6sl7/gt/y 5691 ECC35 6188 cv1984 ecc35 cv1985 6113 6h9c 6n9p cv569 cv3985 vt229. + a top-ranked grail alternative to early bendix usa, rca special red editions, or even those badboy sylvanias. full mutual conductance gm micromhos test + leak/short/gas/life/sound checks + digital test (see above).
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