EMT 140

German company EMT made a breakthrough in 1957 with the release of the EMT 140, which utilized a resonating metal plate to create ambience. Despite its roughly 600 pound weight, the EMT 140 plate provided a smaller solution to large echo rooms. Additionally, a remote controlled damping pad system allowed the engineer to adjust the reverb time, offering substantially more control than possible with a traditional chamber. The sheet metal plate is suspended from its frame by springs, a transducer mounted at the center of the plate drives movement, and returns consist of pickups mounted on the plate. While the 140 was originally available only in mono, EMT released a stereo model in 1961.

Sony DRE-S777 Sampling Digital Reverb

The Sony DRE-S777 Sampling Digital Reverb employs a newly developed DSP (Digital Signal Processor) which allows Real Impulse Response processing. It performs high speed, real-time processing, and provides natural reverberations based on actual acoustic spaces such as concert halls. The supplied CD ROM holds reverb data of existing acoustic spaces for the Sony DRE-S777 such as concert halls and churches, as well as a digitally simulated plate reverb which was previously impossible. Variable reverb data, with different reverb times, are provided for each sound source.The memory stick is capable of storing up to 99 reverb setups, 92 adjusted on the MIXER and SETUP displays plus 7 factory presets. A memory label can be set for each setup. This function is useful when you want to recall the status previously adjusted. Reverb programs based on famous halls, churches and natural environments worldwide are also available in the optional DASK-S70x series sampling reverb software CD ROMs.

Lexicon PCM 70

The Lexicon PCM 70 Digital Effects Processor gives you access to the same astonishing digital effects used by the world’s top artists and studios all in a compact single-space rack mount unit. The Lexicon PCM 70 offers more than 40 digital effects and reverb programs, including chorus and echo, resonant chords, multiband delays, rich chamber, rich plate, tiled room and concert hall. Add to these the 50 programs you can create and store in user registers, and you have instant access to more than 90 programs.

EMT 250

The EMT 250 Electronic Reverberation Unit is a real time audio signal processor, exhibiting high memory capacity and extensive mathematical possibilities. The 250 was introduced in 1976, and it's still regarded as one of the best-sounding reverb units ever made, the EMT 250 was the first digital reverberator to operate through a purely electronic system. 

Although only around 250 hardware units were ever built, the EMT 250 continues to leave an immeasurable mark on record-making history appearing on countless records, including Prince & The Revolution’s Purple Rain, Elvis Costello’s Spike, and modern classics like The Red Hot Chili Pepper’s Stadium Arcadium.

It provides a variety of signal processing functions, namely: 

High quality reverberation with adjustable decay time and frequency response, as well as determination of the first reflection delay for mono, stereo and quadraphonic signals.

Pure delay of an audio signal by as much as 375 ms available at four separate outputs, each with individually selectable delay time. 

"Chorus" with independent pitch variation at four fixed delay taps.

Echo with repetition time adjustable between 5 and 315ms.

Special effect reverberation (SPACE REVERB) with approximately 10s decay time.

Roland SDE-3000 Digital Delay

The Roland SDE-3000 is a high quality delay unit featuring various delay effects and also the Memory function that retains up to eight different panel settings, therefore, it is extremely helpful for both studio and live performance. The Roland SDE-3000 offers such a dynamic range of 100dB and a low harmonic distortion of 0.03%. Long Delay of 4.55 seconds is now available, which is specially useful for live performance. The input and delay output levels can be controlled, so that the lowest Signal to Noise ratio and widest dynamic range can be attainable.

TC Electronic 2290 Dynamic Digital Delay

The TC Electronic 2290 is known as the industry standard Digital Delay. The 100db dynamic range, 20 - 23000 Hz  soft roll off frequency response and 1 Mhz sample rate are part of the t.c. electronics design philosophy. In the studio it means no compromise where recordings for compact disc are concerned and to the performer, the 100db dynamic range means crystal clear sound, eliminated hiss and the headroom for all the punch needed.  Five programmable effect loops and MIDI control allow the TC Electronic 2290 to control your rack boxes and your favorite pedals simultaneously.

The Dynamic Control and Learn function provide you with a very unique tool to create new and exciting effects. The unique Dynamic Function enables you to suppress the effects when you are playing and let the effects reappear when you stop playing or the opposite.

