3.5mm to XLR issue

[luthierwnc]

Hi mcphillips, I don't know if my feeble efforts are sticky quality but I do hope this helps other frustrated ATR3350 owners (or other 1/8" mic owners). This is a Neutrik combination XLR and 1/4 jack schematic. I don't know if this is the kind used on the Scarlett but it fell from the same tree. Ignoring the XLR, the 1/4 has three switched leaves.

Neutrik xlr .25 jack.jpg

If you have a garden-variety guitar cord, the tip is the signal, the sleeve is the ground and the ring (stereo) doesn't matter. If you used a stereo cord because it was in the bag and the gig starts in 5 minutes, it would work fine because the stereo leaf will also ground on the barrel of the jack. Either it is also grounded or it is disconnected. As long as the tip leaf doesn't have continuity with the sleeve, you're golden. I've certainly played with guitarists and singers I wish had a dual-mono cable

Then we get to the concept of dual-mono (new to me) with the tip and sleeve connected. If that stereo leaf is grounded, you are shorting 100% of the signal to the buss. Like in my previous post, lots of gizmos use the stereo leaf to create ground continuity for the power source. It could also use one of the leaf switches to make sure phantom power doesn't get on the plug.

Long-story short for other ATR3350 owners, you can't use a BestBuy headphone 3.5mm to 1/4" adapter to try to plug this into a Scarlett and probably many other combo XLR 1/4" jacks -- even though you can't tell it from a stereo plug without a meter or owner's manual. Just to flog the horse, I think I'll take the DVM to work with a stereo plug and check continuity on the solder pins. If it is something different that what I just said here, I'll say so.

Cheers and enjoy your weekends, sh