Gyraf Audio G10 Der G10 ist ein Vollröhren-Stereo-Kompressor, basierend auf dem klassischen Variable-Mu Prinzip. Die Methode, die Lautstärke durch die Veränderung des Stroms in Differenziellen-Röhrenpaaren zu kontrollieren, ist viel schneller als das elektro-optische Prinzip. Die Geschwinigkeit war der Hauptverwendungszweck in den ersten Limitern, wie dem Fairchild 670 oder dem Universal Audio 176, es sind aber die klanglichen Eigenheiten dieser Schaltung, die sie heute so populär macht.Die Bedienelemente des Gyratec X: Der Eingangspotentiometer befindet sich direkt hinter dem Eingangs-Übertrager und erlaubt somit die Regelung des „drives“ des Kompressors. Der Threshold-Knopf regelt den Schwellenwert der Kompression. Entgegen dem Uhrzeigersinn gedreht, wird ein niedriger Schwellenwert festgelegt und damit mehr komprimiert. Auf Rechtsanschlag wird die Kompression deaktiviert. Am Ratio-Regler wird die Stärke der Kompression in Abhängigkeit des Eingangslevels justiert, also für den Teil des Signals, der den Schwellwert übersteigt. Auf Rechtsanschlag wird die Kompression deaktiviert. Der "Attack"-Potentiometer regelt die Zeit, die der Kompressor benötigt, um auf ein ansteigendes Eingangssignal zu reagieren. Mit dem "Release"-Regler lässt sich die Zeit einstellen, bis die Kompression, nach Unterschreiten des Schwellwerts, wieder aussetzt. Mit dem Ausgangspoti lässt sich der Signalpegel zu den Endstufen-Treibern regeln. Der Bypass-Schalter ermöglicht das einfache Ausblenden aller aktiven Elemente, indem er den Eingang über ein Relais mit dem Ausgang verbindet. Der G10 wurde in jüngster Zeit zu einer G10 /HPF Version weiterentwickelt, die eine Hochpassfilterung des Sidechain-Signals gestattet - und damit eine Kompression von basslastigem Material, ohne pumpende Artefakte, ermöglicht. Die Cut-Off-Frequenzen 80, 160 und 300 Hz können durch einen dreistufigen Bypass-Schalter angewählt werden. Die Filterkurven laufen sanft aus (6 dB/oct). Die Ein-und Ausgänge des Gyratec 10 sind trafosymmetriert und erdfrei ausgelegt. Die Eingangsimpedanz liegt bei >10 kΩ, am Ausgang sind es <1 kΩ. Der G10 basiert auf einem sehr minimalistischen echt-differenziellen Signalweg vom Eingang zum Ausgang. Dabei wurden sehr, sehr gründlich ausgesuchte PCC189 (7ES8) Remote-Cutoff Dual-Trioden für die VCA-Stufen gewählt und rauscharme E88CC (6DJ8) -Trioden als Kathodenfolger für die Endstufe-Treiber verbaut. Beide Typen sind auch heute sehr gut erhältlich. Der Gyratec X ist ab Werk auf 230V Netzspannung angepasst

Gyraf Audio G14S 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 Input impedance – around 5K Ohms, transformer balanced or 24K Ohms Servo/ differential receiver balanced input
 Output impedance – ~1K Ohms, transformer balanced or ~100 Ohms, active servo balanced
 Make-up gain Amplification by 6n23p/E88CC tube stage or contemporary opamp circuit
 Max boost/cut – ~10-12dB, depending on “Q” setting
 Gain trim ~+3 – -5dB – unity gain somewhere between 12:00 and 14:00, depending on tube matching point
 Each of the five bands are individually hard-bypassable (on the “MODE” control)
• Channel tracking better than ~1dB Frequency markings are:
 Low: 35-48-60-70-80-100-120-160-190-220-270Hz
 Low mid: 180-230-280-330-400-430-490-550-590-650-750Hz Mid: 500-570-700-800-900-1K-1K1-1K3-1K5-1K8-2K1 Hz
 High mid: 950-1K2-1K4-1K7-2K-2K5-3K-3K5-4K2-5K-6K3 Hz
 High: 4K5-5K6-6K5-7K8-9K1-12K-14K-16K-18K-20K-22KHz G14-S is as standard available as a 230V mains unit – other mains voltages will be made on request (at no extra cost).

