3-Way In / 2-Way Out Hi-Fi Studio RCA Switcher with Dual EQ Inserts, BBM Switching & S/PDIF A/B Selector

3-Way In / 2-Way Out Hi-Fi Studio RCA Switcher with Dual EQ Inserts, BBM Switching & S/PDIF A/B Selector

This hand-built passive RCA switcher is designed for flexible source selection and amplifier routing in a Hi-Fi or studio system.

It provides three stereo RCA inputs, two stereo RCA outputs, two independently switchable stereo EQ insert loops, and a separate S/PDIF A/B selector for switching between two digital sources connected to a single DAC.

Analog Routing

The analog section provides three stereo RCA inputs for sources such as:

• Tuner – Realistic TM-1001
• DAC – Topping D30
• iPod Touch 2nd Gen – via 3.5 mm to RCA cable

The selected stereo source can be routed through the EQ insert section and then sent to either of the two stereo outputs. The two outputs can be connected to the AUX or line inputs of two AMP 1 and AMP 2 amplifiers, allowing you to select which amplifier receives the signal.

Dual EQ Inserts

Two independent stereo insert loops are available for external equalizers or other line-level processors.

EQ1 and EQ2 can be switched independently, allowing the selected source to be routed through either insert path as required. Each insert can be activated or bypassed independently.

Typical operation:

Selected Source → Insert Section → Selected Output, EQ1 and EQ2 can therefore be used independently without requiring changes to the main source selection.

The insert section shares its signal ground connection between EQ1 and EQ2 only. The main input and output routing grounds remain separately switched according to the selected signal path.

S/PDIF A/B Selector

The digital section provides two S/PDIF inputs with a simple A/B selector:

CD Player 1 → S/PDIF A
CD Player 2 → S/PDIF B

The selected S/PDIF source is routed to the Topping DAC.

Switching and Ground Isolation

The main analog routing uses break-before-make (BBM) switching. The selected connection is disconnected before the next connection is made, preventing the two routing positions from being momentarily connected during switching.

Both the audio signal and audio ground are switched in the main routing section. Non-selected paths are therefore disconnected rather than remaining permanently connected through a common audio ground.

This design helps minimize unwanted interaction between connected source and output devices caused by the switcher itself.

Chassis Ground

The aluminum enclosure provides shielding against external interference.

The chassis ground arrangement is separate from the switched main audio routing paths. The only intentional audio-ground connection between the two EQ insert sections is within the insert section itself.

Passive Signal Path

No active electronics, buffers, amplifiers, or powered circuitry are used in the analog audio path.

The switcher operates completely passively and requires no power supply.

The design provides direct signal routing without active processing or buffering, while keeping the switching and grounding arrangement as electrically simple as possible.

Technical Specifications

Analog Inputs:
6 × RCA
3 × Stereo L/R inputs — A / B / C

Analog Outputs:
4 × RCA
2 × Stereo L/R outputs

EQ Inserts:
2 × stereo insert loops
EQ1 and EQ2 independently switchable

Digital Inputs:
2 × S/PDIF
A/B selector to DAC

Switching:
3-position precision rotary BBM switching for the main analog source selection

Ground Switching:
Signal and audio ground switching in the main routing section

Enclosure:
Shielded aluminum desktop enclosure:

Width 200 mm × Height 60 mm × Depth 100 mm /*7.87 × 2.36 × 3.94 inches (W × H × D)

Operation:
100% passive
No power required

Custom Labels:
Custom source and output labels available on request

System Note

The switcher is designed to prevent unwanted signal and ground interaction within the unit itself. However, noise, hum, ground loops, or crosstalk originating from other equipment or additional connections elsewhere in the audio system are outside the switcher’s control.

Custom Name Engraving and select knob style (let me know)

You can get as many channels and options as you want, so let’s build your gear!

Build time: 10 Working Weekdays after cleared payment

Do not find your controller or switcher? Tell me what you need and I build for you!