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Hello guys,

So i am building a 2015 8 ball (i know, i know, i'm late in my builds).
The circuit is working, but unstable. When i push the gain up, D1 and D2 (LEDs) light up alternatively, like 10 times a second. And the circuit produce a kind of motorboating sound.

Funilly, I had the same issue with the same circuit when i breadboarded it, and with another bluesbreaker type circuit I built before. But not with madbean's King of klones which works perfectly. So i guess it's a common problem for this circuit topology

Does anyone know why this happens? and more importantly, how to solve this?


Hello everyone

I'm usually always putting a ground plane to my pcbs. but since it's usually pretty simple circuits without LFOs or digital parts, i'm not worried about ticking and other digital noise sources.
Now i've heard that if you go digital you have to separate ground planes for the analog and digital part. How can i physically do that?
- the ground is, in the end, common for all my circuit and comes from my power jack, at one single point of the PCB. Do i need to do it another way?
- The way i imagine this is to make a ground plane on top for the digital part of the circuit (where does it stop? coupling cap beyween the digital chip and the first analog 'brick' of my circuit the signal with hit?) and the ground plan on the bottom for the analog part. Will it be enough?

What are the general rules to do this right?

Thanks in advance

Build Reports / Polytone preamp
« on: March 09, 2017, 12:06:06 PM »
As i have a passion for jazz, I also love the jazz sounds and a few of these are linked to the polytone mini brute amps.
I have one myself and it literally kicked out all my other amps of the house when I needed space because of the babies.

I thought of putting the polytone mini brute preamp in a pedal to get closer to that very specific sound even in a normal amp at a gig or jam session.

It's basically an OpAmp clean boost stage followed by a bass/mids/treble bandaxall. The voice switch controls the freq response of the boost stage with different switchable RC network to ground and goes from Wes Montgomery to fusion/rock sounds (hence the name "multitones") and I added the LEC (Low End Control) switch as a request for some people who wanted to control the "boominess" when used with an archtop.

It's actually a project for some jazz guys in a forum who would order me a few of these so wish me good luck


Envoyé de mon iPhone en utilisant Tapatalk

Build Reports / Variation on the RC boost
« on: February 25, 2017, 11:32:19 AM »
Hey guys. I just wanted to show this. Order for a gift to a local guitar player. This is my first build report in years. Because I never dared show anything to people of your level si be kind please

It's a variation on the RC booster with a slightly tuned Tone stack.

I'm pretty happy with how it turned out.

I pcbed the connection part because I can't wire that cleanly to save my life so I thought I'd make a connection board and be done with it.

Envoyé de mon iPhone en utilisant Tapatalk

How Do I? Beginner's Paradise. / closed jacks in a 1590B?
« on: January 03, 2017, 01:25:31 AM »
Dear all,

i would like to try to make a PCB for the 3PDT and the jacks for a 1590B.
I was checking the available space in the pedal with a few closed jacks i have lying around and they are too long to fit in the box by couple millimeters...

Am i using the wrong part? i am sure that some commercial pedals (MXR) use pcb mounted jacks in 1590B.
or maybe i can just shave the extrmity of the jack with a sharp blade?

How do you do this?

How Do I? Beginner's Paradise. / Toner transfer no aluminium box?
« on: November 12, 2016, 11:01:40 PM »
Hello everyone.

I am decided to try my first etch for my next box.

i bought the preprepped enclosures from tayda
i reverse-negative printed my art on a glossy magazine paper
i cleaned the box with acetone
i started ironing the art carefully, for about 5-6 minutes (no vapor, full heat) just leaving the the iron at first, then circular motion without pressing too much.
when i peel the paper off, the transfer is far from being good, the writing is not even transferred, some edges of the drill marks are not round, ...

i tried 2 times yesterday with the same results.. am i doing something wrong?


Mods / fuzzface 'boosting'
« on: November 01, 2016, 07:21:27 AM »
Hello there.

I have made a board for a classical fuzz face with a charge inverter, and the classical pot to blend two different input caps.
the two first pedal coming out of this 'design' sounded great, but i find the sound uninteresting at best if the gain is not 3/4 full or even maxed out. But I would also like to have more gain on tap and a 'bigger' wall of fuzz.

I tried adding a resistor in front of the gain pot, to increase the 'range' of the sweep and go from midly saturated to a higer saturation, but i'm not satisfied with the result. I guess the transistor is already fully saturating. Should i add one more stage then? or maybe even diodes to ground before the output?
Does anyone have experience in that?



Open Discussion / Wtf is this thing (warning ugly work inside)
« on: September 02, 2016, 11:51:26 PM »
Years ago I bought a high level gypsy jazz guitar. With the guitar came a acoustic pickup and with the pickup a preamp. That gear was used for a long time by the professional guitarist who sold me the guitar. I actually used this pickup a few times and found it lacked output level and presence and moved on to a magnetic pickup for that guitar. Lately I thought about mixing both pickups and though I'd open the preamp to check what's inside.

This is what I found

Components are held in the box and together using this kind of paste.
There is a battery, but no active component (except a led?)

