As time has gone by, an audiophile truism has become increasingly obvious to me: everything makes a difference.
For the last 10 years or so, I’ve experimented with all sorts of things which may be generically labeled as tweaks: tube dampers, footers and crystals included. The first two categories are attempts to control vibration and microphonics. Today’s installment will cover two products I’ve used from Herbie's Audio Lab plus another type of damper, O-rings, which I’ve obtained from both conrad-johnson, supplied as original equipment, and from an online vendor.
My observations should in no way be construed as an attempt to either dissuade or persuade you from trying them. What I dislike or like may very well bear little, or no, relation to your assessment of these very same products.
What I can tell you, however, is that you will almost assuredly hear a difference with them in your system. Whether you perceive these differences as benign, malignant or a mix of both is what makes this hobby so interesting.
Tube Dampers
The Herbie’s product I’ve been using the longest is, I believe, no longer available in exactly the same form but may be found both on the used market and their successors are available at Herbie’s web site, too. They are what I will refer to as Herbie’s HAL-Os and they came in a number of sizes and two flavors at the time I purchased them. They’ve been in my system, on and off, ever since.
Herbie’s Hal-Os are intended for use on both small signal tubes and power tubes. They also come in a form designed for “normally” hot small tubes (6DJ8, 12AX7, etc.) and for “really” hot tubes and/or power tubes (5687, 6H30π, 6550, KT88, etc.). As far as I know, the normally hot HAL-Os only come in the smaller sizes.
Additionally, the HAL-Os may be used on the barrels of interconnects and other spots in your system that are cylindrical and where vibration may be a problem. My comments will be confined to their use with vacuum tubes, both big and small.
Small signal tube, normal temperature range Small signal tube, high temperature range

Both sizes and temperature ranges HAL-O on Premier 140 input tube

Rather than use a Listening Impressions section as usually done, I’m going to just cut to the chase and describe what they do. Regardless of whether used on the small signal tubes in my CD-25 compact disc player, Premier 16LS2 preamp or either of my power amplifiers (the Premier 11A and Premier 140), the effect was basically the same.
When in use, the HAL-O tube dampers help to focus the images more clearly within the sound stage. There is an increase, at times, in perceived inner detail or what is also described as truth of timbre. What’s the down side? Initial transients are less sharp, trailing decays are more abrupt, some of the air is sucked out of the presentation, and while individual instruments may in some ways sound more realistic, the music is somehow also more disjointed and less organic. The result is, for me, a less emotionally satisfying experience.
You may appreciate the HAL-Os for precisely the reasons I do not. Herbie’s offers a generous 90 day trial and it may be worth your time (and the shipping charges) to try them and see for yourself. They also offer an unconditional lifetime warranty in which they will repair or replace any of their products free of charge. That’s refreshing, as well.
O-rings
conrad-johnson supplies silicone (maybe they’re rubber) O-rings with both their preamplifiers and power amplifiers. A pair of them is to be used on each of the small signal tubes in their preamps and on the input tube(s)-only for their power amps. Phase splitters should be left naked.
How do they sound when placed approximately one-third of the way from the top and bottom of the tube(s)? Just like the HAL-Os, only more so. Working from the premise that more is more, I’ve also placed aftermarket O-rings on the phase splitters and even gotten really big ones to place on the power tubes.
Premier 16LS2 tubes fully dressed After the bris

How did that work out? Badly. At least for me, it sucked. It sucked not only the air out of the presentation, the music became constricted and lifeless. I was strangling the sound to the point where it became boring. Plus the big ones made my ST-shaped power tubes look like they’d been circumcised. Not necessarily a bad thing when applied to a male’s genitals (opinions differ), but a definite eyesore on power tubes.
Microphonics
The HAL-Os and the O-rings may indeed work properly in reducing low levels of microphonics but I wasn’t pleased, overall, with what they did to the presentation of the music. And if a tube is seriously microphonic to the point where it starts to ring in sympathy with nearby church bells (okay, I’m exaggerating about the church bells part), I found them to be ineffectual. The tube continued to be microphonic.
Herbie’s Soft Tenderfoot
This is a product that I’ve recently acquired and have tried, so far, in two applications.
A pack of Soft Tenderfeet Both sides now

What I used as the bottom
Herbie's web site states that the Tenderfeet may be used with either side placed facing the bottom, that is, on the shelf-side. I initially opted to place the ridged portion against the shelf and the wider portion with the white circle resting under the component. When I reversed the orientation I could not hear any differences in the sound. They also recommend that four be used so that's what I ordered. Three will work, too but the effect is supposed to be more pronounced with four. I've found that the optimal number for me, so far, is zero.
My Clearaudio Concept turntable is especially sensitive to footfalls. This is due to any number of factors including its Verify tone arm which has a friction-free magnetic bearing, the floors in my apartment are of sprung-wood construction, and the fact that pachyderms live in the apartment over me.
I had been using Black Diamond Racing pucks (review forthcoming) under the Concept's three stainless steel pointed feet with some success prior to trying the Soft Tenderfeet (I’m officially changing their name for the purposes of this review). I found that the Tenderfeet didn’t work quite as well in terms of isolating the turntable from footfalls. In addition, they also changed the sound of the Concept. Bass and treble were less pronounced and the music became more midrange-centered. Some detail was lost in the shuffle, too.
I then tried it under my Shunyata Hydra Model 8 power conditioner which had previously been resting on its own laurels. Reputedly, the power conditioner would benefit from some additional support. In this case, there did seem to be some additional sound stage focus (sound familiar?) but at the loss of some presence to the music. Dialogue also seemed to be a bit clearer, as well.
What I’ve Learned
The lesson, for me, has been clear: less is more. As I stated at the beginning of this installment, my intention is not to dissuade anyone from trying these tweaks. In the right circumstances and depending upon your goals, these may be just what the doctor ordered. Just not in my case.
Recent Comments