Author Topic: Snack Shack  (Read 2229 times)

yomanfree

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Snack Shack
« on: April 17, 2011, 11:08:05 AM »
Hello all,
I'd like to share with you my SnackShack pedal pictures and mainly provide few comments and experiences I've had, hoping it will be usefull ....
Photos are attached.
Building this pedal, I've found that
- using the input circuit described in the forum (freestompboxes) with the R=1M pot and C=4.7uF in // of C1 (in order to be able to control the input tone) is not efficient (even using several capa values). Its action seems quite limited. It is more efficient for me to use a ON/OFF/ON switch and add 2 different capa values to the one - C1- used in the PCB (Typically for me: 10nF on the PCB, 33nF on one part of the switch, and 220nF on the other part). 10nF, sound is high pitched, 33nF  (+10nF) is a good balance, 220 (+10) nF increases a bit more the darkness. If MadBean's PCB could offer 2 slots for different capa, I think it could be a nice improvement  ;) ...  
- replacing R2 by a "Gain" potentiometer of 1K lin (NB: with the capa C4 connected to the middle lug of the potentiometer) is a strong disappointment. Sound becomes horrible when potentiometer used. Just the last 10% of the potentiometre is usable. My thinking (even if I never tried) is that it would be better to use an antilog, or perheaps better a Ra (frozen) + Rb potentiometer with Ra+Rb=1K (or something like that).
The best from my opinion remains to use the guitar volume. Sound is then always good and even better compared to the last 10% of the gain potentiometer.

I'm not usually a fan of the fuzz pedal, but this one is quite good ....!

thanks

[attachment deleted by admin]
« Last Edit: April 17, 2011, 11:54:24 AM by yomanfree »

nzCdog

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Re: Snack Shack
« Reply #1 on: April 17, 2011, 02:22:53 PM »
Love the paintjob!  Looks FILTHY, like when you stomp on it your tone will need to wash its hands afterwards ;)

yomanfree

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Re: Snack Shack
« Reply #2 on: April 25, 2011, 06:27:59 PM »
Hello,
After several use of the pedal, i've decided to investigate more and see if I can improve.
In fact, I had too much highs when the 1 first position of my switch was enabled (input cap C1= 10nF selected alone), and it was too much muddy with C1=220 (+10) nF.
Additionnally, I had in my mind to test different transistors.

First I have
- change the output cap C5 from 22 to 47nF
- replaced C1=10nF by a 33nF cap
- kept the 33nF on the switch and
- changed the 220nF by a 68nF.
Now the choices (switches selection) for C1 are: 33nF (switch off), 66nF, 101nF.
I think now that the 3 positions of the switch are quite usefull.

I've tried too several transistors for Q2 (for Q1, the initial present in the scheme is OK for me. NB: The 2N3904 of my pedal has a Hfe=200). It has not been easy to do these trials, because after some times, it is quite difficult (for me) to hear things correctly (the ears are no more "neutral" and a break is then necessary). Below is only my feeling "in the heat of the moment".
BC546B (hfe=240), well balanced, provide enought overdrive but sometimes (mainly when C1 high) a little lack of clarity
2N2221A (Hfe<100), strong lack of gain. Good clarity (perheaps due to the lack of gain) with more highs than the BC108A
BC108A (Hfe=180), good sound, but it misses some overdrive/gain. This transistor sounds more dark than the others.
BC108B (Hfe=230), could be a good choice, the gain/overdrive is quite usable whatever the C1 value .... sound is hot ...
2N2222 (Hfe=230), same comment than the BC108B, but more highs, less hot but more clarity
2N5088 (Hfe=400), is not my prefered choice. A lot of gain/disto (a good thing I think for this pedal), but generate a lot of highs, not enought fat/hot, and becomes quickly muddy with C1 increase.
BC338-40 (Hfe=500), my choice. First the gain/disto is powerfull but can be controlled. Sound is fat but with a minimum of clarity. Due to the gain, the highs are more present compared to transistor having a Hfe <300 (I think that the use of transistors with a high HFE increase the highs, but more test should be needed to conclude). With C1 around 100n, bass becomes a bit muddy (but lesser -by far- than the 2N5088). With the bridge humbucker, the sound is more tight and agressive, with neck humbucker more fat and hot.

A bientot ....
« Last Edit: April 26, 2011, 03:48:08 AM by yomanfree »

gtr2

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Re: Snack Shack
« Reply #3 on: April 26, 2011, 07:56:56 AM »
Great graphic!  Very nice build!

Josh
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bigmufffuzzwizz

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Re: Snack Shack
« Reply #4 on: April 30, 2011, 12:38:02 AM »
I love the artwork for your build! Great job documenting. It of course will help others in the future. We should have a sub section in the forum where we can post documented results w/ cap/resistor changes and tranny substitutions like what you did. Also I know what you mean it gets hard to hear a diffence after a few different transistors!
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