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Callisto is an all-tube linestage suitable for the most demanding audio systems and listeners. Fully balanced circuitry from input to output, including internal balancing of single-ended inputs, results in common mode signal rejection and cleaner sound. The innovative discrete switched resistor volume control maximizes resolution at any listening level. A separate power supply chassis removes any possibility of transformer noise corrupting the delicate audio circuitry. Peter Moncrief Stealth Capacitors are used in the Eclipse Edition for unparalleled sound quality.

  • Fully balanced differential circuitry with ability to internally balance a single-ended input signal.
  • Innovative and unique mechanically switched discrete resistor volume control with 46 positions using Roederstein resistors.
  • Separate volume controls and input selectors for each channel.
  • All tube amplification and output (8 tubes total).
  • Separate vacuum tube regulated power supply utilizing 8 tubes.
  • Two sets of XLR and two sets of RCA outputs per channel.
  • Six inputs: First two single-ended (rca) or balanced (XLR); remaining four single-ended (rca) only.


Mk II, Signature and Eclipse
Callisto is available in three versions: Mk II, Signature and Eclipse (see tabs above for more detail on each version). The Mk II version uses high-grade Rel-Cap polypropylene coupling capacitors. The Signature version uses exotic and expensive coupling capacitors and other critical parts to bring the performance to a higher level. Eclipse is the ultimate realization of the true capabilities of the Callisto, incorporating constrained-layer damped machined aluminum panels and Peter Moncrief's Stealth Capacitors. All versions of Callisto can be factory upgraded to Signature or Eclipse.

Dual Power Supply
Callisto comes with a single power supply standard, or optionally a second power supply may be added for true dual-mono (see "Power Supply" tab above for more detail).

Remote Control
Remote control is optional with the Callisto. Adding the system allows remote adjustment for volume and muting, and optionally phase. The remote system uses motors and pulleys to rotate the volume controls and has a completely isolated electrical system. It may be added to any version of Callisto (see "Remote Control" tab above for more detail).

Faceplate Finish
Callisto Mk II and Signature available with black or silver faceplate.

Custom Finishes
Callisto Eclipse may be ordered with custom finishes - Design your own Callisto Eclipse.


Jupiter Series Io phono stage and Callisto linestage are available in (and factory upgradable to) an Eclipse Edition. The Eclipse transformation takes already industry standard setting products to a whole new level of performance. Io, Callisto and their respective power supply receive enhanced internal parts, improved chassis construction, and stunning customizable casework.

Stealthcap Capacitors

Musical signals passing through a capacitor are blurred or clouded as signal reflections bouncing off the capacitor plate corrupt the original musical signal. StealthCap capacitors created by Peter Moncrief aim to cure this problem by dramatically reducing reflections along the capacitor plate. The "Stealth Technology" is made possible by a combination of laborious precision handiwork and costly exotic materials including new conductors, dielectrics, and composite resins. The resulting signal has a quieter background, rich and detailed spatial imaging, time focused musical coherence, and a broader more impactful dynamic range. The Io Eclipse uses eight .22uF / 600v Stealth coupling capacitors made of exotic copper foil. These are used between the second and third gain stages, and the third gain stage and output stage. The Io and Callisto Eclipse output stages also use eight 4uF / 400v Stealth capacitors in a unique balanced configuration.

Chassis Construction

Eclipse Edition chassis feature an extremely rigid and acoustically damped design, delivering new levels of articulation and clarity. Three separate side and top panels are machined from aluminum billet. Each panel is constrain layer damped with advanced 3M adhesives, requiring a labor intensive application of heat and pressure for proper mating. Advanced interlock material and machine screws are used to attach the panels for easy tube access. Harmonic Resolution Systems Nimbus Couplers, specially made for Aesthetix, are used to intimately couple the chassis with the equipment rack, greatly reducing mechanical noise.

Casework Design and Customization

Eclipse editions feature a stunning multi-piece front panel which includes detailed machining of the front panel casing, inlay and logo. Jupiter Eclipse customers may personalize the appearance of their unit by selecting metal finishes for the faceplate, rings, knobs, dials and logo. Use our interactive online tool to design your own Io or Callisto Eclipse.


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Signature, released in 2001, was the first major step forward for the Io and Callisto. Incorporating improved componentry such as Dynamicaps from Peter Moncrief and hand tuning the individual gain stages, greater resolution and inner detail were achieved without sacrificing the richness and dynamic bloom of the original design.

The Signature version uses custom-made inter-stage Teflon coupling capacitors, replacing the polypropylene units, between the 1st and 2nd gain stages. This change results in very high resolution of the very low signal level. Between the 2nd and 3rd, and 3rd and 4th gain stages (4 total per channel), the standard Rel-Caps are replaced with .22uF Dynamicap. The change in these capacitors results in higher resolution, extension, less grain and more air. The 2uF output coupling capacitors (4 per channel) are also replaced with 4uF Dynamicaps. This change provides more drive, bass extension, resolution and dynamics while also reducing grain. Highly specialized adjustable air-core capacitors, used primarily in the radio-frequency realm, are installed and adjusted to "tweak" each unit to a rigid standard.

Click any image to enlarge.


Click any image to enlarge.


