Thermionic Culture Ltd. was formed in 1998 to manufacture, promote and sell Recording Engineer Vic Keary’s all valve studio equipment designs. Thermionic Culture’s principal aim is to prove that THERMIONIC VALVES (vacuum tubes to U.S. readers) are far superior for audio applications to solid state alternatives. All of Thermionic Culture’s equipment is Made in England to the highest standards, much of it hand point‐to‐point wired in the traditional way.
The Phoenix SB
Stereo valve compressor
The Phoenix SB is now the standard production version of the Phoenix compressor. Alongside the now classic circuit design of the original Phoenix, it incorporates the sidechain filter controls from the previous standard Phoenix SC model with the new addition of an HT standby switch. The additional HT Standby switch allows the user to put the Phoenix into a low power standby mode that is designed to increase the life of the unit’s valves and capacitors. When first switching on, or if the unit’s not in use for a while, have the Standby on. Switch off Standby and it will instantly come back to full life.
We have also placed the meter zero controls on the front panel for much easier access. Both meters should read “0” when the Phoenix is off standby and not compressing.
The sidechain filters can be used to cut the Phoenix’s compression response to bass frequencies.
The filter operates below either 150Hz or 300Hz on each channel and when stereo link is engaged the filters operate at the average of the two sides. This enables the user to choose from 5 filter frequencies when in stereo operation.
The Phoenix is well known for its smooth “soft knee” compression characteristic and excellent specifications. This means that it can be used as a compressor that will not harm your signal quality, whilst subtly controlling dynamic range. It is also possible to drive the unit harder to produce harmonic distortion and higher ratio compression if desired. Many users have found these features bring life to mixes or individual instruments, and control vocals, with a natural “warm” quality.
Contrary to the above, users have found that if the unit is operated in standby mode (it still passes audio) a “symmetrical” distortion occurs, not unlike that produced by overloading analogue tape.
Perhaps this fact alongside an exaggerated compression curve lends to the Phoenix in standby mode another dimension.
- Max. o/p level (MOL): +19dB into 600Ω / +24dB into 10kΩ.
- Max gain: 36dB.
- THD (at no compression): better than 0.06 % @ 100Hz & 1kHz.
- Noise, IEC weighted: better than 100dB below MOL.
- Input impedance: 15kΩ.
- Frequency response: <1dB variation over range of 12Hz to 56kHz.
- Attack time: 0.004s to 0.12s.
- Release time: 0.04s to 2.4s.
- Output impedance: 600Ω.
- All valve signal path and side chain, point to point hand wired in England.
- Subtle control with “soft knee” compression, but more compression effects when pushed hard.
- Continuously variable attack, release and threshold controls.
- Stereo link for mix buss compression.
- Side chain filters to enable compression of all frequencies except bass.
- Flat frequency response over full audio range and beyond.
- Very low phase shift and harmonic distortion (unless pushed hard).
- Push-pull design gives a natural warm sound with high output level.
- Output trim controls for fine adjustment or lower level operation.
- Balanced ins and outs with custom made Sowter transformers.
- Bypass switch on each channel removes all electronics.
- Standby switch to prolong valve life.
- Distortion effects can be created with Standby on.
The Phoenix Mastering Plus
Mastering valve compressor
This is the latest development in the evolution of the classic Phoenix compressor, first introduced in 1998. After requests from mastering engineers the MasterPhoenix was introduced in October 2006.
This was more recall-able with indented pots and slightly different power supply and metering circuit, in which trimming the meter alters the current through the compression valve so compensating for valve ageing.
The compression curve of the mastering Phoenix is slightly gentler than that of the standard one, but it does have a more “positive” effect. This earlier version has 6dB lowergain compared to the standard Phoenix.
The Master Phoenix is in use in many studios and mastering suites around the world, and we do know that one of its users, Ray Staff of AIR London Studios won the MPG award for Best Mastering Engineer in 2009.
The new Mastering Plus is a much upgraded version employing precision Elma switches for the Gain and Threshold and Alpha switches for Attack and Release. Omeg indented pots are used for the Output Level for fine control.
Side Chain Bass Cut switches, which have become an essential mastering tool have been retained.
In stereo mastering, with the link switch in, there are effectively 5 frequency options as the compressor side chain will work at the average of the switch positions.
