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Anybody used silicon in the Black Widow damping trough?

C

crossram

Well-Known Member
I recently mounted a Signet TK-7LCa cartridge on my Black Widow GF (graphite fiber armwand) version. This should be a great combination by the books - high compliance cartridge (~30cu) with ultra-low mass arm (~4g) and, indeed, it does sound awesome.

I am, however, having one issue: the slightest (and I mean slightest) warp at the beginning of an LP side causes the stylus to chatter, which is audible as an erratic rumble at the warp and visible via woofer pumping. It settles down about 30 seconds or less into the side and the combo works flawlessly for the remainder of the side. It also passes all of the tracking torture tests on the HFN test LP, even the one at the beginning of side 2, so tracking is excellent across the arms entire lateral movement, excepting the reaction to mild warps at the beginning of an LP side.

I decided to try silicon in the damping trough to see if that would help. Prior experience is that lighter weight fluids (olive oil, motor oil) made absolutely no difference in sound or tracking, so I went for it and used 300,000 cst (yes, that's 300,000cst!) silicon fluid to see if it would help. I just added enough so that the bottom of the small paddle is skimming the top of the silicon. It did not make any discernible difference in the warp induced chatter or the sound quality.

A google search came up with many mentions of the Black Widow's damping trough but nothing useful regarding what silicon viscosity to use or how much. Anyone out there ever tried various silicon viscosities in the BW damping trough that could offer some advice?

Could it be that the bearing in the BW needs adjustment? Anyone ever done that?

Any other ideas on what is causing this issue?

Dave
 
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Not needed here, the Infinity Black Widow handles the very high compliance options without any extra assistance great. Just install and setup carefully. Enjoy.
 
I've been using a BW and AT-ML170 for the past few years and have not experienced what you're describing and I believe Kent is correct that damping will not address this problem. However damping via a trough has some benefits (and detriments) when compared to an undamped arm. To the best of my knowledge 300,000 cSt silicon is for TA queuing mechanisms. I've picked up an aftermarket BW damping trough (not yet installed) and bought 10,000 and 30,000 cSt which will permit experimentation with light to medium damping.
 
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I don't own a BW arm, but I have built and used a trough-type fluid arm damper. For a damping paddle to work in a fluid bath, it has to be submerged, preferably riding about halfway down from the surface of the fluid. Try adding some more silicone oil and see whether that makes a difference.

However, I can't help but think that with the viscosity so high, there's a danger you'll overdamp, which will show the same symptoms as underdamping.

As for the fear that the pivots are the problem, low-to-moderate pivot friction would actually act to damp the motion of the arm. In my opinion/experience, if the friction were high enough to create the woofer-flap problem, you could tell every time you tried to move the arm, or zero-balance it.

Since I don't know the size or shape of the paddle on the BW, I'd start with SME's low-viscosity recommendation, ie, around 50k cSt, or even lower, and work my way up (if needed) rather than go the other way. A slight underdamp is preferable to a slight overdamp.

In any case, let us know what the final solution to the problem turns out to be.
 
nailer said:
I've been using a BW and AT-ML170 for the past few years and have not experienced what you're describing and I believe Kent is correct that damping will not address this problem. However damping via a trough has some benefits (and detriments) when compared to an undamped arm. To the best of my knowledge 300,000 cSt silicon is for TA queuing mechanisms. I've picked up an aftermarket BW damping trough (not yet installed) and bought 10,000 and 30,000 cSt which will permit experimentation with light to medium damping.
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Thanks nailer. You are correct that 300,000 cst silicon is primarily for queuing mechanisms and that 10,000cst and 30,000cst are most common for arm damping, except in some unipivots (VPI) where the higher viscosity is needed. A while back I ordered 10,000cst, 30,000cst, 300,000cst and 600,000cst so I would have the right viscosity for whatever need might come along. I have tried lower viscosity fluids before with no effect on the BW. I look forward to hearing your results when you get the trough installed.

