So I am new this, I've built an op amp muff kit I got off Amazon and it works great. I figured next step would be bread boarding a fuzz face and tweaking it til I like it and then putting it in vero and boxing it up. I've made it to the breadboarding part lol. So the effect works, I get fuzz. The weird thing is I don't get anything til about 7 on the guitar volume knob. 7-9 is quiet 10 is full volume. I've tried adjusting the bias of the collector for Q2 same results and I've tried several different transistor combinations same results. I'm using the beavis board fuzz layout which looks about the same as the small bear one. If I crank the fuzz pot all the way I can hear further down on the guitar volume knob but it sounds hollow.
Any advice would be greatly appreciated.
Hi Locrian, and welcome. :) I'm assuming you're looking for the famous 'roll-back' of a fuzz, and would like to have mostly the full range of your vol control?
Can you post a like to the schematic you used, and also, can you take a pic of the breadboard so we can see what you built? That would be helpful for us to get a fast answer for you!
Yes I would like to be able to use the volume knob to roll back, as well as just control the volume.
http://beavisaudio.com/beavisboard/projects/bbp_FuzzFace_Rev1_1.pdf
This is the schematic/breadboard layout I used. I am using a 500k volume pot as the schematic says not the 100k shown in the breadboard diagram. As you can see from my picture I put a trim pot in in place of the 8.2k resistor. Though i had the same issue when using the resistor and swapping different values to bias. I have not tried biasing the collector of q1 at this point.
(https://i.postimg.cc/0Kz3L2vy/1574434-C-C68-B-4-C1-B-B6-C5-298036304-CFA.jpg) (https://postimg.cc/0Kz3L2vy)
(https://i.postimg.cc/Cd29bDCB/7-EA92-E92-253-D-4-B59-BBDC-79-EE165-AE227.jpg) (https://postimg.cc/Cd29bDCB)
Hi & Welcome, also.. :icon_wink:
You can try last Beavis mod suggestion:
Experiment with different values for R1. Try values from 1K up to 470K.
Didn't fix the volume issue but the changes are awesome. For sure something to tinker with. Tried a 33k and a 220k. May even try a 500k linear pot there later once I figure out this guitar volume knob thing.
Weird, my program won't open the schematic PDF (WPS Office). I'm just wondering what interaction between the input and your volume knob might be going on. Do you know what your vol. pot is in the guitar? Ideally it will clean up when rolling back, but on some (like mine, with treble bleed caps) it will get thin as you go past 6 or 5 on the knob. Below "5", I wouldn't want to use the vol as it's too bright/weak, but I never go there anyway.
Maybe get it biased with voltages, and see if anything changes?
Quote from: GibsonGM on June 19, 2022, 03:06:15 PM
Weird, my program won't open the schematic PDF (WPS Office).
For your convenience, Sir.. :icon_wink:
(https://i.imgur.com/FEvIZPp.png)
Thank you.
Not sure what the pot is in the guitar it's a 2020 players strat. I grabbed my les paul and tried it and it's functioning as you stated below about 5/6 it gets thin but there's sound even when the fuzz is not maxed. So it's the guitar or the combination of the two. Think I'll change the fuzz knob from a type c to a b. Not sure why I would want it to be set so it climbs so quick at the end but that's what it called for. So I guess that answers that. I'll continue tweaking and see if it gets better with the bias changes and transistor combinations. I was messing around last night and it's got a 796 hfe 2n5089 in it right now way too much lol.
Again thanks!.
Actually I've got your attention if you don't mind. Endgame I was planning on putting the fuzz on vero perhaps following the pictures lay out.
https://4.bp.blogspot.com/-GpJOulSONK4/UW1OFmyB5sI/AAAAAAAAFaA/s2OGVrgP-Fg/s1600/Creepy+Fingers+Effects+Si+Fuzz+Face+-+smaller.png
I notice the pins on one of the transistors is rotated looks like the base and collector switch spots. Do I just twist those and maybe put some electrical tape on there? I will be socketing the transistors. Again thanks.
(https://i.postimg.cc/qzwjJzcR/A06-CF3-E0-7099-4917-BE16-00-A0-F5-E4508-D.jpg) (https://postimg.cc/qzwjJzcR)
Quote from: Locrian99 on June 19, 2022, 04:11:37 PM
Do I just twist those and maybe put some electrical tape on there?
Yes.. :icon_wink:
But after your final mod, smear a drip of solder on each BJT leg, securing it in its respective socket..
