Author Topic: So where did I go wrong??  (Read 5807 times)

Tinman402

So where did I go wrong??
« on: December 20, 2011, 07:35:59 AM »
I followed the instructions.. I have modded amps and pedals before but never built one from scratch...

the outcome.... I get perfect sound in bypass mode, but as soon as I click the boost on the volume drops drastically even with the drive all the way up.. IF the drive is all the way down, I get the local am station perfectly..lol

I mounted it in a plastic box, did not cross the input and output wires and used a 2n2222a transistor...

Is there anyway to add volume to this thing.. I like the sound when thhe drive is all the way up, but I have to crank the amp half way up to even get the same volume I would get at 1/8 of normal amp volume...

Guide me ol wise ones...

Govmnt_Lacky

Re: So where did I go wrong??
« Reply #1 on: December 20, 2011, 07:40:26 AM »
1) Check your circuit for "Ground loops." Try star grounding to eliminate the AM radio (Google "Ground loop" and "star grounding")

2) You will want to mount the circuit in a METAL enclosure. The plastic enclosure will allow outside interference in the circuit.

This project is a PROVEN working unit. There must be something wrong with the build. Also, try here:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Follow the steps and repost.

Good Luck! You will get it fixed!!!
 ;D
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of ‘up to and including my life.’

Tinman402

Re: So where did I go wrong??
« Reply #2 on: December 20, 2011, 08:07:30 AM »
Thanks for the quick response.. I will try the star grounding and check all the voltages when I get back to the house... I never thought about the plastic being a issue.. I have 2 metal enclosures so I will relocate to one of them as well..

Great site you guys got here.. I was looking for a Fuzz schematic when I stumbled on this and thought this would be a great project to start my journey into gear making..lol

.Mike

Re: So where did I go wrong??
« Reply #3 on: December 20, 2011, 10:16:11 AM »
the outcome.... I get perfect sound in bypass mode, but as soon as I click the boost on the volume drops drastically even with the drive all the way up.. IF the drive is all the way down, I get the local am station perfectly..lol

Just to be sure, double check that you have the transistor oriented properly. The booster will still pass sound if the transistor is flipped around, it just won't boost, which is kind of the point... heh.

It's been a while, but I remember my booster being a radio when I first built it. I think the solution was to put a 10k resistor in series with the input, but I would have to look to be sure. I think I posted about it.

Good luck! You'll get it working. :)

Mike
If you're not doing it for yourself, it's not DIY. ;)

My effects site: Just one more build... | My website: America's Debate.

aron

Re: So where did I go wrong??
« Reply #4 on: December 20, 2011, 12:37:58 PM »
It sounds like it's not biased correctly. Please check your voltages on the pins of the transistor.

Tinman402

Re: So where did I go wrong??
« Reply #5 on: December 22, 2011, 12:28:43 PM »
Thanks for all the good info and thre link to the DEBUGGING thread.. I think I found my issues...

First the metal case killed the AM radio... As cool as it would have been to have some old hank comming thru on my solo I just don't think it would do hank justice...

Second.. My voltages were all off... I have plenty of stuff to make another board so I am going to start over and I built a test stand so I can test as I go... This website rocks.. I have always been a DIY guy.. From cars to furniture... Electronics are somewhat new to me but I am quick to catch on to things...

I will let you know how round 2 with the boost turns out..

Tinman402

Re: So where did I go wrong??
« Reply #6 on: December 22, 2011, 05:11:42 PM »
OK so after rebuilding here are my voltage values

C- 8.86
b- 2.80
e- 3.12

???

I followed the schematics perfectly...

.Mike

Re: So where did I go wrong??
« Reply #7 on: December 22, 2011, 05:57:12 PM »
Hmm.

The collector is too high, and the base should be roughly 0.6v above the emitter.

Could you take some photos of your build? :)

Mike
If you're not doing it for yourself, it's not DIY. ;)

My effects site: Just one more build... | My website: America's Debate.

Tinman402

Re: So where did I go wrong??
« Reply #8 on: December 22, 2011, 09:45:09 PM »
Top:


Bottom:


That is just the board... Basically I used the legs of the components to make the traces.  The yellow wire is the input, the red 9v+, the black ground, the light blue closest to the tranny is to the drive and the other light blue is the output..
« Last Edit: December 22, 2011, 09:48:46 PM by Tinman402 »

Tinman402

Re: So where did I go wrong??
« Reply #9 on: December 22, 2011, 10:17:17 PM »
I used a 2n3904 tranny.. I can switch it for a a 2n2222a or 2n4401... I also have some pnps.

Do I have a bad joint do you think or how do I bias the tranny better...

.Mike

Re: So where did I go wrong??
« Reply #10 on: December 22, 2011, 11:31:59 PM »
It's really hard to tell anything from the tiny pictures, but I did try to trace it out against the schematic.

Input is the yellow wire, output is the blue wire closest to the edge, black is ground, red is +9V, and the blue wire in the middle of the board runs to the potentiometer. Is that right? If so, where does the potentiometer/capacitor connect to ground? I don't see it, so on the jack, I suppose.

If I am correct in my understanding of what is what, I think you might have your transistor in backwards. When holding the transistor with the flat part facing you and the pins down, it is E B C left to right for 2n3904. If I traced it right, the capacitor that connects to the blue wire nearest the edge is supposed to be connected to the collector. I think it is connected to the emitter. Please double check.

:)

Mike
If you're not doing it for yourself, it's not DIY. ;)

My effects site: Just one more build... | My website: America's Debate.

Tinman402

Re: So where did I go wrong??
« Reply #11 on: December 23, 2011, 01:22:24 AM »
Ok so I swapped the tranny and gorunded the pot... I didn't think about it really be a part that had to be grounded to complete the ciruit... :doh:

Now I get

C = 4.5
B = 2.97
E = 2.41


Do I have to have the jacks wird in as well.. I thought I would test the board without all the off board stuff...

Also forgot.. yes  the 47uf is on the pot..
« Last Edit: December 23, 2011, 02:24:32 AM by Tinman402 »

Tinman402

Re: So where did I go wrong??
« Reply #12 on: December 24, 2011, 02:04:44 AM »
Working perfectly now.. The debugging thread was the right direction.. Once everything was mounted and retested voltages seem to be in range and it responds how it should.. Boost to about 2 o clock on the dial and a fuzzy distortion the rest of the way.. A pleasant fuzzy though... Kinda raunchy..  :icon_twisted:.. Glad I mounted the socket so I can check the other trannys I have.. Can I run the pnp by just turning them backwards? :Noob out: