Shure - Level Loc Compressor

Stompboxes circuits published in magazines, books or on DIY electronics websites.
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kizzer
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Post by kizzer »

dwrockdoctor wrote: 11 Jun 2022, 02:40 Oh, and is there meant to be a cut beneath the 13k resistor that goes to the threshold switch? I built it off board on the DPDT toggle but I'm guessing it needs a cut on the Vero to work properly?
Another Good Catch! Yep, edited the layout to now show that cut. Cheers!

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tedsorvino
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Post by tedsorvino »

Hi Bow and Error, Kizzer and everyone.
I really like this project since it avoids the transformer stages of the original. I follow the thread for quite some time and now after all the modifications and since I have the time I'm planning on building a unit based on your design. I would like to ask you what modifications should I do in order to make this circuit work with balanced in and out.
Can I use a differential line driver like DRV 134 or THAT 1646 (maybe it's not needed) at the output stage and maybe a couple of other opamps like NE5532 or NE5534 in the input stage along with a +9v -0- -9v power supply?
What mods should I do and how can I integrate them in the circuit (just tell me the changes or a rough schematic of them, if it's easy and possible)?
Is there a general "rule' on how to transform unbalanced circuits to balanced ones?
Thanks for the great work anyways.

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bow_and_error
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Post by bow_and_error »

If you're looking for a balanced, line level IO version, check out irfrench's 500-series Level-Loc project on GroupDIY. As you can see on the schematic, it already has INA134/DRV134 line receivers & drivers on +-9V rails. Here is a link to all of the documents, and I think there is even a PCB available on the GroupDIY White Market.

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tedsorvino
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Post by tedsorvino »

Thank you Bow and Error.
Actually I never go for 500 series packaging (very limiting space wise and usually pay more for particular boxes) , but I will surely study the schematic and compare it along with the unbalanced one and come up with something. Very very useful links.

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cjonesplay
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Post by cjonesplay »

I know it’s a bit late, but the most recent layout’s threshold switch wiring is incorrect. Threshold 3 should connect to the other side of the 13k.

It’s actually easier to just remove the 13k and 47k altogether and wire a 50k pot with lugs 1/2 connected to threshold 2 and connect threshold 3 one row down (without the cut for the 13k). I never understood why this wasn’t a pot to begin with, maybe to keep confused PA operators from making too many decisions?🤔

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