12AX7 tubes

BlueMDPicker
BlueMDPicker Posts: 7,569
in 2 Channel Audio
Was rummaging through the tube box and found a few varieties of these. The search began to see if I had a pair of 12AX7WA (what’s in there currently) for the preamp on my Fender Cyber-Twin amp. Sadly, I’ve probably forgotten more than I ever knew about tubes. So, question for those IN THE KNOW: is there a chance of damaging these Telefunken tubes since the don’t have the WA suffix?
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Comments

  • pitdogg2
    pitdogg2 Posts: 25,576
    Nope
    the W designation is military grade. I believe very few got that designation since the 5751 I believe replaced it.
    It is the same as any other 12ax7 with the exception of a stronger filament
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  • BlueMDPicker
    BlueMDPicker Posts: 7,569
    Thanks for the quick response! You must have known I was chomping at the bit to roll them in. The WA have been in there at least 15 years with 100’s (perhaps 1000’s) of hours of operation. Should make an identifiable difference. Off we go and THANKS again!
    Mike
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  • BlueMDPicker
    BlueMDPicker Posts: 7,569
    Tube rolling in this amp (an original Cyber-Twin) is fairly impractical. I had to disconnect the speakers and pull the head chassis from the cabinet to access the preamp tubes (10 bolts). That was apparently remedied in the SE model with an access panel on the chassis bottom. Good news is the Telefunken tubes have a slightly warmer tone and break up sweetly when overdriven (think Clapton's lead on Strange Brew). The original Groove Tube GT12AX7WA tubes are built like a tank compared to the innards on the Telefunken.
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  • BlueMDPicker
    BlueMDPicker Posts: 7,569
    HeHe! Just looked on Tube Depot and the Telefunken I just put in the guitar amp are selling for $499.95 a copy. The two tubes are worth more than the amp! :o
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  • pitdogg2
    pitdogg2 Posts: 25,576
    NOS Telefunken's are e'spensive.
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  • BlueMDPicker
    BlueMDPicker Posts: 7,569
    IIRC those two came out of a NOS Hammond spring reverb unit I sold before my move south 11 years ago. I had always planned to add it to my B3, but never got around to it and stripped the tubes out of it before I sold it. There was one other small signal tube in the unit (also Telefunken) that I gifted to a Forum member here. I'd probably be shocked if I went through the whole tube box (a cowboy boot box completely full).
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  • dromunds
    dromunds Posts: 10,018
    After my father died a couple years ago I found a tray with a bunch of 1958 and 1959 Telefunken tubes, 12AU7’s, 12AX7’s, 12AT7’s etc. I think they may have come out of a record player he purchased in 1959. Worth quite a penny now. They sound really good by the way.
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