Palmer PRMLS Review: A Proper Way to Split Monitor Outputs

Line splitters are the kind of studio utility equipment that rarely attract much attention until you actually need one. The Palmer PRMLS solves a very specific problem cleanly: taking a balanced line-level signal and sending it to multiple destinations while maintaining proper isolation between them.

We use the PRMLS in our own monitoring system, where it splits the monitor outputs from our API 2448 between the ATC monitoring system and our Dynaudio Core Subs. It is exactly the sort of application where a proper transformer-isolated splitter makes considerably more sense than simply hanging multiple loads from a Y cable.

Four channels of passive splitting

The PRMLS provides four independent channels in a 1U rackmount chassis. Each channel has one input, a direct thru connection and two transformer-isolated outputs. Because the unit is passive, there is no power supply and no active gain stage in the signal path.

That combination is useful in a studio because the thru output can continue feeding the primary destination while the transformer-isolated outputs provide additional feeds without directly tying the connected equipment together electrically.

Why isolation matters

Splitting a balanced line signal is not difficult in principle, but simply paralleling equipment can create problems with grounding, loading and interaction between destinations. Transformer isolation gives each split output galvanic separation from the source and from the other connected equipment.

In our monitoring setup, that is precisely what we want. The API console remains the source, while the ATC system and Dynaudio Core Subs can receive the monitor signal without turning the distribution arrangement into an improvised collection of Y cables and shared grounds.

In use

The attraction of the PRMLS is that there is essentially nothing to operate. Once installed and wired, it simply performs its job. There are no level controls to bump accidentally, no software configuration and no external power supply to fail.

That simplicity is particularly welcome in a monitor path. We are not looking for character or processing from a splitter; we want reliable signal distribution and isolation without having to think about it.

Build and practicality

Like the Palmer PAN 08 active DI that we also use, the PRMLS is fundamentally a utility product. The 1U format keeps four channels of splitting organized in the rack and is considerably neater than using individual transformer boxes for the same task.

It is also a good example of why apparently mundane studio hardware matters. Once a system becomes sufficiently complex, proper distribution, grounding and isolation become just as important as the more glamorous equipment in the rack.

Verdict

The Palmer PRMLS does one job and does it in the way we would want professional studio utility equipment to do it: passively, predictably and with transformer isolation where it matters.

For our API/ATC/Dynaudio monitoring installation it provides a clean solution to a real signal-distribution problem, and that is ultimately the strongest recommendation we can give a product like this.

Recommended.

Specifications

• Type: Four-channel passive line splitter
• Channels: 4
• Per channel: 1 input, 1 direct thru, 2 transformer-isolated split outputs
• Connections: Balanced XLR
• Maximum input/output level: +20 dB
• Format: 19-inch, 1U rackmount
• Power: Passive; no external power required

Manufacturer: Palmer / Adam Hall