Live Lab Hangout #1.1 Posted

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Hi Gerd :)

In a basic CS amp, the effective input capacitance of the 182ES is very, very high, i.e. >14,000 pf. More gain, more Miller. Even with a 600 ohm source, you wouldn't make audio band. Have you measured the bandwidth?

Yes I did now!

:D

You cannot use the THF or SK182 in a drain follower configuration like SIT-1 or 2.

The bandwidth is ugly, so sound not so much, astonishing....

left picture

As a source follower like in the DEFISIT the situation is much better, the sound too!

right picture

Some things need some time!

:wave::wave::wave:
 

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Me idiot!

My ordered 47R Dales CMF55 were only 47R on the package label, but not in real.

They had the value 7k3 instead.

So the horrible decline is due to the 7k3 gate resistor and not due to the Ciss or whatever of the THF.

With the right value 47R the bandwidth is down at 20kHz only -1.9dB.

I hope teabag will enjoy this news.
 
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