Rapco SL-4 Rack Mount 4 channel passive direct box DI

No sales tax for customers outside California.  

The Rapco SL-4 is a rugged rackmount 4-channel passive direct box designed for live sound, studio, and touring applications. Each channel converts high-impedance instrument or line-level signals into balanced, low-impedance outputs suitable for mixers, recording interfaces, or stage snakes. Housed in a 1U rack steel chassis, the SL-4 is ideal for bass, keyboards, acoustic instruments, drum triggers, backing tracks, or any multi-source setup requiring clean, noise-free signal routing.

Each of the four channels features a 1/4" input, 1/4" thru/output, and a balanced XLR output. As a passive unit, it requires no power—relying on high-quality transformers for isolation, signal integrity, and ground loop reduction. This example is in excellent working condition with all jacks and transformers functioning properly, and includes only light rack wear.

At Mahar’s Vintage Guitars, every piece of gear is tested, photographed clearly, and described accurately.

Actual user reviews of the SL-4 rack mount DI:

• “Reliable and quiet—perfect for live rigs.” – Gearspace
• “Great for keyboards and backing tracks.” – Reddit r/audioengineering
• “Solid build and no need for power—super convenient.” – Harmony Central
• “Works flawlessly on bass and acoustic guitar.” – TalkBass
• “Affordable workhorse DI for any rack setup.” – HomeRecording.com

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Shipping policy:

Shipments will require signature on delivery, no exceptions.  If there is damage, the buyer must retain all packing materials intact and picture them immediately and send them to sales@maharsvintageguitars.com.  Less than 1% of our shipments are damaged in transit, and we are committed to making sure your item arrives safely, but we are taking these additional measures to make sure you are happy with your purchase.