known member
TLDR? See "UPSHOT" at bottom.


My Q-Tune arrived a week ago, Wednesday, after a minor hiccup with shipping (which Q-Tune’s Dynamic Duo sorted out for me, thank you again gents).
Then the universe conspired against me building it. Emergency car-rescue for a friend; grocery-shopping, banking with/for my wife, friend’s wife’s birthday-barbeque, family-drama, daily-driver in the fixit-shop, etc… So I chipped away at it whenever I could carve out a solid block of time.

I had meant to build a couple of small pedals prior to tackling the Q-Tune as it’s been a while, however I didn’t get the chance to freshen up my soldering-skills beforehand.

Well packed and organised, as Audandash noted in his first impressions thread. What struck me in particular was that the PCB seemed to be of a very high quality.

I started out with 375ºC and a Small chisel-tip — 37/63 solder .5-gauge but I wasn’t happy with how the first diode went in so I changed to the .6-gauge solder (37/63). While I’ve got some .8, I was worried I’d flood things, it’s been a while since I soldered.

Turned out I could’ve used my thickest gauge, I was having to feed a lot of .5 solder on the resistors. To begin I wasn’t letting the iron heat things up enough before applying solder, but I eventually found my rhythm by the end of the resistors and moved on to the MLCC caps.

From there things went downhill, well, okay faster downhill. The PCB’s MLCC-pads weren’t heating up for me and the solder wasn’t flowing and I was getting mighty frustrated — was it the tiny pads or was it me? Nobody else has commented about problematic pads. 😡 I quit after just two (2) MLCCs.

IMG_0890.jpeg MLCC MADNESS!

The next day I tried different tips, different gauges of solder and different techniques/angles/adjustments… and it was all still hit and miss, mostly miss. C19 specifically did not want to be soldered, extremely reticent, but nearly every MLCC fought me tooth and nail, even after upping the temp to 395º.


I checked all the components as I went, which really slowed me down but I wanted (née needed) this thing to work from the git-go; been a while since I had a win, which is why it’s been a while since I built anything.

Most of what I checked was very close to spec, but a couple of caps came close to colouring outside the spec lines, a 470n that measured 450n for example and a 10µ that went beyond 20%, measuring about 7µ5.


The JST-12pin’s wires were too small for my wire-stripper so I hand rolled them over a utility-knife blade. The middle red wire shed a bunch of strands and I prayed it wasn’t one of the important ones (it wasn’t).


There were a few days where I couldn’t work on it, such as the day it arrived, the weekend, yesterday... So today I was determined to finish it.

Out of frustration I swapped to the original conical tip that came with the Hakko, haven't used it in ages, and things went much better. I was nearing the end of soldering, I had two caps left, the last 47µ and a 220µ. I installed the 47µ first, and for once had good solder-flow, it was the first thing to be in nice and neat, super tight, a perfect install. Well…

Throughout I was checking back and forth between my build and the doc, yet I still INSTALLED THE 47µ IN THE 220µ’s SPOT. GRRRRR 🤬. I think that’s the first time I’ve done that kind of mistake. I considered soldering the 220µ to the underside and grab another 47µ, but I think I’m out of 47µ.

The solder-sucker got rid of the bulk of solder, then I resorted to braid (been years since I used braid) with flux-paste — yet it wasn’t coming out…

🤯


Took a long break to let myself and the iron’s tip cool down.

First time seeing Popeye meeting Sindbad the Sailor…


Needed more cool...The Pink Panther cracking a safe…




After cooling off I went calmly back to work, and back to my broad chisel-tip to help heat up the pads and 47µ’s legs. Snipped its leads close to the board and proceeded to coax the cap out with heat, each side a bit at a time.

IMG_0894.jpeg OUT! OUT DAMNED SPOT!

TESTAMENT TO THE BOARD’s QUALITY — I DIDN'T PULL UP A TRACE OR PAD!

Once out, I tried the solder-sucker again to get the negative-pad a bit cleaner, and it worked thankfully making my 0.79mm drill-bit redundant. HAND-Drilling solder out of PCB pads is laborious and time-consuming, but if you go power or fast, you break the bit, the pad or both.



The long screws for the N1 enclosure — wasn’t clear where they should be placed, but I figured it out after re-RTFM. I gave the stand-off screws 2mm above the lip of the enclosure, following Hammond enclosure spec, even though this is a Tayda enclosure.





After about 10 hours total, spread over a week, I finished building & testing it.

IMG_0899.jpeg

Hallelujah brothers and sisters, it works — no cold solder joints (that I know of) on the MLCCs, no fried traces/components, wires intact…

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If I get another one, I’ll save the JST-12pin for next-to-last soldering, after everything else but just before installing the TO-220 Regulator. That way it’s not in the way, no chance of burning a wire or breaking one off while soldering the electrolytics etc.


