Could someone be so kind to doublecheck my silicon tonebender mkII vero layout?

[Bandwagonesque]

        Hi everyone. I've recently finished up my first original Vero layout for a silicon tonebender mkII. Its based off another Vero layout but wanted to see if I could make one to call my own (sort of). It was meant to fit in a 1590A and I built the first one up last night.
          It bypasses signal and passes signal thankfully, but it seems to be leaving a lot to be desired no matter what npn silicon transistors within spec I throw in it. So far I've tried 2n2222's, 2n3903 and 2n3904's all within spec in or around 90-140ufe. So far with all controls on 10, it sounds very farty and starved. Barely usable and sounds the same with any transistor. I went ahead and replaced the 5.6K resistor with a 10K trim and then for kicks replaced the 47K resistor with a 100K trim. I then tried to tune it to ear and the only usable position was again farty and starved, otherwise I lost signal completely or was left with oscillation/a constant ringing. But I was able to tune it out with the trim pots, but what I was left with doesn't at all sound like a tone bender to me.
         
          After second and triple checking my layout to the original one I based mine from, I couldn't see any error and seemed to work out the usual build suspects in bridged traces, polarity, etc. After all that I started to doubt if my layout was really correct. To where I'm here to ask if anyone may be so kind as to check it for me to give me total peace of mind that my layout isn't at fault so I don't start going crazy. Its great to know it works, but I just can't figure out why I can't get anything but a really bad fuzz tone. Any help to get me on point would be graciously appreciated.
         
        Enclosed is my Vero layout, along with the tagboard effects layout I based mine from. Also Also sticking a wiring diagram just in case, though I hardly think that's the issue or it beeng a grounding issue. enclosed are the voltage measurements for each 2n3904 Silicon transistor when its set to its only sonically useable setting. If I forgot any specifics do let me know and id be happy to provide what I can.

Transistors: 2n3904 silicon

Q1:  120 ufe   C/ 6.84    B/ 0.99    E/ 0.37
Q2:  102 ufe   C/ 2.23    B/ 0.67    E/ 0.02
Q3:  120 ufe   C/ 1.64    B/ 2.23    E/ 1.54

[patrick398]

Are those blackwire the trimpot? There's no track cuts in between them so your pins are all in line and shorted together

[patrick398]

Oh wait no that's the ground trace isn't it

This is kind of hard to follow without a schematic. Also i'm not sure how it compares to the original vero layout in terms of component numbering. the 470k from the base of q1 should go to +9v, i don't think yours is. It's connecting to volume 3. In the original  vero layout theres a track cut underneath the 1k resistor on the same track as volume 3. I feel like you tried to copy that connection but missed the cut

[duck_arse]

schematic, please, it's only polite.

you seem to have the out pot connecting to Q1, that ain't right. there should be only a single connection to the top of that pot, the out cap, 100nF. also, I think your diode is backwards.

a second look - I think you have done the polarity reversal wrong in parts. emitters still go to ground when converting pnp to npn. at the very least, I am massively confused. you should do your layouts from a circuit diagram and not another layout, because of translation errors.

[nocentelli]

...i'm not sure how it compares to the original vero layout in terms of component numbering. the 470k from the base of q1 should go to +9v...

I don't think this is correct - The tagboardeffects layout definitely has a 470k from base to collector via that jumper.

Here's the schematic:


I can't explain the voltage on Q3's collector (which I feel should be higher than the base), but I agree with duck_arse and patrick398 that your layout has the output/volume 3 track (row b) connected to not only the output cap from Q3's collector (correct), but also directly DC-coupled Q1's collector (incorrect).

If you put a cut at c16, you could move the ends of the 470k resistor and the jumper that form the base-collector loop down one row to solve that issue.

DA is also right about the polarity protection diode: I don't really understand how you've got any voltage anywhere with that in backwards.

I think your polarity is OK, though. It's NPN, so input cap should have negative stripe pointing at the guitar input, fuzz pot cap negative to ground, emitters are grounded (with or without resistor or pot in between).

