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Hoffman Amps Forum image Author Topic: KT77 max G2 voltage ? (tetrode connection)  (Read 2276 times)

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Offline kagliostro

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KT77 max G2 voltage ? (tetrode connection)
« on: August 16, 2014, 09:18:49 am »
Reading on Genalex datasheet seems that KT77 used as tetrode must don't exceed 300v at G2

see page 3 on this datasheet

http://www.mif.pg.gda.pl/homepages/frank/sheets/086/k/KT77.pdf

is this correct or I've misunderstand and the 300v limit on G2 is as to have (with tetrode connection) performance similar to the UL connection ?

Thanks

K



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Offline shooter

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Re: KT77 max G2 voltage ? (tetrode connection)
« Reply #1 on: August 16, 2014, 11:03:25 am »
The 2nd line, absolute screen volts, shows 650v, absolute power, 6W.  Most everyone here seems to agree the old data sheets don't correlate well with the modern tube versions.  I've done a couple builds with KT88's and try and keep B+ in the 400-450 range, G2 around 300-350.  I typically start cathode current around 80-110mA, sometimes pushing it to 90 to 95% max I for SE builds and slightly less for AB builds.
Went Class C for efficiency

 


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