Radial McBoost User Guide
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Using The McBoost™

The following page discusses how to use the McBoost. For complete details, we invite you to download the manual by clicking on the icon to the left.


The McBoost is a specially designed amplifier expressly made to increase the signal level of low output microphones using typical 48 volt phantom for powering. The magic lies in the unique circuit and subsequent effort in hand-selecting each individual part so that the device works within the intended specification.

Once connected, you will enjoy plenty of gain to boost your microphone so that you can enjoy the following benefits:

  1. Improved signal-to-noise
    When driving long cables, low output microphones are significantly more susceptible to noise from power cables, transformers and dimmers than line level signals. Boosting the signal near the mic will improve the signal-to-noise ratio and deliver greater clarity.
  2. More reach
    Dynamic mics are less sensitive than condensers. This generally makes them less appealing for low output sources. On the other hand, dynamic mics introduce character that can be quite appealing. By boosting the signal without noise, you can bring your dynamics to a new level.
  3. Higher output
    Low output devices such as vintage ribbon microphones, old dynamics and even early passive direct boxes do not produce sufficient level for many preamps and mixers. Pre-boosting the signal enables you to use your gear with these finicky devices.

Once you start using the McBoost, you will quickly become addicted. So try to control yourself!

Making connections

Before making connections, make sure all levels are turned down in order to prevent power-on and connection transients from damaging more sensitive components such as tweeters.

Connect your mic to the McBoost™ input using a standard XLR cable. The McBoost is wired to the AES standard with pin-1 ground, pin-2 (+) and pin-3 (-). Connect the output to your mixer or preamp using a second cable. The McBoost derives its power from the 48 volt phantom power in your mixer or preamp. Turn the phantom power on before turning up the volume. Slowly increase the volume on your input channel to test. It is a good idea to keep the volume at a low listening level during testing. This way, should a cable not be fully inserted, you will not encounter a loud pop when you assert the connection.

Setting the load

The McBoost is equipped with a 3-position load switch. This lets you experiment by changing the input impedance on various mics to see how they react. To get the lowest noise, the input impedance is usually set higher than the mic's characteristic impedance. Lowering the impedance will often roll off the bass response. Since there are hundreds of types of microphones, there is no set result. So have fun and experiment.