Bourns Model 3600S-1-503 Knobpot®

Vintage 50K Ohm 10-Turn Precision Potentiometer

🔍 Condition Note: Vintage / Bench Tested This vintage component is in excellent structural and mechanical condition. It was kept in clean, dry storage for over 20+ years. Please Note: There is solder residue visible on the rear terminals from a brief, successful circuit bench test in a voltage regulator years ago. It was never permanently installed or deployed in a working environment. The integrated clock-face dial remains crystal clear and fully legible.

Product Overview

Up for sale is an authentic vintage Bourns 3600S-1-503 precision Knobpot. This specialized electronic component ingeniously consolidates a high-precision 10-turn potentiometer, setting knob, and a highly legible clock-face dial readout window into a single compact panel-mount assembly.

Featuring a highly sought-after 50k Ohm value with a ultra-smooth 10-turn linear adjustment, this component sits in the design "sweet spot" for demanding circuits. It is engineered to keep current draw low and signal stability exceptionally high. Perfect for custom valve/tube amplifier bias calibration setups, high-end studio gear restorations, and classic laboratory test equipment maintenance.

🎵 Note for Audio & Music Equipment Buyers: Please note that this is a 10-Turn Precision Wirewound Potentiometer with a Linear Taper. While its 50K Ohm value makes it ideal for valve amp bias networks, studio audio gear calibration, bench testing, and power supply biasing, it is not a standard logarithmic audio-taper volume control pot for guitars or consumer hifi systems. Please verify your circuit schematics require a 10-turn precision linear part before purchasing.

Common Applications

🎸 Audio Restoration & Valve Amplifier Bias
  • Highly favored for setting micro-precise grid bias voltages on power tubes in high-end vacuum tube/valve amplifiers.
  • Used in legendary outboard gear (VCAs, professional compressors) to perfectly balance channels and trim calibration parameters.
⚡ Power Supply Biasing & Calibration
  • Serves as the master "Fine Adjust" voltage control knob for variable laboratory bench power supplies.
  • Enables operators to dial in exact target outputs down to the millivolt without sudden, destructive power spikes.
⚙️ Industrial Controls & Automation
  • Used for highly accurate setting of process control variables.
  • Ideal for variable frequency drive (VFD) analog motor speed inputs requiring a reliable 0-10V reference signal.
📊 Test and Measurement Instrumentation
  • Found on front panels of oscilloscopes, calibration rigs, and signal generators.
  • Allows operators to use the clock-face readout to instantly log and repeat specific circuit settings with absolute accuracy.

Why It Is Chosen For These Tasks

  • High-Stability 50K Value: The 50,000 Ohm threshold represents a classic electronic engineering "sweet spot"—it draws minimal current from the circuit to prevent internal component heat, while remaining heavily resistant to stray electrical noise interference.
  • Space-Saving Integrated Design: Traditional precision configurations require separate component assemblies—a bulky potentiometer body coupled to an external turn-counting dial face. This innovative, all-in-one component format drastically conserves behind-the-panel depth and front panel real estate.

Technical Specifications

Manufacturer Bourns
Manufacturer Part Number 3600S-1-503 (Obsolete / Rare)
Resistance Value 50,000 Ohms (50K Ω)
Number of Mechanical Turns 10-Turn Precision Adjustment
Termination Style 3-Terminal Solder Lug (Shows Solder Residue)
Power Rating 1.5 Watts @ 25°C
Tolerance ±5%
Mounting Hardware Included Original hex nut & lock washer (as pictured)

Photos & Physical Detail

  • Please review the high-resolution listing photographs carefully to view the condition of the rear solder lugs and the dial face.
  • The exact component shown in the pictures is the exact item you will receive.
📦 Packaging & Shipping Commitment: We understand the delicate nature of vintage electronics. This unit will be packed securely inside a padded, rigid shipping container to protect the rear terminal pins and front glass dial face from transport stresses. Fast dispatch with step-by-step tracking info included.