EHX - Deluxe Octave Multiplexer

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

Liquids wrote:Can anyone else post good high-res shot of at least the component side? I believe there are some component errors, particularly in the tracking filter section, but I'd like to be sure, and the current collections of images here and around the net leave a little bit to question.


Does anyone here OWN one?
I am pretty sure I went through and checked the whole thing against Images I had and it checked out when I was doing the tracing/schematic but it was a long time ago and I may have been wrong.

I can't remember who but a DIYstompboxes member gave me some shots but asked that I did not post them here... dunno if they can be found on DIY or not, if not, give me a PM.

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Liquids
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Post by Liquids »

My question involves the highlighed resistors. They look to be either 10k or 100k, but it's a big distinction at this location in the circuit.

Is the EH man here?

I knwo the schematic says 10k's here, basically, but the schematics allegedly have some intentional errors to throw people off, even if not to the point that things wouldn't work, just not work properly if followed blindly...

Measured values would be awesome...

Here's the area I'm talking about...highlighted area, resistors in question highlighted additionally.

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GodSaveMetal
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Post by GodSaveMetal »

Can the TWO CA3094 will be replaced BY ONE LM13600 or LM13700??? there are TWO BUFFERED OTAS inside! :scratch: I have a hundred of these ICs if yes perhaps Please; somebody layout/PCB with these OTAS?? :hmmm:

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Dirk_Hendrik
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Post by Dirk_Hendrik »

Go ahead! :applause:
Sorry. Plain out of planes.

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uncleboko
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Post by uncleboko »

GodSaveMetal wrote:Can the TWO CA3094 will be replaced BY ONE LM13600 or LM13700??? there are TWO BUFFERED OTAS inside! :scratch: I have a hundred of these ICs if yes perhaps Please; somebody layout/PCB with these OTAS?? :hmmm:
Never seen it done on that circuit, it may need some exceptional tricks :lol:

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Scruffie
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Post by Scruffie »

I was actually going to breadboard it but until I run in to 2 cheap ($20 shipped from smallbear while not ridiculous is more than i'm willing/able to spend at present) CA3094s to compare against, it's too much work for a (possibly simple) swap.

If someone had a deluxe, a daughter board would be an option.

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GodSaveMetal
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Post by GodSaveMetal »

Somewere in this site is a proposal to modified a 3080A to fit replacement for a CA3094; umm :scratch: there is in a topic of a EH BASS SYNTH thas is cloned; here is the proposal SCHEMO:
Attachments
CA3080A to CA3094 INTERSIL
CA3080A to CA3094 INTERSIL

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Scruffie
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Post by Scruffie »

That should work, IIRC the 3080 is closer (minus buffers) to the 13700

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