I am really not sure how to interpret Kent's post. The arm/cartridge is setup to the nines - painstaking alignment at 66.6/103.4 null points, 1.15g VTF, VTA moderately positive, A/S at .75. Sails through all seven tracking test on the HFN test record and horizontal resonance tests out at 9-11hz. Sounds fantastic with no IGD, sibilance, or other tracing distortion. Yet, the issue with the warp chatter persists. I am talking very mild edge warps here that my other setups don't react to at all. Pretty hard to "enjoy" when 50%+ of my LP's are displaying this problem. I guess I was hoping for some input on possible causes/solutions when I posted. :(

Dave
 
wualta said:
I don't own a BW arm, but I have built and used a trough-type fluid arm damper. For a damping paddle to work in a fluid bath, it has to be submerged, preferably riding about halfway down from the surface of the fluid. Try adding some more silicone oil and see whether that makes a difference.

However, I can't help but think that with the viscosity so high, there's a danger you'll overdamp, which will show the same symptoms as underdamping.

As for the fear that the pivots are the problem, low-to-moderate pivot friction would actually act to damp the motion of the arm. In my opinion/experience, if the friction were high enough to create the woofer-flap problem, you could tell every time you tried to move the arm, or zero-balance it.

Since I don't know the size or shape of the paddle on the BW, I'd start with SME's low-viscosity recommendation, ie, around 50k cSt, or even lower, and work my way up (if needed) rather than go the other way. A slight underdamp is preferable to a slight overdamp.

In any case, let us know what the final solution to the problem turns out to be.
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Thanks Walt. Great advice as usual. I will try the 30,000cst silicon with enough to submerge the paddle as you recommend and let you know how that works.

Dave
 
I´m not familiar with this arm, but as a general rule arms perform better with additional damping. Even if it´s not directly seen when tracking, arms are vibrating and damping the arm prevents this. Fluid damping is the best IME, but additional damping can be applied also elsewhere with good results.
There are ways to determine how much damping should be applied in each case, but overdamping; when the arm does not follow the low frequency warps is not recommended. An easy way to look at the damping is dropping the arm with the actual needle on a blank record, or a CD or something. Drop it from about 2-3mm height and see how it comes to rest. Theoretically it should perform a Critical Damping movement or slightly less IME.
gusten
 
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gusten said:
I´m not familiar with this arm, but as a general rule arms perform better with additional damping. Even if it´s not directly seen when tracking, arms are vibrating and damping the arm prevents this. Fluid damping is the best IME, but additional damping can be applied also elsewhere with good results.
There are ways to determine how much damping should be applied in each case, but overdamping; when the arm does not follow the low frequency warps is not recommended. An easy way to look at the damping is dropping the arm with the actual needle on a blank record, or a CD or something. Drop it from about 2-3mm height and see how it comes to rest. Theoretically it should perform a Critical Damping movement or slightly less IME.
gusten
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Thanks for the input gusten. I changed out the 300,000cst silicon for 30,000cst with the trough filled even with the top surface of the paddle. A change for the better sonically (than the 300,000cst), but the warp chatter is still there. Looks like I'm just going to have to live with it with this cartridge/arm combo.

I plan to go back to no damping for a comparison baseline and then try the 30,000cst again.

Dave
 
Dave did you try any of your other cart's before changing your fluid? Just thinking you might find a great combo right it down,then do more testing.
 
drtool said:
Dave did you try any of your other cart's before changing your fluid? Just thinking you might find a great combo right it down,then do more testing.
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Hello my fellow Houstonian. Great to hear from you.

Re: other cartridges, the Sonus Gold Blue is fantastic with the BW. Probably should also try the V15 Type III MR and ADC XLM II Improved.

This damping trough thing has always bugged me (never seemed to make much difference sonically) and I wanted to take another run at it after reading recent posts from gusten and dlaloum about the benefits of tonearm damping. I will play with it a little more before throwing in the towel on the BW/Signet combo.

Dave
 
If the BW's paddle is significantly larger in area than the teeny one(s) on the SME FD200, even 30k might be too high. You might even want to give good old STP a try.
 
wualta said:
If the BW's paddle is significantly larger in area than the teeny one(s) on the SME FD200, even 30k might be too high. You might even want to give good old STP a try.
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Damn, Walt! You read my mind (start worrying). I was going to go pick some up this evening but time got away from me. I will get some in the AM and give it a shot.

