Jen - Jumbo Fuzz  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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Kitrae
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Post by Kitrae »

Nice! I'm going to add the gate parts to my Jumbo.

I still need to upload pix of my borrowed Jumbo to the page, but here is a bit of history on Jen and the Jumbo, for those interested.
http://www.kitrae.net/music/History_of_ ... l#JenJumbo
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Solidhex
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Post by Solidhex »

Kitrae wrote:Did it also have white box caps?
Nope. In this one the .1uf's were white colored film caps. The .047's were brownish/orange film caps. 470pf's were ceramic. The .01uf in the tone section was a black box cap and the .0047uf was ceramic.

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Kitrae
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Post by Kitrae »

It appears they used different parts over the time these were made, typical for Jen. My Jumbo Fuzz uses Motorola 2N5225 transistors and white box caps, like the one bluesbreaker posted on the previous page. It also has 560pF cap instead of the 470pF caps I have seen on the early Jumbos.
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http://www.bigmuffpage.com/The_Tonebender_Timeline.html

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bluesbreaker62
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Post by bluesbreaker62 »

Nice write-up, and great work on the layout and schematics Kitrae!
I'll be adding the gate-circuit to mine as well, its an excessively noisy pedal

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fuzzyexpress
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Post by fuzzyexpress »

Hello all, this is my first post! Just want to say that this forum has been exceptionally helpful in learning the basics and I'm so incredibly surprised by the depth of information available here!

I was wondering if anyone knows where to get a PCB of this Jen Jumbo Fuzz? I'm in love with this pedal and really want to make one! If no one is selling a PCB, I wouldn't mind trying to make one but I've never made a PCB before. I tried to have a company make one for me using the information in this thread, but they need a CAD file, and I think I would be in way over my head to try and make that.

Any one have any suggestions on how I can make this pedal?

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fuzzyexpress
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Post by fuzzyexpress »

Hi I just wanted to let anyone reading this know that I've recreated the Version 1 schematic posted earlier in PCBcreator. I have a very tenuous grasp on electronics and I've never used this program before, but I went through it carefully. I've asked on r/diypedals for someone to look over the PCB to make sure that it would work. I'm making the same request here, if anyone has a few minutes and PCBcreator, I would gladly send them the file for them to check it out.

Then we will have a printable PCB to make!

Thanks! :)

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fuzzyexpress
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Post by fuzzyexpress »

Here are download links to both the schematic and PCB layout:
http://www.filedropper.com/jenjumbo
http://www.filedropper.com/jenjumbo1

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digi2t
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Post by digi2t »

Here are some more pictures, these are of a Unicord Jumbo Fuzz. The trace side has "JEN" marked on it. Resistors R23 and R27 are omitted, but all resistor and cap values are as per Kit Rae spec. The voltages are as follows;
Guitar plugged in, all controls at max, battery voltage at 8.81v. Transistor numbering follows the Kit Rae convention (see Kit Rae Jen Jumbo Fuzz Circuit Layout image).
Q4
E-14.4mV
B-0.604
C-3.667
Q3
E-0.1mV
B-0.580
C-3.803
Q2
E-0.1mV
B-0.606
C-3.761
Q5
E-0.1mV
B-112.6mV
C-114.4mV
Q6
E-0.0mV
B-112.9mV
C-14.2mV
Q1
E-1.053
B-1.639
C-4.25

Silicon transistors are marked "FGT102", and the lone germanium is "SYL1851" ("6424" marked on back). The silicon diodes measure between 0.610 - 0.650 vF. and the germanium ones are between 0.40 - 0.47 vF.

Image

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No matter how many times I cut it, it`s STILL too short!

https://www.deadendfx.com/

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