A Standby switch is introduced to prolong valve and component life and this has had an unexpected effect, see *
Mullard and Siemens NOS valves are used exclusively for lower noise and long life stability.
The Gain is now identical to that of the standard Phoenix so that extreme compression effects are possible
Easy adjustment of Meter Zeros, especially important in stereo mastering, is now enabled by front panel access to the trim controls, situated between the 2 meters.
*some users have found that analogue tape type distortion is created when the unit is operated with Standby on. This was unintentional but some people may find it interesting.
- All valve signal path and side chain, point to point hand wired in England;
- Subtle control with ’soft knee’ compression- more compression effects when pushed hard;
- Stereo link for mix buss compression;
- Side chain filters to enable compression of all frequencies except bass;
- Flat frequency response over full audio range and beyond;
- Very low phase shift and harmonic distortion (unless pushed hard);
- Push-pull design gives a natural warm sound with high output level;
- Output trim controls for fine adjustment or lower level operation;
- Balanced ins and outs with custom made Sowter transformers;
- Bypass switch on each channel removes all electronics;
- Elma switches for gain and threshold controls;
- Alpha switches for attack and release controls;
- All Mullard and Siemens NOS valves ;
- Easy recall- ability;
- Zero adjustment on front;
- Precise calibration;
- More gain than earlier Master Phoenix;
- Standby switch to prolong valve life;
- Distortion effects can be created with standby on!
The Phoenix HG15
Mono Hi Gain Valve channel strip
The Phoenix HG 15 is a single channel version of our classic Phoenix Stereo Compressor, having the same gentle “variable mu” type compression curve, though it becomes near to a limiter at high compression levels.
The gain has been boosted to suit mic inputs, particularly valve and FET condenser types, but many moving coil types, such as Shure, Audio Technica, etc. are fine to use if the sound source is quite loud or close-miked.
With the Threshold switch set to Comp Out it’s a clean mic/line amp, now add a little Active Eq, “Presence” and/or “Air” to brighten the sound, then switch in some compression and achieve that gentle “super-natural” effect that only Thermionic Culture can give you.
The Output Level control acts as a reverse linear attenuator after the electronics, and can be used simply to reduce level if feeding a low level input, or to add “Attitude” by reducing the output and increasing the input. If you’re working from line level, it’s OK to switch the input from “Line” to “Pad” but ensure the +48v switch is OFF!
2 HG15s can be linked together for stereo use by a phono-phono lead from the Link socket at the rear. There’s a Side Chain Bass Cut switch, which can also be useful in mono operation.
To sum up, The Phoenix HG15 is ideal as just a mic amp for vocals, violins, horns, guitars…… especially when using a high output mic like the U87. Then having the ability to add compression and a bit of eq.
- High Gain Mic Amp/Compressor/EQ with super-natural valve sound;
- Based on Phoenix design with 52 dB gain available;
- Fully Balanced circuit with XLR in/out connectors;
- +48v Phantom power available;
- Threshold control has 7 way switch with Compressor Out position;
- Time Constant switch has 6 combinations of Attack & Release;
- Side Chain Bass Cut;
- Presence and Air switches to boost mid and high top with In/Out switch;
- Bass Cut to roll off low bass;
- 2 valves, 6AQ8EH input and 12AT7/ECC81 output;
- Solid State side chain! ;
- Link socket to connect 2 HGs for stereo buss operation, etc. ;
- Made in England.
The Culture Vulture
2 channel all valve distorter/enhancer
This is the original and still the only studio unit dedicated to just adding valve produced harmonic distortion to sounds, with no solid state components in the way. This unique unit has changed little since its introduction in 1998.
There are 3 basic settings for the type of distortion:
1. T gives the typically “musical” effect found with triode valves and is good for just “warming up” a sound,
2. P1 means that the “distortion” valve is switched to Pentode mode to add odd harmonics which make the sound more aggressive, but retaining that valve character,
3. P2 is the “No Holds Barred” setting and is very unusual way of configuring an unusual valve, even giving an extra octave at higher bias settings.
