Isolation for tube amps

Another thought on the subject.....I used a RS dB meter and sampled different frequencies around my room. I found that some areas had much lower sound levels at different frequencies than others. I had to use longer ICs, but placed my rack at the lowest "loudness" position. I also placed the amps on stands nearer the midpoint of the wall behind the speakers because this was the "quietest" place. I then mass loaded the mono amps and used points on the bases through the carpet to the concrete floor. Does it help? I think so, and it cost nothing.

Wow gentlemen! thank you for your amazing insight. That's a lot of information to chew on. I really appreciate you all taking the time to put together such thoughtful and thought provoking responses! This is one area where I think the industry is coming up short on. I plan to continue expolring this vibration/distortion relationship. Thanks again for all of your input - very good!

As you mentioned, another room is the perfect solution. All else will disappoint. However, building a screen of Tandy ( Leather Stores) 'pound o board' is a cheap and very effective solution. The only more effective is lead wall paper, toxic and expensive.

Keithmundy, to revist you initial question re tube amps.......

I enjoy all of the responses folks provide regarding how one deals with vibrations. Most, if not all have some basis in theory but I'm amazed at the disconnect between the theory and pratical application of the theory in audio systems. Especially with amps.

Few ever discusses when the amplitude of the vibration under discussion reaches a level when, and with what equipment, it become an audible problem and when the proposed solution actually reduces the sonic distortions caused by the vibrations.

With airborne vibrations its fairly obvious that at low levels, frequencies even those which might interact with the reasonance points of other components (including room stuff) are not audible to the human ear. At some level they will become audible and the question becomes 'what can reduce that specific problem area' at that level. Something that damps a vibration effectively but only when the vibration is at an inaudible level are IMHO worthless except to 'analites'. I think many products fit into this category.

I'm not trying to start another (endless) war on this subject but I would like to suggest that folks (other than salesmen) apply some critical analysis and engineering principles before spending a lot of money trying to solve non-existant problems with generic 'solutions'. This is truly one of those areas in audio where its based in science, not a what 'it sounds good to me', applies.

BTW, and by way of illustration, IMHO, mass loading of the transformers of any amp, especially tube amps, will help damp the sound of transformer vibrating itself, and it will also change the level and or the frequency of the vibration that actually reaches the tube. To the extent that mass loading actually affects the vibrations of the tube elements I don't know but its at least as good as throwing salt over your sholder. You've can't lose much. Its cheap.

Tube dampers will damp vibrations in the glass that can help damp some tube microphonics (depending on vibration frequencies, resonance points of the glass in the tube and in the elements) but I'm not sure that the dampers will prevent airborne vibrations in a critical frequency from passing thru the glass of the tube. Again, some tube dampers are better than salt and cheap, so why not. But before I bought expensive dampers I spend my money on very low noise tubes tested for microphony.

Just some personal thoughts some folks might like to think about. Maybe I'm just whacked out - no need to tell me though. :-)

FWIW.

Fla, the various Promitheus TVC models are all minimalist designs and none of them have a remote volume control. That's not a problem for me personally, but I understand that many others feel very differently about the importance of remote control.

The Promitheus TVC I am currently using is the Reference model dual-box pure dual-mono unit built around the Promitheus rev 3 EI-core transformers. The Signature TVC that I have ordered is an identical dual-box configuration using much larger double C-core transformers with very fine core laminations. The dual-box TVC design consists of a separate chassis for each channel, such that the right channel signal is completely decoupled from the left channel signal. Each box (i.e., each channel) has its own input selector and volume control.

I lived with the Lamm L2 preamp for years, which also uses a separate volume control for each channel. As long as the volume control knobs have distinct "clicks" as you rotate them, it's not a problem to keep the left and right channels at the same level of attenuation. You just count the clicks as you turn the volume up or down.

As for the Living Voice speakers, I am very pleased with them. They are very musical, non-fatiguing, well integrated two-ways that have paired up very well with my SET 300B monoblocks. The LV speakers render the timbre of acoustic instruments in a very natural, relaxed manner. The speakers also have a big, dynamic, weighty sound that is amazing given their diminutive size. The treble is a bit laid back and very refined - basically, just what you would expect from a first-rate soft dome tweeter (i.e., the ScanSpeak Revelator).

The LV speakers pair very well with tube amplification. Your music preferences, the size of your room and your preferred listening levels will dictate how much power you need to drive them. In most situations, I think you will want at least 10 high quality tube watts per channel to drive the speakers most effectively.

Keithmundy, sorry for hijacking your thread. Fla, if you would like to continue the dialogue, we should probably move the discussion over to my SET virtual system thread:

http://forum.audiogon.com/cgi-bin/fr.pl?vscnd&1187064942

Fundamentally all your equipments is attacked by vibrations emanating from three separate sources ... and requires 3 different approaches to dissapate them.

