super high efficiency with ultimate energy transfer
To learn why the Pixie amp is so unique, you must look at recent musical instrument history. In the 1950s and '60s, America's most prolific guitar amplifier designer was Leo Fender and his team in Fullerton, California. The Fender™ 4X10 Bassman, Bandmaster and Twin are legendary amplifiers (whose circuits can be traced directly to the RCA & Western Electric tube manuals). Beginning in the '60s other manufacturers began to recognize the fundamental soundness of Fender's designs and began to "hotrod" these designs into "new" products. Jim Marshall in England built a multi-million $ company based upon modifications to Leo Fender's designs and is himself a "living legend" in the music industry.
The trend of "borrowing" Leo Fender's designs continued throughout the'70s, '80s and '90s with numerous companies continuing the idea of modifying circuitry that dates to the '50s and '60s. While there are guitar amplifier designs that do not trace their heritage back to Leo Fender's original designs, these have not proven to be as popular as those amplifiers that have the signature Fullerton, CA circuits at their heart.
While tube electronics virtually disappeared with the invention of the transistor and the integrated circuit, professional musicians have remained faithful to tubes for their "warm" and musical sound. Every year a company appears that purports to be building "vintage" tube guitar amplifiers. The popularity of some of these small "boutique" manufacturers have even encouraged the larger guitar amplifier companies to re-release modern versions of long discontinued models. Even with all the modern semiconductor-based products on the market, tubes are still the first choice for the working professional.
The Unique Pixie technology
In the previous section, we reviewed the fact that most tube guitar amplifiers employ designs that are based upon earlier designs from the '50s and '60s. Pixie’s designs are a radical departure from the "tried and true" designs found in most of the custom tube amps current on the market. Pixie’s exclusive and proprietary designs include:
A unique 30V "low voltage" pre-amplifier stage that departs from the typical 200+Volt preamp stages. Most amplifiers have preamp stages that run on high voltage and then overdrive the tubes to give that "fat" non-linear distortion that gives an amplifier it's unique sound. The Pixie pre-amp stage, while providing ample gain, offers a very high impedance input, with a sensitivity control to optimize input matching to any kind of instrument pickup. The low voltage technology generates a wide path of even harmonics, up and down the fundamental tone, with a frequency range covering from 20Hz to 50KHz. This circuit delivers a rich, very low distortion to the following stages of the amplifier. This unique Pre-amplifier stage has an unusual low noise figure.
EQ CIRCUIT
The real heart of the Pixie unit is the EQ circuit, and this is the most radical departure from the passive EQ circuits used in most amplifiers. The Pixie EQ circuit is a true Dynamic Equalizer. Based upon a proven recording industry process call Multi-band Compression, the "tone" controls in the Pixie amp give "life" to the amp and help it respond better to the player's touch. How is this done? The frequency spectrum is divided into three frequency bands and each of these bands has it's own compression circuit and gain make-up stage. These three bands are given the common names "bass, mid, treble", just like a regular amplifier but each of these controls has an additional "threshold" control that allows the guitarist to adjust how each of the three bands will respond to changes in playing style and volume. Visual feedback is also supplied using LED gain reduction meters, so the player can see how much gain reduction is taking place. No other instrument amplifier has ever employed such an advanced technology. It must be pointed out that this is all done without any semiconductors in the audio path, as this is an all-tube circuit. At this point, the signal can be "lined out" for recording or PA purposes. The Line output connector on the rear of the unit is used for just that. The Line out is always "on" and this circuit is placed before the power amp stage, so you can use this unit as a true studio device for recording.
60w rms POWER AMPLIFIER
A driver stage with two settings, "normal" for very low distortion transfer, to suit acoustic instruments (guitar, violin, and other string acoustic instruments) and "overdrive" for electric guitar, when rich, fast attack and controlled overdrive effects are desired. Creating a boost in the late stage of the amplifier produces outstanding tonal effects and superb sustain and overdrive, all adjustable from the previous multi-band compression stage.
The output valve circuitry is also unique. The output stage operates in single ended "Class A" circuit utilizing KT88 large output tubes. While this is not unique, the output transformer is designed for use with a custom made Pixie 70 Ohm 15-inch loudspeakers. Most guitar loudspeakers operate in the 4 Ohm to 16 Ohm range. Using a high impedance speaker makes the amplifier combination highly responsive, with much higher power transfer characteristic and brilliance unobtainable from low impedance speakers. This is unique!
LINE OUTPUT
For Studio work, the power amplifier can be shut off (Stand-by mode). In this mode, only the pre-amplifier, compressor and summing stages are on. The output from the "LINE" rear jack can be routed out to other equipment, a PA system or a recording channel.
The LINE OUTPUT can also be used with the power amplifier on (operate) at all times. This allows for monitoring on-scene situations, when the unit "LINE" output is routed to another amplifier or a PA system at the same time. You can also use this feature as a separate source track to double your guitars for a different sound in your songs.
The main "Volume" control not only varies the level of the unit power amplifier, but also the "LINE" output level.
Specifications & Technical description
Optical compression
There are three Optical compressors, one on each EQ band, each threshold adjustable from the front panel. Maximum compression is 10 dB. There is an LED gain reduction meter for each compressor. These three bands are recombined in a buffer stage, before the driver.
The Overdrive circuit, in the driver stage, is selectable from the front panel. This provides a +3dB boost and makes the "attack" characteristic much faster. Overdrive effects are obtainable in this mode.
The single-ended power output stage, uses three KT88 power tubes in parallel, running in pure Class A mode. Useable power output is 60 Watts RMS. There is a custom wound output transformer feeding a high impedance 15-inch, wide range custom speaker (70 Ohm), providing exceptional power transfer and sonic restitution (30 Hz to 14 kHz). The B+ screen supply to the output tubes is stabilized as well as the bias voltage. The Bias voltage is adjustable with an internal 10 turn "Helipot" to match different tube settings.
Please do not calibrate your own amp unless you have done so before. We are happy to provide assistance should you need it.
other features
The unit uses a large inductance choke in the power supply, helping to provide a totally noise free unit. The amp is cooled by a no noise fan, only when the power stage is in "OPERATE" mode.
The rear panel supports 2 "EFFECTS LOOP" jacks at instrument level for a "SEND" and a "RETURN" to an effects processor or pedal, as well as another jack for the "LINE" output. This allows you to have pixie pre-amplify your instrument signal cleanly, THEN send it to your effect pedal, then return to the amp for the final amplification. Now the sound of your beautiful guitar is not being compromised by a $100 pedal.
Also on the rear panel is a selector for the mains voltage: 115/230V AC, 50/60 Hz.Please double check selection is appropriate for your requirements before connecting.
The Pixie GC-1 can be mounted in a standard 19-inch rack making it possible to rack mount this unit in the studio or to install in any amp head cabinet.