Foxx Tone Machine build on breadboard. Something popped, but what?

[Hemmel]

Hi guys,
I breadboarded the following schematic:


Everything was kinda working at first, except the octave switch. I was getting fuzz, the sustain and tone pots were responding correctly.
Then I found that I have faulty 1N34A diodes. So I proceed to change them all to 1N914. But when it came time to plug in D3, I mistakenly plugged it into +9V instead of ground.
Sound went "POP" and now I get nothing. No more fuzz, no more nothing. Some noticeable scratching noise, sometimes.
I put an audio probe on the collector of Q1 and I don't get sound from there. I have tried changing Q1 but still nothing.

Any other ideas would be welcome.

Thanks,
Hemmel   

[antonis]

Can't see the way for Q1 to get damaged..
Most possible damaged part is C8..

P.S.
Do you get sound on Q1 Base..??

edit: 1N914 forward voltage drop is higher than 1N34A one resulting into more "loose" octave effect..

[GibsonGM]

That is VERY ambitious for a breadboard circuit   

[Kevin Mitchell]

That is VERY ambitious for a breadboard circuit   

Is... is this a joke?

[antonis]

Is... is this a joke?

You're my man, Kevin..!!

(I was waiting for somebody else to cause his Highness anger...)

[GibsonGM]

Meh, 4 BJTs, pots, switch...no, it's not a joke.  Known design, it's a lot of work; I'd just solder it up on perf if going thru that effort.  Each person has their own preferences for building, testing etc...not an insult either.  Just lots of places to go wrong, have a bitchy contact and so on.  So, from my POV - ambitious.

[Kevin Mitchell]

Lol I get it.
My reissue microsynth spread on 3 breadboard would give you tremendous nightmares.
And it worked!! (with a little lead wiggling of course).

People often mistaken my poor choices as ambitious. I'll take it.

[anotherjim]

C8 and or other caps may just have charged up and blocked everything and there's no discharge path. It might work again once leakage bleeds the charge off.

[antonis]

A metallic tweezer could tell us the truth..

[GibsonGM]

Lol I get it.
My reissue microsynth spread on 3 breadboard would give you tremendous nightmares.
And it worked!! (with a little lead wiggling of course).

People often mistaken my poor choices as ambitious. I'll take it.

Been there, LOL.  Not for a fuzz tho!  An EasyVibe was the LAST time, ha ha.

[Phend]

?





werks grate,
lol
(marc, did you get yours going ?)

[GibsonGM]

 

[duck_arse]

.... when it came time to plug in D3, I mistakenly plugged it into +9V instead of ground.
Sound went "POP" and now I get nothing.
.....
Thanks,
Hemmel

pull D3 and D4, see if you get sound thru. can't see how D3 to supply wold kill anything except D3.

[pinkjimiphoton]

i've seen this before. hell, i think i've DONE it before.

replace the diodes and electros, and you should be fine. the diodes are probably ok, but the electros would be smoked.

to save yourself hassle, add a small daughterboard off the power jack with like, a 100-220u cap with a parallel 2.2n cap across the rails, and like, a 1n400x as well, cathode band to +

that way if ya plug in wrong, the 4001 will take the hit and you should be fine.

your transistors should be fine, too.

but replacing them 10u electros will likely get ya back in business quick.

[Phend]

Here is Fuzzcentral's schematic.
Note C7 (Sustain) and C12 (Tone) the polarity is flipped compared to the GGG circuit above.
Does it matter which way these caps are inserted ?

[antonis]

In theory, GGG schematic caps are oriented correctly..
(from higher DC voltage level to lower one..)

In practice, as long as "reverse" voltage doesn't exceed 1V or so, there shoudn't be any issue..
(800mV for Sustain pot cap and about 200mV for Tone pot one..)

[Hemmel]

I wanted to thank you all for your replies. I appreciate it!

I decided to abandon the "breadboarding" of the Foxx Tone Machine, since I couldn't find out why it wasn't working.
I then decided to breadboard the Shocktave (whilst promoting this forum on my stream  )
...and I noticed that it too, wasn't working! Or, was half-working. the octave circuit wasn't making any sound but the dry circuit was.

Then I noticed that my power supply was not giving the 9V it was supposed to. At one point, I was getting 1V ! The PSU itself keeps giving out 9V without issue, I think what's going on is between the voltage sag pot (I built the Beavis breadboard thingy) and the breadboard.

So I'll have to look at this to find out what happened.

Thanks again to all and I'll maybe start a new thread about the other issue.

[GibsonGM]

Your breadboard doesn't have split supply rails, does it? Meaning....if you insert a voltage along say the red bottom row - you still read it with a meter all the way down the other end, right?  Just a quick check...some BB's have that row only extending HALFWAY, you have to jumper across the rows for them to be connected.  Worth knowing  anyway    

[Hemmel]

Your breadboard doesn't have split supply rails, does it? Meaning....if you insert a voltage along say the red bottom row - you still read it with a meter all the way down the other end, right?  Just a quick check...some BB's have that row only extending HALFWAY, you have to jumper across the rows for them to be connected.  Worth knowing  anyway   

Yup, I'm aware of this, and I have plenty of little jumpers joining all the rails. I'll post a picture tonight.

[antonis]

Can you locate the point(s) with low supply voltage on 1^st post schematic..??