Trouble with volts going from breadboard to turret with a fuzz face

Started by scotheath, January 04, 2023, 01:17:47 PM

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scotheath

A year ago I used a bread board and put together a basic fuzz using step by step guide from Smallbear.
http://diy.smallbearelec.com/HowTos/BreadboardSiFF/BreadboardSiFF.htm
Tinkered with it on and off for a year replacing resistors caps and transistors, finally settled on 2 SI transistors and got Q2 collector to 4.51v.using a 6.93k resistor instead of the 8.2.
Ordered turret board from Amplified parts cut to size and transferred all components using this layout that is all over internet.
.
I have reversed polarity of electo caps as I did on bread board. For the life of me I can not get less than 9.52v at collector of Q2.
I've got 9.52v at 9v in, through both resistors leading to Q2. I stared at this this for an hr last night trying to figure it out. I'm lost. Was gonna start tearing apart last night but thought I'd sleep on it and ask here. Am I missing something about the transfer from breadboard to turret ?
This is my first attempt at a turret build.

johngreene

Quote from: scotheath on January 04, 2023, 01:17:47 PM
A year ago I used a bread board and put together a basic fuzz using step by step guide from Smallbear.
http://diy.smallbearelec.com/HowTos/BreadboardSiFF/BreadboardSiFF.htm
Tinkered with it on and off for a year replacing resistors caps and transistors, finally settled on 2 SI transistors and got Q2 collector to 4.51v.using a 6.93k resistor instead of the 8.2.
Ordered turret board from Amplified parts cut to size and transferred all components using this layout that is all over internet.
.
I have reversed polarity of electo caps as I did on bread board. For the life of me I can not get less than 9.52v at collector of Q2.
I've got 9.52v at 9v in, through both resistors leading to Q2. I stared at this this for an hr last night trying to figure it out. I'm lost. Was gonna start tearing apart last night but thought I'd sleep on it and ask here. Am I missing something about the transfer from breadboard to turret ?
This is my first attempt at a turret build.
Your drawing shows -9V in. You should have that connected to battery -. If not, then you have your power supply connected backwards.



I started out with nothing... I still have most of it.

scotheath

Yes I have power connected there and have my electrolytics reversed.

johngreene

Quote from: scotheath on January 04, 2023, 02:02:43 PM
Yes I have power connected there and have my electrolytics reversed.
Please use the correct polarity when reporting your measurements as it makes a difference in determining what the issue may be. For example: If the collector of Q2 is actually -9.52V, then the transistor is open and increasing the value of the 8.2k collector resistor should eventually bring it into range. If it was actually +9.52V then that is ground in this circuit which means the transistor is likely shorted which is the opposite problem. However, in that case I would imagine there would be around a 1V drop across the 1K pot in the emitter. If there isn't a short somewhere else. But saying it is -9.52V eliminates any question.
So, try increasing the value of the 8.2k by temporarily replacing it with a pot if you have a 10k-50k handy. 100k in a pinch. If you cannot bring it down that way then there is likely something else so voltage readings around the rest of both transistor pins would be helpful.
I started out with nothing... I still have most of it.

Kevin Mitchell

What transistors did you choose? Are the pinouts correct in comparison to your layout?
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scotheath

I got it figured out. I was so concerned with the +4.5v at Q2 collector I didn't connect either pot to board before testing.
Re populated breadboard and tested w/ out 1k pot and... same results, +9.52v at Q2.
I used a 3904 at Q2 at a Bc108 at Q2 and also used a 1 k reverse log for fuzz pot per the smallbear page  way more sweep.
Thanks for all the input

PRR

> I didn't connect either pot

I was gonna say.... THE reason for 9V at Q2C is forgetting to connect the 1K emitter pot.

Glad you found it!
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