AMS RMX 16

The AMS RMX 16 uses sophisticated 27 bit pipelined data processing and offers an 118 kHz bandwidth and a 90dB dynamic range and 0.03% distortion in delay mode; low power consumption (and therefore cool running); Once programmed, complex setups may be stored in any one of up to 99 easily accessible user memories. 

The RMX 16 also contains several very high quality special effect programmes including the already well renowned nonlin and reverse, stereo echo, image and freeze.

Lexicon 480L

The Lexicon 480L is a modular multi-machine architecture unit . Capable of simultaneous usage by two LARCs (Lexicon Alphanumeric Remote Control) sharing a single mainframe.

With resident software, the 480L has 21 Banks of 10 Presets each containing the widest variety available of premier quality algorithms, including the classic 480 Halls, and Rooms, Brick Wall, Silica Beads,and 40 Voice Effects (like the classic Vocal Whispers), Digital Compression, Stereo Adjust mastering, 3 second stereo or 6 second mono Sampler, Prime Time III, Mix Finish, Doppler and Pitch Effects, Plates, Random Halls, Rooms and Ambience (the smallest room size now extends down to 2 square meters).

Since its inception, the 480L has been used on more gold and platinum recordings, as well as top-grossing film soundtracks, than any other system of its kind. Moreover, Lexicon processing is used by over 80% of all record companies for mixing and mastering.

Lexicon 224

Developed by renowned physicist/engineer Dr. David Griesinger in 1978, the Lexicon 224 is the most ubiquitous and best-selling studio digital reverb ever made. The original 224 was a landmark achievement in digital reverb and served as the very product to put Lexicon on the studio map and a remote control on every console. The 224's Concert Hall A program is considered to be one of the finest reverbs ever made, and its plate programs practically defined the 80's drum sound.

The Lexicon 224 was well known for its spacey, extra long decays (up to 70 seconds) it used a fixed point processor, with a 16-bit word size, and a 20-bit saturating accumulator. The 224 had about 24 dB of headroom internally (4 times the max input volume).

AMS S-DMX

The S-DMX is a dual independent channel microprocessor controlled digital audio processor. It offers two completely independently delayed channels with precisely controlled delay times. The delay times are adjustable without any sacrifice in the 18kHz bandwidth which remains constant irrespective of the amount of delay selected. A total delay of over thirty two seconds is possible with this unit, split over the two channels. The S-DMX is designed as a rack mounting unit 3.5”/2U high and 12.7” deep, excluding knobs and connectors. The choice of components and quality of construction are of a high standard and because of the choice of motherboard system with plug in circuit cards and ribbon cables, maintenance problems are reduced to a minimum.

Lexicon PCM 42

The PCM 42 is a high-performance digital delay line/processor that features 2.4 seconds of high quality audio delay. Delay times are indicated by a highly accurate numeric display, which provides rapid tracking of ALL changes in delay time. The PCM 42 includes versatile audio patching and remote control facilities, and a unique synchronizing clock feature that allows highly musical usage of the very long delays of which it is capable. Long repeat loops and layering effects which were formerly confined to the studio may now be used easily and reliably on stage.

The PCM 42 provides superior audio performance through Lexicon's proprietary method of analog-to-digital encoding. An increased sampling rate gives wider bandwidth without aliasing effects. In addition. a "soft-knee" limiting circuit eliminates the unpleasant distortion that most digital circuits generate when overloaded.

DRAWMER DS201

The Drawmer DS201 is a sophisticated dual channel noise gate incorporating a number of features pioneered by Drawmer, which are invaluable to the sound engineer, and not found on conventional noise gates.Drawmer pioneered the concept of frequency conscious gating, and the Drawmer DS201 was the first noise gate to include this feature.The very fast attack of the DS201 means that it can open in a matter of microseconds, thus preserving the natural attack of whatever sound is being gated and the comprehensive envelope controls mean that the gain can be changed at whatever rate best suits the material being processed.

Helios Type 69 EQ

Helios consoles were used to record and mix some of the finest rock, pop and reggae classics ever produced. The Beatles, Led Zeppelin, The Rolling Stones, The Who, Roxy Music, Queen, Jimi Hendrix and Bob Marley are just a few that recorded with these amazing wrap-around consoles. Of all the Helios consoles produced between 1969 and 1979, the original “Type 69” is considered the most musical.The simple yet powerful Helios Type 69 Passive EQ adds a unique sonic texture to the music that passes through it. It can be pushed to its most extreme boost settings while retaining openness and clarity. The Type 69 Passive EQ replicates all the controls of the original hardware. The Treble band is a fixed 10 kHz shelf EQ, while the Bass band functions as a stepped 50 Hz shelf filter (-3,-6,-9,-12,-15 dB) or frequency selectable Peak EQ (60, 100, 200, 300 Hz). The Mid band operates as a frequency selectable Peak or Trough (Notch) EQ with eight frequencies (.7, 1, 1.4, 2, 2.8, 3.5, 4.5, 6 kHz). Other features include Level adjust, EQ Cut (bypassing the EQ circuit while retaining the native sound of the unit), and Phase Reverse.

