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Aesthetix Io Signature All-Tube Phono Stage with Dual Power Supplies

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Pickup currently unavailable at SkyFi 479

Aesthetix Io Signature All-Tube Phono Stage With Dual Power Supplies Preamplifier

Aesthetix Io Signature All-Tube Phono Stage with Dual Power Supplies

SkyFi 479

Pickup currently unavailable

479 South Broad Street
Glen Rock NJ 07452
United States


This listing is for a reference phono preamp which doesn't come up for sale very often.

The Io is an amazing phono preamp when used with a single power supply, but here we have DUAL power supplies (one for each channel) which takes this phono preamp to the next level.

A quick look inside a single power supplies reveals that absolutely no corners were cut. The complexity, parts count, and attention to detail is astounding for a power supply. We counted no less than 14 secondary power supplies in each box!

This unit was fully tested in our shop where we replaced a few weak tubes.

Aesthetix confirmed that these specific units were serviced by them in 2002. Yes, they're still in business and provide outstanding support.

If you'd like a put together a complete system, we also have the matching preamp that also includes dual power supplies. Just drop us a note.

Aesthetix Io Signature Phono Stage

Io is an all-tube phono stage suitable for the most demanding cartridges including low-output moving coils. A proprietary differential circuitry design achieves high gain with extremely low noise. A separate power supply chassis removes any possibility of transformer noise corrupting delicate audio circuitry. Peter Moncrief Stealth Capacitors are used in the Eclipse Edition for unparalleled sound quality. An optional innovative mechanically-switched discrete resistor volume control yields precise resolution at all listening levels.

• High gain / low noise capable of handling low output moving coils.
• Zero feedback.
• 80dB maximum gain, internally selectable down to 56dB
• Flexible user selectable loading on the back panel from 47Kohms down to 10ohms.
• All tube amplification and output (16 tubes total).
• Separate vacuum tube regulated power supply utilizing 8 tubes.
• Two sets of XLR and two sets of RCA outputs per channel.
• Input can be either RCA or XLR.
• Optional: Innovative and unique mechanically switched discrete resistor volume control with 46 positions using Roederstein resistors, one for each channel.

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 “tweek” each unit to a rigid standard.


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.

Inputs: one phono input, RCA and XLR jacks provided
Inputs (with volume control option): one line level balanced input, RCA and XLR jacks provided
Outputs: 2 RCA (SE) and XLR (balanced)
Gain: 80dB maximum
Volume control (optional): switched resistor network volume control with 46 steps
Frequency response: +- 0.25 dB, 20 Hz - 20 Khz
Signal to noise: 70 dB minimum, A-weighted (ref 1 mv input, 80 dB gain setting)
Input impedance: 10 ohms - 47K ohms (adjustable)
Output impedance: 1K ohms SE, 600 ohms balanced
Recommended load: 10K ohms or greater (SE), 20K ohms or greater (Balanced)
Tubes, each channel: V1-V6 (12AX7); V7 (6DJ8 / 6922); V8 (6SN7)
Power consumption: 350 watts

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

Shipping weights:
Main unit, MkII or Signature: 32 lbs.
Main unit, Eclipse: 37 lbs.
Main unit, MkII or Signature w/vol: 38 lbs.
Main unit, Eclipse w/vol: 45 lbs.
Power supply, MkII or Signature: 50 lbs.
Power supply, Eclipse: 55 lbs.

Aesthetix Io Signature Owner's Manual

The SkyFi Testing Process for Preamplifiers (All):

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.

At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching.

Final testing involves putting actual music through the preamplifier We have learned over time that some issues are only noticeable to a trained ear while listening to a familiar source material. Our test bench has reference vintage KEF speakers that we are super familiar with which will quickly reveal any discrepancies. Some preamps will then move into the listening room where they will be tested with our in-house reference system.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.



Original Box







Yes - Power

Physical Condition


Working Condition


SKU: 101778