Sound City - Distortion DS-04 Traced Schematic  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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Manfred
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Post by Manfred »

I dissected the Sound City distortion.
I made a approximate layout copy of the PCBs and traced the circuit.
The circuit of this distortion is the same as the Panther distortion except for the feedback part, the diode types and the type of operational amplifier.
I cannot figure out the JRC dating code, who can tell me the date of manufacture of the Op-amp.
SoundCityDistortionTopView.jpg
SoundCityDistortionPCB_ComponentSide.jpg
SoundCityDistortionPCB_OPamp.jpg
SoundCityDistortionPCB_SoderSide.jpg
SoundCityDistortionWiring.jpg
MainPCBLayout.JPG
PotentiometerLED_PCBLayout.JPG
SoundCityDistortionSchematic.JPG
Clipping Diodes Soundcity Distortion.jpg
Further measurements in the next post.
Ready to Print PDF-files:
SoundCityDistortionMainPCB_ComponentSide.pdf
(40.05 KiB) Downloaded 138 times
SoundCityDistortionMainPCB_SolderSide.pdf
(13.2 KiB) Downloaded 130 times
SoundCityDistortionPotPCB_ComponentsSide.pdf
(12.47 KiB) Downloaded 119 times
SoundCityDistortionPotPCB_SolderSide.pdf
(10.26 KiB) Downloaded 119 times
SprintLayout6.0-File:
SoundCityDistortionLayout.zip
(59.74 KiB) Downloaded 129 times

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Manfred
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Post by Manfred »

In addition, this is the difference between the two circuits.
SoundCityPanther1stStageCompare.jpg
SoundCityPanther1stStageCompare.jpg (19.61 KiB) Viewed 1957 times

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lolbou
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Post by lolbou »

Very close to the Electra 500 Distorsion (and its siblings) too!

Very good job Manfred!
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.

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Manfred
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Post by Manfred »

Here the measurements I have made:
FrequencyReponseSoundCityDS-04.jpg
FrequencyReponseSoundCityDS-04.jpg (67.98 KiB) Viewed 1871 times
SoundCityDistortionStartClipping.jpg
The comment "start clipping" to the first curve is wrong it must be "clipping".
SoundCityDistortionClipping.jpg

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Post by Manfred »

There is a fault in the schematic above, the value of the DIST potentiometer is C50k not B100k.
The Layout shows the correct value.
Here the corrected schematic:
SoundCityDistortionSchematic.jpg
SoundCityPantherCompare.jpg
SoundCityPantherCompare.jpg (19.87 KiB) Viewed 864 times

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