Want a tweak for your tube amp that costs no more than a few bucks? Try silicone tube damping rings, such as these:
There are many damping products for vacuum tubes; however, many people think they provide mixed results. Looking at various reviews, it seems the majority viewpoint is that the silicone rings bring the most consistent improvements.
With a speaker system, sound waves can hit the tubes and trigger microphonics. With headphones, the only conceivable benefit of damping rings is to damp the universal background vibration or self-generated vibration (which is also the reason we headphone guys use special feet or cones, special shelves and racks, etc.).
I tried them with my DNA Sonett headphone amp, which uses a single 6H30 tube. I used two rings, placed at the upper and lower spacers.
Headphone was AKG K601, digital source was the Naim CD5X.
For music, I used the first movement of Mahler's Fifth Symphony, which runs the gamut of sounds---quiet strings, massive brass chords, bass drum and deep notes on the basses, solos of all sorts, etc.
The symphony opens with a solo trumpet playing a tense "call." The immediately noticeable effect of the dampers was to remove high-frequency "grunge" and increase resolution: the trumpet had more palpable presence, and the direct and reverberant sound were better differentiated.
Re palpable presence, the K1000 has far more of it than any conventional headphone. With most headphones, sounds are blobs in your head with no precise localization... but with the K1000 you sense the location of the sound and bring your attention to it, in a way that resembles natural live listening.
The tube dampers brought the K601 in the direction of the K1000... sounds being a bit more precisely located.
After the initial trumpet call, the rest of the orchestra plays massive chords, while the trumpet continues over them. With the tube dampers, there was better delineation: the musical character of the trumpet was not drowned out by the rest of the orchestra.
Likewise, very loud cymbal crashes overlaid on other sounds did not interfere with the other sounds (did not put down a layer of grunge).
At one point, all the french horns play in unison. French horn is a tricky instrument to capture: it has less live sound and more reverberant sound than other brass instruments because their bells deliberately face backwards. The dampers helped the presentation: the direct sound of the horns was clear with good timbral color, while the reverberation was clearly delineated.
At another point, the strings play quietly. The dampers helped to keep this quiet sound captivating and not lose presence.
There is one section where Mahler writes for low clarinets to contrast them with strings: the timbre was very clarinet-y.
Finally, they helped pitch delineation in the basses as they play pizzicato. In many recordings, these very low plucked notes are just blobs of boom. The dampers helped to bring out the actual pitch and hear it in reference to the higher instruments.
Edited by mike1127 - 8/9/10 at 10:29am
