the TC Electronic schematic

After much searching, I found this schematic online:

https://postimg.cc/Wdn7WMD6

It is clearly not made by TC Electronic; however, it seems to correspond to some "gut shots" (photos of the internals) which I saw on another site, so maybe it is correct.

http://www.modezero.com/tc-3rd-dim.htm

NE571: compandor, similar to NE570 but cheaper and lower specs

I am left with some questions.  Most importantly, there appears to only be one BBD delay line, with one clock generator.  This is implemented much like the delay lines in the Boss circuit, even down to the visual aspect of the two chips being located adjacent to each other with one flipped 180 degrees.  However, the second delay line appears to be missing (it's also not visible in the "gut shots"), and there is no associated inverting opamp to create the out-of-phase LFO signal.  I.e., to all appearances, this is merely a perfectly standard chorus circuit, not a dimension chorus at all!  Yet, it purports to be a replacement for the Boss Dimension-C (it's certainly not an exact clone), and numerous reviews and comparisons on Youtube demonstrate that the two units have very similar sounds: this sounds like a dimension chorus -- but how?  Seemingly, TC Electronic has found some way to make a dimension chorus which uses only one delay line, which "should" be impossible.

Also, while the LFO circuit is very similar, down to the fixed resistor values, the component values inserted by the preset switches seem to be different in several cases.  The presets seem to sound the same as the Boss presets, but this is not necessarily definitive because the sound variations are so subtle anyway.  In any event, the basic nature of the switching is the same, i.e., DPDT switches which change the resistance of the depth and rate circuitry, so it should be possible to substitute pots for the pushbuttons, as I've been planning to do.

I'm going to have to study this schematic quite a bit more!  Right now, I can't shake the feeling that TC Electronic is having a laugh at all of us gullible musicians, who think there's a big difference between dimension chorus and regular chorus, when actually a regular chorus can get close enough to the same sound that nobody can tell the difference.  Maybe it's just a matter of a slower rate?  Whatever, I guess if it sounds good, then it sounds good.



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