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Thehobo
Junior Member
Username: Thehobo

Post Number: 43
Registered: 2-2004
Posted on Saturday, December 24, 2005 - 7:34 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

ok, my ?? is, if a person had a 4 tube 811a, and put the 572b tubes in it, wood the amp do within reason of what the 572b amp produces??? these are ameritron amps!! thanks for any input!!

thehobo
274150 am
monitor ch.
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Kid_vicious
Advanced Member
Username: Kid_vicious

Post Number: 946
Registered: 9-2004
Posted on Saturday, December 24, 2005 - 9:55 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

you also have to change the transformer.

stock, the tubes use about 1800 volts.
you need to increase the voltage to about 3000 volts when using the 572b's.

from what ive heard, it will do more than 1K with the mod.
matt
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Thehobo
Junior Member
Username: Thehobo

Post Number: 44
Registered: 2-2004
Posted on Monday, December 26, 2005 - 8:26 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

thanks on the input on the tubes!! im in the process of trying to talk a freind out of his 4 tube 811s and was going to put the 572's in it to help the plates on the am side?? mite talk to much and melt the 811's!! lol.. agin thanks..

thehobo
274150 am
monitor ch.
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Funtimebob
Intermediate Member
Username: Funtimebob

Post Number: 173
Registered: 5-2002
Posted on Friday, January 06, 2006 - 4:30 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

You dont have to change the transformer unless you want to increase power. They can be used as a "Heavy Duty" drop in replacement on most 811 type tube amps. (some amps like the old collins and a few others need a little more cutoff bias to keep them from oscillating)
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Funtimebob
Intermediate Member
Username: Funtimebob

Post Number: 174
Registered: 5-2002
Posted on Friday, January 06, 2006 - 4:33 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

P.S. if you check out different amp manufacturers you will find that they only use 2200-2500v on the plate. Tube ref in the old arrl handbooks only recomend 2500V@200ma per tube

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