Tube dampeners on ARC gear ... FREE TWEAK

I can attest that Marigo Mystery feet will certainly sound better, however the cost is somewhat excessive ($1500 for a set of the current F8). A further consideration is tha even with the removal of the stock feet there is not enough clearance at the front of my REF40 or Ref 2 phono for the feet to sit flat so it does take some finessing, the sound is worth it however. Much cleaner and crisper, less smearing of microdynamics

also do experiment with removing the top plate on your amps, in the case of the Ref40 this sounded better

Just wanted to add a wholehearted endorsement of the Herbie's tube dampers. I've now installed these on all tubes (signal and power supply) on my ARC Ref40 and Phono 2SE -- all I can say is wow!  Compared with the original rubber rings the difference is night and day, a whole layer of distortion disappears. Vocal tracks that I had written off as etched or edgy are now totally clear and a wealth of high end detail comes through that had been masked before. This is particularly apparent on leading edges of percussion making it much easier to distinguish between different types of cymbals

At first blush it may seem as if some of the "impact" is diminished but I put this down to removal of a sort of echo around major dynamic edges

Anyway wholeheartedly recommended and thanks for the tip oregonpapa -- now to get more for my power amps

Yes, I use the larger ones on the 6550s. They fit very easily and securely and with the adjustments can even accommodate tubes that are very close to one another. I'd heartily recommended using them on all the tubes in your system 

Oregonpapa -- yes I did start with them just on the signal tubes then ordered more for the power supply -- while having them on the signal tubes is good having them on the power supply as well is more than twice as good -- now note that my PS is not as well isolated as my control box (the ARC Ref40 is a two box set up) -- the latter sits on Marigo footers on a custom shelf while the PSU is just on the stock footers isolated by some constrained layer damping pads. Nevertheless I wholeheartedly recommend getting the dampers for the power supply tubes as well

If you are checking out CD mats I can strongly recommend the Marigo Audio Clear Transformation Mat -- I use it all the time in my DCS stack and can clearly hear the difference in terms of unifying the recording into a coherent whole, even the orientation of the mat is readily audible, and it is very slim so works with drawer type loaders -- costs a bit more than Herbie's but has a $ back guarantee I believe

I've ordered a full set of Herbie's HAL-O III dampers for my power amps (went with the heavier duty ones given the het in the amps, plus rumor is they sound better 😀 than the UltraSonic Rx) -- will report back in due course

oregonpapa - actually the Ultima Signature is the older model (dates from 2013-2014) and was superseded by the Clear Transformation which is the current model -- Ron doesn’t exactly update his web site (the Mystery Feet are in F8 for example notwithstanding the web site only describing the F7)

Wanted to report on my experience with Herbie's dampers on my VTL MB450-III power amps

Having had good results with the UltraSonic Rx dampers on my phono and pre I wanted to try something on my (currently undamped) power amps. As these run pretty hot I reached out to Robert for advice -- he said the UltraSonic Rx would work even in a power amp but that some users had had better results from the (somewhat more expensive) HAL-O III dampers so I elected to go with these -- quite a lot of money for the 16 size 50 and 4 size 9 I needed

Relative to the Rx the HAL-O are a little harder to use as they do not have the rubber grommets instead with a titanium to glass contact you will have to be firm to get them on

At first listen they seemed a little edgy and I was wondering if the Rx would be better but as the system has settled in these dampers have brought a quite impressive change. If I could sum it up in one word it would be 'control' -- every note is now vice precise and crescendi that had previously resulted in grain and noise now are completely clean. A vocal line alongside highly modulated bass is clear and independent and on mono records (btw a great way to test the effect of these dampers) you have a much improved ability to pick apart all the elements -- one of my test tracks (don't laugh) is "Mr Sandman" by the Chordettes (this is an old Ken Kessler favorite -- give it a try, with the HAL-O IIIs you can easily discern each voice and hear all the details in the backing tracks

The one downside I see is that these things are so damn revealing that the limitations in my (pretty fancy) CD front end are laid clear -- maybe some fine tuning of the filters I am using can ameliorate this, I'm currently using a wide open filter so may now be hearing some of the high frequency filter effects that had previously been masked

Anyway again highly recommended