I recently had a customer call about returning UltraSonic Rx Damping Instruments that he bought for his preamp tubes. "They don't do anything," he said. The customer wanted to try a set of Tenderfeet instead. He ordered the Tenderfeet and told me he would wait until he had auditioned the footers before returning the tube dampers, in case he wanted to return the footers too.
That Friday, I got an e-mail stating that the Tenderfeet worked fantastic, that they achieved a great upgrade to his preamp and overall system, and that he would be mailing back the tube dampers on Monday.
On Monday, I got another e-mail. "You're not getting the dampers back," he said. "I took them off and packed them up. But then I noticed that my stereo didn't sound as good. There was still an improvement with the Tenderfeet, but the magic was gone. I put the Rx's back on and Voila! Magic! I guess they just needed a little help."
This happens sometimes with tweaks and upgrades; making a localized change often complements a factor elsewhere in the system or itself needs a complementary adjustment to blossom.
This is like having a car with crooked wheels and worn-out shock absorbers. If you change the wheels, you'll still get a bumpy ride because of the shocks. If you were to change just the shocks, you'd still have a bumpy ride because of the wheels. If you change both, however, because they complement each other, you'll end up with a smooth ride.
Damping preamp tubes will almost always bring out an improvement on its own and bring an audio system up to the next level with no other adjustments needed. However, capacitors and other electronic parts are often just as susceptible to microphonic and micro-vibrational distortions as vacuum tubes. Although microphonic distortions at the preamp tubes might be alleviated, these same kinds of distortions might still be tacked on by other electronics, power tubes, rectifiers, etc., masking the benefit obtained at the preamp tubes.
In audio, tweaking efforts can individually seem minimal or subtle, but can have major synergistic effect where the overall result exceeds the sum of the parts. Sometimes a minor tweak or adjustment may create a big "wow!" not just because of the adjustment itself, but because of bringing other factors into play synergistically.
This same kind of complementary and synergistic interplay occurs not just with footers and tube dampers and with vibration issues, but throughout the audio system with all parts, upgrades, and accessories.
Every tweak is not always necessarily going to be beneficial, of course. Going back to the "crooked wheels" analogy: suppose to compensate for a bumpy ride, the car tweaker lets some of the air out of the tires and piles a half ton of bricks in the trunk. Although he enjoys a smoother ride, the remedy is bogus, and the ride is not at all like the car is engineered to provide. Then, at some later point the car owner applies the proper remedy--new wheels and new shock absorbers--but still keeps the air low and bricks in the trunk. The result is better yet, but the car still will not provide quite the kind of smooth ride that it's engineered to do.
In audio, bogus "remedies" are tweaked into systems quite commonly. For example, placing Sorbothane under loudspeakers. Or attenuating high-frequency emphasis and sibilance caused by tube microphonics by damping a tweeter. And then, when a proper remedy is applied like damping the tubes, the accumulative result can be disastrous, an anti-synergy. When low-fi trade-offs or bogus remedies are introduced into an audio system, it's sometimes virtually impossible to ever bring the whole system to its full potential. It's always best to make sure you achieve improvements only--no tradeoffs--at every step of the way.
SteveHerbie's Audio Lab