The Bias control varies the current through the “distortion” valve (6AS6 type) and this current is shown on the milliameter. At low current the Vulture is “starved” and the sound is inclined to be thinner and “break up” easily. High current and the Vulture is over-fed and becomes quite fat and
bloated. At medium current (0.25-0.3 mA) it distorts least, and this is the best setting for just “warming up” a sound. When the Vulture is over-driven, the meter may “twitch” and this gives a good indication of how drastic the distortion is.
The Low-pass filter has a 12dB/octave slope and will remove unwanted frequencies above 6 or 9 kHz (selectable) so as to make the sound more “rounded”.
The Drive control and Overdrive switch give the user ample control over the amount the input signal is boosted before it hits the 6AS6 valve.
The Output Level controls the amount of signal going to the output valve. This control should be set at 8 + for low distortion and turned back when Drive is increased for more distortion, except when P2 is selected.
The Bypass switch completely bypasses the unit so that the Culture Vulture’s effect can be accurately compared to the original.
- The original and only all valve rack-mountable distortion/enhancer;
- Vast range of distortion effects;
- Low pass filters (switchable);
- Bypass and Overdrive switches;
- 2 inputs per channel. DI at front cuts out LINE at rear;
- 2 outputs per channel, line and low level;
- Standard ¼” jacks, stereo wired unbalanced for all connections;
- Long life high quality valves;
- Made in England.
The Culture Vulture Super 15
Dual channel Distorsion box
The Culture Vulture Super 15 is the most comprehensive Vulture to date. It incorporates all the features found on the 11th Anniversary edition such as the 7 extra distortion functions, but also now features a 2 position Presence switch.
The Drive switch has three positions with a +10dB option sitting squarely between ‘Normal’ and ‘Overdrive’, enabling users to make their sounds ‘a little more crunchy’ with increased brightness.
The Function switch now offers further enhancements including special dynamic tunable mid-lif in the P positions and extra drastically-processed harmonics in the SQ positions.
The Output Level controls have a -10dB attenuator which can be used in conjunction with Drive+10dB for comparison purposes or just to reduce high levels.
The module’s line inputs are balanced while the line plus low level outputs are unbalanced. Five NOS military-grade valves are utilised for long life, low noise and enhanced performance, mirroring The Culture Vulture Mastering Plus. And of course dials now up to 15, and it really does have more gain.
- Even more distortion effects including 3 SQ (“squash”) settings.
- 5 musically tuned sharp dynamic mid lift settings;
- Bias control is more useful than ever before for type of sound and mid lift;
- Extra mid way +10dB setting on Drive switch, before Overdrive (+20dB) ;
- Broad Presence control on + 10 dB position;
- -10dB attenuator enables comparison between the above, or useful to control high levels;
- Extra Output level to easily drive DAWs;
- Transformer balanced line input, unbalanced DI input;
- Unbalanced Hi & Lo outputs for better transparency;
- Line inputs and outputs now on XLRs.;
- Low pass filter to remove unwanted HF overtones;
- Extra low noise. Long life, selected NOS valves, carefully matched for stereo;
- Bypass switches connect Line In direct to Hi output avoiding all electronics;
- Made in England;
The Earlybird 2.2
2 channel preamp with EQ
The Earlybird 2.2 contains 2 channels of very high quality valve pre -amplification. The circuit design utilises a ‘push pull’ ‘class A’ type of amplification in order to provide ultimately clean gain, giving the lowest noise and distortion figures possible in a mic pre-amplifier.
The input and output transformers have been designed by working together with Sowter transformers to provide results that are optimised for this unit. This design work provides the Earlybird 2.2 with the lowest phase shift and highest headroom possible from a mic pre- amplifier.
This version of the Earlybird pre-amp design also includes extra features such as 3 bands of active lift EQ with switchable mid range frequencies and high pass filters, and a function switch to help interface the unit in different usage scenarios. The essential mic-preamp settings such as gain, impedance, 48v power and phase are all catered for by the front panel controls.
The active EQ uses the unique ‘varislope’ EQ curves for the ‘bass’ and ‘top’ lifting controls. The ‘mid’ lift control provides a broad, musical curve that can be centred at 800Hz or 2.8KHz by the frequency select switch. This curve interacts well with the top and bass controls to provide a wide degree of tone shaping possibilities.
