Hi everyone, so I ordered my parts and attempted to build my first pedal, Axis Fuzz.
But of course, when I plugged in the guitar to the amp, there was no sound.
I did the continuity test with my multimeter with probe on the tips of both input and output jacks, and it made a beeping noise (if it actually means something in terms of my build process)
Here are some photos and veroboard layout that I used to build the pedal.
FYI, I didn't order a LED light yet so I didn't include it in my 3dpt switch connection
Can you please tell me what I'm doing wrong here? Thank you.
(https://i.postimg.cc/SXzDp5np/Kakao-Talk-20201008-021734717.jpg) (https://postimg.cc/SXzDp5np)
(https://i.postimg.cc/K3mNB8JZ/Kakao-Talk-20201008-021734940.jpg) (https://postimg.cc/K3mNB8JZ)
(https://i.postimg.cc/PpWyCwb3/Kakao-Talk-20201008-021735118.jpg) (https://postimg.cc/PpWyCwb3)
(https://i.postimg.cc/ZBtjYcNv/Kakao-Talk-20201008-021735286.jpg) (https://postimg.cc/ZBtjYcNv)
(https://i.postimg.cc/gnSDLdRW/Axis-Vero-V2-my-wiring.jpg) (https://postimg.cc/gnSDLdRW)
I used this guide from Sabrotone.com to wire 3dpt switch
(https://i.postimg.cc/qNYHLPff/True-Bypass-Wiring.jpg) (https://postimg.cc/qNYHLPff)
Are the grounds of both jacks connected together?
(not thru the switch)
What Phend said.. !! :icon_wink:
IN jack ground should be connected via metal enclosure but it's "open" when effect unboxed..
Use an alligator clip to connect both jacks GNDs and your circuit will work.. :icon_wink:
Thank you everyone!
I connected ground wires from both output jacks on the ground section of the circuit and now the pedal is functioning properly.
Now I just gotta figure out how to make this thing to sound "okay" cuz it's really wimpy-sounding right now.
I assume I have to find a matching pair of transistors to make it sound at least decent, right?
> find a matching pair of transistors
No. (They are not even the same type or gender!)
Something is done wrong. Post the *schematic* you used. Post your voltages. You can't see electricity, but many wiring flaws are exposed with simple DC voltages.
That sabrotone picture isn't great, for the reasons Antonis mentioned. Take a look at the Tonepad wiring diagrams (for example) for schemes that are known to work (I use diagram #5 for pretty much everything: never had a single problem with it).
Quote from: PRR on October 07, 2020, 09:52:14 PM
> find a matching pair of transistors
No. (They are not even the same type or gender!)
Something is done wrong. Post the *schematic* you used. Post your voltages. You can't see electricity, but many wiring flaws are exposed with simple DC voltages.
(https://i.postimg.cc/JtJsjfhS/axisfuzzschem.gif) (https://postimg.cc/JtJsjfhS)
This is the main schematic that I used. I used the veroboard layout made by JohnK that I found on Guitar FX Layouts. I compared the schematic and the layout and it seems that the layout is pretty correct (to my eyes at least) The only modification that I made was getting rid of 220 resistor and 0.001uF capacitor just like the how the schematic recommends.
All voltages measured by probing negative end of the battery case and the legs of the transistors
Multimeter set to 20V
2n3906: hfe 250
e: 1.47
b: 0.7
c: 0.85
2n3904: hfe 257
e: 0.34
b: 0.81
c: 1.79
battery: 2.38
Disconnect your battery, measure it and in case its voltage remains at about same level give it a funeral, by proper recycle disposal.. :icon_wink:
P.S.
In case you already have your enclosute wired, add A & B wires and you'll have a In & Out grounded effect when bypassed.. :icon_wink:
(https://i.imgur.com/2urHLy1.jpg)
I went straight to a corner store and bought myself a new battery.
Old Battery: 3.83
New Battery: 9.89
2n3906
e: 4.57
b: 3.81
c: 4.08
2n3904
e: 3.67
b: 4.09
c: 6.60
now that you tried a new battery, have you tried playing through it...? :icon_mrgreen: :icon_mrgreen:
Quote from: 11-90-an on October 08, 2020, 09:29:31 AM
now that you tried a new battery, have you tried playing through it...? :icon_mrgreen: :icon_mrgreen:
As soon as I read your comment, I plugged it into my amp right away :icon_mrgreen:
Well, the fizziness is gone now. I suppose the wimpy sound was caused by the lack of power supplied by my old battery.
Now, unfortunately, it's not producing enough distortion, if any, to call it a "fuzz pedal."
All those demo videos of RM Axis Fuzz on YouTube have wayyy more clipping sound than my circuit.
