4. European NOS 6SN7s
Amperex 6SN7GTB
These tubes are likely Russian-made. Be wary of overpaying for them!
Base: black
Glass: clear, orange Amperex labeling with globe logo, may have white ‘6SN7GTB’ labeling
Plates: grey, T-plates
Getter: bottom, ‘flying saucer’ getter holder, flashing extends a little bit past base, usually more so on one side
Top mica: rectangular, has ‘spring-loading’ for plates (U-shaped structures)
Other significant features: bottom mica identical to top mica. micas appear whitish. 2 support rods on either side between both micas.
STC/Brimar 6SN7GTY / CV1988 (UK)
Brimar stood for ‘BRItish Made American Range’ and was originally part of STC (Standard Telephone and Cables), which in turn was the British agent of Western Electric. Only Brimar made the CV1988 – known relabels include Cossor, STC, Zaerix, ITT (International Telephone and Telegraph) and Mullard. Sometimes labeled as 6SN7GTY.
Base: brown, no printing
Glass: black or clear (less common), if applicable blackening extends up from ¼ from bottom of tube to top, white printing on glass with factory code FE (indicating STC Oldsway production)
Plates: grey, ‘flattened oval’ cross section
Getter: bottom, ring getter holder, flashing does not extend past base
Top mica: round with spiked edges, spikes contact glass, 2 small anode plates extensions extend vertically
Other significant features: bottom mica round with smooth edges
Brimar 6SN7GT (UK) version 1
This tube is identical to the CV1988 except that black bases may be used.
Base: black or brown (less common) with printing
Glass: black or clear (less common), if applicable blackening extends up from ¼ from bottom of tube
Plates: grey, ‘flattened oval’ cross section
Getter: bottom, ring getter holder, flashing does not extend past base
Top mica: round with spiked edges, spikes contact glass, 2 small anode plates extensions extend vertically
Other significant features: bottom mica round with smooth edges
Brimar 6SN7GT (UK) version 2
This tube came next chronologically and differs from earlier examples by not having anode plate extensions on the top mica and having a differently shaped getter holder. No black glass examples of this tube have been yet found by the thread author.
Base: black with printing, printing may be reddish-orange
Glass: clear
Plates: grey, ‘flattened oval’ cross section
Getter: bottom, rectangular getter holder, flashing does not extend past base
Top mica: round with spiked edges, spikes contact glass
Other significant features: bottom mica round with smooth edges
Brimar 6SN7GT (UK) version 3
Latest vintage. Often found as Cossor relabels. Note the different top mica shape. No black glass examples of this tube have been yet found by the thread author.
Base: black
Glass: clear, often with Cossor labels
Plates: grey, ‘flattened oval’ cross section
Getter: bottom, rectangular getter holder, flashing does not extend past base
Top mica: round, smooth edged
Other significant features: bottom mica identical to top mica
Brimar 13D2 (UK)
6SN7GT equivalent produced for industrial use. Extremely rare.
Base: dark brown, no labels
Glass: clear, has white labels printed onto it
Plates: grey flat plates
Getter: top, on top-most mica (more on that later), dual ring getter – one above each plate
Top mica: 2 round top micas; top-most mica has smaller diameter than next top mica
Other significant features: bottom mica round, diameter roughly same as top-most mica
Cossor 6SN7GT (UK)
Cossor bought tubes in bulk, and then relabeled them. Tubes labeled ‘Cossor’ have been seen that were made from anyone from RCA to Brimar to Sovtek.
Fivre 6SN7GT (Italy)
Fivre stands for ‘Fabbrica Italiana Valvola Radiofonica Elettronica’. Original tube retail boxes are red and black.
Base: black
Glass: clear, has a colourful label on it
Plates: grey
Getter: bottom,
Top mica: rectangular with a few ‘spikes’ on either short end
Other significant features:
GEC B65 (UK)
GEC stands for ‘General Electric Company’.
Base:
Glass:
Plates:
Getter:
Top mica:
Other significant features:
Haltron 6SN7GT
Haltron bought tubes in bulk, and then relabeled them. Tubes labeled ‘Haltron’ have been seen that were made from anyone from Brimar to Sovtek. Many were also made in eastern-bloc countries.
