Do old tube amps wattage ratings change with speaker load??

faster100
faster100 Posts: 6,124
edited February 2003 in Electronics
I am looking into later this year getting a old tube amp/amps, either a Dynaco 70 or heathkit w-5m Mono amps x2, both rated at 35 wpc and 25 wpc respectivly, I see nothing stating at 8ohms, 4 ohms, I see the heathkit amps have a common speaker lead hookup and 3 others, 4,8,16 ohm... But does the wattage change at said ohms, or what is the rated watts for?? The lowest load 4ohms, or is it the same no matter what on old tubers?? I wanna know, i am hooking them to a set of RTI28's or possibly lsi 7's, neither do i have yet so its open, later this year also will this project for a 2 channel rig take place,
MY HT RIG:
Sherwood p-965
Sherwood sd871 dvd
Rotel 1075 amp x5
LSI15 mains
LsiC center
LSIfx surround backs
Lsi7 side surrounds
SVS pb12/plus2


2 Channel Rig:

nad 1020 Pre-amp
Rotel 1080 stereo amp
Polk sda 2B
kenwood grunt Tuner
realistic lab 450 TT
Signal cable IC
Post edited by faster100 on

Comments

  • madmax
    madmax Posts: 12,434
    edited February 2003
    The wattage stays the same. These different ohm outputs are different windings on the transformer which keep the voltage and current within spec. So you hook up an 8 ohm speaker to the 8 ohm tap. You get a given voltage and current which gives you a certain wattage. (voltage x current = watts). If you hook up a 4 ohm speaker to a 4 ohm tap the voltage and current vary but the voltage x current equals the same wattage.
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited February 2003
    Did not know that mm, thanks. Makes a little more sense why there are different speaker taps now.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.