Yeah, sometimes a project like this shows off something in a guitar or other equipment we weren't aware of. Fuzzes really work with the guitar electronics, where most other stomps have higher input impedance so are more immune. I just 'get used to' where 'clean' is when I use a fuzz, and go with the flow. They're just about the only time I even use the vol knob!
Is there a way to test the output from the guitar and see if it is a pot issue ? Since it's happening on all 3 pickups I would think it wouldn't be an issue with the pick up. Moving away from a stomp box issue here I realize.
Strat (?) all going to one volume pot. If you have a humbucker in the bridge, they may have compromised and put in a 500k pot for it instead of the customary 250k, tho what wouldn't cause your problem. OR, the taper may be different than what we'd expect, cutting you off sooner than another pot would. A vol. pot should be log taper, but may vary from one manufacturer to another. Or a previous owner (if it had one) may have played around in there....
If it's a strat you can take a look next time you change strings (take out the 30 screws, lol)...if a Les Paul type, of course just take off the back plate! I hesitate to think there is 'something wrong' with your vol. pot...I think of these variations as 'features', lol. But if it's REALLY bad, yes, explore further. Maybe there is a wiring error in there or something (?)
Copy that may just have to chalk it up as a feature of this pedal. I did wonder if maybe it's a c type or something weird like that, as it does seem to really have a difference in that last bit of turn. Anyways thank you. I'm just going to fine tune it for now and hopefully get it committed to vero and boxed up.
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.
What that suggests is some 'interplay' between your volume pot and the fuzz input. The LPB is raising the input impedance of the fuzz (and boosting the signal of course!). Have you biased the fuzz, adjusted the transistor voltages?
One thing that just occurred to me is that if the bypass cap isn't connected properly, you'd have far less gain - I just wonder if something could be going on there. Maybe take a look around the 1k pot and make sure all is wired right, and also be sure the pot taper is a "B" taper...just a thought.
It does have a 1kC style pot for the fuzz control which makes the taper less than ideal. My understanding is it should just effect the taper. I have new pots arriving today so I'll change that out, the original directions from small bear call for a reverse audio which is why I used that. I've got the collector of q2 transistor biased at 4.6 but the volume thing was happening with all transistor combinations I tried before I settled on the 2 2n2222a's. I'll try the pot thing out tonight hopefully that changes it. As far as the wiring I'm pretty sure I've got everything right I've gone over it several times literally made a second one on another breadboard I had, did use same pot though same thing.
Thanks for the direction.
Let's see what's happening here.. :icon_wink:
100k feedback resistor interacts with input signal impedance, setting Q1 stage gain..
(just lift it from Q2 Emitter and place it on Q1 Collector)
Overall FF gain formula is complicated a bit but, in general terms, it can be tweaked by altering R1/Rsource ratio (besides VR1 pot)..
LPB-1 output impedance is considered about 10k so you need a similar resistane pot - in case of your FF build is correct..!!
Could you plz post some voltage measurements..??
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.
Hey guys I'll post some voltage measurements tonight. I made a little audio probe last night and was thinking I'd probe the signal tonight to see if there's a point where it loses the volume. I know off the top of my head q2 collector is between 4.6-4.7, base is right around .5 I don't remember the emitter. The q1 collector was i 1.17 and the emitter was 0 I don't recall the base. Both are 2n2222a right around 200 hfe. Q2 was slightly higher than q1.
Here are the voltages
First is q1 c-b-e then q2 c-b-e
1.38
.57
0
4.69
1.38
.76
You got some weird voltages there, but hang on, I think maybe someone INTIMATELY familiar with yer fuzz might happen along soon!
Yes they are weird when I look at what the electro smash page says on voltage. I'm going to play around with r4's value as the collector and emitter voltage from q2 are pretty close to recommended 4.5, and .5 recommended but too much of that .5 is making it back around to the base and I'm already running 150k there. I'll just keep going until that gets to .2 as well as I guess keep upping the 33k feeding the collector of q1. But those values will be no where near regular by the time I get there. Seems like I have to be doing something wrong here lol
Hang in there bud...help WILL be coming, LOL....just takes some time for your problem to be seen...
Well I figured it out and I'm a little embarrassed to :icon_confused:say what it was. I always work on my pedals after the kiddos go to bed. Amp is on 2. It's fine for everything I do, and typically I can turn the volume knob down some no issue. Well amp at 3 I can turn down all the way it sounds fine and cleans up nicely. I feel a little silly now. Still doesn't explain the weird voltages. I tried a 470k in place of the 100k and it didn't really effect base voltage at c1 at all.
