Fluid dampers - do they really work?

[Angsty]

I did a search but could not find much discussion on this topic on ASR. I recently acquired a KAB tonearm damper for my PLX-1000 turntable. After installing the damper and fluid, I could hear some differences but I do wonder how much of what I'm hearing is due to a change of effective tonearm mass versus fluid damping.

Adding the damping paddle has definitely changed the effective mass -- I did have to reset VTF after putting the paddle on. Unfortunately I did not have the presence of mind to run the turntable with the oil well dry as a comparison before filling it. It's conceivable that even with the higher effective mass, the damping fluid still mitigates the low resonant frequency issues.

What are the real physics behind tonearm fluid dampening? If it really is such a big benefit, why would it not be a more mainstream option? The Well Tempered tonearm was famous for this, but it did not have a whole lot of close imitators.

 

[DonH56]

My experience is from ages ago so take with a grain (or block) of salt. Damping shifted the tonearm resonance lower but I was never sure it improved anything beyond "standard" damping. On flat records flutter was reduced, but on most the damping simply led to higher distortion and more mistracking as the arm resisted following record warps and wobbles. My take-away as I recall it is that it could help, but the optimum amount of damping was tricky to find, at least for me, and may vary depending upon the record (there were a lot of thin, warped records coming out back then). Again, vague memory from long ago. I would expect the manufacturers of damping systems and arms would have treatises on their benefits, but probably mostly marketing...

 

[Angsty]

I would expect the manufacturers of damping systems and arms would have treatises on their benefits, but probably mostly marketing...

"Mostly marketing" seems about right to me. I'm not prone to buying a lot of tweaky things, but the damping trough seemed like a relatively low-cost curiosity back-scratcher, so I'm giving it a shot.

 

[Count Arthur]

Would damping at that end of the arm have much effect?

I remember the Townshend Rock turntable with it's damping trough at the headshell end of the arm:

I imagine this would have some effect, and should appeal to those that think vinyl is just too convenient without having to faff about moving a trough filled with fluid out of the way each time you want to play a record.

 

[sergeauckland]

Damping should be applied at the cartridge, like Shure do it, not the arm. Damping applied at the arm, whichever end, will cause stress on the cantilever with any swings or warps. This will put the cartridge generator out of its linear region and cause additional distortion. As ALL records are slightly off-centre and warped, arm damping is always a bad thing. A tiny bit of damping on a unipivot is OK, otherwise no.

S

 

[Angsty]

Would damping at that end of the arm have much effect?

I remember the Townshend Rock turntable with it's damping trough at the headshell end of the arm:

View attachment 188459

I imagine this would have some effect, and should appeal to those that think vinyl is just too convenient without having to faff about moving a trough filled with fluid out of the way each time you want to play a record.

I remember reading that Max Townshend (RIP) said that fluid damping was more effective closer to the stylus than at the tonearm rear. I understand that the Rock turntable was a legend of its day, but again, the design principal was not widely adopted as a superior approach even at the high end.

 

[Angsty]

Damping should be applied at the cartridge, like Shure do it, not the arm. Damping applied at the arm, whichever end, will cause stress on the cantilever with any swings or warps. This will put the cartridge generator out of its linear region and cause additional distortion. As ALL records are slightly off-centre and warped, arm damping is always a bad thing. A tiny bit of damping on a unipivot is OK, otherwise no.

S

But some tonearm designs feature damping as part of the design, like the Jelco 750D. On a Jelco tonearm review, I found this interesting note with a photograph:

"This is the little chamber that holds the silicone damping fluid, accessed by unscrewing the knurled lid on top. The damping fluid helps take the edge off a lively cart. It can also help reduce tracking misbehaviour with a non-optimal arm/cart combination."

Perhaps damping is best suited when the tonearm mass and cartridge compliance are not a good match?

Jelco SA-750D Tonearm Review | LiQUiD AUDiO

This review examines the excellent Jelco SA-750D tonearm, often fitted as original equipment on many turntables past and present.

liquidaudio.com.au

 

[sergeauckland]

But some tonearm designs feature damping as part of the design, like the Jelco 750D. On a Jelco tonearm review, I found this interesting note with a photograph:

"This is the little chamber that holds the silicone damping fluid, accessed by unscrewing the knurled lid on top. The damping fluid helps take the edge off a lively cart. It can also help reduce tracking misbehaviour with a non-optimal arm/cart combination."

Perhaps damping is best suited when the tonearm mass and cartridge compliance are not a good match?

Jelco SA-750D Tonearm Review | LiQUiD AUDiO

This review examines the excellent Jelco SA-750D tonearm, often fitted as original equipment on many turntables past and present.

liquidaudio.com.au

Possibly, but then, it's one error to ameliorate another. Much better to avoid the error in the first place.
Anyway, arm manufacturers, like loudspeaker manufacturers with biwiring terminals, do what their customers like to see, not what's right.

S

 

[Deleted member 21219]

Anyway, ...... manufacturers ....... do what their customers like to see, not what's right.

The perfect description of the audiophile world. Jim Taylor

 

[Thomas_A]

Uni-pivot arms need damping, and I use 600 000 cst silicon oil on my UP-4 tone arm, according to Moerchs recommendation. But this is more for "wiggle stability".