and here is a short follow up to this story.my experience with the dampers (similar to many other reports from users) is that improvement (or not) is dependent on too many factors to make a prediction without trying them. Tube type, specific tube (i.e., brand and type), mounting, circuit used, rectifier vs. output vs. input, etc all come into play
I was talking to LeifS about his use of Herbie's rings
I was quite impressed as to the ability of these tube damping rings with respect to eliminating "ringing" The placement of damping rings along the fattest part of the tube as well as where the narrow bottom part of the tube joins the thick bottom part of the tube completely eliminated the ring as we'll as making listening more enjoyable , no fatigue and an improvement in sound quality. There seemed to be more air at the top and bottom making for cleaner and more distinct sound
Leif is a big proponent of these damping rings and said that I had to take the experiment one step further in the direction that he went
Leif said that also adding a 3rd set of rings at the top (cap) of the tube produced such a dramatic improvement that they were able to hear every change in the development of their Ultra 11 speaker as it was in production. Leif commented that the 3 rings on the output tubes was so dramatic that they simply could not listen without that 3rd ring
Interestingly enough I had planned for this possibility as Leif had put that bee in my bonnet when I bought my lampizator along with Marty who also uses them on his Lampi GG and feels that they are indispensable. Marty as well it turns out was also using 3 damping rings on his KR242's
So I went to school on their putt and ordered 3 extra rings for the tops of the KR242 and the RK-KR 5u4g. As it turned out I bout all 3 in the same size BUT the 3rd ring was just too small for the rectifier tube.
Applying these rings is quick, safe and simple and the auditory changes are heard immediately
So what was the revelation. For my ears I can honestly agree with Leif.as the addition of this 3rd ring made such an improvement from top to bottom. Of note was there was far less smearing or bloating in the bottom end.Simply put I have never heard bass in my system so clean, open and well defined.
So my final piece to the puzzle will be to see if I can order a proper size ring for the top the rectifier tube to see what additional (if any benefit) would be derived
Suffice it to say, the quick and simple application of Herbie's tube damping rings not only eliminated the ring (which I never knew I had until was proved to me) as well as cleaning up the sound
There is now a natural ease to listening. The sound is far more pleasant and my biggest concern in using these proved to be a non concern, to wit there is absolutely no overdamping of the sound or loss of sound quality.
This is a recommendation I would offer to any Lampi owners( or tube owners of all brands). In fact I am now tempted to add some rings to the large GM-70 tubes in my amplifier[/QUOTE]