A serious discussion on resonance and feedback

[Reeltarded]

I recently added a stage to an amp that wanted to explode into feedback around Cmin. Now it is much more tamed. I had experimented for a while before adding the stage, but could not pin the reason it was so reactive.

It's phase angle, right?

I would love to have the skills to tune that in and widen the range. It was very much like the white Showman Dumble, only with a british throat.

If the ^ stages are focused into this reaction and you add a v stage.... am I even close?

[martin manning]

You added an inverting gain stage, yea? If so, then you flipped the phase of everything that follows. If at some point there was some feedback, in-phase leads close together say, you shifted them out of phase and killed it. The feedback would have to be across the added stage, of course.

[Reeltarded]

Yeah that is what I thought. Stage is between previous stages and cold.

This reactive thing is hard to predict.

My favorite amps are insanely reactive at moderate gain and highish volume. If there was a thing I wish I could understand and even master, it would be this one thing.

[erwin_ve]

My favorite amps are insanely reactive at moderate gain and highish volume. If there was a thing I wish I could understand and even master, it would be this one thing.

If there is one goal in ampbuilding, this is it.

[Reeltarded]

I think (i hope) I am starting to see a little hint of green. Maybe the matrix is starting to reveal something.

Here are my ideas.

Replace my cold stage with a trimmer with a large cap and second trimmer as bypass. Dial in the cathode to almost ring between 200-800Hz then trim the bypass until notes start to smile after attack settles. It seems like there are harmonics to be alligned that might be a better approach to overall similar response across a wider range. (than the bunched up around Cmin6 and related)

Add another stage with virtually no gain and rebalance the highs.

Live my life never knowing that I was 27 minutes from magical insanity..

I think I am going with trimmers and a cap!

EDIT: This is a perfect time to play the inductor card. I am not exactly sure where.

[martin manning]

I think (i hope) I am starting to see a little hint of green. Maybe the matrix is starting to reveal something. :)

I think the random amalgam of layout and lead dress plays a part in the last few percent of awesomeness, and there is a significant amount of luck involved there. Not quite like monkeys with typewriters producing great literature, because the layouts that work and sound good have already been discovered. It's small things that come and go unnoticed that make it seem like magic.

[Reeltarded]

I was worried to move anything, but I did nudge an inch of wire and it changed a little so I played for 30 minutes!

We get super picky and pretend we choose this. haha