Fender Bassman 100 cab config.

Discussion in 'Amps and Cabs [BG]' started by dphunk76, Jul 21, 2009.

  1. dphunk76


    Nov 12, 2008
    I have a mid 70's silverface bassman 100 with the matching 2x15 cab rated at 4ohms.

    my question is:
    what ohm rating should a 2nd cab be if i wanted to run it from the ext. speaker jack?

    i know that the super bassman could run 2 4ohm cabs (as it claims under each speaker jack "4ohm min" and you used to be able to buy it with 2 2x15 4ohm cabs.) BUT the bassman 100 only says 4ohm min by the main jack. i'm not sure how the outputs are wired but what i DON'T want to do is try to (accidentally) draw 2ohms from the head.

    i'm not an expert in this sort of thing so i'm hoping somebody can help me out.

  2. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    I'm not 100% sure, but if it says 4 ohms minimum, you're already there, and cannot add on another cab. It's been a long time since I played with a Bassman 100, (about 1976), but, unless someone comes along here with better knowledge, I'd stick with what you've got. Besides, 100 watts through 2 15's is a glorious thing.
  3. dphunk76


    Nov 12, 2008
    that's what i'm thinking too. i'm with you though, not 100%.

    i have another 4ohm cab sitting around. haha, but i guess maybe i'm just getting greedy.

  4. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    4 ohms, so that both receive the same power. Those Fenders had no problem handling even 1 ohm loads, which I know from firsthand experience.
  5. kaiser_sosea

    kaiser_sosea Supporting Member

    So your saying with the Fender Silverface in question (I have one too) it is safe to run a 4 ohm cab off each speaker out = 2 ohm load?
  6. dphunk76


    Nov 12, 2008
    ditto on above.. took the words out of my mouth.
  7. rbonner


    Sep 25, 2008
    What those heads REALLY DON'T LIKE IS PUTTING high impedence loads on them.

    I plugged one of my 16 ohm Vox Foundation bottoms on the thing and it put out very little power and sounded like a FUZZ BASS. I played my Black Face 67 at 8 ohms for years...

    The 100 and 135's are a little more picky but those 50 watters didn't make enough power to hurt themelves. AKA: Didn't make enough power to get out of their own way.

  8. kaiser_sosea

    kaiser_sosea Supporting Member

    I've read somewhere that with these older tube amps, if they are rated @ say Min 4 ohms, they prefer (respond better) to being run @ 2 ohms for instance than 8 ohms, if you aren't matching the load exactly, any truth to this?