JJ / Groove Tubes 12AX7 ECC83 7025 GTECC83 Vacuum Tube Vacuum Tube Valves They have 4-48 188-5 and

They have 4-48 188-5 and 5-43 188-5 date/provenance codes

new in box National Union 14X7 -- and another just like it -- tested to spec on our Paul Hart-calibrated TV7/U

Realistic / Radio Shack-BRANDED 12AU6 tube tested to spec on our Paul Hart-calibrated TV7/U

nostalgic-looking matched pair of GE 6P5G triodes was tested on our Paul Hart-calibrated TV7/U for shorts

JJ / Groove Tubes 12AX7 ECC83 7025 GTECC83 Vacuum Tube Vacuum Tube Valves They have 4-48 188-5 andThis JJ MANUFACTURED, Groove Tubes LABELED 12AX7 7025 GTECC83S dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas and it measured 36 46 where minimum (65%) is 32 32 and 100% is 49 49. It has excellent silkscreening; excellent flashing and an O getter. I am playing it in my Pro Ject Tube Box S phono preamplifier with an Ortofon X5 MC high output moving coil cartridge as I write and