The Effect of Damping on Sound: Racks and Turntable Plinths

[tima]

When mechanical energy is applied, *how* is it absorbed by Sorbothane? I.e. the Sorbothane must react in some way: maybe it bounces and oscillates at a particular frequency or maybe it converts to thermal energy. Probably some of both. But it doesn't simply destroy the applied energy, which "absorb" may imply to some people. One thing I've observed is that Sorothane doesn't pass simple finger tap tests The other being that whatever it does, the result isn't pleasing to the ears in audio applications. At that point, I suppose I never concerned myself with why.

No laws of thermodynamics are violated. The mechanical energy transferred to Sorbothane converts to heat.


https://www.sorbothane.com/technical-data-sheet.aspx

 

[ack]

Extreme?

Isodamp between the cartridge and headshell, only other contact points are the plastic washer of the screws. Huge sonic improvement, and easy to verify by tapping the headshell with a metal object, like a screwdriver - very well damped and dull impact, a lot of ringing without the Isodamp. Downside: much harder to set up the cartridge, took me well over an hour.

 

[ack]

I'm better off buying sheets of Isodamp and cutting to size for greater area coverage.

We need to be careful here, and mindful of heat transfer characteristics when placing stuff on top of components. For this reason, I do not use Isodamp with the steel damping blocks I have over my amps' top plates.

 

[spiritofmusic]

You mean yr power amps or your preamps as well? I've been at an HRS Damping Plates demo where they were installed on preamp that got warm, but not the hot monoblocks' transformers.

So avoid extremely hot gear, but ok on chassis' that get warm, keeping clear of vent grilles etc?

 

[ack]

You mean yr power amps or your preamps as well? I've been at an HRS Damping Plates demo where they were installed on preamp that got warm, but not the hot monoblocks' transformers.

So avoid extremely hot gear, but ok on chassis' that get warm, keeping clear of vent grilles etc?

Well, in a nutshell, yes. We just don't know what any long-term effects there may be if heat is not dissipated correctly. It's a risk.

 

[PeterA]

Extreme?

Isodamp between the cartridge and headshell, only other contact points are the plastic washer of the screws. Huge sonic improvement, and easy to verify by tapping the headshell with a metal object, like a screwdriver - very well damped and dull impact, a lot of ringing without the Isodamp. Downside: much harder to set up the cartridge, took me well over an hour.

View attachment 63387

Tasos, that is a nice photo and clearly shows what you have done. Did you try to place the cartridge upside down on a sheet of Isodamp and cut out the outline plus two holes for the mounting screws for more complete coverage or contact between the cartridge top and headshell bottom?

In what ways did the sound change?

 

[ack]

Tasos, that is a nice photo and clearly shows what you have done. Did you try to place the cartridge upside down on a sheet of Isodamp and cut out the outline plus two holes for the mounting screws for more complete coverage or contact between the cartridge top and headshell bottom?

In what ways did the sound change?

No, I just cut a small rectangular piece that sits between the screws. The sound has less of treble shrillness and is a lot more natural. Mind you, all the mods I have made in the last 3 months have also enabled me to turn up the gain in the XP-25 to 76dB, for a more dynamic sound as well. There is one last thing I need to figure out - slight hum when the motor runs, and it's a social distancing thing, LOL. Phono needs more mu-metal

 

[spiritofmusic]

Tasos, that blue Isodamp would nicely match my blue glowing Straingauge cart Lol.

Re chassis damping plates, Isodamp or HRS, yes, heat egress is a practical issue.

I've not seen one negative report re the HRS Plates, each 4" wide and 5"/10"/15" long.

 

[Folsom]

@ack

How many of your mods you perform get rejected?

 

[PeterA]

No, I just cut a small rectangular piece that sits between the screws. The sound has less of treble shrillness and is a lot more natural. Mind you, all the mods I have made in the last 3 months have also enabled me to turn up the gain in the XP-25 to 76dB, for a more dynamic sound as well. There is one last thing I need to figure out - slight hum when the motor runs, and it's a social distancing thing, LOL. Phono needs more mu-metal

Thanks Ack. I remember the immediate transmission of taps on my SME headshells being a good thing, now you seem to prefer a very dull thump in your system. If you are lessening the treble shrillness for a more natural sound, that can only be good.

AJ vdH wrote me that using the lowest gain setting in my Pass phono stage would produce the greatest dynamics. He specifically recommended the 55 dB setting. Of course my Master Signature is 1.1 mV output and your A90 must be much lower than that.

What other mods have you been making to your system in the last three months that may be appropriate to discuss in this thread? Any others to the turntable or rack system? I'm curious.

 

[ack]

Thanks Ack. I remember the immediate transmission of taps on my SME headshells being a good thing, now you seem to prefer a very dull thump in your system. If you are lessening the treble shrillness for a more natural sound, that can only be good.

Tapping on your SME V-12 is also dull, which is great - magnesium has that property. And I do prefer as dull a thump as possible; I do try to remove artificial, unwanted and unnatural signal - not add it - everywhere, as best as possible. The only signal that I care about is the signal off of the recorded media.

AJ vdH wrote me that using the lowest gain setting in my Pass phono stage would produce the greatest dynamics. He specifically recommended the 55 dB setting. Of course my Master Signature is 1.1 mV output and your A90 must be much lower than that.

