Made in USA by Tung-Sol (early 1960s).
Solid gray plate, no hole version with Triple O-Getter (one on top and two on each side).
One of outstanding 6550s ever made from Tung-Sol (USA).
Hard to find a nos nib matched quad at the moment. Only from us
Nos in box. Matched pair and quad are available. Tested under 3%.
Made in USA by Tung-Sol (1967 - 1971).
Three holes on gray plate with Triple O-Getter. Last version from Tung-Sol ever made.
This version has been produced by General Electric in the same time and they are same quality and out looking. One of famous Power Pentode from USA.
Tested like new. Matched pair and quad are available. Tested very strong (under 4%).
Made in USA by General Electric (after 1980s)
If you want the best tone for your amp these are the tubes to get. An added benefit to having NOS GE 6550A is that these can handle much higher plate voltages and will last much longer in both Hi-Fi and musical instrument amps than most 6550 made today.
Nos in box. All same date code. Matched pair and quad are available. Tested under 2%.
Made in USA by Tung-Sol (1958).
Twin mono plates, black glass. Bottom Pan-Getter.
Very very good type. Sweet and balance sounding.
One of the best 6A3 from USA.
Nos in original box. Matched pair are available. All same date code