Help setting up KT88

Get support and show off your MetroAmp JTM 45 kit builds.

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chopperferrari
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Help setting up KT88

Post by chopperferrari » Sat Aug 13, 2016 10:13 pm

Hi guys,

I want to try some KT88 in my JTM45. Currently running KT66s. Anything I need know? Screen resistance?

Thanks!

Littlewyan
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Re: Help setting up KT88

Post by Littlewyan » Sun Aug 28, 2016 5:50 pm

I doubt you'll gain much as the KT88s will need a larger PT and OT than stock. Are you trying to increase the output or are you just experimenting tonally?

Roe
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Re: Help setting up KT88

Post by Roe » Mon Aug 29, 2016 5:00 am

try to rebias and to decrease the 220k bias splitters to ca 82k. Also you might like to decrease negative feedback. dependent on voltage, You probably need to increase the screen resistors
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