The Trident A-Range EQ

The unique EQ section of the board is what the Trident A-Range sound is all about. A series of three high pass filters at 18 dB per octave and three low pass filters at 12 dB per octave are arranged at the ends of the EQ section. They are unique in that the switches can be pushed in simultaneously, offering distinct cut filter combinations with unusual filter curves. The rest of the EQ section allows four frequencies at any one time, switchable to one of four frequencies. Low Shelf: 50, 80, 100, 150 Hz; Low-Mid Bell: 250, 500 1k, 2k Hz; High-Mid Bell: 3k, 5k, 7k, 9k Hz; High Shelf: 8k, 10k, 12k, 15k Hz. With a unique tactile experience, linear faders control the gains, with around +/- 15 dB of boost/cut.

TELEFUNKEN / TAB W395A EQUALIZER

The W395 is a fully discrete Class A transformer Equalizer manufactured by TAB / Telefunken. 

It was the direct successor of the germanium-W95, with identical EQ circuit, but with improved amplifiers based on the emerging silicon transistors. In later versions of the W395a the EQ circuit was again revised and still used more complex coil filter.

 

Neve 1081

Designed in 1972, the Neve 1081 was originally conceived as a combined mic/line preamp and equaliser section for the Neve modular consoles.The 1081 provides remarkable sensitivity, fast and musical response to transients, 5 switchable EQ bands, HP and LP selectable filters (18dB per octave) and Mic and Line inputs. Over decades engineers have found the 1081 an indispensable tool for recording and mixing drums, bass and percussion.

Neve 1084

The Neve 1084 mic pre/EQ delivers an incredibly fat, smooth sound. While the 1084 builds on the same basic design of the world-famous 1073, it offers a significantly different palette of frequency selections. The 1084 also features a "Q" switch, allowing the user to choose between two different Q types, either narrow or wide with respect to the parametric band.  The 1084’s three EQ bands provide selectable frequency, with cut and boost capability, and a mid-frequency band which benefits from a High Q Presence switch. The high pass filter can be switched between 45Hz, 70Hz, 160Hz & 360Hz, and the low pass filter between 6kHz, 8kHz, 10kHz, 14kHz, & 18kHz. Both boast 18dB per octave slopes.

Neve 1073

Launched in 1970, the 1073 is the first choice of leading producers and artists, delivering the unique Neve sound on some of the most famous recordings of the past 40 years. The big, punchy sound of the 1073 complements any musical genre – from rock to pop, hip-hop to rap, thrash to classical. The Class A design 1073 microphone preamplifier features 3 bands of EQ, with one fixed high frequency band, two switchable bands with cut and boost capability, and a high pass filter.

The Neve 1073 mic pre and EQ combination adds warmth and depth to recordings, brings out subtle ambience, maintains spatial positioning, and more effectively captures a precise image. That’s why the 1073 mic preamp is considered by many to be the very essence of the Neve sound.

Maag EQ4

The Maag Audio EQ4 is a one channel 6 band equalizer with AIR BAND (shelf boost from 2.5 to 40 kHz) compatible with the API 500-6B lunchbox® and 500VPR rack systems. Following its EQ3 and EQ3-D predecessors, the EQ4® provides unparalleled transparency and top end presence while maintaining the true natural sound behind the mix. EQ adjustments are obtained with minimal phase shift and detent controls allow for easy recallable settings.
Presented in the flagship lunchbox® portable format, the EQ4® offers the legendary 

AIR BAND® and five other sonically superior band passes.

API 560

The 560 was originally conceived for use in API consoles of the '60s and '70s.
The 560 offers ten bands of graphic EQ, making it an ideal tool for shaping your mix with surgical precision. API’s proprietary “Proportional Q” intuitively widens bandwidth at lower boost/cut levels and narrows it at higher levels, giving you more musical control over precise bands of your mix.

