RCA Hewlett Packard 6K6GC 1964

Offered by The Guitar Armory

Up for sale is a fantastic piece of vintage American electronics history: an original RCA 6K6GT power pentode tube, custom-selected and branded for Hewlett-Packard.

Dating to early 1964 (64-04), this tube was manufactured by RCA to meet HP’s famously strict laboratory test-equipment standards. Industrial contracts like these required the absolute highest tier of factory screening for low noise, minimal microphonics, and long-term stability.

In the guitar world, the 6K6GT is a legendary specialty tube—celebrated as the stock driving heart of vintage standalone Fender tube reverb units, as well as various mid-century low-watt practice amps. Getting a premium, instrument-grade HP-selected version ensures maximum reliability and a smooth, classic performance.

This tube was sourced directly from a carefully stored private estate collection.

Physical Condition:

• Glass envelope is rock solid to the base with zero structural play.
• Internal plate structures and support rods are straight and pristine.
• The top getter flashing is thick, dark, and highly reflective (no air leakage).
• The center plastic octal guide pin and all metal base pins are clean and fully intact.

Testing & Shop Policy: Because this tube came directly out of a large collection and we do not currently have a calibrated mutual conductance tube tester on-site at the shop, it is being offered As-Is / Untested. Visually, the tube looks excellent, showing no signs of heavy runtime or heat stress. We have priced it competitively to offer an excellent deal on premium, instrument-grade vintage US glass