AuditoryCanvas
500+ Head-Fier
@AuditoryCanvas one more question. How would you rate Siemens E88CC halo getter to the ones you describe above? I'm asking because I'll most probably be getting a nice pair for a moderate price.
Those are some of the better 6922 types, though quite neutral in character. I'd say they were close to some of the 12AT7 variants like the Telefunken ECC81.
Try and get early to mid 60s Siemens E88CC with grey plates rather than silver plates (rectangle plate attached to the mica just under the getter platform), and try and get the single getter post ones rather than A-frame.
Give me a shout if you need help deciphering the date stamps/codes. Some of the 60s Siemens have etched codes, some have a stamped silver plate on the getter platform.
Good reference here for deciphering them here too: https://frank.pocnet.net/other/Philips/PhilipsCodeListAB.pdf - it says Philips codes, but covers most other European tubes too. Philips branded tubes as Valvo, SQ, miniwatt, and many others, and you'll often find brands making tubes for other brands - it's not uncommon to find Siemens tubes branded as Telefunken sometimes for example (you can tell because they won't have the Telefunken diamond on the bottom). you can usually tell the actual manufacture by the date code and/or construction.
The main thing with the 12A*7 types and variants, aside form some of the more expensive ones, is that they're typically more readily available, for a better price than the 6922 types they compete with. Unfortunately ones like the Valvo 6201s have jumped significantly in price compared to a few years ago - the triple mica pinched waist ones used to go for around $350 or less a pair, and now they're going to $800 plus. Similar to how the 6922 types kept going up in price, and rarity, and began getting more exploited in price on ebay. Fortunately, a lot of the 12A*7 types/variants haven't met the same fate yet. So in short, you'll generally get a much better quality tube, for less than you'd pay for a decent 6922 type, with a few exceptions as always.
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