Vintage Ducon Stacked Dual-Concentric Potentiometer

1K / 1MΩ Dual Independent Coaxial Control | Integrated SPST Rotary Switch | Vintage NOS

👨‍🛠️ Bench Verification & Technical Condition

Up for sale is an ultra-rare New Old Stock (NOS) vintage 1960s Ducon Australian-Made coaxial dual-concentric potentiometer with a built-in rear rotary power switch. This premium component features a stacked independent shaft layout, allowing two stacked control knobs to operate entirely distinct circuit paths out of a single mounting hole, while the initial clockwise turn acts as the system mains switch. It features an exceptionally long 3-10/16" (approx. 92mm) total shaft setup designed specifically to pass through thick wooden cabinet faces or deep-chassis configurations.

Coaxial Dual-Concentric Mechanics: Features a 7mm round brass outer sleeve (with keyway slots for the front knob) wrapped around an inner 4.9mm brass shaft with a flattened D-edge (protruding an extra 16.5mm past the sleeve for the rear knob).
Integrated SPST Power Switch: The rear phenolic plate features a highly reliable Single-Pole Single-Throw (SPST) switch operating on active terminals 1 and 2. It sits completely open (Normally Open / Off) in the anti-clockwise detent position and clicks firmly shorted/closed (On) when rotated clockwise.
Verified Bench Diagnostics: Directly swept and verified with a digital multimeter to guarantee smooth continuity and confirm authentic legacy era-specific operational curves:

🔹 FRONT POT (Outer 7mm Sleeve - Legacy Stamp 1KE):
• Total Track Resistance (Pins 1 to 3): 1.2 kΩ Max (1.0 Ω Minimum Floor)
• 50% Mechanical Midpoint: Legacy linear curve profile sweeping quickly to ~990 Ω

🔹 REAR POT (Inner 4.9mm D-Shaft - Legacy Stamp 1MEGC):
• Total Track Resistance (Pins 1 to 3): 1.0 MΩ Max (0.9 Ω Minimum Floor)
• 50% Mechanical Midpoint: Registers an authentic vintage Log/Audio taper curve at ~50 kΩ

🔹 ROTARY SWITCH BACKING (Terminals 1 & 2):
• Off Position (Fully CCW Detent): Open Circuit (NO)
• On Position (CW Rotation Past Click): Solid zero-ohm continuity short between terminals

📊 Stamped Component Specifications

Brand / Manufacturer	Ducon (Made in Australia)
Front Casing Stamp	214 DUCON 1KE 75B11 (1.2 kΩ Measured Total)
Rear Casing Stamp	214 1MEGC (1.0 MΩ Measured Total)
Architecture Layout	Dual-Ganged Concentric Independent Potentiometers + Rear Switch
Taper Profiles (Legacy System)	Front Track: "E" Linear Curve \| Rear Track: "C" Logarithmic Audio Curve
Integrated Switch Specification	Rotary SPST Power Switch \| Terminals 1 & 2 Active \| Rated 2A 250VAC / 10A 12VDC
Total Shaft Dimensions	Extra-Long 3-10/16" (approx. 92mm) Length Including Thread Block
Shaft Profiles	Outer: 7mm Round Solid Brass with Keyway slots \| Inner: 4.9mm Brass D-Shaft
Terminal Architecture	3-Pin Hollow Solder Lugs Per Potentiometer Section + 2 Rear Switch Pins
Era & Origin / Condition	1960s Classic Vintage Stock \| Made in Australia \| New Old Stock (NOS)

📻 Historic Radio & Television Restoration Focus

This highly specific dual-value coaxial component with an integrated mains switch is crucial for period-correct bench work:

Vintage Australian Televisions & Stereograms: The required drop-in stacked replacement node for deep wooden console cabinetry (such as vintage Astor, Kriesler, or HMV sets) managing shared-shaft volume and gain paths combined with a main power click switch.
Classic Valve Radios & Ham Transceivers: Highly targeted for dual circuit adjustments (such as fine-tuning/volume or RF-Gain control stacks) running out of a single faceplate opening while managing safe high-voltage system lines.
Premium Custom Tube Builds: An invaluable piece of authentic Australian electronics history for custom amplifier circuits requiring a low-resistance linear sweep side-by-side with a high-resistance audio path and full power switching utility.

📮 Combined Shipping Policy

Clearing out multiple vintage assets from your workspace project bins? I will gladly manually combine shipping costs across all active listings to save you money on postage. Please add your items to your cart and request a final total before making your payment so I can issue an adjusted invoice based on the true package size and weight.

⚠️ Vintage Electronics Disclaimer

This item is a premium New Old Stock (NOS) component from an accumulation of classic workshop stock. While it has been cleanly bench-tested to confirm precise track resistance, switch continuity, and smooth tracking, vintage electrical hardware components are sold as-is without modern commercial warranties. Please review all dimensions and chassis shaft profiles closely before purchasing.