The Heathkit TT-1 is a classic, professional-grade mutual conductance tube tester, popular in the 1960s for its accuracy in testing tube health (transconductance, leakage) by loading tubes like real equipment, unlike simpler testers. Key features include constant current heater supplies, an ultra-sensitive grid current test, and a direct-reading ohmmeter.
The unit powered up and the meter responded appropriately to a line adjustment The needle falls back to 0 and has smooth action. It comes with instructions (Both from manufacturer and a previous owners notes) Also comes with supplemental chart info. Roll chart operates smoothly and background lamp functional. Carry case in very good condition with only minor blemishes in the covering. It is a very clean example of a very sought after tube tester.
This vintage unit may require capacitor replacement (re-capping) and calibration. It was part of a large estate purchase and extensive testing was not performed.
