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White rectangular wall-mounted speaker volume control with slider and matching colour kit

Monoprice Inc.

Monoprice 138175 100W Impedance Matching Volume Control

SKU CH-BQ1Q-G5G0P

An impedance-matching volume control lets you connect multiple speaker pairs to one amplifier, protecting it by raising the overall impedance and handling up to 100 watts

  • Product typeVolume Control
  • Product weight1.27
  • Key featuresAllows you to connect multiple speaker pairs to a single pow
  • Connect multiple speaker pairs to one amplifier safely
  • Impedance matching protects amplifier from overload damage
  • Handles up to 100 watts of amplifier output power
  • Fits standard single-gang low-voltage junction boxes
  • Lightweight design at 1.27 weight units for easy installation

Whole-home audio volume control

The Monoprice 138175 is an impedance-matching speaker volume control designed for multi-room audio systems. It allows several speaker pairs to share a single power amplifier or receiver without overloading the amplifier output. The unit fits standard single-gang low-voltage junction boxes for in-wall installation. Installers and homeowners use it to distribute audio safely across multiple zones.

Passive operation with 100 W capacity

The device operates passively, drawing no mains power and adding no active circuitry to the signal path. It raises the impedance presented to the amplifier so that combined speaker loads remain within safe limits. The control handles amplifiers rated up to 100 watts per channel during normal listening levels. No fan noise or heat dissipation issues arise because the design is completely passive.

Included colour kit matches décor

A colour kit ships with the volume control, providing interchangeable faceplate options to suit different wall finishes. This lets the installer match the visible trim to the room without sourcing separate plates. The supplied hardware mounts directly into standard low-voltage brackets, so no extra adapters are required. The accessory set simplifies the final aesthetic integration.

How it compares

Measured against everything we stock in AV Accessories & Components, at today’s prices. Recalculated every night.

Price $20.99
Cheaper than about 70% of the 3,838 comparable items (median $41.99).

Specifications

Product
Brand nameMonoprice
Model name138175
Part number138175
Product typeVolume Control

Questions about this item

How is the 138175 volume control installed in a wall?

Mount it into a standard single-gang low-voltage junction box or bracket, then wire the amplifier output to the input terminals and the speaker pair to the output terminals. The step often missed is setting the impedance-matching jumper to match the total number of speaker pairs connected to the same amplifier.

What maintenance or replacement will the 138175 need over time?

The slider track can collect dust, causing scratchy operation; clean it occasionally with a dry brush or contact cleaner. If the slider wears out or the impedance-matching transformer fails, replace the entire unit — no user-serviceable parts inside.

What limit appears first when driving the 138175 at high volume for long periods?

The 100-watt power rating is the first limit; sustained amplifier output above that level will overheat the internal transformer and cause distortion or permanent damage.

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