6550 Tungsol branded Sylvania smooth gray plate used/tests like new 1960 era - 3 good getters in white box

138ma

Gm=10,400

Good NOS Ma range 125-140ma

Good NOS Gm range 10,0000 - 10,100

Recommended for

- ARC VS 110 and other ARC amps
- Audio Research Reference 3 line-stage power supply 
- Rogue 90
- VTL amps; MB300, 450, many others
- Gibson guitar amp
- McIntosh 275
- Beard P100 MKII 1984
- Cayin A-88T