Whirlwind

Whirlwind PB12 Pressbox Microphone Output Expander

5.0 (5 reviews)

Expand Your Audio Output Capabilities with Professional-Grade Isolation The Whirlwind PB12 Pressbox is a passive microphone output expander designed for press conferences, forums, and live events. It takes one line-level input and distributes it to twelve microphone-level outputs, each transform...

$867.00*
In Stock on Amazon.com
View on Amazon

*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

Affiliate Disclosure: Studio Supplies may earn a commission from qualifying purchases made through links on this page, at no additional cost to you. This helps support our editorial team.

Notice a mistake? Let Us Know

Overview

Expand Your Audio Output Capabilities with Professional-Grade Isolation

The Whirlwind PB12 Pressbox is a passive microphone output expander designed for press conferences, forums, and live events. It takes one line-level input and distributes it to twelve microphone-level outputs, each transformer-isolated to eliminate noise and ground loops. Housed in a rugged steel case, the PB12 ensures reliable performance and superior audio quality.

  • Type: Passive Pressbox
  • Input: 1 Line Level Input
  • Outputs: 12 Microphone Level Outputs
  • Isolation: Transformer Isolated Outputs
  • Transformer Type: Whirlwind TRSP-2
  • Case: Rugged Steel
  • Signal-to-Noise Ratio: 65 dB
  • Connector Type: XLR
  • Number of Channels: 12
  • Dimensions: 11.9 x 11 x 2 inches
  • Weight: 6.1 pounds

Key Features

Passive Pressbox with 1 Line In to 12 Mic Out

Specifications

Function
Pressbox Microphone Output Expander
Input Type
1 Line In
Output Type
12 Mic Out
Power Requirement
Passive

Pros & Cons

👍 Pros

  • Functions as a passive pressbox, ensuring robust and reliable operation without requiring external power.
  • Effectively expands a single line input to twelve microphone outputs, ideal for press conferences and broadcast events.
  • Designed by Whirlwind, a brand known for professional audio equipment, suggesting durable construction and reliable performance.
  • Simplifies signal distribution by providing multiple isolated outputs from one source, maintaining signal integrity.
  • Offers a practical solution for scenarios where a single audio feed needs to be shared with numerous recording or broadcast devices.

👎 Cons

  • As a passive unit, it does not provide any active gain or signal conditioning, relying on the source signal's strength.
  • The unit is strictly 1 Line In to 12 Mic Out, meaning it cannot combine multiple inputs or provide different output types.
  • Lacks individual level controls for each output, which could be a limitation when feeding devices with varying input sensitivities.
  • No information is provided about isolation transformers or ground lift switches, which are important for preventing ground loop noise.
  • The design is specialized for pressbox applications, and may not be versatile for other studio or live sound needs beyond signal splitting.

Frequently Asked Questions

The Whirlwind PB12 Pressbox functions as a microphone output expander, taking one line-level input and distributing it to twelve microphone-level outputs.
No, the Whirlwind PB12 Pressbox is a passive unit, meaning it does not require any external power for its operation.
It features 1 Line In and 12 Mic Out, allowing a single audio source to be fed to multiple recording or broadcast destinations.
While designed as a pressbox, its function of splitting a line signal to multiple mic outputs can be useful in any professional audio scenario requiring signal distribution without active components.
The Whirlwind PB12 Pressbox provides 12 microphone outputs from a single input, but the features do not specify individual level controls for each output.