Transmi'Son

Additional information

The board comes bare, without cables or amplifier.

Photos, videos, components, colors, version, etc.: non-contractual.

In detail

When do you need it?

The Transmi'Son is needed as soon as your player and your amplifier are powered by the same source: a single adapter, a single battery, or a splitter feeding both. It's the most convenient setup for an installation, and it's precisely the one that causes the hum.

If each device has its own power supply, the hum usually doesn't appear. The Transmi'Son is then still useful for its volume control.

Where and how to connect it

Each side of the board offers two ways to connect, your choice:

• a 3.5 mm stereo jack socket, for a standard audio cable;
• a 3-screw terminal block (left, right, ground), for stripped wires, no soldering needed.

The jack and the terminal block on the same side are connected together: use one or the other.

• Input: connect it to the audio output of your player (Ambi'Son, Exposi'Son, phone, computer…).
• Output: connect it to the input of your amplifier.

You can mix them freely: for example, the jack on the input from your player and the terminal block on the output to a small amplifier.

The right setting. Turn your player's volume all the way up, then set the level with the Transmi'Son's potentiometer. This keeps the sound as clean as possible, with no unnecessary hiss.

Why the hum appears

When a player and an amplifier share the same power supply, their grounds are never at exactly the same level. This small difference finds its way into the sound, and the amplifier amplifies it: that's the hum. The problem isn't specific to my modules: it affects every player, from phones to the Raspberry Pi.

The Transmi'Son's two transformers fully separate the input from the output, much like a DI box in live sound. No wire links them: the sound passes from one side to the other, but the noise no longer does. You can therefore keep a single power supply for your whole setup.

The potentiometer

Many small amplifiers, very common in DIY setups, have no volume control at all: they always play at full level. The Transmi'Son's potentiometer gives you that control back, on both channels at once.

It is placed after the transformers: the bass is preserved, whatever the knob position.

Good to know

• The board is stereo: one transformer per channel. For a mono amplifier, use a single channel.
• It is designed for a line-level or headphone-level signal, not to be connected after an amplifier, on the speaker output.
• Like any transformer, it slightly reduces the deepest bass. This is inaudible on a small speaker or an exciter.

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