|To:||jeff millar <email@example.com>|
|Subject:||Re: [Amps] 8877 Input network testing|
|Date:||Sat, 17 Jul 2004 06:00:03 -0700|
On Jul 15, 2004, at 6:54 PM, jeff millar wrote:
I'm restoring an 8877 on 2M and it needs a better match on the input network. I've designed several input network options and now need to test them. Here's some questions that I hope someone can answer...
Jeff --- Not as well as driving the cathode since a g-g cathode in not the same thing as a fixed resistor -- i. e., the 8877 cathode driving R fluctuates from c. 8-ohms on the negative half of the driving cycle to well over 100k-ohms on the positive half of the cycle. So, 54-ohms? is just an average.
Can I expect the input capacitance to remain the same even with the tube off?
* How much additional stray capacitance comes from the tube socket? The matching network isn't working as expected and I'm not sure why.Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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