API 550A

Introduced in 1971, the 550A was the standard channel EQ module on API’s first consoles. Its sonic quality quickly reached legendary status, and the 550A and 560 modules soon gained new popularity in custom designed consoles and the personal “lunchbox” racks of audio pros.

The 550A gives you three overlapping bands of parametric EQ at 15 points with up to ±12 dB of gain, controlled by three dual-ganged rotary switches. The HF and LF bands feature individually selectable peaking or shelving modes, plus an independent 50 Hz to 15 kHz band-pass filter. It’s the perfect secret weapon for helping drums and guitars stand out in the mix.

TubeTech EQ 1A

The TUBE-TECH EQ 1A is a full range one channel unit, featuring low and high cut,

low and high shelving as well as three overlapping bands of equalization.

The cut filters are designed around unity gain amplifiers and the shelving and the bell filters are designed around two tube operational amplifiers.

The unit is all tube based except for the power supply. Input and output have fully floating transformers. All DC voltages are stabilized, except the anode voltage for the output stage.

RETRO 2A3 Dual Program EQ

Vintage Tube Amplifiers and Custom-Designed Transformers set the soundstage. True Passive Equalization creates Bountiful and Musical Equalization curves. 

The new RETRO 2A3 is designed as an ultra High-Fidelity Program Equalizer whose sonic benefits go beyond the equalization process. Accurate to the industry-standard Pultec EQ performance, the RETRO 2A3 adds HF boost frequencies in several new sweet spots. Carefully implemented HF boost circuits capture the signature sound of the original passive equalizers.

The RETRO 2A3 passive equalizer circuits do not rely on amplifier feedback, which can cause a harsh and clinical sound in typical active equalizer designs. By incorporating pure passive Capacitor - Inductor based equalization; the RETRO 2A3 sounds so natural and effortless even with extreme boosts and cuts.

MANLEY ENHANCED PULTEC EQP1A

MANLEY LABORATORIES is the only authorized user of the original Western Electric passive EQ circuitry previously licensed to Pulse Techniques, Inc. found in the well-known antique Pultecs.
EQ may be set to 'flat' positions or BYPASSED entirely. All BOOST and CUT controls are continuously variable conductive plastic potentiometers for absolutely silent operation and long life.
The rear mounted input switch selects 0 degrees or 180 degrees phase invert for the balanced gold pin XLR input or the transformerless unbalanced bridging input (1/4" jack) may be selected.
The Manley Enhanced Pultec has a vastly superior B+ power supply, with regulated and balanced heater supply.

PRISM - MASELEC MEA-2 MASTERING EQUALIZER

The MEA-2 is a very special equalizer that has been designed to achieve a certain sound. It has a distinctive character, discernable both sonically and in the unique shape of its EQ curves. It provides the warmth, punch or air you need with a minimum of effort and without compromising the signal path.

The Prism Sound Maselec MEA-2 is a stereo or two-channel, four-band precision analogue equalizer with variable Q/shelf, frequency and cut/boost controls on each band. 

The MEA-2 was developed for Prism Sound by engineer/producer Leif Mases. Leif's work with a diverse range of artists including Abba, Led Zeppelin and Black Sabbath provided the essential experience using the "tools of the trade" needed to define and implement new and improved professional audio components. Also qualified in electronic design, Leif Mases developed the highly acclaimed Maselec 9001 retrofit equalizer for SSL 4000 mixing consoles used in top film and recording studios. Later, Leif teamed up with Prism Sound to provide the Maselec Master Series which embodies the ideals of technical excellence and creative capability that both share.

Manley Massive Passive Mastering Version

The Massive Passive equalizer excels at everything from the drastic shaping needed for tracking to the most subtle of shadings needed for affecting vocal tracks or the whole mix.

The Manley Massive Passive Mastering Version equalizer features a simple, passive design - not a standard parametric design - for more natural, organic shaping. It also offers mechanically detented knobs for both Gain and Bandwidth controls, so you can easily repeat your settings. On the Massive Passive Mastering Version, both the Gain and Bandwidth controls intentionally interact, and the bands interact, as well - this creates an incredible-sounding result without sounding "colored" or "processed.

GML 9500

The 9500 is the Mastering Version of the 8200. 

The Gain, Frequency, and Q controls are fully-detented for absolute precision and repeatability. With 1/2dB steps of Boost and Cut and 24 different frequency choices per band, the 9500 is a powerful and comprehensive workhorse for Mastering Engineers around the world.
The 9500 is an all-discrete transistor unit, and is useful in many stages of the recording process and highly regarded for its extraordinary resolution, transparency, high headroom, broadly overlapping bands and ease of use.

