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Old 6th March 2011, 08:29 AM   #1
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Default Pumpkin_pre_question

Question about Pumpkin preamp: can it be made with FQP4N20 and FQP7P06 instead IRF-s. Or should I go for IRF
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Old 6th March 2011, 10:46 AM   #2
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compare voltages , capacitances and xconductance

I presume that IRF's are easy to find , wherever you are ( Cro or abroad ) so I can't see why banging head about ;

if you look for Generg's , you can find that he put Zhoufang's small Toshiba mosfets instead IRF9510
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Old 6th March 2011, 10:53 AM   #3
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The biggest difference is in xconductance so that I ask FQP has higher xconductance and VGS(th)(4-5)V(FQP4N20) one and the other (3-4)V(FQP7P06)
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Old 6th March 2011, 10:58 AM   #4
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you'll hardly hear difference because of xconductance difference , because of closed loop operation ; you remember that Pumpie is SUSY .

you can hear difference using Toshibas instead 9510 , because they're less 'switch-like " parts , than IRFs ( transfer curve issue )

lower ones , in CCS position - you can use whatever you have - they're just CCS
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Old 6th March 2011, 11:07 AM   #5
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thanks for the info
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Old 6th March 2011, 11:09 AM   #6
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you are welcome
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