I've built a "Bass Enhanced Crossfeed" from a kit, which I believe is based on Meier's Crossfeed design.
I prototyped it first on a breadboard, forgot to ground the output jack because it wasn't explicitly in the diagram. It sounded terrible. After I grounded, it seemed to sound pretty good! So I built the 'hi' version.
Now that I've built it, the low range just seems very subdued compared to my previous test. I suspect I didn't solder it correctly, though I've looked over it with a magnifying glass.
So, how can I verify the build without an oscilloscope and just a multimeter?
I've done some checking, like checking for shorts between left and right ... where are the useful points to check for the right value of resistance? Between R/Lin and R/Lout? Should that be R9/7? Should I check the resistance between each leg of each capacitor?
Probably overkill, but could I put this into a simulator and see what the simulated values would be vs. actual?
Apologies.. I'm a software guy. I'd write unit tests if I could!