[Bandwagonesque]

ahhh you guys are beautiful! it works! i didn't see but you guys were right on the money with that resistor not being were it was supposed to go. moved the resistor down a strip per patrick398's instruction and it works great!. thanks again you guys.

so my last questions are now that its up and running, how do i properly bias a silicon tonebender or what voltages am i looking for per transistor? I have a 10K trimpot in place of the 5.6K. do i set that at 4.5V like a fuzz face or do i park it elsewhere?

speaking of that trim. if I wanted a bias control brought to the surface, would I replace the 10K trim with a 10K potentiometer? Or would I leave the 10K trim in place and bias it where its needed and then stick a 10K pot along with it?

thanks again you guys, so far ive got 2n2222's in mine and its ripping. more of an overdrive flavored fuzz more than anything too fuzzy but I hope adding a surface mount bias control will help me in dial in more hair, fuzz, and gated breakup.

[cab42]

This circuit was also my first vero layout, when I started out:



However, I can't remember which transistors I used. But it's pretty cool. It has a picture with Fat Freddy and his cat on it 

I built after hearing RDV's sound samples. Unfortunately he passed away a few years ago. He was such a great guy.

There's a slightly smaller layout in my gallery, but I don't know if any one ever build that.

[patrick398]

moved the resistor down a strip per patrick398's instruction and it works great!. thanks again you guys.

Bring that 470k resistor down 6 more rows so it's connected directly between collector and base, then remove that jumper that's next to it. Your missing a cut as it is so your Q1 collector is jumpered straight to the output pretty much. Forget about the cut and just move the 470k and remove the jumper. See how that sounds.

For the bias, yes if you want it on the enclosure use a potentiometer of the same value. If you used it 'along side' the trimpot, depending on how you wired it, you would have them in series or parallel which would double or half the overall resistance respectively, so just use the one potentiometer.

EDIT: And as pointed out by others your protection diode is the wrong way round in the layout.

[Bandwagonesque]

thanks again patrick, duck-arse, and nocentelli for noticing that diode. turns out on my build i had put it in the right direction so there wasn't an issue but only noticed after the fact on the diagram thanks to you guys. duly noted and fixed. and thanks again patrick, i went ahead and moved that resistor down right between q2's collector and base. didn't notice a difference in sound but i got rid of a jumper!

[sopapo]

Bump this topic to not clog the board with redundant topics.. I have made this silicon tonebender MKII circuit by RDV, I have used the same veroboard layout that the opener of this topic, http://tagboardeffects.blogspot.com/2013/07/npn-si-tonebender-mkii.html

I have used three 2n2369, with an hfe of (q1-q3):70/70/100
I too would like to know wich voltages to look for... I put a 10k trimmer instead of the 5,6k resistor and first biased at 4,5v, sound good, with certain tonebender character, later biased at 8v,  looking for what I have read are the usual voltages of the germanium tonebender, and the sound was equally good too, but with less tonebender character in my opinion, more overdrive like...

The voltages are (with an vcc:9,58)
Q1:  70 Hfe   C/ 7.51    B/ 1.10    E/ 0.45
Q2:  70 Hfe   C/ 1.78    B/ 0.67    E/ 0.01
Q3:  100 Hfe   C/ 8,03    B/ 1.78    E/ 1.09

Lots of questions... Can i look for the same voltages and Hfe of the the germanium tonebender?
(to sound good).. the others voltages are fine? are important?
what other voltages (B,E) must care for?
A second trimmer for q2? another transistors (Higher Hfe?)

Thanks for you time
Best regards

[sopapo]

I have adjusted the trimmer on q3 until 3,6v and the tone is better, with more grain and just the right sputtery tone that I believe is the tonebender trademark
My question is, why this voltage to sound good? all the measures about I have read of the mk2  are in the 8v realm, the hfe of q3 is 100, I dont know why
Sound good becouse is a fuzzface?? q1 is doing nothing?
I think a trimmer for q2 is in the way....