How To Reduce An Aikido's Gain?

[SRMcGee]

I hope I'm not derailing SRMcGee's thread too wildly here.

You folks have fun; I've gotten adequate answers to my question.

Regards.

 

[Fully Articulated]

Thank you Rongon and Chris for the great info. I appreciate the time you've both taken to write it up. It seems that with a little experimentation this may be achievable.

Couple of things:

My primary source is an ANK DAC 2.1 which has a listed output impedance of 1.3K (I've swapped out the 6922s for 6N3Ps, so it may be different). Will this be too high?

Chris, you mentioned a separate grid stopper. That would go between Rfb1 and the input grid, and be of regular value (currently 300ohm)?

 

[Chris Hornbeck]

You'll be fine. Grid stops work by swamping out stray tiny resonant combinations of tiny L's and tiny C's, and catch the most of them if right up next to the valve, as possible. They're especially important in circuits with larger external impedances because stray capacitance to signal ground forms a zero for the feedback path.


Actually, that's a terrible explanation. Hopefully someone else will do better.


All good fortune,
Chris

 

[NickKUK]

You'll be fine. Grid stops work by swamping out stray tiny resonant combinations of tiny L's and tiny C's, and catch the most of them if right up next to the valve, as possible. They're especially important in circuits with larger external impedances because stray capacitance to signal ground forms a zero for the feedback path.

Actually, that's a terrible explanation. Hopefully someone else will do better.

All good fortune,
Chris

You get a free filter from the miller grid capacitance 🙂