ID these valves

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  • tekbowtekbow Frets: 1686
    edited January 2019
    DiscoStu said:
    I have a Blackstar HT60 Stage. It has 2xECC83 and 2xEL34.
    I'm showing my naivety here but could I put the 12AX7 in my amp to see if it works or would I be risking my amp?
    Wouldn't really tell you anything electrically about it. Could be on the verge of going and you'd not know.

    I guess it'd tell you in the most basic terms if it's operational or not. V1 is usually the spot for that. You'll know right quick if its noisy, or microphonic.

    I wouldn't though. You've no idea why it was sitting in a box loose.
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  • DiscoStuDiscoStu Frets: 5373
    Electrickery makes me nervous as I don't understand it. Yes my Blackstar has valves but it's the first valve amp I've had and I've never had to change one.
    I thought that replacing valves was a science so thought the chucking any of thing would be highly dangerous!
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  • tekbowtekbow Frets: 1686
    edited January 2019
    Replacing power tubes requires know how, messing around with preamp tubes *shouldn't* cause problems if you're careful, but I don't anyway because I'm electronically inept.

    If I know a tube is bad, it doesn't go in the amp. If I don't know, it doesn't go in the amp till I know. If I'm fannying around trying out V1's and 2's, I turn the amp off while I do it.

    Btw, if it does turn out to be good, or you do decide to brave shoving it in to check, then it flashes first time you use it, don't panic. Old tubes can do that as a part of normal operation.

    I put all my flashers in my amp a couple months ago for the fun of it.
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  • tekbowtekbow Frets: 1686

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  • DiscoStuDiscoStu Frets: 5373
    tekbow said:

    I wouldn't though. You've no idea why it was sitting in a box loose.

    Yes I do. Because it might come in handy one day! My dad kept everything. If you were on my Facebook then you'd have thoroughly enjoyed the 'what's in the tin' game I shared when clearing the rest of the shed! He had all the default screws/bolts/washers in separate boxes/jars/tins but this game was about his keeping of seashells/castors/clothespeg springs!
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  • tekbowtekbow Frets: 1686
    edited January 2019
    Well, if you know  then I'd defer to the advice of @Maynehead. Give it a go
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  • DiscoStuDiscoStu Frets: 5373
    I don't know for sure, I just think he'd have chucked it if it was borked. I pulled some of them from his home made record player but other than the Brimar BVA in the last photo I couldn't tell you which ones.
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  • MayneheadMaynehead Frets: 1782
    DiscoStu said:
    Electrickery makes me nervous as I don't understand it. Yes my Blackstar has valves but it's the first valve amp I've had and I've never had to change one.
    I thought that replacing valves was a science so thought the chucking any of thing would be highly dangerous!
    I test all the random old valves I got off eBay in my Mesa Boogie, never had a problem.

    If you’re going to stick it in, while it’s in there, turn the volume up and tap it gently(!) with a pencil. A dull thud is good, continuous ringing or a bell-like “dinggg...” is bad. Also do the same with your old valve and see if it sounds any different.

    Knowing the valve is working and not microphonic is going to add a lot of value.
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  • DiscoStuDiscoStu Frets: 5373
    Thanks. Like, what sort of value?
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  • tekbowtekbow Frets: 1686
    I endorse the above ^^
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  • DiscoStuDiscoStu Frets: 5373
    I take it the only valve of interest here is the 12AX7?
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  • tekbowtekbow Frets: 1686
    Primarily for guitarists yeah. I think some amps use EF86's as a preamp tube (matchless maybe?) and if the last one is an EL84, it would need to be part of a matched set I guess.
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  • tekbowtekbow Frets: 1686
    DiscoStu said:
    Thanks. Like, what sort of value?
    Not NOS Mullard or Telefunken levels sadly.

    I think current prices on good NOS Brimar's can go from 25 to 50 quid for the short plates, so maybe up from there?
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  • DiscoStuDiscoStu Frets: 5373
    tekbow said:
    DiscoStu said:
    Thanks. Like, what sort of value?
    Not NOS Mullard or Telefunken levels sadly.

    I think current prices on good NOS Brimar's can go from 25 to 50 quid for the short plates, so maybe up from there?
    Decent.
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  • MayneheadMaynehead Frets: 1782
    DiscoStu said:
    Thanks. Like, what sort of value?
    40-50 quid would be a good price, maybe less since it’s not NOS (or can’t be proven to be).
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  • DiscoStuDiscoStu Frets: 5373
    I've had a look on eBay and newer valves and reissues (if that's a thing) have white ink printing. My Brimars have a brown/orange stamp.
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  • ecc83ecc83 Frets: 1589
    Probab
    DiscoStu said:
    I have a Blackstar HT60 Stage. It has 2xECC83 and 2xEL34.
    I'm showing my naivety here but could I put the 12AX7 in my amp to see if it works or would I be risking my amp?
    That would tell you that it lights up and works but little more. Even "V1" in the S 60 is post a chip that gives some 12dB of gain and thus no hum, no noise to speak of, no microphony and lives forever. The preamp valves are DC heated so even if it was a hummy bugger, you would never know.  But, even if the valve is buggered it won't damage the amp's circuitry.

    BUT! Note that I am sure one of the pre valves is an ECC8 TWO! If you put an 83 there you will kill it in short order and the amp will sound shit. (must check the schemo'. Been a while, getting old...)

    LOUD fekkin' amp tho'but.

    Dave.
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  • ecc83ecc83 Frets: 1589
    Yes, ECC82 in the Stage 60/100. Runs hot so watch pinkies but I never had one fail.  I have a theory that regulated, DC heater power prolongs valve life but have no hard data to prove it.

    Dave.
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  • ICBMICBM Frets: 71951
    ecc83 said:

    I have a theory that regulated, DC heater power prolongs valve life but have no hard data to prove it.
    My experience is that in amps where there is a mix of AC and DC heated valves, if a filament fails it’s usually one of the DC-heated ones. Not a large sample though, so may not be meaningful.

    Or by regulated do you mean that the voltage should be reduced too? All the amps I can think of with partial DC filament supplies just rectify and smooth the AC supply, so the voltage is effectively higher.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • ecc83ecc83 Frets: 1589
    ICBM said:
    ecc83 said:

    I have a theory that regulated, DC heater power prolongs valve life but have no hard data to prove it.
    My experience is that in amps where there is a mix of AC and DC heated valves, if a filament fails it’s usually one of the DC-heated ones. Not a large sample though, so may not be meaningful.

    Or by regulated do you mean that the voltage should be reduced too? All the amps I can think of with partial DC filament supplies just rectify and smooth the AC supply, so the voltage is effectively higher.
    No IC becuase  6.3V "rms" means the same heating power as 6.3V DC.  Most of B's heater supplies are regulated and I think that protects the filaments from mains surges. As you say, no hard data but if you are going to put valves on a PCB DC is SO much easier to use.

    Actually, old brain has dredged that AC heater volts were often above 6.3? Sometimes nearly 7 volts.

    Dave.
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