Quote from: Locrian99 on June 24, 2022, 10:58:16 PM
Yes they are weird when I look at what the electro smash page says on voltage. I'm going to play around with r4's value as the collector and emitter voltage from q2 are pretty close to recommended 4.5, and .5 recommended but too much of that .5 is making it back around to the base and I'm already running 150k there. I'll just keep going until that gets to .2 as well as I guess keep upping the 33k feeding the collector of q1. But those values will be no where near regular by the time I get there. Seems like I have to be doing something wrong here lol
if your Q1 has emitter at ground, a silicon transistor base can't be anything but 650mV, plus/minus a few. you'll never get it to 200mV, unless you switch to germanium. I think yer volys measured is good for Si, try messing w/ bias on Q2, see if you find a bias point you like, and leave it there. don't worry about the voltages [after you've measured and recorded them] .
What duck_arse said.. :icon_wink:
Q1 Collector voltage calls for about 230μA quiescent current, which in turn calls for about 1.9μA Base current (hFE = 120)..
That current creates a voltage drop of 190mV across R1 (100k) which is accordance with Q2 Emitter voltage minus Q1 Base voltage..
(actually, hFE of 120 comes as an estimation after your measurements.. :icon_wink:)
What puzzles me is Q2 Collector voltage 'cause for a 760μA Emitter current (.76/1k), Collector should sit at about 2.5V [9 - (0.00076 X 8530)]..
Are you sure for R4 "correct" value..??
I'm running a 5.6k resistor at r4 to get it to the 4.69.
If so, ALL your voltage measurements are FINE..!! :icon_wink:
So, to recap.. What's your issue..??
At this point there isn't one anymore. The volume thing was my issue, which was operator error in the end. I just got done doing some more tinkering on it decided I liked a 2n4123 better in q1. Had to change r4 to a 3k and 680 in series surprisingly to me I could tell the difference between the 3.9k sitting at 4.45v and the two in series sitting at 4.63v with my ears. I was surprised I hadn't change r4 with the change to q1. Went with 150k for r1 sounded better. And put a 680pf cap between the base and collector of q2. Sounds good to my ears at this point. Thank you guys for all your help and ideas here. I'd say this is ready to move from the breadboard to vero which I'll start hopefully tonight.
Ended up finding a vero layout with a bmp tone stack with the millers caps so Added that to the breadboard to try it and liked it so put it all on vero and works great for it boxed up. First not kit and first vero pedal for me. Butchered the paint job on the enclosure I was going for, it looks like my first attempt at it lol. Anyways thanks for the help guys. Is there a way to mark the thread closed or solved.
Good work, Locrian. You don't have to mark the thread any way - it will disappear as new topics are added. There are even topics on paint, BTW, lol.
Quote from: Locrian99 on June 27, 2022, 03:44:21 AM
Is there a way to mark the thread closed or solved.
The easiest way is by begging on your knees (equipped with some bottles of fine cider, also)
duck-arse to settle your wish.. :icon_wink:
glub glub glub, yeah, ok, it's glub glub closed.
Are you SURE?
Cool, everything I build sounds good to my ears too.
And that is what diy is all about..the final test, the ole vestibulocochlear nerves. (old in my case)
Hunh
Quote from: antonis on June 27, 2022, 08:29:08 AM
Quote from: Locrian99 on June 27, 2022, 03:44:21 AM
Is there a way to mark the thread closed or solved.
The easiest way is by begging on your knees (equipped with some bottles of fine cider, also) duck-arse to settle your wish.. :icon_wink:
still think there should be labels or flairs a moderator can add to a thread to mark it as [solved] [de-railed] or a few difficulty categories to denote the level of the circuit(s) in question
cheers
Quote from: iainpunk on June 28, 2022, 07:14:27 AM
still think there should be labels or flairs a moderator can add to a thread to mark it as [solved] [de-railed] or a few difficulty categories to denote the level of the circuit(s) in question
As usual, you DO insist for half-arsed works, like almost all of yours, Iain..:icon_mrgreen:
(I tend to presume that's a bombed city residents feature..) :icon_razz:
I lived thru the 70's once - I don't want to be wearing flairs again.
and how do we know a derail when we see it - when most of the time, we cause it?
(https://live.staticflickr.com/825/42161122452_da7ae1a654.jpg)
Texting while driving is hazardous.
You might get derailed.
