Io is an all-tube phono stage suitable for the most demanding cartridges, including low-output moving coils. It is in the Jupiter Series (link to Jupiter Series description), sharing common design characteristics with the Callisto. It has won numerous awards, receiving worldwide acclaim for its superior sound quality.

• High gain / low noise capable of handling low output moving coils.
• Zero global 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.

Io is available in three versions: Mk II, Signature and Eclipse. 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 io, incorporating constrained-layer damped machined aluminum panels and Peter Moncrief’s Stealth Capacitors. All versions of Io can be factory upgraded to Signature or Eclipse.

Io Options and Upgrades

• Io Signature Version Detail
• Io Eclipse Version Detail
• Io comes with a single power supply standard, or optionally a second power supply may be added for true dual-mono. Power Supply Detail
• Io may be optionally configured with volume controls and a line level input. This is ideal for phono-only systems. Volume Control Detail
• Io Eclipse may be ordered with custom finishes. Design your own Io



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 impedence: 10 ohms – 47K ohms (adjustable)
Output impedence: 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.

Specifications subject to improvement or change without notice.