Ceramic insulator cone under phono stage shocker!

I suspect it's more than coincidental that the PH-10 is solid state while the Chinook uses tubes. Probably having the cones in the new orientation lessens vibrations that previously were affecting some or all of the tubes.

It might be a good idea to try to determine if any of the tubes are excessively microphonic, in which case they should be replaced. You can do that by removing the cover of the Chinook, and while it and the rest of the system are operating **very gently** tapping each tube with the eraser at the end of a pencil. If you do that with the volume control set at or a bit below a setting you would normally use, and the tapping results in a particularly loud noise, it would signify a problem in the particular tube.

Best,
-- Al
 

Al
You could have something there.
I know one pair of Amperex tubes in it are well used to be polite......

Sounds like a project for tomorrow morning.

Interesting.
No microphonics from either of the 4 tubes inside the Chinook that I could hear at all by performing Almargs suggested test, not even the slightest pop.

It just has to be the difference in the way the vibrations are borne away being much more noticeable through the tube phono.

Whatever it is a great cheap tweak! Lol.

Maybe an additional benefit or way to explain what @almarg was pointing out is the latest orientation is a superior way to funnel vibrations out of the Manley.

Ever tried Herbies tube dampers?

Cones act like mechanical diodes, so you always want the points down so the excess energy will exit the system. Points up actually allows more seismic energy to be transmitted to the component 🔝 and less excess energy in the component to escape.