Up for sale is a matched pair (2 Pcs) of vintage NOS Tung-Sol VT-137 / 1626 single power triode vacuum tubes, manufactured in the USA and supplied in clean white boxes. Relevelled in high-end custom audio circles (frequently utilized in “Darling” single-ended triode amplifier builds), these iconic tubes feature robust black plates, bottom square getters, and classic dark brown bases.

Both tubes have been thoroughly tested and matched on a precision Amplitrex AT1000 tube tester. Plate Current (Ip in mA) and Mutual Conductance (uMhos / µmhos) measurements along with percentage performance ratings relative to target reference specs (20.0 mA / 2000 µmhos) are detailed in the table below.