As the active EQ works in the feedback part of the circuit, switching the active EQ in does not, therefore introduce any extra gain stages into the signal path. This means that the EQ can be used without fear of introducing unwanted artefacts from extra gain stages.This perhaps makes recording a little easier when a subtle amount of EQ can be added without fear of signal degradation.
The high pass filters are arranged so that the first two switch positions provide 12dB/octave filters to cut out unwanted low frequencies at 40Hz or 100Hz. The last position provides a filter with more of a shelving nature that can combine with the bass lift control to give a simultaneous mid cut and bass lift if desired.
The Function switch
The Function switch allows the unit to take it’s input from either the ‘mic in’ XLR sockets, the ‘Line in’ sockets or the ‘Pullet’ sockets. So the unit can be connected for different uses whilst remaining in an equipment rack. The variable impedance and pad settings on the switch allow the input circuitry of the Earlybird 2.2 to be optimised for use with a large variety of mics and signal levels. They can also be used for creative tonal choices if so desired.
We find that the variety of functions possible with the Earlybird 2.2 make it extremely versatile and coupled with the outstanding sonic results it is a great addition to any type of studio that is used to record or mix sound.
The Pullet, is the perfect companion to the Earlybird 2.2 to complete a superb mastering equaliser.
- Figures for distortion, noise, phase shift and eq 44dB mic gain, 0dB line gain.
- Input Impedance: 300 or 1200 ohms, switchable , balanced.
- Output Impedance:
A) output level control at max: 55 ohms balanced
B) output level control at min: 500 ohms balanced
- Maximum Gain: 60dB
- Maximum Output Level (MOL): 31dBv (28V RMS)
- Phase Shift at 10kHz: 20 degrees (5.6%)
- Distortion (THD), 1kHz/100Hz: 0.007%/0.010%
- 2 Channels of extremely high quality push pull’ ‘class A’ type of valve pre amplification;
- 3 bands of active lift EQ with 2 mid range frequencies and switchable high pass filters;
- Clean gain, giving extremely low noise and distortion figures.;
- Essential mic-preamp settings such as gain, impedance, 48v power and phase are all catered for by the front panel controls
- Can be optimised for use with a large variety of mics, signal levels and different uses whilst remaining in an equipment rack;
- Function switch will allow the unit to take it’s input from, mic. in, line, or the Pullet sockets;
- Massive clean output, but can be trimmed by output level controls,some colouration can be obtained if desired.
The Earlybird 4
4 Channel preamp
The Earlybird 4 contains 4 channels of extremely high quality valve pre-amplification. Originally made in black in 1999, this is a special “revival” limited edition in red (limited to 49 only). The black edition is still available with the updated circuitry.
As the individual channel circuitry in this version of the Earlybird has been simplified in order to provide 4 channels in one 19” unit, so the individual channel specifications have risen. Thus making this the most natural sounding, high quality version of the Earlybird preamp to date. Effectively giving the user the cleanest possible valve gain with a range from 3dB to 62dB and a switchable input impedance to help in matching the unit with different microphones.
This is one of Thermionic Culture’s all handwired products with point to point wiring throughout.
The circuit design utilises a ‘push pull’ ‘class A’ type of valve amplification in order to provide ultimately clean gain, giving the lowest noise and distortion figures possible in a microphone amplifier.
The input and output transformers have received special attention and by working together with Sowter transformers, designs have been created that bring better results than ever before. The lowest phase shift and highest headroom are both benefits brought by these designs.
It’s unusual to hear a mic amp with the Earlybird 4’s qualities and after years of improvements Vic Keary proudly declares this “The best, most real mic. amp ever ”. We hope that on hearing the unit’s beautiful results yourself, you will agree with Vic.
The pair of VU meters show the signal levels for 2 selectable channels. VU meter A is switchable between channels 1 and 3. VU meter B is switchable between channels 2 or 4.
4 red LEDs light up when the output of the amplifiers exceeds +10 dBm, though don’t worry – there’s still 20dB of headroom left in the Earlybird!
- 4 Channels of extremely high quality push pull’ ‘class A’ type of valve pre amplification.
- Clean gain, giving the lowest noise and distortion figures possible in a mic. Amp.
- Hand wired with point to point wiring throughout.
- Lowest phase shift and highest headroom.