GML 8200

Brought to you from the man who invented the term “Parametric Equalization”, the 8200 has been an industry standard for over twenty years, and can be found on virtually every major recording studio. Each of the five broadly-overlapping bands offers 15dB of Boost or Cut and adjustable bandwidth (or “Q”) from 0.4 to 4. 

The lowest and highest bands also can be switched to Shelf mode. Quite simply, the 8200 is the archetype Stereo Parametric Equalizer. Its extraordinary resolution, benchmark transparency, generous headroom, and surgical precision have been the reference for many other equalizers but exceeded by no other.

Chandler Limited Curve Bender

The Curve Bender was conceived by Chandler Limited designer Wade Goeke and is based on the vintage EMI TG12345 desk used to record The Beatles and Pink Floyd. This newest EMI equalizer continues the tradition of EMI EQs started in 1954 with the RS57, the 1969 TG12345, and the 1974 TG12412.
Wade turned the nine selections of the vintage version into 51 EQ points plus a multiply switch that increases the boost/cut to 15dB (as well as sharpening the Q), filters and bell/shelf selections on the high and low bands.

Pultec EQP1A 3

The Pultec Model EQP1A 3 Program Equalizer consists of a passive equalizer, an amplifier and a self contained power supply. The amplifier restores the insertion loss of the equalizing network, thus providing a no loss, no gain unit.

Operating the key switch away from the "in" position is equivalent to returning ALL boost and attenuate controls to their zero positions. The amplifier remains in the circuit.

PULTEC HLF-3C

The HLF-3C is a very wide range Program and Sound Effects Filter. It has been designed specifically as an effective aid in the production of good music and dramatic presentations.
It provides 12 dB per octave low and high cut filters. Not only is the HLF-3C helpful for tweaking instruments, this powerful steep-sloped filter can also remove unwanted hiss and rumble from your tracks.

Pultec EQH-2

The EQH-2 is a 2 band passive program EQ that uses a 12AX7/6AQ5 tube gain stage driving a 

Triad HS50 output transformer in class A mode. The 2 Bands have selectable frequencies with continuously variable boost and attenuate functions.

Low frequencies: 20-30-60-100 Hz
Boost: 13.5 dB, attenuate: 17dB
High frequencies: 3-5-8-10-12 KHz tube
Boost: 16 dB, attenuate: 16dB (10kHz shelf only)

PULTEC MEQ-5

The MEQ-5 was built for mid range use and focuses in on the power range frequencies from 200Hz to 7kHZ. Essential for guitars and vocal, this equalizer features separate boost and cut bands, which can help to create powerful sounds with bite. 

The MEQ-5 Midrange EQ provides two boost bands and one dip band in the midrange region. This EQ is very useful for adding presence and punch to your tracks. It’s also helpful for clearing out problem areas in the midrange frequencies that can make a mix cloudy.

Pultec EQP-1A

The original EQP-1 was launched in 1951 by Pulse Techniques, a company formed by Ollie Summerland and Gene Shank in Teaneck, New Jersey, USA.Summerland and Shank hand-built the first units and, following a very early modification to the design, the original Pultec EQP-1A remained in production for the best part of 30 years.

The Pultec is a 3U all-valve design that makes use of EEC-82 and EEC-83 valves alongside a 6×4 rectifying valve in the onboard push-pull amplifier. The amplifier restores the signal level that is reduced when an audio signal is fed into the unit, making the EQP-1A a no-loss passive equalizer. This means that the signal level remains the same regardless of whether EQ is switched in or out, which is very useful when comparing a flat signal to an equalized one.

The low-frequency section of the EQP-1A is a shelving EQ, providing four selectable frequency bands at 20, 30, 60 and 100Hz. These frequencies can be boosted to a maximum of 13.5dB and attenuated (cut) by 17.5dB. Sound engineers long ago discovered that interesting (and useful) equalization curves could be achieved by simultaneously boosting and cutting at the same time, as the boost and cut frequencies overlap.

This has become known as the ‘low-end trick’. On a bass drum, for example, if 30Hz is simultaneously boosted and cut, the curve created gives a boost at 80Hz with a dip at around 200Hz – a very pleasing curve on some bass drums. The sound can be further sweetened using the high-frequency controls.

