Author Topic: question relating adding distortion to the booster  (Read 12499 times)

bazzwazzle

question relating adding distortion to the booster
« on: August 28, 2004, 02:35:57 AM »
Can i put the diodes right after the output cap, but before the 100K resistor?

remmelt

question relating adding distortion to the booster
« Reply #1 on: August 28, 2004, 01:24:05 PM »
yeah, just put the diodes after the cap. see also here: http://www.diystompboxes.com/pedals/lava2.GIF. same basic idea.

kingnimrod

question relating adding distortion to the booster
« Reply #2 on: September 08, 2004, 11:47:08 PM »
I get the concept, but am having a little trouble figuring out how to add the diodes with a DPDT switch into the circuit. Can someone post a diagram of how that works within the booster circuit? How would you add a second LED to that arrangement?

I have a micro dpdt toggle switch that I'd like to use for this.

aron

question relating adding distortion to the booster
« Reply #3 on: September 09, 2004, 03:32:30 PM »
Can you explain a little more on what you want to do with the mini-DPDT?

kingnimrod

question relating adding distortion to the booster
« Reply #4 on: September 09, 2004, 04:29:36 PM »
I have a feeling I am going to put this together the wrong way, so that's why I'm asking. Your build pictorial and the subsequent diagrams on wiring this stuff was incredibly helpful. Where I get confused is:

1) where exactly on the board to solder in a socket for these diodes

2) how to wire it into the rest of the circuit with a switch that turns the distortion off and on, plus an LED to indicate that distortion is engaged.

one other question - how varied will the distortion be if I try different diodes?

By the way - I just recently stumbled onto this site after looking for references to help me fix an old delay pedal, and now I've got the pedal-making bug. I just ordered a few of the 3pdt switches last night - can't wait to get them.

kingnimrod

question relating adding distortion to the booster
« Reply #5 on: September 09, 2004, 04:34:55 PM »
oh yeah, forgot - the switch I want to control the distortion with is either a micro-toggle dpdt switch from radio shack, or a momentary stomp switch (maybe spdt??? dunno). Which would be better?

aron

question relating adding distortion to the booster
« Reply #6 on: September 09, 2004, 06:48:52 PM »
see if this picture looks like what you imagined.

The DPDT is the mini-DPDT or you could use a DPST (ignore the other lugs).


kingnimrod

question relating adding distortion to the booster
« Reply #7 on: September 10, 2004, 09:23:28 AM »
thanks - very helpful. However, I have a problem - The switch lights up the LED, but there is no distortion. The wiring looks OK, but I'm wondering if there's something wrong with the diodes. I twisted them together on one side and soldered - then plugged the loose ends into a 2-pin socket I put on the board.

Also, I have a question about the range control. turned all the way up, the range knob provides a slight treble boost, but it's very subtle. Is it supposed to be really noticeable? I would compare it to about 1/2 a turn on a guitar's tone knob. The .68uf capacitor is this really big yellow cylindrical mylar thing...

aron

question relating adding distortion to the booster
« Reply #8 on: September 10, 2004, 01:45:37 PM »
I would imagine the range control to be subtle. Try different cap values to make more of a difference.

As for the diodes, do you have them "back to back" and reversed in polarity? What kind of diodes did you use?

kingnimrod

question relating adding distortion to the booster
« Reply #9 on: September 10, 2004, 06:16:42 PM »
I wired the "top" of one to the "bottom" of the other -- twisted the ends together and soldered it - leaving two free posts to plug into the socket.

To tell the truth, I'm not sure what kind of diodes- i asked the guy at the electronics store to give me a couple that are good for distortion.

At this point, I'm probably going to go out and buy some more to see if that's the issue. These are so battered from pulling out and switching around so many times I may give up on them. Of course, maybe it's a wiring issue.

At any rate, the booster works and sounds cool - I will go out and get some more caps for the range control to see if I can get something more noticeable.

By the way - I am using the "cheapo" radio shack transistor in this circuit and it works fine.

aron

question relating adding distortion to the booster
« Reply #10 on: September 10, 2004, 07:44:22 PM »
There should be a level change as you kick the diodes in. Does it drop in volume when you do that? If so, they are probably "working" just not distorting as much as you might want.

kingnimrod

question relating adding distortion to the booster
« Reply #11 on: September 10, 2004, 10:15:20 PM »
There's no change to the signal at all - Is that more indicative that there's a wiring issue or a problem with the diodes?

I made another stop at the 'shack this evening for some stuff and picked up a 10 pack of silicon diodes and a 22uF cap to try on the range control.

can't wait to get that switch and get this thing boxed up!

kingnimrod

question relating adding distortion to the booster
« Reply #12 on: September 10, 2004, 10:24:54 PM »
well, looks like I just answered my own question - stuck in 2 new diodes and still the same - looks like I need to desolder and clean up the wiring on the board and retry....

aron

question relating adding distortion to the booster
« Reply #13 on: September 10, 2004, 10:51:37 PM »
Well one end of the pair of dioes should touch the "signal" line. The other end should touch ground. Once connected, you should hear a drop in signal volume.

bazzwazzle

question relating adding distortion to the booster
« Reply #14 on: September 11, 2004, 12:47:27 AM »
so this means whenever i put the switch on the volume will become lower? Is there any way to fix that?

aron

question relating adding distortion to the booster
« Reply #15 on: September 13, 2004, 12:54:41 AM »
Well, given that the diodes _will_ clamp down -there are  2 ways to "fix" this. Put a level recovery stage after the diode which will bring the volume back up when the diodes are kicked in, or put more diodes in series until you get a decent level you can live with and then pad the output when the diodes are not switched in.

bazzwazzle

question relating adding distortion to the booster
« Reply #16 on: September 13, 2004, 09:20:59 AM »
Quote
pad the output when the diodes are not switched in.


What do you mean by this?

aron

question relating adding distortion to the booster
« Reply #17 on: September 13, 2004, 02:01:59 PM »
You could switch in a pot when the diodes are not in. However, this is like disabling the boost function somewhat.

kingnimrod

question relating adding distortion to the booster
« Reply #18 on: September 14, 2004, 07:41:52 PM »
okay, I still need help. I've desoldered and resoldered the distortion section in a couple of times, but there is still zero effect when I switch it on.

Please tell me if there's something wrong with how Im doing this part:




if i switch the diodes going the other way, still the same thing....


HELP!!!

aron

question relating adding distortion to the booster
« Reply #19 on: September 14, 2004, 08:08:31 PM »
OK, looks correct now you do know that the diodes will only kick in when the drive is turned up enough to turn on the diodes right? That means you need to have the drive knob up enough OR use low threshold diodes such as germanium ones.