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10-28-2008 Post does not mapped to Knowledge Tree
Romy the Cat

Boston, MA
Posts 9,740
Joined on 05-27-2004

Post #: 1
Post ID: 8644
Reply to: 8644
About rationalism of twin-units isolation efforts.

Audio people frequently go astray in their thinking and actions and this creates a good breeding ground for all possible audio sale opportunists. I would like to explore one moment that has not a lot of public attention and to look at the moment slightly deeper. A few weeks back there was a conversation with and about Mike from Audio Federation


…where Mike unexpectedly-violently stressed the need for audio equipment isolation.  You might read his comment at his blog where he stresses to importance of use isolation platforms under audio equipment. I have no idea why he is so hyped about it. Perhaps he just discovered the phenomena or juts signed a new products line… Anyhow, the seasoned people know the isolation kinks and use it to various degrees. It is important to mention that in many cases the isolation of decupling from the base is not as important as the changing the chassis dampening pattern. However, this thread is not about the isolation/dampening/suspending techniques but about a rational for a very narrow moment of isolation – the degree in which we do into isolation control when it might not be necessary.

(BTW, in context of this thread I would like to use the word “isolation” as a general term that would imply ALL mechanical affords for chassis and components best performance: would it be isolation, dampening, suspending, decoupling,  or whatever.)

So, what make me to think about was the Federated Mike cements about his live with Lamm ML3 posts at his blog


Mike said:

“Thinking about it now - it is apparent that the system itself, even this system, in support of the Lamms, was a limiting factor... Another example: The ML3s were all on HRS M3 bases, which are the best vibration isolation available today. But the M3s were on the carpet, and putting the M3 on SXR amp stands would add another little extra boost in performance, The point is that with these amps, the system can evolve and continue to be upgraded for a very long time and you will just hear more and more of what the amps can REALLY do. “

Reading it I was thinking: why such an amplifier as LAMM ML3 needs to use 4 isolation bases? The ML3 is a twin amplifier that has a separate power supply chasses and control unit chasses. All vibration-inducing sources (transformers, chokes etc) are located in power supply section. Surly currents flowing in control unit do induce some vibrations but for 60 point chassis and the ability to control those vibrations by EXTERNAL mean (external isolation platform) I think those vibrations are absolutely negligible and the EXTERNAL isolation should not have any deference or meaning. Then I looked at the ML3 insistences (Mike’s phonographs from the last year show)


it looks like the amp has the filament chokes  sitting  at control unit’s side. Well, this is a huge foolishness of layout from my perspective, the foolishness that pretty much disqualifies ML3 from a topology of being a pure twin amp and from the benefits of having dual chassis. Not to mention that GM70 has lot of current on heaters and thereof the ML3 most like use input choke – so the high ripples just after rectifier, not filtered by choked or caps  have brought into suppose to be AC-sterile ML3’s control unit… Not kosher, particularly for $150K amp… I would like somebody to listen the ML3’s control unit with a stethoscope

Anyhow, let the ML3 go and to look at the problem wider: the twin-chassis and a need for control unit isolations.  I dealt for prolong time with the following twin audio elements and here are my observations regarding the need control unit‘s “isolation”:

1)     Lamm L2. Power supple isolation was beneficial. The external isolation of control unit had no difference. My L2’s control unit has a lot of internal dumping the as the shahs in L2 was very week.

2)     Pacific Microsonics: the isolation of both PS and control unit are beneficial. However there is A LOT what going on in Pacific’s control unit.

3)     7788  68dB-gain all active phonostage. Nether isolation for  PS or control unit are important. The phonostages control unit is made from very thick steal with lead loaded at the bottom of the chassis. The tube elements are all shock-mounted. I have a custom SRA-made suspension platform build for this phonostage but I do not use it as it has absolutely no impact.

4)     “End of the Life Phonostage”. No isolation used. I honestly tried everything imaginable (and I have a LOT of toys for it) under this phonostage and I detect no positive or sensible impact to sound.

5)     Super Melquiades amplifier. When Milq was used as two separated chassis sitting on floor then I use them with my SRA platforms that I have left from my 4 pairs of ML2 (With ML2 the SRA platforms did work very nicely). However, I can’t report that I heard a lot of difference when I used Melquiades sitting on juts bare floor, nether PS nor control unit had no impact. Later, when I started  to use Milqs on two different floors of the same stand:


..the situation have changed and the prominence, in fact the supper prominence, of the  isolation management under the amp’s control unit when back.

6)     Bidat. This DAC is the most vulnerable unit from a point of view of “isolations”. If to know how to use it then it is possible to do with “Bidat acupuncture” some outrages things. Taking the PS out of the chassis and converting it into twin makes Bidat do not need isolation. The “acupuncture” still might be apply with much less effectiveness but the “platform” isolations become not so useful.

So, if to look at all of it then the pattern then very obvious that with more or less proper implementation of control units the need for  isolation, dampening, suspending, decoupling ether totally eliminated or dramatically reduced. Probably it makes since to look for implementation of the given unit in order to evaluate if the twin-unit need any isolation. A stethoscope might a voluble tool to look further. The isolation of a power amp’s control unit from floor vibrations is totally different subject that hardly addressed by isolation platforms.

Romy the Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-28-2008 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,265
Joined on 10-12-2006

Post #: 2
Post ID: 8646
Reply to: 8644
Noise, Mode, Frequency, and Death by Knowledge
Well, if cost if no object, why not put everything on those cool SRA stands?  Besides, Mike probably uses the most affordable version, anyway...

Of course those will not in any case address all sonic intrusions, which include not only structural but also air-borne vibrations, and also most discrete components and component interfaces, with noise emanating, propagating and disseminating in electrical, mechanical and electro-mechanical modes throughout any given real world circuit.  Decoupling and/or adding weight is not always the best solution, or it is not always the only solution.  Theoretically, in cases of mechanical noise transmission, there could be instances where merely loosening something could lessen a frequency spike, resulting in "better" sound.  There are always innumerable ways to simply change the noise spectrum, to re-distribute noise, and this fact has been well explored and thoroughly exploited by all manner of hopeful tweak vendors.

There are probably plenty of cases where isolation efforts are akin to wearing a tinfoil hat.  For instance, I still use the old PEEK tube dampers, mostly out of habit, but also because there have been times when the benefits were quite obvious.  At this point, I think of them mostly as cheap insurance.

Is this a question of when and where very specific noise-mitigation measures should be undertaken, or is this a question of just going through the noise-mitigation drill?  Without fairly rigorous prior and post-mitigation testing, who can be certain?

But here I should issue a warning:  Adding tap tests to stethescope listening can cause palpitations and even heart failure when applied to hyper-expensive system components.  And God save us from the lowly volt meter!

Best regards,
Paul S
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