I shared the following in another forum:
If interested, here are the tubes in my Blackhawk (directly from Raven, not rolled):
1. Preamp stage, 12AT7: both RCA, left marking: 67 43, USA 6201; I think this indicates mfr'd in 43d week of 1967. Can only make out RCA on rightside
2. Power amp first stage, 12AT7: both GE, left 57 43 (and 188-5 marking?); right GE, 58 4 (1957 and 1958 resp, I think.)
3. Phase inverter stage, 12AU7: both Philips ECG/USA, both say JAN 5814A, right-side says 8813 APX
Power tubes, 6L6GC, made in Russia, (written in English), all say OTK 61, Front/right 1103, Front/left 1115, Back/right 1050, Back/left 1115. These aren't date codes as I bought the amp 6/2015
Any help in further translating this information is welcomed!
If interested, here are the tubes in my Blackhawk (directly from Raven, not rolled):
1. Preamp stage, 12AT7: both RCA, left marking: 67 43, USA 6201; I think this indicates mfr'd in 43d week of 1967. Can only make out RCA on rightside
2. Power amp first stage, 12AT7: both GE, left 57 43 (and 188-5 marking?); right GE, 58 4 (1957 and 1958 resp, I think.)
3. Phase inverter stage, 12AU7: both Philips ECG/USA, both say JAN 5814A, right-side says 8813 APX
Power tubes, 6L6GC, made in Russia, (written in English), all say OTK 61, Front/right 1103, Front/left 1115, Back/right 1050, Back/left 1115. These aren't date codes as I bought the amp 6/2015
Any help in further translating this information is welcomed!