The Pultec’s high-frequency section features a boost-peaking EQ and offers seven centre frequencies – at 3, 4, 5, 8, 10, 12 and 16kHz – which can be boosted by up to 18dB, while a Bandwidth control alters the Q of the equalization curve from sharp to broad. The high frequencies can also be cut at 5, 10 and 20kHz. This is a shelf-cut with up to 16dB of attenuation available.

Retro 176 176 Limiting Amplifier

The Retro 176 is based on a Bill Putnam classic, the UA 176.

The 176 design shares many functional details with the more commonly used 1176LN. Similarly to the 1176LN, it has a fixed threshold and input/output potentiometers to control compression and output level. This is a very intuitive design, which has proven its value over the course of more than half a century. The 176 offers four ratio settings (2:1, 4:1, 8:1, 12:1), and thus is capable of fairly mild compression as well as heavier limiting. Attack and release are fully adjustable via front-panel potentiometers, and, just as with those on the 1176LN, their fastest settings are in their fully clockwise position.
The large backlit VU meter, made by the American manufacturer Hoyt, can display gain reduction as well as input and output levels. The unit has a power switch (accompanied by a red status light), and also, just as you'd expect on a modern high-end unit, a switchable hard-wired bypass.
The Retro 176 uses six vacuum tubes, a 6BC8 dual-triode tube provides the variable gain stage, the actual compression element. A negative bias (the detector or side-chain signal) is applied to the grids of the triode elements, determining the output gain of the valve. The signal is then, via the inter-stage transformer, fed to the output amplifier, which is based on a pair of 12AX7 and 12BH7 dual triodes, operating in a push-pull configuration. The other three valves are not placed directly in the signal path, but they perform some very important duties nonetheless. Firstly, a 5Y3GT power rectifier valve is used in the power supply, a task that nowadays (apart from in certain guitar amps) is most commonly handled by silicon diodes. There's also a second, smaller 6AL5 rectifier valve for the side-chain signal and, finally, an OB2 voltage regulator valve, which feeds the 6BC8.

TubeTech SMC2BM

The TUBE-TECH SMC 2BM Stereo Multiband Compressor features three independent

optical stereo compressors.

The signal is divided into three bands (Low, Mid & High) by 6 dB/octave x-over networks with 12 selectable frequencies: 60 – 1200 Hz for Low/Mid band and 6 selectable frequencies: 1,2 – 6,0 kHz for the Mid/High band.

Switchable crossover points ensure precise control of all three bands of opto-compression.

Independent band specific Threshold, Ratio, Attack, Release & Gain parameters make the SMC 2BM as flexible as it is accurate.

Gain controls are fitted with 12 position gold plated switches with 1dB/step. Threshold, Ratio, Attack, Release and Balance controls are fitted with potentiometers with 31 detents.

The design of the x-over networks optimizes the summing of all three bands, resulting in a flat frequency response (within +/-0,25 dB), when the gain controls for each band are set at the same level.

The three compressors feature Threshold, Ratio, Attack, Release and Gain and a display showing gain reduction. Master levels are set with Output Gain and Balance controls.

Both Input and Output are balanced and have fully floating transformers with a static screen. The power supply and the sidechain circuit is based on a solid state circuit. With the exception of the output stage all DC voltages are stabilised.

Universal Audio 175

Perhaps not as widely known as their later relative the 1176, the UA 175 and 176 Limiting Amplifiers are nonetheless still used and sought after in the audio community, and are rare on the vintage market. The design began as the 108 tube preamp, which was found in the original console at Bill Putnam’s first studio, Universal Recording in Chicago; It was also found early on at his Hollywood digs as well. This amp predates the first groundbreaking modular mic pre, the UA 610. The 175 was one of the first commercially available Universal Audio products, and was introduced in 1961. Like the Fairchild compressor line, the 175 and 176 were based around a variable-mu tube gain reduction design. This means that gain reduction is controlled by highly unique variable-mu dual triode tube, which is no longer manufactured. Variable-mu tubes have the ability to reduce their mu (gain), as the input signal increases.The 176 shortly followed the initial release of the 175 and were concurrently available models. Apparently, the original 175 was stripped, and had no Input or Output gain control. Other units such as the 175B/C and 176 had gain control for Input and Output. Later, in addition to these units there was also the 177, which was without metering.

