Way Huge - Swollen Pickle

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oneleg
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Post by oneleg »

???

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sevinisthenumber
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Post by sevinisthenumber »

Anyone have a PCB layout?
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Post by phibes »

You could redraw this.

http://www.super-freq.com/?p=7
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ShortScaleMike
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Post by ShortScaleMike »

Unverified as yet, but I'll be building shortly. People may find it useful though.

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Post by mattpas »

ShortScaleMike wrote:Unverified as yet, but I'll be building shortly. People may find it useful though.

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hey Mike. Nice job.
I think the transistors are 2N3904s in the SP.
Also, there is a 330uf filter cap.

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ShortScaleMike
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Post by ShortScaleMike »

Thanks for the input. I've changed the transistor type, and added the 330uF filter cap, had to do something ugly with the 3rd clipping stage however.

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sevinisthenumber
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Post by sevinisthenumber »

[quote="ShortScaleMike"]Thanks for the input. I've changed the transistor type, and added the 330uF filter cap, had to do something ugly with the 3rd clipping stage however.

hows it sound?
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Post by mictester »

sevinisthenumber wrote:
ShortScaleMike wrote:Thanks for the input. I've changed the transistor type, and added the 330uF filter cap, had to do something ugly with the 3rd clipping stage however.

hows it sound?
Like a smooth example of a Big Muff Pi! There is no magic here!
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Post by ShortScaleMike »

Not built it yet, just knocked it up when I was doing some layouts.

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Post by mattpas »

ShortScaleMike wrote:Not built it yet, just knocked it up when I was doing some layouts.
Mike,
R22 should be 15k

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ShortScaleMike
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Post by ShortScaleMike »

Cheers, that's a typo - clearly.Thanks.

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Post by Thaxt »

The quad transistor array chip - 4 X 2N3904s - is available (as usual) from Steve Daniels @ Small Bear Electronics (www.smallbearelec.com)

It might prove interesting to experiment with in any circuit using multiple 2N3904s.

Is there something about using this type of T array chip that produces superior sound -- due to the fact that the chip-embedded transistors have exactly uniform specs?

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Post by marshmellow »

Not in a Big Muff context. Transistor arrays are handy when you build differential amplifiers, VCAs, ...
where close matching specs and thermal coupling are necessary.

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Post by SGJarrod »

I am gonna build this pedal per Mike's Vero layout and was wondering if I can put on a mid switch ala Skreddy Mayo... I know the SP is known for huge scoop but was thinking of running a DTDP with one side being the .0033uf highpass cap and the other side being two .0033uf caps in parelel for C10, I know this would not make the mids flat but would be close and make this pedal much more versitile... Anyone have thoughts or input on this? or would it just be better to run a higher cap value instead of the .0033's in parelel? Thanks

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Post by SpencerPedals »

The answer you seek is in the free download of the Duncan Tonestack Calculator. Plug in the Pickle values and adjust to taste.

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Post by SGJarrod »

I put this thing together an I am seeming to have an issue with it... It bypasses and turns on and off fine but when it is turned on the sound level is cut to a whisper and u can hear a smooth dull muff sound.... I triple checked everything...from wiring to the board and part placement..I figured the signal was being bled to ground so I re-did all my grounds and ran a razor blade between the strips on the vero board to make sure there was no solder jumping strips..has anyone else used this layout? Help Please..... :scratch:

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Post by ShortScaleMike »

Is R22 15K, not 15 like my typo value?

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Post by SGJarrod »

yep....I used 15k...I read the whole thread multiple times before I built it

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Post by ShortScaleMike »

Well besides checking transistor orientation and that you've implemented the layout correctly, you could check it reflects the schematic correctly.

Check for the signal using an audio probe after the coupling cap on each collector.

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Post by SGJarrod »

I went thru this with an audio probe and it seems the volume is cut or never recovers after R11, I tried some different values for R11 but no difference was audible.... Any advice....?...

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