Aesthetix Callisto Signature Edition Tube Preamplifier w/Dual Power Supplies

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This is the Flagship line stage preamp from Aesthetix (Jupiter Series), utilizing dual power supplies (one per channel) along with dual mono construction. These don't come up for sale very often.

Working as it should all around, and a great match to the IO phono preamp that is also currently listed as of this writing.

This unit was sent to Aesthetix back in 2001 for the Signature Edition upgrade. Then it was It was sent to Aesthetix again in 2002 and updated to independent power supplies back.

Aesthetix is still in business and still offers service and upgrades to this model.

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Power Cords - Better

CALLISTO TUBE LINESTAGE

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.

Dual Power Supply
Callisto comes with a single power supply standard, or optionally a second power supply may be added for true dual-mono.

JUPITER POWER SUPPLY DETAIL

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.

CALLISTO SPECIFICATIONS
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 

CALLISTO TECHNICAL DOCUMENTS:

Callisto Owner's Manual
Callisto Tube Placement
Callisto Important Notice

The SkyFi Testing Process for Preamplifiers:

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCB’s for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.

When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope. We then switch to a 1KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment. Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.

We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected. If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.