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Small rectangular audio module with screw terminal connectors on the front face

TOA ELECTRONICS

TOA ELECTRONICS B-21S Balanced Line Level Screw Terminal Input Module

SKU CH-GE1Z-SJWAX

Balanced line-level input module with screw terminals, transformer isolation and remote volume control for TOA 900 series amplifiers

  • Secure screw-terminal connection for balanced or unbalanced line signals
  • Transformer isolation prevents ground loops with remote equipment
  • Remote volume control adjusts output level from a distance
  • Designed for direct integration with TOA 900 series amplifiers
  • Accepts sources such as CD players, tape decks and AM/FM tuners

TOA B-21S balanced line input module

The TOA B-21S is a balanced line-level input module that connects to 900 series amplifiers through a screw terminal block. It accepts both balanced and unbalanced signals from sources such as CD players, tape decks or AM/FM tuners. The transformer-isolated design reduces ground-loop interference when the module links to remote equipment. A remote volume control allows output level adjustment via an external potentiometer.

Installation check list

Verify that the amplifier in use is a 900 series model so the module seats and functions correctly. Confirm the source devices provide line-level outputs compatible with balanced or unbalanced wiring. Ensure the screw terminals can accommodate the wire gauge you intend to use for a secure connection. Plan the routing for the remote potentiometer cable if distance volume control is required.

Sustained load behaviour

Transformer isolation maintains consistent signal integrity during continuous operation by suppressing ground-loop hum that can build up over long cable runs. The passive screw terminal connection introduces no active circuitry that could drift with temperature, so gain and noise floor remain stable. Remote volume adjustment relies on an external potentiometer, meaning the module itself dissipates negligible power and does not heat up under extended use.

Highlights

  • Secure screw-terminal connection for balanced or unbalanced line signals
  • Transformer isolation prevents ground loops with remote equipment
  • Remote volume control adjusts output level from a distance
  • Designed for direct integration with TOA 900 series amplifiers
  • Accepts sources such as CD players, tape decks and AM/FM tuners

Specifications

No published specifications for this item yet.

Questions about this item

What comes in the box with the B-21S input module and what extra parts are needed?

The B-21S module itself is supplied; you must provide the TOA 900 series amplifier it plugs into and any external potentiometer you want for remote volume control.

Which version of the B-21S should I choose for a balanced line-level source?

The B-21S is a single model that accepts both balanced and unbalanced line-level signals through its screw terminals, so no separate version is required.

How does the transformer-isolated design affect the signal when the module is installed in a 900 series amplifier?

The transformer isolation breaks ground paths between the source and the amplifier, preventing ground-loop hum when remote equipment is connected.

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