An XLR cable adapter

[MarkZ]

Hi everyone,

I’m not a fan of the BNC cables. I mainly use the QA403 for commercial amp/preamp/… testing and much of this stuff is unbalanced while some is balanced. This means I use almost exclusively RCA and XLR jack/cables and I never use BNC cables.

I tried making custom dual BNC->XLR and dual BNC->RCA cables and frankly just failed at it. All the BNC connectors I found were designed to use coax and connecting other cables was problematic at best.

Anyone, rather than constantly suffer icky cables I just built a BNC->XLR converter that stays on my QA403 constantly. A few photos->

I started by 3d printing the front/back panels and supports and did a sanity check - which worked well. Then I milled front and back panels from 2mm aluminum. Note I rear-mounted the XLR adapters to make it easy to replace the front panel for an additional output connector (RCA?).

If anyone wants the models I’m happy to post the Fusion360 design/manufacture files or the .STL 3d printing models.

Mark

[MarkZ]

Here’s the result of a quick loopback test with a stock 1/2M balanced XLR cable:

[MarkZ]

I made some shielded rca and xlr cables and retested the loopback.

Straight XLR shield connected to output xlr

XLR->RC->barrel->RCA->XLR (both are two wire shielded twp). The output uses plus and gnd. The input uses 2,3 balanced input.

[restorer-john]

That’s extremely cool.

You could also use three pieces of plastic light pipe drilled through the adaptor plates and up against the LEDs on the QA403 to duplicate the indicators on your adaptor.