I'm actually not sure what the blue components are but they look like trimpots with long legs.

It looks like a passive network of resistors and caps to me

What I don't understand if that it the pickup is plugged directly into an amp.... Nothing happens so it's like there is some kind of amplification there. Or could it be that the pickup needs power like some kind of Fantom power and this is actually providing it to the pickup?

Anyway it's so ugly I thought I'd share it :)

Open Discussion / pedalpartsplus drill template for mad bean projects?
« on: March 04, 2016, 03:37:08 PM »
Since i can't drill at home these days, I need to ask pedalpartsplus to drill the boxes for me.

I found it takes some time to report the measures of the doc from madbean's projects onto their file and i thought that maybe we could share these files between forum members to gain some time?

maybe we could set up a shared dropbox or idk what to host the vector files required for the madbean projects.

Good idea or not? am i the only one using pedalpartsplus custom drilling option?

Available so far :

Tech Help - Projects Page / cupcake debugging - help welcome
« on: February 22, 2016, 03:58:42 AM »

So i built a cupcake a while ago and it was not working correctly ... i just found the time to get it out today and analyze a bit.

So, i started reading voltages at the opamp
at the power plug (yes i boxed before i rocked :) ) voltage between ground and positive side is 9.24V

at the IC
1 : 1.43
2 : oscillation between 1.90 and 1.40
3 : 1.19
4 : 0
5 : 0
6 : 1.85
7 : 1.85
8 : 2.43

so i started looking at the power stage: 2.43 at either side of R12 and the diode.

.. i don't really know what to look for next: the voltages at the input are good, but not in the power stage which would be, for me the very first place where it ca go wrong .. but i imagine it would be either grounded and 0 everywhere, or 9v everywhere..

other voltages:
E: 0.24
C: 0.24
B: 0

C: 2.43
C: 1.28
B: 0.25

Have you got some ideas?

thanks in advance for your time/help

Open Discussion / drilled enclosures at madbean
« on: February 12, 2016, 02:14:16 PM »
I  don't know about you guys, but i myself would love to be able to buy the enclosure with the required drilling, with the pcb of a project. i don't have a lot of free time these days, and i can't drill at home anymore (my building time is when the kids sleep, next room). So when a project requires an unusual drilling template, i have to take the measurements from the pcb, put it on a template, send it to pedalpartsplus, pay huge fees in transportation, ...

it would be so much easier if i could buy the enclosure directly from madbean. who would maybe order a certain amount to pedal part plus, have a price on that, and sell these to us at a reasonable price.

what do you think of it?
am i alone in this situation
i totally understand that stocking enclosures is not the same as stocking pcbs, so maybe it's just not possible for practical reasons :)

Build Reports / in praise of the karate shop
« on: February 10, 2016, 04:54:45 AM »
Just a quick note to let people know about this :
the karate shop is awesome. it can be used as a filter to get the 'old radio' sound, which can be prertty inspiring, to select a band f frequencies after or before distortion and make it really really mean and focused, or really help your guitar cutting through a mix in an amazing way (that setting sounds like ass when i play alone, but in a band .. wow). i love that last setting more than in can express in words.
it's the secret weapon in my pedalboard.

thanks for making this projet available

Open Discussion / karate shop: power stage?
« on: February 04, 2016, 04:08:04 PM »
Hello all,
i'm would like to try to put a karate shop being a TS type overdrive (i love doing this with 2 pedals) in order to give that resonant filter option in a pedal.
however, i don't get what is happening in the power stage of the karate shop: what is the function of this network of resistors (R15,R16,R17, of C12, C13 , D1 and the transistor?). the diode has to be for polarity protection, but the rest.. why can't i use the traditional caps for stabilizing the 9v and then the voltage divider + caps again for have 4.5v for biasing theopamps?


Open Discussion / best circuit for getting the late django sound?
« on: January 23, 2016, 12:41:55 AM »
There is more into a lot of brains that in one.
That's why i'd like to ask you this question:
Which would be, according to your experience, the best circuit to get close to the electric Django Reinhardt sound?
it's coming from a lightly/medium overdriven amp.

2 situations i'd like to consider:
- input is an acoustic gypsy guitar.
- input is a jazz archtop.

examples of the sound i'm talking about

to me the job could be done with a simple electra distortion with heavy low pass filter in the end (+ a stupidly wonderful tone control that would make it versatile enough to be used with an electric and an acoustic?)

Or should it be more medium boosting?

Tech Help - Projects Page / mangler not not mangling
« on: May 19, 2015, 03:37:18 AM »
Hello all,

So i'm building my first fuzz face with the mangler PCB.
finished the build a few days ago, tried to rock it.. no sound. as it was late i decided to check for errors another day, looked at it yesterday: no obvious errors, double checked all resistor and cap values and orientation. Looks good to me.

Not so sure about the trannies orientation so i tried to plug silicon trannies instead and see what happened.. still nothing.

with a transistor in the socket, i put the trimmer to have 4.5v at the collector. can't remember if it was 4.5 or - 4.5, should be -, right?

What shoud i check to help you guys helping me finding the proble?

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