Menqi DPLPG kit problem

Thanks. I’ll be on the look out for a replacement vactrol!

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I found some replacement vactrols on eBay for very a reasonable price. Thanks for the schematic. Having the part number made it easy.

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I got myself a DPLPG yesterday and sadly I had to start searching web knowledge on why Maths unity outs did not work. Ended up here and want to ask if someone can explain why this is happening and if there’s something to ‘fix’ it without workarounds, buffered mults, attenuated outputs on Maths etc.

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It’s a known issue with the maths circuit (and the classic function generator circuit it is based on) when used with a passive lpg. I don’t understand it fully but I believe it has something to do with impedance?

The direct outs of channels 1 and 4 if maths are unbuffered while the scaled/combined outputs are.

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With Rampage I found that even a passive attenuator would fix the problem.

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Yes, I’m having the same problem. A byproduct of it not drawing power? Any workarounds?

I have the same question

My solution was to patch from the attenuated outputs of Maths. That solved it. From what I understand this is something that happens to all DPLG / Maths. Not faults in ours. It’s got to do with how electronic circuits work, that’s where I left the issue.

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It’s not necessarily limited to passive LPGs. For example, Maths won’t modulate AJH’s Gemini 2412 filter (not passive) without an intermediary. (No problems I’ve noticed with other AJH modules.) I’m pretty sure this is down to “no standards in Eurorack”, but since Maths is so popular, it starts to build this false impression that there’s something “wrong” with Maths.

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Oh totally, nothing wrong with maths, those two outputs just don’t work with everything and as long as you don’t think something in your rack is broken the scaled outs work great.