8ohm or 4ohm Baseman?

Discussion in 'Ampage Area' started by slickfaster, Aug 17, 2019.

  1. slickfaster

    slickfaster Electromatic

    72
    Dec 29, 2009
    Redondo bch.
    i got a 62 6g6a Bassman. The serial number on op transformer says 125A5A 606 146 is this a 8ohm Trani? I believe it is from the 6g6 run that had one speaker/ tone ring. How can I be sure?
    Is there a way to check other than the stamped code?
    I believe it should have 125A13A which is 4ohm.
     
    Last edited: Aug 17, 2019
  2. swivel

    swivel Synchromatic

    864
    May 13, 2018
    PNW
    The code should do it. Many 8 ohm were the 6G6 though... ? I think...
    There is a way to measure the resistance but I don't know what the numbers you are looking for are. Maybe someone else will. But the code should do it.
    Does it have a tube rectifier or SS rectifier?
     
  3. slickfaster

    slickfaster Electromatic

    72
    Dec 29, 2009
    Redondo bch.
    6g6a OT 125A5A. 606 146
    SS rectifier
     
    Last edited: Aug 17, 2019
  4. swivel

    swivel Synchromatic

    864
    May 13, 2018
    PNW
    That should be the 8 ohm tranny then.
     
  5. slickfaster

    slickfaster Electromatic

    72
    Dec 29, 2009
    Redondo bch.
    Thanks! Is running a 4 ohm cab safe?
     
  6. wildeman

    wildeman Gretschified

    May 10, 2015
    norcal
    Not "safe" probably ok (fenders are tough) but definitely not safe.
     
  7. Winnie Thomas

    Winnie Thomas Gretschie

    306
    Jun 13, 2011
    Cochise AZ
    Fenders can take the mismatch okay.
     
  8. GreTschocaster

    GreTschocaster Gretschie

    Age:
    65
    368
    Feb 11, 2013
    Canada
    Here is how I remember. Instead of ohms think of it as a fluid. You can't safely pour 8 fluid ounce of water into a 4 fluid ounce container, it would spill all over the place. But you can safely pour 4 fluid ounces into a 4 fluid ounce container or larger.
     
  9. Lionpotato

    Lionpotato Gretschie

    393
    Oct 10, 2018
    Upland
    8 to 4 ohm speaker is not ok. 4 OT to 8 ohm speaker is fine. Matching is best.
     
  10. Tony65x55

    Tony65x55 Gretschified

    Age:
    63
    Sep 23, 2011
    The 'Shwa, Ontario, Canada
    Ampwares lists the 1962 Bassman as 4 ohms. Standard cab is a 2x12". Take this with a grain of salt though as Fenders were all over the map. Your Bassman should be fine with four ohms load, as Winnie said, "Fenders are tough."

    I have a 1961 Bassman with the tube rectifier. The original transformer was smoked when I got it so it was replaced with a Mercury Magnetics 8 ohm. The amp sounds amazing.

    Have fun!
     
    hcsterg likes this.
  11. Winnie Thomas

    Winnie Thomas Gretschie

    306
    Jun 13, 2011
    Cochise AZ
    Back in the late 60's early 70s I played a BF Bassman through two 4 Ohm 2 x 12 cabinets 2-4 nights a week.. Never had a problem.
     
  12. Tony65x55

    Tony65x55 Gretschified

    Age:
    63
    Sep 23, 2011
    The 'Shwa, Ontario, Canada
    You have to really work at it to kill those old Fender amps!
     
  13. swivel

    swivel Synchromatic

    864
    May 13, 2018
    PNW
    according to Fender it is safe. I have a multi tap Bassman transformer 4-8-16 ohm I'll trade you! haha! :D
     
  14. hcsterg

    hcsterg Country Gent

    Feb 13, 2012
    France
    Hi slickfaster,

    Last year a restored an early Blonde Bassman 6G6-B (dated 14-64, solid state rectifier, but still the 6G6-A tone stacks) with its 2x12" baffle with original UTAH speakers.

    [​IMG]

    It was a 4 Ohms model, able (once restored) to give 45W RMS clean tone (= at onset of clipping) on 400Hz sine wave, resistive load 4R/100W.

    The original transformer (still in place) is stamped on cover :
    125A13A
    606407

    It's not the same numbers as yours, so yours may be different... o_O

    A+!
     
  15. Lionpotato

    Lionpotato Gretschie

    393
    Oct 10, 2018
    Upland
    Most Bassmans are 4 ohms from this era. Never seen an 8 ohm blonde or blackface Bassman.
     
  16. slickfaster

    slickfaster Electromatic

    72
    Dec 29, 2009
    Redondo bch.
    Yep I’ve now found....125A13A is 6G6A and 6G6B=4ohm
    125A5A is 6G6 =8ohm
    Someone installed a 6G6 OT in my 6G6A back in the day...
    @hcsterg I had those Utah’s in a cab that I Pulled out without trying. I dropped in Celest V30s. Did you like the Utah’s??
     
  17. hcsterg

    hcsterg Country Gent

    Feb 13, 2012
    France
    So if you have 2 V30 in 16ohms connected in // you have the requested 8ohms. If they are 8ohms then you have 4 ohms. The amp will accept it, you will simply have a bit less power and a rounder sound.

    The 6G6 I restored belongs to a luthier pal (we made a deal on a guitar refinish - but he's late with me me, so I'll have to "shake" him ! :D;)) and he find the speakers very good sounding, like I do. That said, they are very smooth, "Jazzy" sounding, and it may not be your taste...

    If you intend to sell them, contact me, I may be interested for a project... :)

    A+!
     
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