- Controls on each channel for:
Switchable input impedance to help in matching the unit with different microphones.
Switchable 48V phantom power .
Switched gain 42 dB to 62 dB, 20dB pad.
2 position high pass filter.
Variable output trim with phase inverter.
Vu meters switchable between channels.
Peak overload indicators.
The Rooster 2
Pre mic/line DI EQ
The Rooster 2 is a 2 channel all valve preamp with EQ and distortion controls. It is designed for a wide range of applications and can produce a large range of tones, harmonic distortion and subtle dynamic control.
The pre-amp section can be used to add gain to mic, line or DI input signals. The double triode input valve (12AX7) provides a smooth sounding gain stage after the balancing input transformer.
48 volts can be applied to phantom powered mics by using the special toggle switch. The DI input bypasses the transformer to give a suitable high impedance unbalanced input.
The ‘Attitude’ section
The ‘Attitude’ section provides control over the amount of distortion inherently produced by the 5654 valve.
The natural distortion figure for the Rooster 2 is well below 0.1% at low Attitude settings. As the Attitude is increased, extra harmonics, mostly musical, will be added to give a warm ‘valvey’ sound.
Similarly to the Culture Vulture, the unit will tend to produce predominantly more 2nd order harmonics when in ‘Triode’ mode and 3rd order harmonics when in ‘Pentode’ mode. This provides a creative means of both tone and dynamics control over the input signal as well as allowing the user to select how much and what kind of harmonics are present in the signal.
The EQ section
The EQ section provides a simple yet powerful musical control over frequency content.
The Bass lift control gives a continuous control over the amount of bass using a unique ‘ varislope’ curve which peaks at 60Hz.
The ‘mid/high’ lift control gives a bell type curve with variable gain peaking at either 2.5KHz / 4KHz or a ‘varislope’ curve peaking at 12KHz, all selected by the frequency select switch.
The ‘Mid cut’ control provides a bell type curve centred at 700Hz with continuous control over the amount of cut.
The ‘Bass cut’ switched control provides 5 positions with different cutting curves. The curves start off as high pass filters which get progressively higher in frequency and then turn into a shelving type curve that will also increase in frequency as the switch is advanced. These controls are intended to interact with the other EQ controls for a very flexible control over the entire frequency range.
The ‘LPF’ or low pass filter switch control will allow the high frequencies to be cut at a frequency suitable to stop harsh sounding harmonics standing out when excessive distortion is used, smoothing the resulting sound.
The output level control
The output level control adjusts the signal going to the PCF 80 output valve and the final signal is balanced by a Sowter custom made transformer.
The level of output signal is represented by the 3 LED display.
- All valve signal path;
- Sowter Transformer balanced ins and outs;
- Unique 2 channel clean mic. amps with ‘Attitude’ control;
- Option of 2 settings to select type of introduced distortion;
- Versatile eq. with ‘varislope’ control of top and bass lift;
- 48v Phantom Power switchable to one or both;
- Phase invert switch on both channels;
- Mic./line and DI input;
- Low pass filter;
- High Pass filter;
- Low noise, High gain and High output level;
- Made in England
The Purple Bustard
16 ch tube summing-mixer
Following on from the phenomenal success of The Fat Bustard summing mixer whose features include Attitude, EQ, stereo width, and of course a big fat sound, we fInd there’s a demand for a similar warm sounding summing mixer with more channels at a lower price, keeping the unique Attitude control.
This new unit utilises the same input circuit and Attitude section as the Fat Bustard, using the same type twin triode valves. Instead of having eqs and Stereo Spread, etc., there is only the “AIR” control which works on the very high end. Because the unit contains no solid state in the audio path, the use of this control will enhance the sound with a lovely velvety sheen typical of the best all-valve equipment with none of the harshness found in some solid state units.
Enter The Purple Bustard
The output stage is very similar to that of The Fat Bustard, except that for reasons of space and heat, smaller double triodes are employed. All valves are “mil spec” NOS types.The max output level is still well above +20 dBv, adequate for any DAW.
All inputs and outputs are on XLRs, with inputs “semi floating” and outputs unbalanced. A balancing box containing 2 Sowter transformers is available if required.