Osram B65 (UK)
Base: metal base with no labels
Glass: grey glass beginning ¼ of way from base, tube data print on glass
Plates:
Getter: bottom, inverted cup, flashing rarely extending up past metal base
Top mica: round with ‘umbrella spokes’ coming off bottom
Other significant features: usually has color print ‘Osram’ logo on glass
MWT B65 (UK)
MWT stands for ‘Marconi Wireless Telegraph’.
Base: metal, no labels
Glass: smoked, has colorful label on it, also may have (fragile) white print
Plates:
Getter: bottom, inverted ‘cup’ getter, flashing does not extend much past base
Top mica: round
Other significant features:
Neotron 6SN7 (France)
Commonly confused with TungSol round plate 6SN7GTs.
Base: black
Glass: smoked with orange “Neotron 6SN7” logo, black glass extends from base of tube
Plates: round
Getter: bottom
Top mica: rectangular
Other significant features: top mica has two rectangular mica ears on it and two large U-shaped structures, (looks similar to Tungsol RP except for top mica shape)
RFT 6SN7GT (West Germany)
An extremely unusual tube.
Base: black, ‘short’ base
Glass: clear with yellow RFT logo and labels
Plates: grey, flat with NO ridging and an unusual ‘monolith’ look
Getter: top, flat disc
Top mica: NOT mica, but
ceramic! round with 2 mica ‘ear’ supports
Other significant features: bottom ‘mica’ is also made of ceramic, round and has ‘cutouts’ on 2 sides.
Philips 6SN7GT (Holland)
Philips Holland had numerous subsidiaries - examples include: Adzam (exclusively an export name), Amperex, Pope (exclusively an export name), Philips Miniwatt, Mullard, Miniwatt, Miniwatt Dario, Radiotechnique, etc. This tube has been known to be relabeled with the following brand names: Pope, Philips Miniwatt, Miniwatt and Mullard.
Base: black with white labels
Glass: clear (less common) or grey-black (similar color and luster to pencil lead). If grey-black glass, begins ¼ of way up tube from base and ends near top. May have white print on glass (Mullard).
Plates: grey, flat with ‘ladder’ ridging
Getter: bottom, D-shaped, flashing rarely extends past plastic base
Top mica: racetrack shaped
Other significant features: bottom mica is racetrack shaped with mica ‘spikes’ coming off shorter sides
Sicte 6SN7GT (Italy)
Base: black with orange print
Glass: clear with a very colorful label
Plates: grey
Getter: bottom, flashing extending slightly up past base
Top mica: rectangular
Other significant features:
Sovtek 6SN7GT (Russian)
Base: black
Glass: clear, labels in silvery ink
Plates: grey, T-plates
Getter: bottom, ‘flying saucer’ getter holder, flashing extends a little bit past base, usually more so on one side
Top mica: rectangular, has ‘spring-loading’ for plates (U-shaped structures)
Other significant features: bottom mica identical to top mica. micas appear whitish.
Telefunken 6SN7GTA (West Germany)
May be marked ‘Radiotron’ on base.
Base: black, usually clear of any labels
Glass: clear, white labels, says ‘Made in West Germany’
Plates: grey, plates have 2 horizontal ‘holes’ midway in them
Getter: top, ring, flashing is restricted to topmost portion of tube; does not extend down much
Top mica: round with scalloped edges
Other significant features: bottom mica is identical to top. Top of tube glass is obviously less ‘rounded’ than most other 6SN7s.
Tungsram 6SN7GTY / CV1988 (UK)
Extremely rare.
Base: brown
Glass: black, blackening extends up from ¼ from bottom of tube to top
Plates:
Getter:
Top mica:
Other significant features:
Zaerix 6SN7GT
Zaerix was a company name owned by Z&I Aero, London, England. Zaerix, like Haltron, bought tubes in bulk, and then relabeled them. Tubes labeled ‘Zaerix’ have been seen that were made from anyone from Brimar to Sovtek. Many Zaerix tubes were also made in eastern-bloc countries. Zaerix bought tubes in bulk, tested them to ensure that they were within spec, and then relabeled and supplied them to the UK government and various OEM companies.
