03-27-2016, 04:04 PM
my gemini 1 had some Realistic "lifetime" tubes in there, 7591's.
they work fine i guess but they are burning blue, and i figured i'd see what a new set of tubes would sound like so i bought a matched set of jj's 7591's and threw them in...
the amp lost almost all of the bass, and half of the volume.
i shut it down fast. after a few minutes of cooling i decided i could pull the tubes back out. they were so hot. i couldnt touch them with a rag in my hand.
after about 20 mins i swapped my old realistic pieces back in there.
the temp is alot cooler and sound is better.
so i suppose this is bias?
so...back in'66...every time you changed a tube in a gemini 1...you had to bring it in for biasing?
i had thought that these were "fixed bias" but i'm reading that these are "cathode bias"?
and cathode bias, in laymens terms, means what?
they work fine i guess but they are burning blue, and i figured i'd see what a new set of tubes would sound like so i bought a matched set of jj's 7591's and threw them in...
the amp lost almost all of the bass, and half of the volume.
i shut it down fast. after a few minutes of cooling i decided i could pull the tubes back out. they were so hot. i couldnt touch them with a rag in my hand.
after about 20 mins i swapped my old realistic pieces back in there.
the temp is alot cooler and sound is better.
so i suppose this is bias?
so...back in'66...every time you changed a tube in a gemini 1...you had to bring it in for biasing?
i had thought that these were "fixed bias" but i'm reading that these are "cathode bias"?
and cathode bias, in laymens terms, means what?