COMPEX F760X-RS

In 1973, ADR came out with a stand-alone three-rackspace, 2-channel rackmount version that was subsequently repackaged into a two-rackspace unit and badged as the Compex Limiter F760X-RS.Renowned for decades by top engineers as the quintessential box for larger-than-life drum sounds!

The ADR Compex F760X-RS may be the best compressor/limiter available for drum room mics and drum bus duties and is also highly sought-after for the character and punch it adds to guitars along with a myriad of other sources. The Compex limiter provided peak limiting with a multi-ratio, variable threshold compressor. Ratio settings ranged from 1:1 to 20:1 and there were controls for threshold and release time. The inclusion of an expander/gate provided attenuation of the gain during pauses in the audio signal to reduce noise caused by compression; the expander/gate could also be used for special 'punchy' effects, favoured on drum and percussive sounds. Noise gates were often criticised at the time for 'hunting' around the threshold point.

Summit Audio TLA-100A

The Summit Audio Tube Leveling Amplifier is a hybrid of technologies. 

It contains both vacuum tube and solid state components. This combination of old and new technologies produces an incredibly warm and smooth sounding compression device without the inherent disadvantages of the older designs.

The TLA-100A features a vacuum tube amplifier driving an electronically balanced 990 output stage. All the signal amplification in the audio path takes place in the tube circuit. The 990 amplifiers provide a low output impedance for driving cables and 600 Ω loads. The 990 is a high performance op amp made of discrete parts, and then potted for thermal stability. The input is electronically balanced, and directly feeds the unique compression cell. The sidechain allows for stereo coupling, or the insertion of an equalizer. 

Due to the combination of tube and solid state circuitry long term drift of the compression circuit is minimal and tracking of two TLA-100As stereo linked is within .3dB.

The TLA-100A is program dependent, meaning it automatically adapts to the incoming signal.

Vertigo - VSC-2 Quad Discrete Compressor

The first product from Vertigo Sound is the VSC-2, a.k.a. Quad Discrete Compressor. 

It is so named, because it uses 4 VCAs built by hand using only discrete components. Its design is a nod toward the best VCA based compressors of the 70s and 80s. 

The Vertigo VCA is in fact named 1979. Some of the best features of these classic Compressors have been complimented in the VSC. This classic based sound is combined with a modern mastering grade signal path. Some unique and innovative features lie beneath the bonnet, such as the ratio which increases with level in ‘Soft’ mode.

The Quad Discrete Compressor uses four discrete 1979 VCAs in it’s two channels. Each channel has one VCA in the Audio Path and another in the sidechain.

In Stereo mode both sidechains are fully active; they are not summed together. 

The higher signal peak on either channel results in equal compression of both. 

The VSC-2 reacts even to out of phase signal peaks without image shift.

EAR 660

The EAR 660 Fairchild-type valve limiter-compressor is designed to limit or compress the signal with the barest minimum of interference below threshold, and give the most subjectively satisfying operation on high-level signals. The unit has the standard range of attack and release times, making it easy to use. 

Considerable effort has been spent optimizing the behavior around the "knee" of the attack/decay envelope and it is this that greatly contributes to the outstanding transparency and transient response that has made the EAR 660 the first choice of so many top audio professionals.

FEDERAL TELEVISION CORP AM-864/U

Tube broadcast limiter built during the Korean War for use by the US Army Signal Corps.

Balanced circuitry throughout, high quality transformers and a push/pull circuitry.

The compression is achieved by reducing the G2 voltage on the input stage during peaks. Input and output impedances are both 600 ohms, (typical for broadcast applications). 

Very warm tube limiting with compression.

CHANDLER LIMITED GERMANIUM COMPRESSOR

The Germanium Compressor starts with the same all class A amp found in the Germanium Pre and Tone Control and is transformer balanced in and out. The Compression circuit uses a FET gain reduction element but with the tricks and flexibility of all the Germnium a units. Some of the most notable additions include a wet/dry mix, for “submixing” tracks within the comp, Comp Curve, which selects the knee using various diode combinations, clean/dirty comp, side-chain filter. Many of the Germanium Comp parameters have been purposely set by studio use and listening not by over analyzing them with test gear. The result is a musical powerhouse ready for tracking, mixing, and mastering.

