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Mid-Century Custom 20-Watt Tube Amplifier ChassisFeaturing Premium Stancor HF-67 High-Fidelity Output IronUp for sale is an exceptional piece of mid-century audio history: a custom, hand-wired 20-watt push-pull tube amplifier chassis. This unit was a personal passion project built by a professional electrical engineer based out of Los Angeles, California.The layout underneath is an absolute masterclass in clean, point-to-point vintage engineering. Every lead dress, ground scheme, and component placement reflects the meticulous eye of a trained engineer. It is an untouched, pristine time capsule—completely free of modern hack-jobs or butchered wiring—making it the ultimate clean slate for a premium boutique hi-fi restoration or an elite guitar amp conversion (perfect for a custom boutique studio amp).The Star of the Show: Stancor HF-67 IronThe crown jewel of this build is the legendary Stancor HF-67 high-fidelity output transformer. Highly sought after by audiophiles worldwide for its incredible flat frequency response and pristine harmonic depth, this iron is rated for a clean 20 watts of power. It is entirely original to the build, structurally immaculate, and features untouched factory leads.Bench Test Results & Technical DataTo ensure total transparency and protect the historical integrity of this engineer's build, the chassis was safely evaluated on the bench using a Dim Bulb Tester (DBT) and an analog tube tester. No transformers were un-wired or desoldered, preserving the original solder joints. Power Transformer (DBT Idle Test): PASSED. Tested with all tubes removed on a Dim Bulb Tester. It idles beautifully, safely, and quietly with zero internal shorts or catastrophic faults. High-Voltage Secondary Output: PASSED. Voltage readings taken directly from the rectifier socket confirm a beautifully robust and perfectly balanced 442VAC / 445VAC to ground across the plates (894VAC plate-to-plate). Filament Winding: The power transformer features a native 5V rectifier filament winding (currently reading a strong 4VAC to ground on Pin 2).Premium Vintage American Glass IncludedThe chassis comes complete with its original, vintage American-made tube set. Every tube has been pulled and tested on the bench for emission with excellent, strong results: 6L6 Power Tube #1: Tests at 105 (Extremely Strong) 6L6 Power Tube #2: Tests at 96 (Strong, excellent close match to Tube #1) 6J5 Triode: Tests at 100 (Practically Brand New) 6SJ7 Pentode: Included 6SC7 Dual-Triode: Included(Note: The octal rectifier socket is being left empty. While the transformer iron is natively spec'd to run a classic 5U4G or 5Y3GT rectifier, the socket wiring path needs a quick, minor trace and cleanup by the next owner to get the heater lines properly landed on Pins 2 and 8. A standard Ken-Rad 5Y3GT tube testing strong at 75/82 is included with the sale as a bonus).Condition & Sales TermsThis is a 70+-year-old vintage electronics project chassis. Due to its age and the fact that the original electrolytic capacitors are still in place, it is sold strictly As-Is, for parts or restoration. It has not been tested for audio throughput or plugged directly into a speaker cabinet.This is a heavy, industrial-grade piece of iron. It will be packed with professional care—tubes pulled and individually wrapped, and the chassis double-boxed and securely padded—to ensure it arrives safely on your workbench.Don't miss out on a pristine piece of LA audio heritage with a verified healthy Stancor HF-67! Worldwide shipping available via eBay Global Shipping.