Gyraf Audio G21 The G21 is kinda an elaboration on our G14 parallel-passive eq - the parallel topology enables multi-band control without running into the traditional problems in multi-banding (i.e. the problem in phase at recombining)Use carefully - this is in no way a fire-and-forget gadget: Multiple types of interacting nonlinearities are at large, even a few in macroscopic time-domain because of components heating and temperature coefficients. Changing something in one band will sure as hell result in something else showing up somewhere else. Feels organic in that.Classic problem is that multi-banding gives inadequate results because of filter phase shift messing up recombining. We deal with this by NOT band-splitting, but in stead dealing with all frequencies in parallel fashion, only opening frequency-selective channels into the clipping circuitry. Byproduct of this is that spike/peak phase is altered first, only to be real-clipped if pushing the phase won't get the total signal below threshold. Kinda like an audio file hair-remover (work title of the G21 was "The AudioShaver")As we all know, clipping generates harmonics - there's simply no way around that. But what you do with those harmonics will make a lot of difference. The beauty is here, that as the clipping is done at the remote end of a frequency selective channel, the clipping byproducts (harmonics, at frequencies multiple times the clipped) have a hard time getting back out and into the audio, because they are now no more in the right frequency range..And other than the three bands of clipping, we have an overall clipper that can be set for linear (white), pink -3dB/oct or red -5dB/oct emphasis - enabling gradually lower "threshold" at higher frequencies.Then there's a fine-trim for output level and a 18dB/oct lowcut at the input - mainly because most of our test pilots were mastering engineers :-)

Gyraf Audio G22 Gyraf Audio Gyratec GXXII - Dual/Stereo/MS Vari-Mu Kompressor G22 is an elaborated and dualified version of our venerable G10 vari-mu compressor. It can be set to dual-mono, but still keeps a backwards-compatibility "G10 mode" where one set of knobs controls real stereo, like you'd want most of the time in mastering.The audio part of the circuit is a faithful reproduction of the G10 that has been our flagship for more than 15 years - if it works, don't fix it. The only minor change is a re-bias of the output stage, which allows some 4-5dB more headroom while preserving the original stage's soft transition into overload.Some changes has been made to the sidechain functions, including a wider threshold range (to allow S compression in weak-S M/S-mode) and even faster fastest attack time (because we can, it's a vari-mu you know...)A simple sidechain high-pass filter was added (located on the bypass switch) which cuts off compressor keying below ca. 80Hz at a slope of 6dB/oct. This mainly to keep pumping artifacts under control when working fast in bass-heavy material.Input and output transformers can be switched between standard two-channel L/R mode and the M/S mode where both matrixing and dematrixing done is internally: M/S mode allows you to independently control dynamics (and levels) in mono and side parts of program material and still have the result on the output as standard stereo information.Linking/dynamic interaction between channels in dual-mode can be set continuously from none to full by the Vari-link control knob - enabling you to dial in a difference in channel processing, and then varying difference amount in a simple mode. When initially getting to learn the unit, I myself was amazed how intuitive this control worked.Bypass is, off course, hard and relay-based. You bypass, G22 acts only like an additional piece of cable.The G22 is as standard available as 230V or 115V mains voltages - Please specify when ordering

Gyraf Audio G23S  Gyraf Audio Gyratec XXIII Ambler Tilting Equalizer The G23 is a Tilt-type Equalizer aimed mainly at mix and mastering - for the situations where you have a mix that is already nearly-perfect balanced, but you want it a tad darker or brighter without messing up the overall definition.Gentleness and subtlety were main design targets here: Nothing anywhere near surgical: Tilt and Highs at +/-4dB, mids at +/-2dB, and lows at +/-6.5dBWhat sets it apart from all other tilt EQ designs is that we designed it around a highly linear 1dB/oct slope filter, so that rotating the tilt control will tilt an almost ruler-straight response curve, to a maximum steepness of 1dB/Oct.Our reason for doing it like this is that although a standard tilt (which is basically a Baxandall control, that cuts top while boosting low and the other way around) does come with the associated phase roll that is a side effect of all analogue-domain filters. And this group delay/phase roll (which is distributed just around cutoff frequency) easily identifies the sound to our ears as "equalized".So what we acheive in the 1dB/Oct tilt function is to "spread out" or distribute the "needed" phase roll across the whole spectrum, meaning that at any given interval, only minute amounts of group delay is apparent.In total, it allows quite some correction without sounding "Eq'ed".And because you'd occasionally want to correct outer ends of spectrum, we have added a gentle Baxandall tone control, shelving lows and highs, wide-Q bell mid, each at three selectable frequencies, that we spent quite some time optimizing. G23 is stereo, single set of controls - and off course based on tubes and passives alone. Bypass is full-relay, and it has a gain trim function for easing comparison between direct and processed material.The G23 is as standard available as 230V or 115V mains voltages - Please specify when ordering