(https://i.postimg.cc/mh3gRJkS/1880s-steam-locomotive-derailed-fullsize.jpg) (https://postimg.cc/mh3gRJkS)
Well I had some issues with pedal cramming all 4 pots etc into the enclosure was fine until I tried to put the back on (also I bought the 1590b enclosures not realizing the 125b was just a little larger) Decided to redo my pot wiring and man did I screw up, was trying to hurry while the wife had the kids at her sisters lol. Apparently I managed to somehow ground everything in my screw up. Both input and output tips on the jacks I can put my black lead to, place read lead on + and I get 9 volts. Every pin on the 3pdt too. So I looked at everything I've got a couple pot leads I've noticed are wrong which I'll fix. My big screw up is I added the "smooth" pot to the input, 1 would go to the 3pdt and 2 would go to the board input lug 3 does nothing worked great. Well I got myself confused and put heatshrink over lug 1 and ran lug 3 to the 3pdt. And that was the long winded way to my question. I haven't decided if it's worth redoing that part if it's just going to cause the taper to be backwards, which I think is all it would do. Is that the case or would that cause other issues. Thanks guys, and next order 125b and enclosed jacks for sure!
Argh well all the pots are wired back correctly. No audio from the audio probe at input jack and the tip still appears to be grounding out to me. Along with everything else on the 3pdt. I am correct in that I should get 0 volts with the black lead on the tip of the jack and red lead at 9V+ right?
at the in and the out jack tips, you should always read 0V DC, or only a bit of a millivolt.
K. Am I correct that since the black probe is on the on the input tip and red to +9v (in this case I'm reading at my dc jack or the boards +9 that it's is grounded?
By placing BLACK probe on to power jack GND (0V) and RED probe ANYWHERE outside PCB, you should read 0VDC..
(provided In & Out DC blocking caps, of course..) :icon_wink:
(https://i.imgur.com/6rz8zgi.gif)
I'm not sure what it is you are trying to measure at the tip_in and +9V. generally speaking, in the pedal universe, we reference to ground [that is, put the black probe to ground (whether positive ground or negative ground)], and then poke at the DC parts of the circuit with the red probe [which will result in minus voltage readings w/ positive ground, and which will indicate correct method].
the sleeve of the jacks is always ground. the tips of the jacks are always considered AUDIO parts of the circuit, not DC parts of the circuit.
Thank you guys, I'm a bit confused on what was happening there. I didn't change any wiring and for some reason I was getting what appeared to me to be voltage at the tip of the input jack my reason for measuring this was I was getting jo audio signal there with the audio probe. I found a book im reading through a chapter on this portion to understand it better. As I was getting confused as to what was happening and apparently my issue was either unheard of or I wasn't searching correctly for it.
Antonious I understand there are different ways to wire the 3pdt. I was using this one: http://1.bp.blogspot.com/-k5Sh68yVU18/TzGRFKbiALI/AAAAAAAAAlk/CbfaaduUjYQ/s320/%21Offboard+wiring.png
You mentioned the dc filter cap is that is basically just preventing any voltage from finding its way back to switch?
This circuit is getting frustrating, it was working fine until I tried the screw the back on the enclosure. I had to force it a little. Spent more time on it last night, was getting no guitar signal, there was a fair amount or "noise" and turning the fuzz and tone pots seemed to affect it. Checked voltages first and was reading just over 1 volt at the q2 collector, also noticed a couple questionable solder joints so I fixed those and replaced the q2 collector resistor with another 5.6k. Thought it was weird that I was getting such low voltage now as I had it at 4.69-4.7 before so I check the resistor ohm reading after it was off the board and I got 5.57k which seems about right 1% tolerance plus whatever I'm getting from my probes and alligator clips. I Had the voltage back to 4.7, had kind of a muffled sound, that sounded fairly clean though. But for sure a lot of noise in front of it if that makes sense. In my twisting and turning of the circuit I broke one of the solid core wires to to the tone pot, I replaced it with stranded and got out the audio probe. Followed the signal it sounded good from the input clean tone. Jumped over and checked at the q2 collector/base emitter all have sound all sound clean. Etc etc audio everywhere but it's clean. I hook the output of the board up again to try it out, and I've got a nice clean tone without all the noise. But I was making a fuzz! I check the voltages again just because we'll it seems like the thing to do. Q2 collector is now reading 8.8, but it was just 4.7 and I've done nothing to anything near there on the board. I check other spots in the board everywhere I'm getting 8.8. Where the 33k comes off the 9v check the other side I'm getting 8.8. Here's the vero layout I used. https://2.bp.blogspot.com/-nPaHDtR-WzI/U0lTqr3hJjI/AAAAAAAAGsI/W3wd1dkZ9CY/s1600/NPN+Fuzz+Face+with+BMP+Tone+Stack+2.png
Oh the volume knob works, the tone knob works but the change doesn't seem as drastic but that might just be in my head. Fuzz doesn't really do anything that I can hear. I don't understand what could be causing those voltage swings, and I'm feeling somewhat confident that is why I'm not getting any fuzz. Prior to putting the board together I checked for continuity with the multimeter to make sure my cuts were good. And I've examined the strip side pretty well to make sure there are no solder bridges between the strips. I didn't see any couple places I run and exacto knife through a few times just to make sure.
