Condition: Used / Vintage / Excellent Cosmetic Shape
Brand: Stromberg-Carlson
Model: AU-63 (Signet Series)
Wattage: ~20–22 Watts
Up for sale is a remarkably clean, mid-century Stromberg-Carlson AU-63 from the "Signet" series. This is the highly desirable 20-watt version, often called the "Sweet Spot" of the Signet line. It offers the perfect power bracket for guitarists looking for that legendary vintage tube breakup without the overwhelming volume of the 50-watt PA heads.
Housed in its original green textured portable case with the integrated speaker and coiled multi-tap cabling, this unit is a true "time capsule" find. These AU-63 units are sought after for their massive, high-quality output transformers that deliver a depth of tone modern amplifiers struggle to replicate.
Key Features & Technical Specs
Tube Complement: Features a premium set of original Stromberg-Carlson branded tubes, including:
(2) 6L6GB / 5881 Power Tubes (Push-Pull Configuration)
(1) 5Y3GT Rectifier
Original Preamp/Phase Inverter glass
Output Taps: Rear terminal strip provides 4Ω, 8Ω, 16Ω, and 70V options—plug directly into any modern 8-ohm or 16-ohm guitar cabinet.
Controls: Front panel includes individual controls for Mic, Phono, and Tone.
Chassis: Clean "Signet" series faceplate with original knobs and the iconic S-C logo.
Condition Report
Cosmetic: 8.5/10. The chassis is exceptionally clean. The green textured case shows light vintage wear but is structurally solid with a sturdy handle.
Internal: The circuit is largely original, featuring vintage carbon comp resistors and a newer "Red Rocket" electrolytic capacitor.
Testing: The unit powers on and all tubes glow. As with any 60-year-old tube electronic, this is sold as-is for restoration or professional service. It is a prime candidate for a basic recap or a boutique guitar amp conversion.
Why the AU-63?
The AU-63 is favored by builders and collectors because its circuit architecture is very similar to Tweed-era Fender amps. With 20 watts of high-quality "iron," this amp provides incredible headroom and a rich, harmonic overdrive when pushed. Finding one with the original S-C branded tubes still intact is a rare bonus for any enthusiast.
SAFETY WARNING READ THIS!!
YOU MUST CONVERT TO A 3 PRONG MODERN PLUG BEFORE POWERING ON/PLAYING THROUGH!!
thats because theres a slight chance this thing might have the original capacitor, lovingly known as the DEATH CAP😅😶😬, blow up causing the amp to become electrified as well as the guitar plugged in to it and the unfortunate dumdum playing it and KILLLLL YOUUU !!! easy fix ... big payoff.
Fun Fact: theres another precious nickname associated with these cute little guys : WIDOWMAKER
death cap...widowmaker ....
Here's how AI said it ....almost seems like it kinda wants you to die. Or just doesnt give a shit if you were to accidentally electrocute yourself to death :
" For modern stage or studio use, a 3-prong grounded cord and a standard recap are recommended for safety and quiet operation."
LOL "quiet operation"... ohh, gemini you rascal, you !!
Technical Specifications:
Year: 1957
Manufacturer: Stromberg-Carlson (Rochester, NY)
Output: 80 Watts (Sine Wave)
Tube Complement: 4 x 6L6G (Power), 2 x 5U4G (Rectifiers), 1 x 6SJ7, 1 x 6SC7, 1 x 6N7 (Preamp/Drivers).
Weight: ~35 lbs (Pure high-quality iron).