TWhat other mods have you been making to your system in the last three months that may be appropriate to discuss in this thread? Any others to the turntable or rack system? I'm curious.

The Tubulus DB-25 umbilical and the dual Isodamp layer under the VPI feet; don't ask me why dual works better, but it probably has to do with the ball tip of the VPI feet; weird. I also removed the cork layer under my motor.

 

[ack]

Thanks Ack. I remember the immediate transmission of taps on my SME headshells being a good thing, now you seem to prefer a very dull thump in your system.

I think I now better understand the basis of your question:

1) The claim that tapping on the headshell or armwand is a "good" thing, in my mind, is because it simply says there is a very low noise floor in the chain for it to be heard; not all phono set ups have that kind of sensitivity, and it's a crude measure of resolution, if you will.

2) At the same time, when that tapping is very short lived, without ringing (or with less ringing), is also a very good thing, and the duller the better - or at least, what I aim for.

3) It would be best if there was no audible feedback at all, but only if a result of damping and isolation, not lack of system resolution.

Hope this makes sense

 

[Sunny]

I would listen to a Harmonic Resolution Amplifier stand. It will be absolutely amazing.

 

[denimhunter]

Extreme?

Isodamp between the cartridge and headshell, only other contact points are the plastic washer of the screws. Huge sonic improvement, and easy to verify by tapping the headshell with a metal object, like a screwdriver - very well damped and dull impact, a lot of ringing without the Isodamp. Downside: much harder to set up the cartridge, took me well over an hour.

View attachment 63387

Have u try just mounting the washers between the cartridge and headshell, therefore allowing air gap between the components. i found that decouples the cart and the head shell and allow the cartridge to breathe.

 

[remdeck]

Update on my Garrard Plinth project.

Now I actually had the time to get on with my plinth.
As I read about the different materials, I tried to get some Panzerholz, but didn't find any.
So I toke the advice of Ovenmitt to try some bamboo.
I've also found an idea to use a bamboo board, spacers of some very hard material, than bamboo again. Tonearm board separated from the motor board.
This is what I've come up with:


2 Bamboo boards 18mm, motor and armboard separated and brass spacers.



All this is gone be on standing on another 2x 18mm bamboo.(Still mpx-particleboard) q Upper and lower boards including spacer will be screwed together as to make one ridgid system.

As of now (overhang is not 100% alligned) the sound it incredible!! There is a never heard open midrange, the bass is full of power but not fat anymore, the highs are very open and all over the freq.range there is very good dynamics. 3d is much enhanced, have to align the OC9 better to get it even more deep soundstage, as it is still not really very deep. Overall clearity is much better.
Can I get even better sound somehow?
Still, when tapping on the bamboo board, this is still audible and I understand this can be minimised.

Shall I try steel /aluminium/isodamp between the bamboo boards? (18mm bamboo - steel / Aluminium / Iso - 18mm bamboo)

Will update when I have more news

Regards, Remco

 

[remdeck]

Further developments:

after getting the cartridge alignment optimized, the sound was realy good. 3d enhanced, sounds seperated more.
I than ordered the idler wheel from Audiosilente in Italy. Ordered it on thursday and had it delivered at mondaymorning in Germany....that was quick!!

This wheel helped improve rumble levels a bit, but mostly sounds are more dense, more grip in the sound and blacker background.

Than I put a layer of 3mm aluminium between the 2 18mm bamboo boards:

This is it!!!
This sounds incredible! There is a very nice intimacy. The sound is more black and layered (maybe because of the blackness) and the rumble vanished to almost inaudible levels. Tapping the motorboard isn't heard that loud anymore.
The dynamics are very good top to bottom and details are enhanced. What suprises me most, is that the sound is musically involving like never before. Sitting there, foot tapping, head nodding, just closing the eyes and having the music pull you into it....love it!
I really like this and will build the turntable like this further.
The lower board will be made ofo 18mm bamboo-aluminium-bamboo too as will the armboard. Under the turntable I will put some Soundcare spikes, which I like under my speakers also. When all is done, I'll try some damping.

When my new listening room gets ready at the end of the year, I will upgrade the hifi-rack with better choice of material than 3 layers of mpx (although in the middle there is around 3/4 of sand between the mpx)

I'll keep you updated

 

[PeterA]

Wonderful report and congratulations on your progress, Remdeck. It is fascinating to read about these kinds of DIY improvements and the resulting sonics. Thank you for sharing the information. Great stuff.

 

[remdeck]

Yeah, I'm really happy @the moment
Give it some time, if things stay like that

Regards Remco

 

[analogsa]

Interestingly, I have never had good luck with bamboo. Tried it mostly as armboard material and preferred olive wood by a big margin. Even 10mm acrylic sounded better. Used as shelves the bright and thin character remained. Perhaps not all bamboo is created equal.

 

[remdeck]

Interestingly, I have never had good luck with bamboo. Tried it mostly as armboard material and preferred olive wood by a big margin. Even 10mm acrylic sounded better. Used as shelves the bright and thin character remained. Perhaps not all bamboo is created equal.

Do you also have a Garrard?
The strange thing for me is that the arm board is less important than the motor board for the Garrard, but maybe the Garrard is really hard to get right.
Thanx for your input!