Pro-Ject Debut III RCA Box

A simple RCA jack and grounding screw modification for the entry-level Pro-Ject Deubut III record player that originally shipped with a hard-wired RCA/ground cable.

My record player's original integrated RCA cable was getting a bit ragged after a decade of use and a few moves and in its current location the factory cables wouldn't reach my preamp anymore. So I decided it was time to replace the built-in cable with a pair of RCA jacks and a grounding screw to allow me to use my own cables.

This model was designed to be easy to print and simple to install. It relies on using the existing screw holes drilled into the main high-density MDF frame to avoid having to drill new holes. The mounting holes may not line up perfectly on all variations of this design from the early 2010's but they fit perfectly on mine. It also doesn't provide for any EMI shielding and I didn't reuse the factory "shielding" card, but in my setup (which doesn't have any electronics near the record player) I haven't noticed any interference coming in.

To make future rework and remixing easier I've included a Fusion 360 source file which has a mockup of the record player's underside screw positions to make it easier to visualize while desigining.

Factory Setup and Wiring

RCA Box After Installation

Installation Notes

Here's the order of operations that worked best when I installed this

1. Remove factory screws
2. Desolder factory RCA cables
3. Clean up connection points with desoldering wick
4. Place the newly printed box in place (without jacks installed) for a fit check
5. Measure out and cut/strip connection wire lengths to fit
6. Solder the new connection wires on to the RCA jacks, RCA jack ground flange washers, and barrier block
7. Install the box on the record player
8. Install the RCA jacks and barrier block on the box
9. Solder the new connection wires on to the connection points
10. Test it out, close the box, and enjoy!

Parts Required

• 2x Switchcraft BPJF0xAUX panel mount RCA jacks
  • Switchcraft BPJF02AUX (red), Digikey, $2.88 each
  • Switchcraft BPJF03AUX (white), Digikey, $2.88 each
• 2x Curtis GFTX-1 single-terminal barrier block for ground passthrough
  • Curtis GFTX-1, Digikey, $2.97 each
• 5x M3 heat-set inserts (⌀4.6mm) for barrier block mounting and lid
  • CNC Kitchen M3 Threaded Heat-Set Inserts, $8.00/100pc
  • Also available from Prusa shop, $10.00/100pc
• 3x M3 10mm Screws (max 5.5mm head diameter) for lid
  • McMaster Carr 91290A115, $9.54/100pc
• 2x M3 12mm Screws (max 6.5mm head diameter) for barrier block
  • McMaster Carr 92005A122, $4.32/100pc

Printing Notes

Both the case and the lid are simplel and easy to print at 0.20 layer height with no supports. I used PETG but PLA or other materials, even resins, may work fine as well.

Design Notes

This was a “version one” attempt that worked well enough for me right away. If I were doing this again, or if I update it in the future, I'll probably redesign it with a few additional things in mind.

• Consider using a simple heat-set insert for ground passthrough, since a barrier block is overkill
• Redesign the case to more easily add decent, grounded EMI shielding around the exposed wires
• Investigate options for adding a build-in preamp for line output or even ADC for digital output