Gyraf Audio G24 Gyraf Audio Gyratec XXIV Passive Compressor The G24 is an entirely new type of stereo compressor - aimed at mix and mastering functions. Like it's sister and predecessor, the G23 EQ, it's for those situations where you have a mix that is already nearly-perfect balanced, but you want to control some part of its dynamic without messing up the overall definition.Gentleness and subtlety were again our main design targets here: This compresor is based on a carefully designed fully passive signal path, consisting of one metal film resistor, one audio transformer and one photo resistor per channel. That's it. Nothing more.Yes, the elaborate sidechain and controls need active electronics (and thus a power supply, contrary to G21) - but all these analogue engines only ever interacts with your audio by directing a bit of light to an array of photo resistors dragging that channel towards one or the other phase of the opposite channel signal. Nothing else. We believe this to be the most important innovation in the G24, the passive audio path - inspiration and technology borrowed from the notorious G21. But this is far from the only innovation that sets it apart from every other compressor out there: Most of it's intricate control system was conceived from scratch, following a stringent "what-if" paradigm of research, trial and error. This  Dual sidechain. No, not just a dual-mono option, but two separate stereo-compressor sidechains acting simultaneusly on the signal. Equals two separate stereo compressors. You can use one to grab short transients with fast timong, and the other to slowly ride gain... On top of this we give you the "Control" pot, that morphs seamlessly between the two compressors Gradually variable all the way from L/R to M/S. Yes, although the G24 can be thought of as a couple of stereo compressors, it is in reality two M/S compressors that are fully variable all the way from from M-only (Mid component) to S-only (Side component) - the beauty being that when the "Elliptic" control is centered, (M-compression = S-compression), it acts (and is) the same as a stereo compressor. or rather: Two stereo compressors.. Compression Fully variable from FeedForward to FeedBack. Now wait, two individual compressors, you say: But how do we decide which of those comes first? Kinda important factor in compression, is it not? Aah yes. We included a "Feed" control for your convenience, allowing you to dial in a setting from feed-forward to feedback INCLUDING everything in-between. You are not limited to having just one of them first (or last) - you can set both of them as you want, e.g. having both first (!). Uh - and you can set them in-between also, off course - you may realize that FF and FB compression are subjectively perceived as two very different beasts - and the continous fade between their ways makes a lot of sense. Mono-compatible Sidechain signal summing for M/S collapsing to make sense. When initially trying to think up this compressor, the main design obstacle was about keeping the sidechain (relatively) simple. As we really want both L, R, M, and S to be able to contribute to the derived control voltages (because it's a MS-compressor as well as a LR), we could not simply add input/output signals to derive a singular signal for the sidechain, as this would completely cancel out the "Side" part of the signal, leaving us with only "Mid" component. One - in reality almost impossible - option would be to build four tracking sidechains, and then sum them before Ratio control. What we did is something old and new: We re-purposed an ancient signal processor that was designed to maintain mono compatibility for stereo signals e.g. when transmitted over AM - this processor shifts signal phase +90 and -90 degrees in the two (LR), which ensures that when adding the two channels after processing, you get +3dB Side component and +3dB Mid, in stead of loosing all "S" and getting +6dB of "M" Sidechain Tilt emphasis  One meter - some metering compromises. As you may or may not know, optical compressors can no longer be sold in the EU or California. No execptions. The industry (of which I'm part) is trying to ignore this away, and the G24 was conceived as a protest against an environmental legislation that allows massive amounts of Cadmium for batteries, yet bans an entire division of audio processing in order to save the environment from the very-small amounts of Cd in these OptoCouplers. All very technical and sad, don't get me started... The "Aggressive" part of the unit's name comes not from it's way of behaving, but from my aim of stirring up the soup to get some sort of focus on the unbearable situation for real pro audio because of these rules... What it sums up to is the fact that the G24 is not really for sale, as we can't sell you it's heart - the CdS cell. We will need to remain legal owners of that central part, and only only lease it to you temporarily. That is; You want one, we will need you to sign an agreement that we own the heart, and that at some time (if ever), when we have found a suitable replacement material and shipped you a module containing a new and legal part, that you will open the unit, plug the new one in, and send the old one home to us. We have arranged a disposal ritual as a small yellow-orange dot on a piece of pottery from a local artist - this is one of the legal uses of cadmium. So prepare for some paperwork if you're in the EU or California like 95% of our customers. G24 is M/S, two sets of controls - and passive. There is an option to buffer output to ensure drive capability for difficult loads if such are encountered. G21 anyone? Bypass is as always full-relay, and G24 has a output trim function for easing comparison between direct and processed material.The G24 is as standard available as 230V or 115V mains voltages - Please specify when ordering