Jen Double Sound Super - schematic-layout-pics+demo

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

Hi, I'm new here.

I traced the circuit of my Jen Double Sound Super many years ago, had some help from Paul Marossy from the old DIYGuitarist site. The wah section is identical to the original Cry Baby, and the fuzz section seems to be a no knob Vox Distortion Booster. It sounds great.
JDSSschem.png
jen_doublesound_super_v3b.gif
JenDSSfront.jpg
JenDSSfront.jpg (48.25 KiB) Viewed 707 times
JenDSSbottom.jpg
JenDSSbottom.jpg (49.47 KiB) Viewed 707 times
component_side.jpg
component_side.jpg (150.21 KiB) Viewed 707 times
The switches are made by Marquedt, the original wah pot is a Centralab. The inductor is a white Fasel. Fuzz transistors are Motorola BC238B's, wah transistors are Motorola BC239B and BC238B.

I made my own board for the fuzz, I socketed every component, replaced the 10k Q2 bias resistor with a trimpot to adjust for half battery voltage on collector of Q2. Fuzz transistors are BC238B's. In my clone I've tested 2n3904's, BC108's, BC548's and a few other NPN's, they're all quite similar when biased correctly. The original BC238B's sound the best though, not as harsh.
Fuzz_brd1.jpg
Fuzz_brd1.jpg (29.16 KiB) Viewed 707 times
Cheers.

Edit: Here's a demo of the Jen, I recorded this 10 years ago. 17 minute improvisation, starts quite tame, searching for ideas, no edits, mistakes and all. Guitar used was a 1989 Fender Deluxe with Lace Sensor pickups.
Last edited by Frank Triggs on 16 May 2021, 16:53, edited 2 times in total.
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Frank Triggs
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Post by Frank Triggs »

I've just noticed on here is a schematic of the Jen Double Sound, the fuzz and wah are in series on that.
Seems my Super version has the fuzz and wah in parallel.

Maybe this will help clear up any confusion between the differences between the standard and super versions?
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TWSpedals
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Post by TWSpedals »

Frank Triggs wrote: 16 May 2021, 13:01 I've just noticed on here is a schematic of the Jen Double Sound, the fuzz and wah are in series on that.
Seems my Super version has the fuzz and wah in parallel.

Maybe this will help clear up any confusion between the differences between the standard and super versions?
I traced out a Dallas Arbiter Fuzz Wah Face I had in for repair a while back and found the wah and fuzz were in parallel in that too. It seems to be an aspect of a few of these old fuzz/wah units that's been completely overlooked.

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Frank Triggs
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Post by Frank Triggs »

TWSpedals wrote: 17 May 2021, 02:42 I traced out a Dallas Arbiter Fuzz Wah Face I had in for repair a while back and found the wah and fuzz were in parallel in that too. It seems to be an aspect of a few of these old fuzz/wah units that's been completely overlooked.
Interesting. The Jen factory also made lots of the Dallas Arbiter pedals.
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Frank Triggs
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Post by Frank Triggs »

I tested the voltages of the fuzz transistors in the Jen. Q3 and Q4 on schematic above = Q1 and Q2 here for reference:

Battery = 8.84v

Q1 (Motorola BC238B)
C = 1.36
B = 0.63
E = 0.0

Q2 (Motorola BC238B)
C = 5.95
B = 1.36
E = 0.75
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Frank Triggs
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Post by Frank Triggs »

According to this Fuzz Face Calculator here: http://www.muzique.com/lab/fuzz_face.php
Silicon transistors have 0.65v across base-emitter junction.
Here, Q1 has 0.618 and Q2 has 0.636, same type BC238B, but with different Vbe. Is this usual?
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Manfred
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Post by Manfred »

I made a PCB clone for vintage pedal hobbyists.
The part names are in accordance with the schematic in thepost above.
The connection wire of the negative wire of C7 leads up around the electrolytic capacitor to a solder tag,
in the modified version a solder tag and a trace were added for connection.
JEN_DoubleSoundSuperLayout.JPG
JEN_DoubleSoundSuperC7_ModLayout.JPG
Ready to Print PDF-files:
JEN_DoubleSoundSuperComponentsSide.pdf
(23.36 KiB) Downloaded 15 times
JEN_DoubleSoundSuperSolderSide.pdf
(4.3 KiB) Downloaded 15 times
JEN_DoubleSoundSuperC7_ModComponentsSide.pdf
(23.86 KiB) Downloaded 14 times
JEN_DoubleSoundSuperC7_ModSolderSide.pdf
(4.34 KiB) Downloaded 14 times
SprintLayout6.0 File:
JenDoubleSoundSuper.zip
(50.33 KiB) Downloaded 15 times

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Frank Triggs
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Post by Frank Triggs »

Manfred wrote: 30 May 2021, 14:59 I made a PCB clone for vintage pedal hobbyists.
Nice one. You forgot to add the fuzz in hole though. The C7 electrolytic cap is non-polar, but doesn't really matter.
Cheers.
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Post by Manfred »

You forgot to add the fuzz in hole though. The C7 electrolytic cap is non-polar, but doesn't really matter.
Thanks for checking the layout here the corrected documents:
JenDoubleSoundSuperLayout_2.JPG
JenDoubleSoundSuperLayoutC7-Mod_2.JPG
Ready to print PDF-files:
JenDoubleSoundSuperComponentsSide_2.pdf
(24.11 KiB) Downloaded 7 times
JenDoubleSoundSuperSolderSide_2.pdf
(4.34 KiB) Downloaded 7 times
JenDoubleSoundSuperComponentsSideC7-Mod_2.pdf
(24.07 KiB) Downloaded 7 times
JenDoubleSoundSuperSolderSideC7-Mod_2.pdf
(4.38 KiB) Downloaded 7 times
SprintLayout6.0 file:
JenDoubleSoundSuperCorrected.zip
(50.17 KiB) Downloaded 6 times

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