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Alembic F1-X gurus...best tube??

Discussion in 'Amps and Cabs [BG]' started by JohnL, Feb 20, 2003.

  1. JohnL


    Sep 20, 2000
    Grayson, GA
    I've got one onthe way! (courtesy of a fellow TB'er, thank you very much!) It'll be my first tube preamp; a couple of questions. I've heard you probably need to re-tube every year or so, but is there a way to know for sure? (ie: hours in service, specific tonal difference, or just to be in the routine of changing it) Also, anyone experiment with different kinds of tubes that may yield better/different tone, other than what Alembic specs from the factory? Thanks!
  2. As far as tone goes, just buy a couple of different brands of tubes and try them. They don't make a world of difference, but you may hear something you like about 1 or the other.

    That thing only has preamp tubes, and they last for years and years. You may even get close to 10 years out of a tube in that unit.

    If it sounds good, no need to replace the tubes.

  3. Chuck M

    Chuck M Supporting Member

    May 2, 2000
    San Antonio, Texas
    Preamp tubes can indeed last for years. The Telefunken ECC83/12AX7 is supposed to last about 100,000 hours!

    I have found that NOS USA or European tubes sound worlds better than any tube made today. I personally like the GE shortplate 12AX7A/ECC83 in the Alembic F-1X which uses only one tube.

    DanGR likes this.
  4. JohnL


    Sep 20, 2000
    Grayson, GA
    Thanks guys! Being that this is my first tube experience, I wasn't sure. I had heard that some pre's benefit significantly by replacing the factory tube with something else. I sort of figured Alembic wouldn't put a second-rate tube in theirs, though.
  5. Allow me to draw upon your experience if you would and save myself much time and $$$ in the process. What have you found is the best sounding tube for this pre? Mullard? Electro Harmonix? RCA? I recently picked up an F1-X and it has a Sovtek in it, I'm thinking I can do much better. What are your recommendations?
  6. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    I'd try a sampling. Some swear by the Telefunkens, others like JJ's (they're a little raw for my taste, in that particular pre), and so on. One you might want to check out, is the GT 12AX7M (that's the Mullard clone). You can never go wrong with RCA's. :)
  7. Ostinato

    Ostinato Guest

    Feb 7, 2005
    Toronto ON
    Some people would actually consider Sovteks pretty good. My F-2B came with Chinese PM12AX7, which typically go for around $3.00 a pop. I noticed a nice improvement when I replaced them with the GT 12AX7M (Mullard copies).

    I'd really like to try a set of Ei Platinums though. They're apparently based on the Telefunken design. Get one of them and let me know how they sound. :D
  8. jokerjkny


    Jan 19, 2002
    NY / NJ / PHL
    whatever Dave Wilson put into the F-1X he recently sold me. ;) :p

    but my goodness, can i get a witness?!?! is this preamp not a gem unto its own? its like butter creme oozing from my speakers... :)

    FYI, i'm going to my local guitar shop to pickup some GT "Mullard" reproductions. i'll put up a nice little review soon enough...
    DanGR likes this.
  9. AlembicPlayer

    AlembicPlayer Im not wearing shorts

    Aug 15, 2004
    Pacific Northwet, USA
    I have a pair of the Groove Tubes Mullard reissues (GT 12AX7M) in my F2B..these are very nice, stable quiet tubes...a good choice for a modern production tube in your Alembic preamp.

    If you can find a reliable NOS RCA 7025..that's a very nice choice... I also have tried JAN GE 12AX7's with nice results...but for the road, I'll use the new production tubes.
  10. RHFusillo

    RHFusillo Supporting Member

    Mar 20, 2000
    Phoenix, AZ
    I found that the choice of preamp tube makes a world of difference in an Alembic F-1X. I put an old Sylvania 5751 tube into mine. It sounded smooth!
  11. zombywoof5050


    Dec 20, 2001
    My Alembic F-2B that I bought new in 1982 came with RFT tubes (though they were labeled Amperex made in W. Germany, they are in fact RFT's), and the RFT's still sound great after two decades.

    About a year ago I tried these different tubes in it:
    GT 7025
    GT ECC83
    Amperex (Japanese versions)
    STR 7025

    The Telefunkens sounded the best to me and are staying in there.

    The RFT's were the next best ones below the Telefunkens.
    The Japanese Amperex were surprisingly good sounding, about as good as the RFT's.
    The STR 7025's were next, followed by the GT ECC83's, and the worst of the bunch were the GT 7025's.
  12. secretdonkey


    Oct 9, 2002
    Austin, TX
    What would be a direct "OEM" replacement?
  13. Geoff St. Germaine

    Geoff St. Germaine Commercial User

    I'm looking at slapping a telefunken into my F1-X. Could someone let me know a good place to pick up such a tube?
  14. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA

    or eBay. (be careful though) :)

    Now that I think about it, a 5751 is probably a very good option, in terms of investigating the sound that can be achieved with a bass and an F1-X (or F2-B).

    It's slightly lower gain, meaning that you won't get as much "crunch", and depending on your style, that may be desirable for bass work.
  15. zombywoof5050


    Dec 20, 2001
    I don't know what they put in there these days, but my '82 F-2B came with RFT tubes.
    kcanostubes has the RFT's for $30. In their description they say they have less clean headroom (I'll agree with that, since I can crank the Telefunkens much higher and get less distortion), but the RFT's in my F-2B didn't start distorting until I cranked it pretty high at about 8 on the dial. I never turn it up past about 5 or 6, so it never posed a problem for me, and they really are great sounding tubes in the Alembic.

    I got my Telefunkens from Brent Jessee.
  16. secretdonkey


    Oct 9, 2002
    Austin, TX
    Would the GT Mullard clone tube tend to smooth out the high end a bit? When I put one into my old SWR SM-900, it tamed the brittle top end. I LOVE my F1-X... but one real challenge is that the treble knob has to stay within a very narrow range to sound right for me. It's not brittle like the SWR, but it's still a challenge... I'm running mine with volume around 5, bright switch ON, bass = 2, mid = 10, treble = 1 ...with a *tiny* amount of variation for each room on the bass and treble controls.

    Ideas? Suggestions?

    Thanks :hyper:
  17. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Are you good with a soldering iron? Try putting a 100-500 pf cap across the output (you can solder right across your output cable if you want). Then, you'll get a little better "range" with your treble control. You can experiment with the exact value of the cap, for me a 220 pf was just about right. Another thing you can do, is put a classic-style "passive treble-cut tone control" on the output, kind of the same thing they have in passive basses. A 500k pot, in series with a small-value cap to ground, will do the trick. I've found the Showman-style pre's have a tendency to emphasize the upper mids, as distinct from the extreme high end. One of the really nice things about the passive tone control is that if you're clever, you can use it to boost the "extreme highs" a little, relative to the upper mids. A judicious combination of the built-in treble control, with the outboard control, can work wonders. :)
  18. r379


    Jul 28, 2004
    Dallas, Texas

    Those settings: Are you talking about the numbers on the knobs or is that a "clock" reference?
  19. depalm

    depalm Gold Supporting Member

    Apr 22, 2004
    And what about the F-2B to be used wuth the ND Design upright? I'm looking for a stereo Preamp for live aplication.

    Thanks in advance
  20. secretdonkey


    Oct 9, 2002
    Austin, TX
    Numbers on the knobs... where 5 = noon. :)