Perfectionist: A few issues to answer your question as to why I tried this other tube ring instead of the Herbie. The Io and Callisto each with one PS totals a whopping 40 tubes. Looking at the cost of the Herbie rings, that's a lot of pizzas. These other rings are very inexpensive to try before going to the next "level".
Another issue is that the Io has 4 pairs of 12ax7 tubes that are only about 1/8" apart. The Herbie rings here would just not fit. And the set of 6 12ax7's in the PS's are placed just as close. These other rings just barely fit if I strategically position the rings on these adjacent tubes. All other tubes in the Io and Callisto would handle the Herbie rings with no problem.
If I had 4 or 6 or so tubes total, I would be very willing to put forth the effort to try all sorts of positions of the rings on the tubes. But with this many tubes, it would be insane. I'm still recovering from all the cable auditioning over the last 2-3 months!
I simply put a pair of rings on the tubes last night that were the most microphonic. This is easily determined by lightly tapping each tube with a pencil....and let the ringing begin. Even with a couple tubes, there was some ringing in the system while adjusting the Callisto's volume pots. But with these rings placed last night, that is now entirely gone. This was great news alone.
With the Dominus cables now in my system, I have so much more low-end extension and dynamics that when the volume has become quite loud, I can hear some of the tubes start to ring.....specifically in the Io. This made be partly due to the Io's cover being off but also surely because I have very poor isolation under these components. Hopefully tonight I can crank up the volume and determine if these rings have alleviated (or at least greatly reduced) this issue.
John
