U20411 Used MFJ-557 Deluxe Morse Code Practice Oscillator

U20411 Used MFJ-557 Deluxe Morse Code Practice Oscillator 

Overall Condition: Used, very good physical condition overall showing only minor storage dust! Cosmetic Details: The black metal base plate, plastic oscillator housing, and silver control knobs present cleanly with no scuffs or cosmetic defects beyond light dust accumulation. Straight Key Assembly: The heavy-duty chrome telegraph key lever, adjustment screws, spring, contact points, and black plastic straight key knob are intact and fully functional.

The MFJ-557 Deluxe Morse Code Practice Oscillator is an all-in-one standalone CW code practice unit designed for beginner radio operators learning Morse code or experienced hams sharpening their sending technique. It combines a fully adjustable heavy-duty straight key mounted onto a sturdy non-skid metal base alongside an integrated tone oscillator and speaker housing.

Featuring front-panel controls for variable sidetone volume and pitch frequency, the MFJ-557 allows users to tailor the audio tone to their preference. Powered via an internal 9V battery or an external DC power supply, it also includes a side 3.5mm headphone jack for quiet, private practicing without disturbing others.

Condition Breakdown

• General: Pre-owned, very good overall physical condition with no cosmetic defects beyond light storage dust

• Oscillator Housing & Controls: Black plastic sloped housing and labeling (VOLUME and TONE) are good

• Straight Key Mechanism: Chrome-plated key lever, return spring, contact screws, and round black plastic knob are clean and rust-free
  

• Jacks & Switches: Side 3.5mm earphone/headphone jack and power connections are solid

Key Features

• All-In-One Practice Station: Integrated straight telegraph key and built-in audio speaker oscillator on a single base

• Fully Adjustable Straight Key: Custom tension, contact gap spacing, and height adjustment screws for personalized sending feel

• Variable Volume & Pitch Controls: Dedicated front rotary potentiometers to adjust audio loudness and sidetone pitch frequency

• Silent Practice Ready: Side-mounted 3.5mm headphone jack automatically mutes internal speaker for private code training

• Flexible Power Options: Operates using a standard 9V battery or an optional external 12V DC power adapter

• Solid Desktop Base: Heavy non-skid metal plate prevents key sliding on desk surfaces during sending practice

What's Included

• MFJ-557 Deluxe Morse Code Practice Oscillator Unit with Mounted Straight Key

Warranty

Comes with our 90-Day Warranty!

S/N: n/a

QR-0330