Alamo Paragon Bass Amp: what impedance does it run at?

Discussion in 'Amps and Cabs [BG]' started by ihixulu, Mar 28, 2004.

  1. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    getting warmer
    Our practice space, which is rapidly turning into a graveyard for vintage tube gear, has a 60's vintage Alamo Paragon bass amp. It has no labels marking any kind of technical info on it so I am not sure what impedance cabs are safe to attach to it. Is anyone familiar with these things?

    Related to this, is there a way to easily find out what the imedance taps on the output transformers of tube amps are?

  2. Not sure, but it's probably 8 or 4 ohm just because that's so common. Just try one of those.

    The only sure way to determine the output taps is to open up the amp and inject an AC signal into one of the output transformer windings, then measure voltages on all the different output taps. Back calculate the turns ratios and then you can guesstimate it according to what power tubes the amp uses and what primary Z they like to see.

    Pair of 6L6's like around 5K
    Pair of EL84's like around 8K

    You pretty much have to have a test bench setup to do this kind of detective work. Also remember that the impedance ratio is the square of the turns ratio.