Beginner breadboarded fuzz issue

[Locrian99]

K it was pretty shiny.   I hit it with 600 grit sand paper and isopropyl alcohol before i started soldering on it.  I noticed it was noticeably less shiny when I took the picture than it was before I started.   I however was not being careful not to touch it.   I'll try the steel wool as well.  On attempt #2. 

Thanks   

[Locrian99]

Figured I'd share a win.  I needed one in this new to me little hobby.  Pretty happy with how my little test box turned out.    Going to attach breadboard to this left over chuck of butcher block countertop I had left over from a recent house project and it'll be my own little beavis board without the power sag thing. Originally I was going to use a multi meter probe with a second switch for that banana plug terminal on the bottom but my multimeter has the insulator stuff around the plug and decided not to butcher it, Ihad an extra set of probes around so I cut the end off one added the capacitor and can just plug it into the speaker terminal out when I need to use it.   

[bluebunny]

K it was pretty shiny.   I hit it with 600 grit sand paper and isopropyl alcohol before i started soldering on it.  I noticed it was noticeably less shiny when I took the picture than it was before I started.   I however was not being careful not to touch it.   I'll try the steel wool as well.  On attempt #2. 

Thanks

That's fair enough.  I was concerned that was both the "before" and the "after" picture you posted!   

[Locrian99]

Well I figured I might as well take a few pics as I go through the 2nd attempt at this.   If you see anything that should be mentioned please do.   I really appreciate the advice guys.   Have to take a break in the soldering.  Changes made thus far.   8.2k is a 5.1k, and 100k is 150k.

[Locrian99]

Argh!!!   Alright so have it all made again hook it up and I'm getting the same weird voltages I was on the other build.   Im about to just scratch this idea and find a different fuzz to build, but I've already got the enclosure drilled out for the 4 pots (was adding the smooth pot like an axis face, but left that off for test purposes.)  Or find a different vero layout.

Here are the voltages

From Power supply 9.3v
C1 2.28
B1 0.0
E1 0.0
C2 1.63
B2 2.28
E2 1.6

Going into R4 (8.2k that feeds c2, I have 5.6 there) 8.83v
Coming out 1.63

Going into R1 (100k, I have 150k there) 1.6
Coming out 0.0

Audio probe results signal at c1
No signal at c2

Let's see pictures are out of order here.  First picture all components on board no off board wiring.  4th picture strip side no off board wiring.   

Oh I'm also using some different values for the miller caps wouldn't think that would matter but they are 680p on the c1 and the listed 47 on c2.

[Locrian99]

Also just to check it.  Hooked test box up to breadboard that I had an lbp-1 set up on and that worked fine.   

[PRR]

B1 0.0

C1 shorted to ground?

[Locrian99]

B1 0.0

C1 shorted to ground?

I'll check that when I have some time to get back to it.   Holiday today, I was thinking I must have some weird grounding issue.   Thank you for the comment. 

[Locrian99]

Well I figured I had 5 minute after zooming in on the picture with the wiring there was a solder bridge between the ground and the second rail (where the q1 base is.   Fixed that and now I'm getting. 

C1 1.18
B1 0.57
E1 0

C2 9.27 (seems like there must be a bridge between the + rail and this?) getting this reading at the output of the 330 coming off the rail and output of the 5.6 coming off the 330)
B2 1.17
E2 0.68

[antonis]

Suspect hides somewhere around those 8 pads..

[Locrian99]

I thought that as well with the cuts etc.   I didn't see anything.   I kind of scored between the rails with an exacto but I'll look again when I have more time.   Thanks again.

[Locrian99]

So in the one picture the "suspect area" is top right, the other is top left.   I don't see any bridges.   I did score a bit between rails.   And a picture of the reading at the solder joint for r4 which heads to q2 collector.   Am I missing something here?

[Locrian99]

So now I'm really confused.   I had done a little light solder removal in the "suspect" area.   And decided to switch over to my ohm meter to just check between the power rail and the rail the collector of q2 is on.   I got 5.47k ohms, but am still reading 9.29v right there.   Does that mean the power must be coming from a source other than the power rail?   

[Locrian99]

Doh I didn't realize I had to have the fuzz pot hooked up for it to bias correctly.   Which I don't fully understand I guess that controls how many volts are going to ground from the emitter?   So without it none of them we're going ground I still don't understand exactly why that would work that way.   Lots to learn I suppose.    Anyways got the voltages reading correctly hooked up to test box and it is all working as it should sounds great!   

[antonis]

I guess that controls how many volts are going to ground from the emitter?   So without it none of them we're going ground I still don't understand exactly why that would work that way.

Actually it controls Q2 Emitter current..

Without Fuzz pot, Q2 Emitter is solely connected to about 600mV above GND (Q1 V_BE) via 150k feedback resistor..
The above calls for 4μA (4*10^-6 A) working current and a voltage drop across 5k1 Collector resistor of ONLY 20mV below power supply voltage..!!!

So, for a +9.30V supply, it's quite normal to measure 9.28V on Q2 Collector..

EDIT: Don't mess with above numbers.. Just follow diagram below..

[antonis]

Nothing to add..

Just to overcome "6666" posts..

[pinkjimiphoton]

Well I couldn't stop tinkering with it.   Tried several things the input pot like an axis.   Dropped the volume pot to a 100k etc.   then decided if it was not enough output from the strat I'll just put a booster in front did up a little lpb-1 in front of the fuzz and my volume knob works!   I also get that roll off I was looking for.

first thought in that case would be partially open input cap, or serious misbias. a couple posts later, you post.....:

[pinkjimiphoton]

If you're in a hurry to look inside a Strat, a hack is to clamp the strings to the fingerboard with capo or cable ties then slacken the strings, remove the neck screws and then you have access. Not actually ideal and still not super quick  ('cause all them screws) and you have to make sure any shims in the neck pocket don't fall out of place. It's the way to go if you need to test and try different changes to the electrics.

hell, i usually just pull the trem springs, usually that will give me enough slack

[Locrian99]

Well I couldn't stop tinkering with it.   Tried several things the input pot like an axis.   Dropped the volume pot to a 100k etc.   then decided if it was not enough output from the strat I'll just put a booster in front did up a little lpb-1 in front of the fuzz and my volume knob works!   I also get that roll off I was looking for.

first thought in that case would be partially open input cap, or serious misbias. a couple posts later, you post.....:

It was just serious operator error.   I play quietly I've got a little fender super champ had the volume at 2, I couldn't hear when the volume pot down because the amp was too low 😂😂😂

I guess the boost just gave me enough.   This thing has been boxed up for a bit.