Shin-ei Mute Box  [schematic]

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Shin-ei Mute Box  [schematic]

Postby Addy Bart » 17 Jan 2018, 00:20

Saw this on a local listing and thought it might be of interest here.
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karul (17 Jan 2018, 17:17), modman (18 Jan 2018, 10:25), Nocentelli (17 Jan 2018, 19:14), Zokk (21 Jan 2018, 13:48)
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Re: Shin-ei Mute Box

Postby Nocentelli » 17 Jan 2018, 19:22

Schematic appears to omit the actual filter section :scratch: I can't see how the envelope controls the filter sweep
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Re: Shin-ei Mute Box

Postby tube-exorcist » 18 Jan 2018, 02:03

Nocentelli wrote:Schematic appears to omit the actual filter section :scratch: I can't see how the envelope controls the filter sweep


Hmmm... maybe the led illuminates a double LDR which is symbolized by 4 dots inside a circle (in the left lower corner - in parallel to R19, R20) ?
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Re: Shin-ei Mute Box

Postby Addy Bart » 19 Jan 2018, 00:16

tube-exorcist wrote:
Nocentelli wrote:Schematic appears to omit the actual filter section :scratch: I can't see how the envelope controls the filter sweep


Hmmm... maybe the led illuminates a double LDR which is symbolized by 4 dots inside a circle (in the left lower corner - in parallel to R19, R20) ?


I think you're right. I found a discussion about these 4 dots here, and it appears to be a dual photoconductive cell.

http://archive.ampage.org/threads/1/fxs ... III-1.html
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Re: Shin-ei Mute Box

Postby Nocentelli » 19 Jan 2018, 15:26

It seems to be a virtually the same as the Mutron III, which uses a dual LDR/single LED optocoupler - Marked with the question mark in the pic below:

Image
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