To be honest, I'd try a brand new build.. :icon_wink:
(after all, it's just a 12 X 9 stripboard..)'
edit: Just a moment..
Do all the above happen with curcuit still on breadboard..?
It's on strip board. I was leaning towards making a new I was just hoping I'd have that a-ha moment Looking at it as to what was causing the problem. Just seems so weird that it's doing what it's doing. Thank you again for the suggestions. I was debating even posting what I had going on, I was pretty determined to figure it out last night. I just didn't get it how the voltage would change like that.
:icon_smile: :icon_smile: :icon_smile:
Twisting and turning doesn't help a ciruit's health, does it..?? :icon_wink:
Topped(8.8V) or bottomed(1V) Q2 Collector calls either for cut-off (perhaps due to "open" Emitter) or saturated (perhaps due to "shorted" Emitter) working region..
Could you plz take some measurements on Q1 Base & Collector..??
(the later should be identical to Q2 Base voltage..)
I swear this thing is changing voltage every time I check it which leads me to believe I have some cold solder joints etc that are intermittently connecting. When it is reading the 4.7, q1 collector and q2 base are off by .2 volts. It's time for me to just start another piece of perf board and give this a fresh start. I've soldered, removed solder, etc etc on here too many times in a few spots I feel like anyways.
as antonis always sez, don't make duck ask for photos. why no photos of your stripboard build yet?
also, to save me another posting - did you test your soldered build before you put it in the enclosure? have you tried dissassembling it from the enclosure and testing it on the bench?
I guess I could've posted pictures of the strip board. It worked outside the enclosure. Worked everything wired up in the enclosure. Then I tried to screw the back of the enclosure on and kind of make it fit. It no longer worked. Then I rewired my pots as things were tight and looked like thag could be an issue. Then I had weird (to me at least voltage at the input tip and no sound in bypass. So I took it out and have been testing it outside again. Which is where I was able to get the just clean tone passing through. I keep getting different voltage readings at different points constantly. So I think I'll just as Antonious suggested start over on a new piece of strip board before that though I'm making up an actual test box rather than just some jacks and power ran to a terminal strip sitting on my bench. Hopefully I'll get that done start fresh wire inside of the enclosure cleaner and be much more careful about forcing this time and have learned a couple lessons from this one.
Quote from: Locrian99 on July 02, 2022, 01:11:43 PM
It worked outside the enclosure. Worked everything wired up in the enclosure. Then I tried to screw the back of the enclosure on and kind of make it fit. It no longer worked.
Those enclosures which ought to be hermetically closed have caused countless issues.. :icon_wink:
(honestly, no irony at all..)
Yea I should've just stopped and strategized the wiring better. I think that will be a focus on attempt #2. And using stranded wire at least for the pots.
Here is the stripboard in case you guys spot something obvious before I start my 2nd attempt.
(https://i.postimg.cc/18CFv3FQ/820-DB6-CC-8-E73-4-A1-A-816-F-A5900254-A0-A6.jpg) (https://postimg.cc/18CFv3FQ)
(https://i.postimg.cc/DSysQX86/9-CA24926-D558-431-A-8-EB6-F9-CF85073-C14.jpg) (https://postimg.cc/DSysQX86)
Quote from: Locrian99 on July 02, 2022, 07:42:29 PM
Here is the stripboard in case you guys spot something obvious before I start my 2nd attempt.
(https://i.postimg.cc/18CFv3FQ/820-DB6-CC-8-E73-4-A1-A-816-F-A5900254-A0-A6.jpg) (https://postimg.cc/18CFv3FQ)
If your stripboard was this tarnished before you started soldering, then you likely have some dodgy joints. The copper needs to be shiny pink before you start. Try not to touch it with your fingers once it's cleaned.
