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McIntosh MX121 Pre/Processor w/Dolby True HD, DTS-HD, and Phono

Sale price£3,033.00
Free Shipping on *ALL* Electronics (Excluding Speakers, Contiguous 48 US States Only)

Pickup available at SkyFi 479

Usually ready in 24 hours

Mcintosh Mx121 Pre/Processor W/Dolby True Hd Dts-Hd And Phono Recaeljd0Snywaxum

McIntosh MX121 Pre/Processor w/Dolby True HD, DTS-HD, and Phono

SkyFi 479

Pickup available, usually ready in 24 hours

479 South Broad Street
Glen Rock NJ 07452
United States



This listing is for an MX-121 from McIntosh with an official McIntosh shipping carton and remote control.

We also have a compatible Sennheiser calibration microphone and a McIntosh mic stand from the factory.

Almost as capable as the latest version (MX123) at a fraction of the cost, yet still able to manage HDMI signals. If you require 4K video you would just connect your sources directly to the TV and use this unit for audio processing which is where McIntosh shines.

As an audio preamp this will blow away the competition as you'll find the same type of circuitry employed in their dedicated preamps. It's even equipped with a capable phono section for your turntable.

We have several multi-channel amplifiers available, and of course you can pair this with higher-end stereo only amplifiers from McIntosh, Audio Research, Krell, etc., to truly customize your home theater amplification per channels/front and rear soundstage.

This MX121 was also updated to the very latest firmware version available.

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Phono Interconnects - Better

Kimber Kable - Flagship Phono Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Coaxial Digital Interconnect

Kimber Kable - Optical Digital Interconnect

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

Performance Features:

• HDMI 1.4a with 3D Passthru Switching

There are six HDMI 1.4a Inputs. HDMI Output 1 includes the new Digital Audio Return Channel (ARC) signal from the TV1, thus eliminating the need for an extra cable and simplifies operation. HDMI inputs are compatible with Deep Color, x.v.Color, Auto Lipsync and HDMI Component Control.

• Analog Video/Audio Switching with Scaling

Component Video Inputs and Composite Video Inputs (Analog Video Signals) are also converted to a Digital Video Signal with resolution up to 1080P at the HDMI Outputs.

• Balanced Inputs and Outputs

A pair of Balanced high level Inputs and an eight channel Balanced Output are provided, permitting long cable lengths without a loss in sound quality.

• Moving Magnet Phono Input

There is a Precision Phono Preamplifier for Moving Magnet Cartridges.

• Built-in Dolby True HD and DTS-HD Master Decoders

The MX121 also provides built-in decoding of the Dolby Pro Logic IIz, Dolby Pro Logic IIx, Dolby Digital EX, DTS Neo6 and DTS-ES Sound Tracks.

• Audyssey DSX®

Audyssey DSX is a scalable system that adds new speakers to improve surround impression. Audyssey DSX first adds Wide channels for the biggest impact on envelopment and then creates Height channels to reproduce the next most important acoustical and perceptual cues. Surround Envelopment Processing is used to enhance the blend between the front and surround channels.

Audio Specifications

Unless otherwise noted, the below MX121 Specifications where taken with Audyssey bypassed and manual Tone/EQ set to flat setting.

Frequency Response

±0.5dB from 20Hz-20,000Hz

Total Harmonic Distortion

0.005% maximum from 20Hz to 20,000Hz at rated output

Signal To Noise Ratio

Phono: 86dB below 10mV input (A Weighted) 

High Level: 96dB below rated output (A Weighted)

Rated Output Voltage

2.5V Unbalanced Outputs (Main Zone) 

5.0V Balanced Outputs (Main Zone)

Maximum Voltage Output

6V Unbalanced 

12V Balanced

Output Impedance

220 ohms

Input Impedance

Phono: 47k Ohms, 65pf

High Level: 20k Ohms Unbalanced and Balanced

Sensitivity for Rated Output

Phono: 4.5mV

High Level: 450mV Unbalanced, 900mV Balanced

Maximum Input Signal

Phono: 50mV

High Level: 4.5V Unbalanced and Balanced

Tone Controls

Bass Control: ±6dB at 30Hz 

Treble Control: ±6dB at 10,000Hz

Video Specifications

Signal System



Version 1.4 (includes support for Deep Color, x.v.Color, Auto Lipsync, Audio Return Channel and HDMI Component Control) 


Analog Video Inputs scaled to a 1080P Digital Signal

Component Video Output Level

Y Output Level 1.0Vp-p (75 OHM) 

PB/CB Output Level 0.7Vp-p (75 OHM) 

PR/CR Output Level 0.7Vp-p (75 OHM)

Composite Video Output Level

1Vp-p (75 OHM)

Overall Dimensions

Width is 17-1/2 inches (44.45cm)

Height is 7-5/8 inches (19.37cm) including feet

Depth is 19-1/2 inches (49.53cm) including the Front Panel, Knobs, Rear Panel Connections and USB Drive


30 pounds (13.6Kg) net, 54 pounds (24.5Kg) in shipping carton


McIntosh MX121 Original Sales Brochure

McIntosh MX121 Original Owner's Manual

The SkyFi Testing Process for Preamplifiers/Processors:

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.



McIntosh Shipping Carton

Yes Included


Not Included (Online)


Yes Included


Yes - Power Only

Physical Condition (Info Here)

7 / 10

Working Condition

10 / 10

SKU: 104398
Mcintosh Mx121 Pre/Processor W/Dolby True Hd Dts-Hd And Phono Recaeljd0Snywaxum
McIntosh MX121 Pre/Processor w/Dolby True HD, DTS-HD, and Phono Sale price£3,033.00