ALSO, I’ll solder the momentary switch’s wires up while the iron’s hot. According to the build doc, it’s to be soldered after fixing up the PCB’s hardware Board-Mounts, but there’s no need to separate it from the other soldering, it’s got a JST quick-connect.


I thought about putting this missive in the Q-Tune subforum, but it’s a build-report so here ’tis.




UPSHOT:
It’s a great-looking unit with thick glossy paint, and everything is of a high-quality, and it’s been well thought out.
I can’t wait to dig in to the functions to tailor it further to my needs.
 
Sounds like it's got large ground plane that's sucking the heat out. I'd love a solder station but for now I'm stuck with an old 25W Antex and an old inherited 85W iron for those PITA jobs. Solder I use MG chemicals SAC305 32-gauge that's unleaded that works for most things at which point I switch to Chipquik TS3195NL solder paste. I also use a MG chemicals 837-P water soluble flux pen as it has brush nip that's great for scratch cleaning solder pads and component wires (even for getting that mess on the pad you had).

The solder paste is a revelation for soldering SMT. Even applying by hand rather than using a paste mask. Rather than water, some IPA works wonders for bringing up a shine on non-leaded solder and removes any residual flux.

I found the technique with a largish tip soldering iron for SMT is to paste, position the component, then place the soldering iron on the exposed pad so the iron touches the side of the paste. It then fluxes, melts and a change of state 'wave' goes across the solder and component pin. Works really well for soldering up some nasty small pinned SMT with a large tip soldering iron but you can't do that with solder wire.
It also works nicely with small through hole components.

I have a strobostomp, it's decent but it would be interesting to see your experience with the Q tuner. I'm tempted to make a daisy based tuner simply because I want to know the deviation of from the designed fret location to test output. Think of it as a luthier's tuner (checking fret accuracy across the entire fretboard). The daisy board should be fine for 0.01 Hz up to 2.4KHz based on the sample rate which is fine for most guitars.
 
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Some of those pads did seem a little small. I have been soldering a lot this summer so it didn’t give me much trouble. I did have to clean my tip a lot during the build and use the side of my soldering tip more than normal to get a few heated up well for it to flow. The board is definitely high quality though. Glad you made it through the build :)
 
Yeah I didn't mention it in my build report, but the pads on this thing are small, definitely small enough to make a noticeable difference in soldering. I had to switch to a smaller tip in order to actually heat them enough, my usual chisel tip wasn't cutting it. It was especially noticeable on ground connections where the thermal relief gap wasn't big enough for the small pad, it was tough to get some of them to flow. It's a cool project and a good design, but that was my biggest note.
 
Hi, my names Feral, I'm a tuner junkie.

Thanks for all the comments folks.


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While I've tried Strobostomps and PolyTunes, I've never owned either, because after getting my Turbo Tuner, I stopped buying tuners.
I'm hoping this Q-Tune becomes my umero nuno and relegates the Turbo to back-up and second-board status.

I'm still using whatever solder/paste/braid/etc I could get my hands on at the brick-and-mortar shops in Hong Kong — so mostly Japanese-brands, but some Chinese stuff too.

During the build I went from my normally-used chisel-tip to a smaller chisel to the pencil-tip so I could get the tip right on the (smallish?) pads.
For the removal of the incorrectly-placed capacitor, I went back to my biggest chisel — just as well, as that's what I'll be using for my next pedal.


~~~~~~

I adhered to Audandash's tip-cleaning procedure, in fact, cleaning the tip between every joint at least 90% of the time if not 99%.


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I'm with Vigilante398 on the IC-sockets, I saw in his build report he'd swapped out the flyleafs for machined — I, too, find those flyleaf ones flimsy and failure-prone. I considered swapping them out for machined IC-sockets as he did, BUT I wanted to
  • build this according to instructions
  • not be stuck with sockets I'd never otherwise use
  • my machined IC-socket supply is thin to non-existant for 8-pin at the moment.
So I used the supplied flyleaf sockets with kid-gloves, being overly cautious during handling/soldering/IC-insertion.
 
I did a double take at how India pale ale worked a good solder cleanser, then, (metaphorically) slapped my head.

When I’ve run into solder plane issues (getting solder to flow), I’ve been able to help things along a bit with warming up the board. Initially I placed it near the incandescent bulb in my work light, but in more recent years, I use a hot air gun for that (and an LED bulb).

Still came out nice and tidy, even after all the difficulties.
 
I do that every time ... IPA...

Try some Twisted Thistle

db8c239c701b490a976871d4f19ce809



Belhaven Black is a great stout.




Thanks for the tip on heating the boards, @Alan W, it never occurred to me to do that for anything other than SMD.
 
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