Purple Audio MC77

The Purple Audio MC77 supersedes the MC76 re-engineered 1176 type FET Limiter. The MC77 recreates the audio circuitry of the revision E 1176, using modern components matched to the original.One significant component is the input attenuator. The input attenuator that was custom made for the original revisions A-F 1176 and for the Purple MC76 by Clarostat was discontinued in 2002. It was a J series T-pad attenuator with two 600Ω "build out" resistors to keep a constant 600Ω load on the source and primary of the input transformer. Clarostat changed carbon manufacturers and the new carbon manufacturer was unwilling or unable to make the part. Purple temporarily stopped making the MC76 to find a solution.They used several three deck Clarostat 70 series pots in different configurations to achieve the same loading and to match the taper.

Joe Meek SC2.2

The Joemeek SC2.2 uses a photoelectric gain-control element with modern servo-control techniques to maintain accuracy and speed of response to the light source. Its specifications boast distortion within 0.004% 100 Hz to 10 kHz at all levels and system noise generally better than 94 dBu from 20 Hz to 20 kHz. The box is flat from 5 Hz to 30 kHz with minimal phase shift at extremes and crosstalk is better than 60 dB at 10 kHz.Since the SC2.2 came out it been upgraded. One upgrade feature was the switchable power transformer, and the other was a new feature called "Dark Mode". The dark Mode switch is an added circuit that replicates the sound of the old Joemeek V1.05 by slowing down the speed of the attack and release times creating a darker sound originally offered by the early Joemeek SC2 V1.05

dbx 160A

The dbx 160A is a legendary dbx 160 family of compressor/limiters. The same classic sound, easy set-up and no compromise metering is now married to an improved signal path and stronger chassis design. The result is industry standard compressor/limiter which is digital-ready and road tough.

Featuring switch-selectable OverEasy and Hard Knee compression curves along with extremely wide-ranging threshold, ratio and output controls, the dbx 160A is up to any task. True RMS level detection provides the most natural-sounding dynamics processing available, from subtle compression to "brick wall" peak limiting.The dbx 160A's unique "INFINITY +" inverse-compression mode actually decreases the audio output level below unity gain when the input exceeds threshold, a real lifesaver for correcting overbearing vocal choruses and controlling runaway house mix levels.

Elysia Mpressor

The elysia mpressor is a new tool for creative dynamics processing. Each of both linkable channels offers a switchable Auto Fast function that allows very fast yet distortion-free compression without any artifacts. The Anti Log circuit generates explicit compression effects such as pumping and breathing. As the mpressor is a true feed forward design, it also allows negative ratios which result in the most extreme over-compression effects. The Niveau Filters can change the character of a track from subtle to striking with the possibility of a continuous frequency shift. 

The Gain Reduction Limiter is a novel feature that lets the user choose the maximum amount of Gain Reduction he wants to draw from the unit, and this at the twist of a knob. The switchable external sidechain inputs make for further flexibility in terms of compression behavior.The circuit design of the mpressor is completely based on discrete analog technology. The entire signal processing is implemented with single transistors in permanent class-A mode, even the sidechain and power supply are composed of fully discrete circuits. The combination of these elements aims at the maximum reachable signal quality and guarantees clean and powerful sound characteristics even when extreme settings are used.

GML 2030

The Model 2030 Mastering Dynamic Gain Control is a precise tool for mastering and other critical applications where the utmost in control, flexibility, and transparency is demanded. Based on the proven GML Series III control and audio architecture, this no-compromise dynamic range controller continues the GML engineering tradition and expands familiar Model 8900 capabilities, including multi-channel operation. 

GML 8900

The 8900's psychoacoustic approach uses multiple true-RMS detectors, remarkably accurate log converters, and fast peak detectors to respond intelligently to real signal energy, not just level. The GML8900's unusual design employs unique controls, like Crest Factor, Timing, and Release Hysteresis to access the parameters that you really want to adjust.The entire audio path of the GML 8900 is all-discrete, including the VCA, for unsurpassed transparency and low-level resolution.

RCA BA6A

The B6A6 is a balanced, three stage amplifier which uses commonly available tube types that do not require special selection or matching. The use of high quality components and the straightforwardness of design, employing only 9 tubes including rectifier and voltage regulator, insure a maximum degree of reliability. Fewer tubes, fewer types (only 6) and fewer stages of simplified design result in lower tube costs, low initial cost and reduced power input requirements.

The B6A6 Limiting Amplifier also incorporates those features which are found in other RCA high quality broadcast audio amplifiers.

The rotary switch (Bal Lim) provided on the front panel also permits selection of a filter with either a single or dual time constant. In the single position the attack time is 0.0006 seconds. In the dual position the recovery time is lengthened to two seconds on sustained peaks.