National (GE) 6550 Gold Line Tubes (Matched Quad), New Old Stock (NOS)

Free Shipping on *ALL* Electronics (Excluding Speakers, Contiguous 48 US States Only)

The other matched set of these we listed sold out in under an hour.

This set of tubes is actually a New Old Stock (NOS) matched Quad set.

We believe these to be NOS GE Tubes rebranded under National's Gold Line Series.

They have matching date codes and test extremely close to one another on our calibrated modern and professional Amplitrex AT-1000 Tester. 3% Plate Current Match, 1% Gm Match.

For reference we generally see plate current between 40-60% for NOS tubes on the Amplitrex. (This value can vary due to different internal construction).

We test all of our 6550s with 450V on the plates. Results are written in the following format.

Plate Current % of NOS / Gm % of NOS - Measured Plate Current at 450V
Tube 1:   61% / 101% - 36.7 mA
Tube 2:  62% / 101% - 37.6 mA
Tube 3:  63% / 100% - 38 mA
Tube 4:  64% / 101% - 38 mA