One defining characteristic of the Jupiter Series is separate power supplies. Each main unit, or audio chassis, is dual mono in construction; there are completely separate left and right audio boards and each has its own power connector on the rear of the chassis. Each main unit requires at least one power supply, a single power supply cannot power both an Io and a Callisto.

There are two versions of power supply available: Stereo or Dual Mono. In the stereo configuration, a single power supply powers both audio channels and has two power connectors on the rear. In the Dual Mono configuration, two separate power supplies are used, each with a single power connector. In the Dual mono configuration, the unit becomes pure dual mono, all the way down to the ac wall connection!

The Jupiter Series Power Supply is the size of a power amplifier and weighs approximately 50 pounds. The Power Supply has two main sections, the heater supply and the high voltage plus and minus supplies. At the heart of the heater supply is its massive, low flux, 210 VA power transformer which has fourteen separate secondary windings that are individually regulated and supply both the Power Supply and main unit heaters. The high voltage supply is composed of a similar massive 170 VA transformer which feeds a common-mode choke input filtering network and then high current vacuum tube regulators (one EL34/6CA7, three 12AX7 tubes per regulator). Each regulator is capable of supplying 600 volts at 100mA. There are two such regulators in the Power Supply. Each separate amplification or buffer stage has its own power supply filtering network and regulated heater supply to isolate individual sections and prevent stage interaction.


The Callisto may optionally be configured with remote control. This is not your average remote control, it is an entire system consisting of a main remote receiving / control unit and large stepper motors that turn the volume controls through a belt drive system. The system is completely electrically isolated from the Callisto, there is not even a ground connection between them! Audio performance of the Callisto is not compromised in any way with the addition of the remote control system.

Main unit
The main control unit contains the power supplies necessary to drive the stepper motors, the IR receiver, control system and displays. The display is a large four-digit blue LED numeric, which can indicate both left and right volume levels at the same time. There are four buttons on the main control unit: Volume Up, Volume Down, Mute and Phase.

The main control unit is connected to the Callisto through an RS232 cable. Inside the Callisto, there are two large high-torque stepper motors (one per channel) that are connected to the volume shafts through belts and pulleys. Also at each volume control is an optical sensor system that allows the remote system to determine if the user has manually changed the volume control and display the change.

A small circuit board is added at the rear of the Callisto with muting relays. These relays are not in the signal path, they simply short the output signal to ground when muted.

This is an option with the remote system. Two small circuit boards are added with phase relays.

Handheld remote
The handheld remote provides direct access to the following functions:
    Volume Up
    Volume Down
    Balance Left
    Balance Right
    Phase (optional)


Simply phenomenal inner detail, vast soundstaging, and a dynamic and harmonic bloom that seems to bring every kind of music to vivid life" The Absolute Sound Golden Ear Award (2003, CALLISTO SIGNATURE linestage and IO SIGNATURE phono stage)

The Callisto is as fast, neutral, dynamic and authoritative as any preamp I've ever heard, solid-state or not... entirely worthy of the high esteem in which it's been held..." -Shane Buettner, Audio Perfectionist Journal (2007, CALLISTO linestage)

In practice, (the remote) is a marvel to use and makes listening to music a joy." -Albert Porter, Positive-Feedback.com (2006, CALLISTO linestage with remote), read review

stunning dynamics, remarkable transparency, and a life-like recreation of space and volume... jaw-droppingly three-dimensional" -Wayne Garcia, The Absolute Sound (2002, CALLISTO linestage) "Centerstage" and "Harry Pearson's Workshop" feature.


Inputs: Six inputs: First two single-ended (rca) or balanced (XLR); remaining four single-ended (rca) only
Outputs: 2 RCA (SE) and XLR (balanced), 1 tape RCA
Line level gain: 23 dB single ended (SE), in/out, and 29 dB balanced/out
Volume control: switched resistor network volume control with 46 steps
Front panel controls: Left and right input select, left and right volume
Remote controls(optional): Volume, mute, balance, phase (option)
Frequency response: +- 0.25 dB, 20 Hz - 20 Khz
Signal to noise: measured at 70 dB minimum, A-weighted (ref 1 mv input, 75 dB gain setting)
Line input impedence: 100K ohms SE, 200K ohms balanced
Output impedence: 1K ohms SE, 600 ohms balanced
Recommended amplifier load: 10K ohms or greater (SE), 20K ohms or greater (Balanced)
Tubes, each channel: (line section) V1 (6922), V2 (12AX7), V3 (6922), V4 (6SN7)
Power consumption: 300 watts

Physical dimensions:
Main unit, MkII or Signature: 5 5/8" high, 19" wide, 18" deep including jacks
Main unit, Eclipse: 5 1/2" high, 17 1/2" wide, 18" deep including jacks
Power supply, MkII or Signature: 5 5/8" high, 19" wide, " deep including jacks
Power supply, Eclipse: 5 5/8" high, 17 1/2" wide, 18 1/4" deep including jacks

Shipping weights:
Main unit, MkII or Signature: 42 Lbs
Main unit, Eclipse: 47 Lbs
Power supply, MkII or Signature: 50 Lbs
Power supply, Eclipse: 55 Lbs

Specifications subject to improvement or change without notice.


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click any image to enlarge



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Moorpark, CA 93021
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