8 toggle switches to switch in pairs of channels,2 more toggles to switch channels 15 & 16 to make 2 mono channels.AIR, a rotary pot, ATTITUDE, a 6 position switch, and a matched pair of pots controlling output levels. There’s also a mains power switch and of course the Little Red Bustard’s eyes light up and go bloodshot as the sound gets louder !
The frequency response goes well above and below audio range,similarly all other specs are practically the same as The Fat Bustard.
- All valve 16 input summing mixer;
- Each pair of inputs has its own on/off switch;
- Inputs 13 to 16 can be switched to centre;
- Attitude control adds musical 2nd harmonics;
- Air control increases high top end without solid state harshness;
- Frequency response extends well above and below audio range;
- Easily enough output to drive your DAW and very low noise;
- All inputs are “semi-floating” on XLRs;
- Outputs are unbalanced. A separate Balancing Box is an optional extra;
- Shares the same natural warmth as the Fat Bustard;
- Extremely low distortion (< 0.1%) before Attitude is added.
The Fat Bustard MKII
12 Channel Summing mixer
The Fat Bustard mkII is an all valve passive input summing mixer. It has 14 inputs with 4 stereo inputs, 4 mono pan-able inputs and 2 ‘Aux’ inputs with a pan switch. The Fat Bustard is unique in it’s exceptional sound quality and also the extra degree of control and processing it offers over the stereo mix output. The mkII version is now the standard production model and it has been upgraded to include a monitor output with level control.
Much of the attractive sound provided by the Fat Bustard is down to the choice of valves used. The summing is done by a pair of 5965 valves and the output stage uses a pair of 6SN7 valves. This combination provides a very large amount of headroom and a unique smooth sounding response. It’s also worth noting that the unit has “semi-floating” inputs and unbalanced outputs.
This combination provides a very large amount of headroom and a unique smooth sounding response. It’s also worth noting that the unit has “semi-floating” inputs and unbalanced outputs. This was a decision made at the design stage purely because the unit sounded better this way and performed excellently when connected for use in all situations.
The Fat Bustard employs our unique “varislope” curves for top and bass lift. As the control is turned up, the peak frequency of the curve becomes more extreme so as to add heavier bass/brilliant top – without the hardness found in solid state eqs. The bass and top cuts provide a variety of options to tailor the sound – too many to list here. They are of course independent of the lifts. All controls affect both stereo channels equally.
The ‘Attitude’ control
The ‘Attitude’ control is the next to control the sound of the mix.This switched control gradually increases the amount of harmonic distortion in the stereo summing stage. It is relatively subtle (at least in the lower positions) to provide just the right amount of 2nd harmonic content for a stereo mix. At high positions the mix can be quite aggressive.
The stereo spreader control
The stereo spreader control allows the stereo to be widened by a continuous amount over a selectable frequency range.
The‘Spread filter’ control allows the frequency above which widening occurs to be selected from full band widening to only widening above 5KHz. Again, this control can be used to vary the tone of the stereo mix as well as the stereo width. Along with stereo widening at higher frequenciession.
The ‘Bass to Centre’ control
The ‘Bass to Centre’ control allows bass frequencies in the stereo mix to be summed to mono for 2 different low frequency ranges, plus there is a setting for all frequencies to mono.
Stereo ‘balance’ control
A Stereo ‘balance’ control and rotary 31 position ELMA switch for ‘Output level’ give full control over output levels.
The ‘Monitor level’ control, int/ext switch and extra outputs provide a useful way to connect and control monitors to the Fat Bustard. Especially useful when the Fat Bustard is the only mixer being used. If this is not a requirement then the int/ext switch in conjunction with the monitor outputs can be used to provide an insert in/out switch.
- All valve 14 channel passive summing mixer with many extras !
- Pan controls on 4 channels;
- Unique Varislope Top and Bass lifts plus filters;
- ‘Attitude’ control to add harmonics;
- Stereo width controls / Bass to centre and mono;
- Precision ELMA switch to control main level (fadeable);
- Monitor outputs with level control and switching;
- Hand wired with point to point wiring throughout;
- Exceptional sound quality- very low distortion except when required and massive ‘headroom’;
- Frequency response extends from below audio range to well above.
