Palmer Audio Tools – Ready at all times! – Test Report by Soundcheck

A path for every signal.

The German manufacturer Palmer offers an extensive range of DI boxes and splitters of all kinds.
Musicians, studio operators, and any sound technician in search of the right box will find what they are looking for here.
Palmer offers a broad spectrum of products tailored to a very diverse assortment of audio transformer applications. The transformers used are all the result of in-house development. Just as in any tube amp, the audio transformer also has sound shaping characteristics that must be optimised in DI boxes and splitters. The Audionomix product line is designed with limited budgets in mind. The DI boxes in this product line all have a well-crafted steel plate housing. All inputs are jack sockets. There are also link/thru outputs for looping out the input signal. All variants have a separate ground lift switch, as well as selectable 30 dB input attenuation. The PAN 01 is the single-channel, passive variant in this series. The PAN 04 contains the same technology for two channels in one housing. The markings are exemplary and highly legible. The PAN 02 is the active equivalent of the single-channel PAN 01.

The inner values of the active PAN 02 differ considerably from those of the passive variant, for example, when it comes to output level. While the passive PAN 01 reduces the input signal by 20 dB even when the attenuator is off, in order to make line signals compatible with microphone inputs, the PAN 02 has an attenuation of only 4 dB. The input impedance of the active DI box is always 1 MΩ – ideal for the electric guitar. The input impedance of the passive PAN 01, on the other hand, depends on the mixing desk connected and, in the worst case, can drop to 60 kΩ. For this, it offers more headroom (+54 dBu) and a very frequency response curve well past the limits of human hearing. The active PAN 02 runs on both battery power and phantom power. Battery replacement necessitates disassembling the housing with four screws, and there is no battery status indicator. At least the battery voltage stays switched off unless there is a plug in the input socket. A four-channel version of the active variant, the PAN 03, is available in 19″ format.

Palmer’s PDI models are uncompromisingly conceived for audiophile applications. The massive housings seem to be of higher quality than those in the PAN line. Nevertheless: the whole design of these devices looks a little like one-off production; screws that have not been countersunk, unattractive burrs, glued on rubber feet – all a little rustic. Oh but you should see the inner workings! The active PDI 02 is a textbook example of a consummate DI concept. It can be operated with a 9V battery as well as on phantom power. Unlike many other active DI boxes, in the PDI 02, the phantom power also undergoes sophisticated transformation, so that its ground lift switch works just as reliably as that of a passive DI box. An LED lets the user check the battery status. With the help of a three-stage attenuator, the input adapts optimally to any signal.

At an impedance of 1 MΩ, the 0-dB setting reduces the input signal by only 4 dB and thus is exactly compatible with electrical guitars and high-impedance piezo pickups. In the 20-dB setting, the DI box converts line-level signals into microphone-level signals and also provides the usual line impedance of 47 kΩ at the input. The 40-dB setting permits direct connection of speaker signals. The passive variant is the PDI 01. It also provides a three-stage attenuator, which, however, is intended only for speaker signals. With the attenuator off, the PDI 01 provides an attenuation of 20 dB. At 200 Ω, its output has a much lower impedance than that of the less expensive PAN 01, making it less susceptible to mismatches and interference on the mixing desk end.

In practice, when it comes to interference-free feeding of audio signals to systems with different ground potentials, passive splitters are especially popular because of their reliability for line signals. This application makes especially high demands of the audio transformers used, because the high signal level quickly leads to signal discolouration. This can extend all the way to saturation overdrive of the kind encountered with analogue tape recordings. In this 1:1 transformer sector, Palmer also offers tailored solutions for every field of application. The PLI-03, for example, comes with RCA connectors and always uses full potential separation. It is a boon to anyone who has ever struggled with ground loops in unbalanced cables – whether with a computer, in video cabling, or in a car. The PLI-02 is the dual-channel splitter for all situations.

The ground lift switch simultaneously lifts the ground on both channels. The Neutrik combo input socket accepts jack plugs and XLR plugs. I advise anyone who can think of other potential applications for audio transformers to have a look at Palmer’s overall portfolio. There you will find active and passive splitters for line and microphone signals that offer up to two isolated outputs, or even press systems with 20 outputs. Even those in search of specialties such as transformers that passively mix line or microphone signals will not seek in vain at Palmer – not to mention their extensive palette of offerings for electric guitarists.

Attenuator: This word stands for “reducer”. Switches so marked usually make it possible to reduce signals in defined increments so that the sensitive electronics downstream in the circuit are able to process them. They are also available in adapter plug form for in-line use.

Concept: Palmer Audio Tools are useful little helpers that help get the soundman out of a bind when confronted with workaday problems such as ground loop hum, adaptations, etc. Many devices were created in response to customer suggestions. The devices, which are housed in die cast aluminium cases, were uncompromisingly designed to be of enduring professional quality. I recommend the PAN series to all quality- and price-conscious customers. Martin Schmitz, developer and founder of Palmer Audio Tools

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Conclusion: Indeed, the Palmer product portfolio contains a solution for every purpose. The PAN 02 is especially interesting in terms of economy. Here, even users on a budget can afford a product made by a renowned manufacturer. Users who are in the market for a more high-end solution should have a look at the reliable PLI-02 keyboard DI box.

Source: Soundcheck Magazin, Germany,  September 2003

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