GYRAF G14-S

NEW – Sept. 2020: The G14-S is a passive stereo equalizer, equipped with two different topologies for makeup gain and interfacing. The filter itself consist of five bands – each with 11 switchable frequencies, continuous variable “Q”, and individual boost/bypass/cut selection. The unit has an overall output level “TRIM”, and a hard relay bypass serving as reference for your work.

The stereo channels are linked – controlled with one set of knobs, so you won’t ever have to match settings of two channels. The “Q”s, filter sharpness, are rather low when boosting, but higher at cut – approaching notch behavior at extreme cut settings. This is both a side-effect of the applied passive technology – as well as quite desirable in situations where sound integrity is the paramount factor.

Frequencies for the five bands have been selected with special attention to controlability of the midrange area, with approximately half a frequency-range overlap to the adjacent bands.

This equalizer technology is a very extended version of the classic passive inductor/capacitor type filter. Although the classic versions are very useful tools in many situations, they often feel somewhat limited due to their simple construction and coverage. Our engineers wanted – as engineers tend to do – much more of everything. So we came up with the parallel-passive design, the G14.

G14-S is based on this truly passive design – switching a set of inductors and capacitors in and out of circuit. This passive filter set is then matched with input/output interfacing for trouble-free interfacing to the outer world, and a gain stage to make up for the approximate 20dB passive loss in the filters.

For this, we give you a selection of two different technologies – at a flick of the bypass switch: When set to “IN”, you have the traditional and much-loved selection of tube makeup gain based on 6H23n (E88CC/6922) tubes combined with transformer-balanced input and output interfacing.

If this gets to be too much of a good thing, you switch the bypass to “S” – and we replace everything but the filter and controls with entirely different technology: The inputs are now integrated balanced differential receivers, amplification is handled by a high-grade opamp, and output is driven by state-of-the-art active servo balancing circuits. Two entirely different personalities in one box.

An important feature – for us – is that the original signal path of the classic G14 is fully preserved in the G14-S: Only parts relating to the solid-state path has been added, in “tube mode”, the G14S

•G14-S is as standard available as a 230V mains unit – other mains voltages will be made on request (at no extra cost).

Note that the following reviews, manuals and recall sheets are for the “classic” version of the G14, i.e. only valid for the “IN” part of the G14-S. We are working on updating in near future..