2 Channel Valve Equilizer
Thermionic Culture The Swift has been designed to be as much at home in tracking individual instruments or sitting across a stereo mix bus to equalise the final mix. As with other units of ours, such as The Phoenix, all controls are clearly labelled and setting up the EQ is quick and easy, so we named it after Britain’s fastest bird in level flight.
THE SWIFT utilises influences of 2 classic designs of the “golden days” of all valve recording with improvements to bring the specs up-to-date for today’s pro use, plus added features of our own designs. The main electronics are based around a 1950s EMI desk but with extended top and bass response. It had a Baxandall type active EQ which we’ve kept and we added a Presence switch to give a broad band lift to mid/hi frequencies. This is based on one invented by Vic Keary in 1963 and used in his own mixing desks.
The mid lift controls are based on the Pultec design and are passive. For speedy operation and economy, we have chosen just 4 frequencies, with 3 “Q” settings.
Special features of ours are Hi Pass Filter, Mid Cut and “Air” (all passive). An interesting (Pultec type) effect can be obtained by setting the High Pass Filter at its last setting which combines a shelving bass cut with a filter at very low frequency, then using plenty of bass lift at either 50 or 100 Hz.
All pots are continuously variable. We have chosen not to use indented ones for subtlety and reliability reasons.
Gain is on switches, for comparison purposes. BYPASS switch disconnects the electronics so you hear the unadulterated original signal. No metering is provided as it was deemed to be just a distraction. The Swift can output +20dBu without noticeable distortion and it’s practically noiseless.
- Shelving bass and treble lift/cut controls at 2 frequencies each
- Mid cut and lift at 4 frequencies each with three “Q” combinations
- TC presence and air controls
- A switchable high pass filter with a special last position which, used with bass lift, can be a very interesting combination
- Adjustable gain in .75 dB steps
- Custom-made in England using the same chassis as the classic Phoenix and the same
- Valves (Tubes) as its Little Red Bustard
Mini Passive stereo equaliser
The Pullet is a passive EQ which has a sharp focus on mid range frequencies.
The Pullet will provide the EQ network to a signal but will reduce the signal level so that a preamplifier with a gain of up to 40dB is needed in order to lift the signal back up to unity gain when the Pullet EQ is set to ‘flat’ or bypass.
The preamplifier is used at the output of the Pullet. The fact is that most people will already have a preamplifier that can be used, either a standalone outboard unit, or a mic-preamp built into a console, so the Pullet can make a lot more use from the preamps that would otherwise be sitting around unused during a mix.
The Pullet provides a variation on the classic passive EQ designs that have proved so popular (eg. Pultec).
However, there is far more control and choice in the mid range frequencies than can be found in previous designs. The Pullet can provide a variable Q boost of up to 21dB over 11 different frequencies and fixed Q cut at 11 frequencies. There is also a ‘High top’ control that provides a switched set of shelving style filters to boost or cut high frequencies.
The Pullet was originally designed for use with the Earlybird 2.2 mic preamp but early on a decision was made to alter the design so that the Pullet can be used with any mic preamp available with a gain of up to 40dB.
The input impedance of the Pullet is set at 10kΩ and the Sowter input transformer is utilised so that it will function normally when placed in a chain after any piece of equipment.
The Pullet can produce some radical EQ curves due to the very high amount of boost and cut available but the passive nature of the EQ will always allow the results to sound as natural as possible.
It is “balanced” in and out on XLR connectors. Short, high quality leads are supplied for connection to mic amps.
Mid frequencies boost
800 Hz – 3,5 Khz
1,2 Khz – 4,4 Khz
1,6 Khz – 5 Khz
2 Khz – 6,3 Khz
2,5 Khz – 8,5 Khz
Mid frequencies cut
230 Hz – 2 KHz
340 Hz – 2,8 Khz
500 Hz – 4 Khz
700 Hz – 6 Khz
1 Khz – 8 Khz
- Passive natural sounding EQ with a sharp focus on mid range frequencies;
- Provides a variation on the classic passive EQ designs with an improvement in choice and control in the mid range;
- ‘Air’ type control for high top lift/cut;
- Can be used with almost any mic preamp available with a gain of around 40dB;
- Exceptional amount of lift (over 20dB), and cut available;
- Balanced” in and out on XLR connectors.