Air Born (Speakers) ... Self Generated (motors, transformers, and chips switching on, and off within our equipment) ... Structurally Coupled (HVAC motors, Cars and Trucks passing your location, and don't forget the Geo-Seismic shudder generated by the earth's shifting tectonic plates)

IMO the most deliberating of all the different forms of vibration is the equipment's self generated vibes, which need to be drained into a higher mass platform or rack ... vibrations will migrate from lower mass (CD/Turntable) to higher mass platforms and racks.

Your component's stock feet are an attempt to provide a path way to drain the component's vibrations ... as are after market cones (Wood, Brass, Carbon Fiber, or Roller Bearing set ups) ... the reason all these draining devices sound differently is you are now introducing the resonate frequency signature of the draining diode into the mix,

Air Born ... which seems to be the focus of this thread, can be defeated by "Mass Loading" or adding weight to the component ( which can be tricky with exposed tubes) to lower the component's "Resonate Frequency Point"

When a speaker pressurizes a room ... it pushes on your equipment, causing whatever is inside to vibrate. If your equipment weighs more ... it's harder for the Air Born pressurization to move your equipment around.

What would be easier to push around ... a 12 pound OPPO DVD player or my 40 pound Denon DVD5000 mass loaded with a 40 pound Bright Star Little Rock.

All the speaker pressurization sees is 12 pound OPPO vs my 80 pound Denon set up .... "Did you all skip class the day we talked about MASS LOADING" (;-{

The last area of deliberation is Structural Born Vibrations which couples to all the walls and floors in your home and are transmitted to your rack and eventually your components.

You must decouple these vibrations so they never reach your equipment.

To understand decoupling you must know a little about "Resonate Frequency Point" of a component and how to lower it.

The R/F/Point is your component's point above which it can handle and dissipate the attacking Structrual Vibrations .

"ABOVE" the components R/F/Point it will/can dissipate the vibes ... unfortunately below your components R/F/Point ... instead of Decoupling the vibes it actually gets overwhelmed by the vibes and "LOCKS UP" coupling instead of decoupling and allowing the vibes below the R/F/Point to pass right through to your equipment.

The easiest way to lower the components R/F/Point is to MASS LOAD ... add extra weight to it.

Pre Load your Viberpods, Ginkgo Cloud, Superballs, Isopods, or any other type of Elastomer decoupling device incorrectly and you will do more harm than good.

I've provided 2 links to pictures my setup .... ignore the pi$$ing contest about the solid core wires I'm involved in and view the setups

Bright Star (Mass loading) .... Denon 5000 (source) .... Symposium Double Stack (GR3) Roller bearings (Drains internal vibes) .... into the Audio Resolution/Vibraplan 120lbs combined weight for vibes to migrate to and finally the Vibraplans decouples everything down to about 10 or 15HZ

My set Up

House and Gardens meets Depths of Mordor

Pop quiz on Friday ... no more skipping class.

I am using the Ceraballs under my ARC VT100 MKII with excellent results. Improvements in clarity, focus and bass definition were not subtle. Also, the soundstage opened up considerably.

I use Herbies Halo rings and isocups and acrylic balls on my tube integrated. The Isocups are cheap and made a real difference. I am sure as Cincy bob says, a dedicated platform would be better, but costly. The other problem, not oftened mentioned, is clearance above the amp. If you put the amp on a rack, you need significant clearance above for isolation. A high amp stand may reduce that clearance, unacceptably. I use 845 tubes and need 10" above for ventilation. I know many do'nt put tube amps on a rack with other equipment.

Thank you all for your responses. Airborne vibration just does not seem to be discussed much and I would think this type of energy would be the largest contributor to vibration in all components. I suppose it is not addressed because one can not do much about it. I am going to continue to research this. Thanks again for your input

Cincy:
Does the TVC you've ordered come with remote volume control? How are you liking the Living Voice? I'm interested in both products.

Don't underestimate the ability of a well designed isolation base - like the Silent Running Audio bases - to deal with airborne vibrations. The SRA isolation bases literally attenuate airborne vibration by converting the energy to heat. In my experience, there is no product that is as effective as an SRA iso base in dealing with the vibration problems inherent in an amplifier sitting on the floor - especially a tube amp, which tends to be more sensitive to vibration than a solid state amp.

"Herbie's Audio Lab" sells several models of very effective tube dampers for most sizes of tubes.

Galen Carol Audio in San Antonio,TX sells inexpensive tube damping rings for small preamp tubes which I've found to be quite effective. I don't know of anything available for power tubes though.

Would the HALO tube dampers help with airborne vibrations?

You are correct. You really can't protect from 'airborne' vibrations. However there is a lot of other equipment or room floor induced vibrations which can be audible by thier effect on the signal, especially tubes and phono playback. So proper isolation is important. And you can eliminate most of the airborne vibrations by using the volume control. :-)