Dave
 
Well, a few trials over the last couple of days and here's what I learned:

The 30,000cst silicone did in fact reduce the chatter significantly, but I could hear a slight reduction in air and sparkle in the highs. Then went back to no fluid to confirm this and did. Tried the STP (reported to be 5200-6320 cst @40 degrees C) and the air/sparkle returned, but very little improvement in the chatter. With the STP, the overall sound is a touch smoother than without (in a good way). I need to get some 10,000cst to try - this may be the sweet spot.

Several folks have suggested that the Signet may have issues with an age-hardened suspension. Maybe, but I stumbled onto this from a cartridge comparison by Fremer, Analog Corner #32, referring to the Grado The Reference on a Graham 2.0 arm:

"There's one other problem: The underdamped, high-compliance suspension, while making the Reference a superb tracker—better than any MC I've ever auditioned—made the cantilever oscillate wildly on the lead-in grooves of many records that presented no problems for lower-compliance cartridges. When records are pressed, the hot vinyl biscuit is spread from the center outward. By the time the vinyl reaches the outer area of the stamper, it has begun to harden—especially with improperly pressed 180gm records (many of the recent German-pressed WEAs, for example), which take longer for the vinyl to spread. While the record looks flat, under illumination you can see a surface oscillation that causes the Grados to go wild. While I never experienced audible tracking problems, woofers pumped and watts were wasted—it wasn't a pleasant sight. Perhaps a low-mass arm like the Infinity Black Widow or the Grace 707 could tame this, but who's using them today? Once you're in an inch or so from the edge of the LP, the problem goes away."

Sounds like the chatter is a function of an underdamped, high compliance cartridge when tracking poorly pressed LPs on the outer grooves. Ironic that Fremer suggests the Black Widow as a possible solution.

Dave
 
I'm a little surprised/disappointed myself that the BW couldn't "solve" the problem all by itself. That cartridge must have a very compliant stylus, or else someone filled the arm tube with lead shot. A very light arm or headshell doesn't really solve the problem, but rather moves it sideways (so to speak) to a less-dangerous spot. Still, this is just a tad puzzling.

Your experiments with the different fluid viscosities should bear fruit soon. When you get close to the sweet spot, the arm/cart should be able to handle just about anything. Can you mix different oils and get intermediate viscosities?
 
wualta said:
I'm a little surprised/disappointed myself that the BW couldn't "solve" the problem all by itself. That cartridge must have a very compliant stylus, or else someone filled the arm tube with lead shot. A very light arm or headshell doesn't really solve the problem, but rather moves it sideways (so to speak) to a less-dangerous spot. Still, this is just a tad puzzling.

Your experiments with the different fluid viscosities should bear fruit soon. When you get close to the sweet spot, the arm/cart should be able to handle just about anything. Can you mix different oils and get intermediate viscosities?
Click to expand...

Thanks Walt. No lead shot in the arm tube, but the TK-7LCa was one of Signet/Audio Technica's highest compliance cartridges back in the low mass/high compliance heyday. Yet, the ultra-high compliance Sonus Gold Blue does not exhibit this behavior in the BW. I suspect that it has more to do with internal damping of the stylus' suspension than compliance per se.

After some intense listening this afternoon, I will say that the sound is better with the STP in the trough than without damping. Hard to describe, but it just sounds more cohesive.

Re: mixing oils - I have the STP (~6,000cst) and several high (30,000cst and up) silicone fluids, but I don't know how they would react to mixing with the STP. Any ideas on what to mix with the STP to get it closer to 10,000cst?

Thanks again Walt.

Dave
 
No, I never had to mix oils, so I have no experience with possible reactions between the STP and the pure silicones from the hobby shop. Still, hobby shops are fun places, so see if they have 10k on hand. At least that way you can leave repeatable data for future Signet pilots.
 
Thank you Balifly. Much appreciated.Those guys have a great variety of viscosities. I will place an order.

Dave
 
FWIW
The suspension damping on these ATs follows the spring constant, or inverse to the compliance, the damping will be lower if the compliance is high.
On a few of these needles I have seen the compliance to be higher than it should be, the damping lower than it should be.

This can be adjusted by loosening the compliance screw, increasing the force on the rubber doughnut, and tightening the screw. Though I don´t recommend doing it on an expensive stylus if you haven´t done it before. Test on a cheap stylus.

The difference in sound one hears with tonearm damping is of course that the sound will loose the character from the resonances, it will be more correct with lower distortion, can take a little time to adjust to this.
gusten
 
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