Maybe there's a set of certain voltages for each transistor that I should go for? Or perhaps the 22uf electrolytic capacitor's voltage rating is too low? (3 of them are 25v. One is 50v and the brown film capacitors are 100v)
Quote from: mushjoon on October 08, 2020, 10:32:27 AM
Quote from: 11-90-an on October 08, 2020, 09:29:31 AM
now that you tried a new battery, have you tried playing through it...? :icon_mrgreen: :icon_mrgreen:
Or perhaps the 22uf electrolytic capacitor's voltage rating is too low? (3 of them are 25v. One is 50v and the brown film capacitors are 100v)
No, with 9V supply the only thing that can be wrong with those ratings in mind is the polarity.
one thing about your build - don't solder wires into the pot lug rivett holes. those rivets are all that's connecting to the carbon track, and you can stretch them with heat enough for them to loose contact and ruin the pot.
and, your wires can be so un-dressed that they short to the pot body. use the lugs and wrap a wire around, or cut a tiny perf, push the pot pins into it, and then solder wires thru the perf and link to lugs. then, the solder lugs are right and can't move, and the wires are straight and well terminated.
Quote from: mushjoon on October 08, 2020, 10:32:27 AM
Maybe there's a set of certain voltages for each transistor that I should go for? Or perhaps the 22uf electrolytic capacitor's voltage rating is too low? (3 of them are 25v. One is 50v and the brown film capacitors are 100v)
No. Those caps are just fine. The voltage ratings won't matter in this circuit. The electrolytic caps are polarized, so you might check that their positive and negative legs are connected correctly.
I can't see the schematic or layout here at work, but have you verified that you have the correct transistor in the correct socket and that they are in the correct way? (Don't worry, you won't be the first person to make that mistake.)
I just realized that I made the most embarrassing and frustrating mistake I've ever done so far. :icon_redface:
I didn't know that when you are reading the veroboard layout, you are supposed to drill holes and place the components while looking at the plain side, NOT the copper strip side.
Since I basically drilled holes with the copper strip facing me and pushed the components into their position with the legs toward me, no wonder the pedal didn't give the sound that I wanted.
Ughhhh.... I guess it's time to desolder everything and start from zero again. :icon_evil:
excellent. well found. you have a pedal that works backwards. also, bad on us - we are supposed to spot that error in double quick time, as it happens quite often.
but it's a mistake you only need to make once.
Dang... looks like we're all not in the game now eh? :icon_cry:
(https://i.postimg.cc/d7JcdWRC/Kakao-Talk-20201010-051101134.jpg) (https://postimg.cc/d7JcdWRC)
Despite my effort to completely re-solder everything in the correct way, it ended up sounding wimpy without enough distortion again.
Perhaps I just simply chose the wrong pedal to make.
But thank you everyone for helping me out! :icon_biggrin:
WAIT! Can you try picturing the solder side of the board? Also, can you give some voltages..?
Are your in/out jacks in the right way..? :icon_biggrin:
Quote from: mushjoon on October 09, 2020, 04:14:58 PM
Perhaps I just simply chose the wrong pedal to make.
This is a simple circuit, don't give up!
Post some photos of the solder side, making sure the image is clear and that all your off-board connections are easy to see.
Thank you everyone for the encouragement!
Here are the pictures.
I soldered in the 220 ohm resistor and 1nF cap, which was recommended by the original schematic to omit, to see whether if it would improve my tone but didn't help haha
(https://i.postimg.cc/9zKw0Hdr/Kakao-Talk-20201010-194445606.jpg) (https://postimg.cc/9zKw0Hdr)
(https://i.postimg.cc/LJBJxqr1/Kakao-Talk-20201010-194445778.jpg) (https://postimg.cc/LJBJxqr1)
(https://i.postimg.cc/Mc6vN6Sr/Kakao-Talk-20201010-194932769.jpg) (https://postimg.cc/Mc6vN6Sr)
(https://i.postimg.cc/K1yK77sb/Kakao-Talk-20201010-195225247.jpg) (https://postimg.cc/K1yK77sb)
I also measured the voltage of each transistor with the new battery.
Battery: 9.88v
2N3906 (264 hFE)
e: 4.54
b: 3.81
c: 4.12
2N3904 (260 hFE)
e: 3.69
b: 4.10
c: 6.57
Some easy learnings for audio transistor DC voltages.... (Silicon like the ones you have).
You want the base to be about 0.7v different from the emitter.
If the emitter or collector are connected to the rest of the circuit by resistors, you won't expect to read either 0v or supply voltage on them. In amplifiers, collector volts are usually expected to be near half of supply volts (4.5v for us lot).
If it's NPN (2n3904), the base will be higher than the emitter. If PNP (2N3906), the base will be lower than the emitter.
So from the last voltages posted, the 2N3906 looks workable, but the 2N3904 is starved (base emiiter not forward biased enough). Consequently, the collector voltage is too high.
You also post Hfe measured that is believable for those parts, so we can assume you know which way around the ebc pins are.
As Duckarse spotted, those pot connections are not good. If you have flat side flush wire cutters, I would crop the wires close in rather than risk damage by unsoldering. While the wires are off, use the meter on resistance to confirm the pots are ok. Remake the wires by a short wrap around the pot legs before soldering.
Use the meter on resistance (or audible beeper if it has one for basic continuity proving) to confirm strip board track cuts and isolation between adjacent tracks. Use the schematic to show you what connects to what and just as important, what shouldn't connect. Confirm resistor values as it's easy to misread colour codes. You probably can't easily measure capacitors, but you can at least check that none have a short circuit.
Don't do resistance/continuity tests with the power on the circuit! Much of this can be done before you even wire the board up or apply power.
Finally, your basic workmanship is good & neat, so don't give up. You should be able to produce working pedals.