I like to clean them with #0000 steel wool prior to soldering. If you want to go an extra step, after that wipe the copper w/acetone to remove any 'process oils' and any that may be in the wool.
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
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.
(https://i.postimg.cc/FkzxzSWs/461-C4773-2-E11-4-D71-B5-B9-03-E0-B24-B1-DB9.jpg) (https://postimg.cc/FkzxzSWs)
Quote from: Locrian99 on July 03, 2022, 10:44:27 AM
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! ;D
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.
(https://i.postimg.cc/TLJph3Fh/52-EAB5-D8-3763-4981-ABCA-BA884-E3-C164-C.jpg) (https://postimg.cc/TLJph3Fh)
(https://i.postimg.cc/9wXz9jHb/7411-F7-E5-450-C-4883-A5-F7-002-AC23-C3-ED5.jpg) (https://postimg.cc/9wXz9jHb)
(https://i.postimg.cc/Vr8JYC73/A7866755-1-CDE-47-BB-BD6-B-F6-DA353-DA239.png) (https://postimg.cc/Vr8JYC73)
(https://i.postimg.cc/xq9XhLNm/FCD58-E57-F18-D-447-F-9-FDC-15-E4334899-A1.jpg) (https://postimg.cc/xq9XhLNm)
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.
(https://i.postimg.cc/XG6YGDRq/4-D198-C8-B-3-A95-4-ABD-8-C2-B-6-A16-EDA1042-E.jpg) (https://postimg.cc/XG6YGDRq)
(https://i.postimg.cc/nXMz6mKF/50-E670-D6-2448-408-C-BDA9-DFF7374-C4357.jpg) (https://postimg.cc/nXMz6mKF)
(https://i.postimg.cc/SjrxRdDQ/894-E9-B12-2-B71-42-EE-8-DC7-2-BBF1-BC422-F8.jpg) (https://postimg.cc/SjrxRdDQ)
(https://i.postimg.cc/z35fq6wP/D5-B8-FCA4-426-F-4-B41-A123-21387-EE75-D5-A.jpg) (https://postimg.cc/z35fq6wP)
(https://i.postimg.cc/MfWZtfK8/F51-B6-CA0-DA2-E-4811-8-BE9-A83-A0-E2-C46-B9.jpg) (https://postimg.cc/MfWZtfK8)
Also just to check it. Hooked test box up to breadboard that I had an lbp-1 set up on and that worked fine.
Quote from: PRR on July 04, 2022, 04:06:47 PM
Quote from: Locrian99 on July 04, 2022, 03:14:57 AM
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.
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
Suspect hides somewhere around those 8 pads.. :icon_wink:
(https://i.imgur.com/zlpiKHh.jpg)
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.
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?
(https://i.postimg.cc/2bLsQ0FL/68-ABA7-F3-217-C-4-A95-85-A2-ACF0-ADBC56-F6.jpg) (https://postimg.cc/2bLsQ0FL)
(https://i.postimg.cc/ppK2bLj5/805414-DC-6669-4392-B3-A1-1-BF96155809-B.jpg) (https://postimg.cc/ppK2bLj5)
(https://i.postimg.cc/5HrcQhvM/B582835-C-3681-4226-830-A-449227-B8-B54-D.jpg) (https://postimg.cc/5HrcQhvM)
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?
(https://i.postimg.cc/qzYb3qsb/04-D5061-A-B04-D-4-EBC-A036-126-B82-F36399.jpg) (https://postimg.cc/qzYb3qsb)
(https://i.postimg.cc/vgQ3sVyB/A4528210-6-E94-4543-BDAB-804-F6-A2-A0157.jpg) (https://postimg.cc/vgQ3sVyB)
Doh I didn't realize I had to have the fuzz pot hooked :icon_biggrin: 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! :icon_biggrin:
Quote from: Locrian99 on July 06, 2022, 03:21:31 PM
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.. :icon_wink:
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.. :icon_wink:
EDIT: Don't mess with above numbers.. Just follow diagram below..
(https://i.imgur.com/LuantUF.png)
Nothing to add..
Just to overcome "6666" posts.. :icon_twisted:
Quote from: Locrian99 on June 22, 2022, 01:58:58 AM
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.....:
Quote from: anotherjim on June 24, 2022, 10:38:36 AM
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 ;)
Quote from: pinkjimiphoton on July 22, 2022, 02:53:11 PM
Quote from: Locrian99 on June 22, 2022, 01:58:58 AM
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.