Stacked Triple LPB-1

[rthryhorysak]

Will this work? I am thinking the gain knob is just pushing into the 3rd LPB. I heard that the Dwarfcraft She Fuzz was 3 LPBs, so anyone know what this will sound like, hopefully like a fuzz? Do I not have to connect the 9v because they are on the top few rows?




There is also this layout which looks more accurate the LPB and the She Fuzz, but I don't know how you would connect 3 of them with a gain and volume, so if someone could help me with that, I would appreciate it.

[duck_arse]

your top layout won't work. the input line seems common to all three stages. I can't follow the output. the gain pot can't be connected to two stages unless it is a dual pot. there are simpler ways to do this, start by finding a circuit diagram for the lpb1. then follow through from input to output 1st stage, feeding input 2nd stage. output 2nd stage into input 3rd stage, 3rd output to the real world.

once you have a circuit diagram, you can worry about doing a vero layout. this is as easy a project as you will find to learn with, then you can name it something good, like "rocket frog", maybe.

[nocentelli]

http://www.diystompboxes.com/smfforum/index.php?topic=81179.0

Check out Rick Holt's Assassin of Silence. The vero at the top of the thread seems to be an attempt at adding another Q1 stage in front, using a dual gang pot to control the overall fuzz level by simultaneously controlling the level sent from the first stage to the second and the level from the second to the third. I'll wager three stages will be extremely hissy, noisy and self oscillating. If that's the case, you could try the BMP trick of a small (200p?) cap between collector and base on each of the transistors.

[peterg]

I built a fuzz using cascaded LPBs. I'll dig up the schematic over the week end.
http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg979348#msg979348

[nocentelli]

Beautiful build, please do post the schem as I'm interested in the blend part.

[bluebunny]

Jimi's Lardacious Phat Bastard is also something similar.

[rthryhorysak]

Ok, how is this? Sorry its kinda messy, this is one of the first times I've drawn up a schematic. I added a diode based on how people were modding their lpb-1s. Also I kept in the 1st and 3rd volume control. I was thinking the 1st volume would be how hard it was being pushed into the last 2. Will the volume ever be at zero, or is it like the lpbs were no boost is about unity?

[GibsonGM]

I would breadboard it and see how it sounds. It LOOKS ok...can't tell ya what kind of fuzz you'll get.  The GAIN control (1st "volume") will silence the thing when it's all the way to ground - will short the signal to ground.  You can avoid that by using a fixed resistor to ground AFTER the pot and before ground.   10K maybe?   This is just for drive, anyway - the other end of the pot is more important

The "?" resistor...seems like you'd try a few "to taste".  It will drop voltage with the 1M pulldown following it, reducing the drive to the last stage - Not sure those 1Megs are entirely necessary after the 1st one, but hey - you can work it to your advantage...adjust 1M to taste, too, maybe put a 220K or 100K in that spot after "?" to make dividing (attenuating the signal) here easier.     Why just the one diode?  Someone trying assymetrical clipping with the old LPB?  You can add another, opposite polarity, in parallel with that for symmetrical clipping.  Seems you want to keep an eye on how much you're driving that last stage, or you could 'fizz out'.  If it sounds like crap but is OK with gain control lower, that's the 1st place I'd look...

Sorry if you know most of this already...your idea is on the right track!

[peterg]

Here's the schematic I came up with for a triple LPB fuzz:

Happy tweaking!

[tubegeek]

peterg:

2M || 2M - because that's what you had on hand or was there another reason? (R3A & R3B)

Is the arrow pointing at the left of R17 meant to say that C3 ended up to the right of the dot there?

Thanks for the schematic and I LOOOOVED the way that layout ended up as shown in the other thread, nice work.

[nocentelli]

Also peterg, what is the value of Q3 emitter resistor? 100r, 1000r?

[peterg]

Tube Geek and Nocentelli

2 2M resistors were used for layout purposes only. The layout needed an even number of resistors.
R17 and C3 are as shown. Ignore the circle and arrow
R14 is 100R

The scheme doesn't show the polarity protection diode or the AC filter cap.

[tubegeek]

I did a little clean-up:

[peterg]

Correct. R2 is 1k5. No resistor between C6 and ground. An earlier version had a pot at that location. I can't see the document you posted on my hand held device. I check it out when I'm on my PC.

[UKToecutter]

Hi Peter,
Can you identify pin 1 on the pots please (where pin 1 is the left most connection when the pot is viewed from the front and the connections are on the bottom).
Many Thanks

[tubegeek]

All 3 pots are oriented the same way: the upper end on the diagram corresponds to the end which is furthest clockwise. More treble, more fuzz, more volume will be on the clockwise end of the corresponding pot.

[Mark Hammer]

There doesn't seem to be anything to contain treble.  Given that the intent is to produce distortion, you may want to tend to that.

[aron]

Check out the Wiki - secret of stacked stages:
http://www.diystompboxes.com/wiki/index.php?title=Simple_mods