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The grid inductance you describe is series inductance right?

It was inevitable that after amp basics in place, I would need to re-visit 'inductance in the grid circuit'. I got lucky here and there but it's time to address this. Thank you for quantifying it around 1uH Nomad. Thats a good start. Been winding coils to get a feel for 1uH. Small-ish, 7-8 turns ballpark (on 43/140 Toroid & without). Trick will be switching it in and out but can deal with that later.
I'd settle for PO on 10 and figure out switching later.

Edit 1: Scrapped all the caps & resistors I had from 1st matching attempt. Now have simple 1:6 balun with one, 300 ohm NI resistor across balanced outputs. Short wire from 1 balanced output to capacitor to New coil to tube grids. Coil is 1/2" diameter 7T 18 gauge magnet wire (best I could estimate to 1uH using cheapo meter).

Trying to replicate coil pictured in the single tube RF Deck below (K2VCO at: https://www.qsl.net/k2vco/4CX1000A/K2VCO 4CX1000A Amplifier.html)

Edit 2 The insertion of inductance between capacitor and grid did not do much for 10/20 but seemed to help 40. Nothing to really measure. So onto the next approach: I have 2 tubes so I can use a toroidal inductor to connect both tubes on the other side of the socket from where RF is fed. Such an arrangement can't hurt & may even help to the extent it qualifies as "placing an inductance across the grids"
to be continued

<blockquote data-quote="Naysayer" data-source="post: 840530" data-attributes="member: 57429">The grid inductance you describe is series inductance right?It was inevitable that after amp basics in place, I would need to re-visit &#039;inductance in the grid circuit&#039;.&nbsp; I got lucky here and there but it&#039;s time to address this.&nbsp;&nbsp; Thank you for quantifying it around 1uH Nomad.&nbsp; Thats a good start.&nbsp; Been winding coils to get a feel for 1uH. Small-ish, 7-8 turns ballpark (on 43/140 Toroid &amp; without). Trick will be switching it in and out but can deal with that later.I&#039;d settle for PO on 10 and figure out switching later.Edit 1: Scrapped all the caps &amp; resistors I had from 1st matching attempt. Now have simple 1:6 balun with one, 300 ohm NI resistor across balanced outputs. Short wire from 1 balanced output to capacitor to New coil to tube grids.&nbsp; Coil is 1/2&quot; diameter 7T 18 gauge magnet wire (best&nbsp; I could estimate to 1uH using cheapo meter).Trying to replicate coil pictured in the single tube RF Deck below&nbsp; (K2VCO at: <a href="https://www.qsl.net/k2vco/4CX1000A/K2VCO%204CX1000A%20Amplifier.html" target="_blank">https://www.qsl.net/k2vco/4CX1000A/K2VCO 4CX1000A Amplifier.html</a>)Edit 2&nbsp; The insertion of inductance between capacitor and grid did not do much for 10/20 but seemed to help 40.&nbsp; Nothing to really measure.&nbsp; So onto the next approach:&nbsp;&nbsp; I have 2 tubes so I can use a toroidal inductor to connect both tubes on the other side of the socket from where RF is fed.&nbsp; Such an arrangement can&#039;t hurt &amp; may even help to the extent&nbsp; it qualifies as &quot;placing an inductance across the grids&quot;to be continued</blockquote>

[QUOTE="Naysayer, post: 840530, member: 57429"] The grid inductance you describe is [I]series[/I] inductance right? It was inevitable that after amp basics in place, I would need to re-visit 'inductance in the grid circuit'. I got lucky here and there but it's time to address this. Thank you for quantifying it around 1uH Nomad. Thats a good start. Been winding coils to get a feel for 1uH. Small-ish, 7-8 turns ballpark (on 43/140 Toroid & without). Trick will be switching it in and out but can deal with that later. I'd settle for PO on 10 and figure out switching later. [B]Edit 1[/B]: Scrapped all the caps & resistors I had from 1st matching attempt. Now have simple 1:6 balun with one, 300 ohm NI resistor across balanced outputs. Short wire from 1 balanced output to capacitor to New coil to tube grids. Coil is 1/2" diameter 7T 18 gauge magnet wire (best I could estimate to 1uH using cheapo meter). Trying to replicate coil pictured in the single tube RF Deck below (K2VCO at: [URL='https://www.qsl.net/k2vco/4CX1000A/K2VCO%204CX1000A%20Amplifier.html']https://www.qsl.net/k2vco/4CX1000A/K2VCO 4CX1000A Amplifier.html[/URL]) [B]Edit 2[/B] The insertion of inductance between capacitor and grid did not do much for 10/20 but seemed to help 40. Nothing to really measure. So onto the next approach: I have 2 tubes so I can use a toroidal inductor to connect both tubes on the other side of the socket from where RF is fed. Such an arrangement can't hurt & may even help to the extent it qualifies as "placing an inductance across the grids" [I]to be continued[/I] [/QUOTE]

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