SRA Clarification From Peter Ledermann

I just spoke with Soundsmith's Peter Ledermann. He confirmed that the contact patch is as seen in the above photo. But note that this is with VTF of zero. He made a few observations about this discussion we're having here on Analogplanet.com.

First of all, we should not jump to the conclusion that this represents an accurate sampling of what comes from his company and that he works very hard to produce cartridges within a low tolerance margin (low tolerance means greater uniformity). But more importantly he said that while he strives to produce within a certain spec, inevitably there will be examples that fall outside of it.

Understandably from a consumer's perspective that's hardly satisfying. However he also pointed out that while he specifies VTF to the first decimal point (ie: 1.3g), you should feel free to experiment well above that setting because you will NOT damage either the cartridge or your records because of the low VTF starting point. He said, somewhat facetiously of course that you can go up high enough to bottom out the cartridge and no harm done.

He also said break in is important too. That over the first forty or so hours, there could be as much as a 3 degree SRA shift as the suspension settles. I usually see 1% in other brand cartridges but clearly break-in plays a role here.

He also said, speaking from the manufacturer's point of view, that before consumers had access to digital microscopes, much guess work was involved in setting SRA and few if any consumers were aware of how far "off" their expensive cartridges might have been. And as Stereophile readers have seen, I've shown some very "off" and very expensive cartridges—far more expensive than these Soundsmiths.

He also reminded me that shimming at the headshell was commonplace back in the days before easily adjustable VTA/SRA tonearms were introduced.

He encouraged owners to shim if necessary and he said it would in no way compromise performance. "Even a business card or two" can easily be used without negative effect.

So, between VTF adjustment, break-in and shimming, it should be possible to achieve approximately 92 degree SRA.

COMMENTS
AndyPrice44's picture

I would like to say thank you to Mikey, Wally and Peter for taking the time to clear this up. This was very informative. I have well over 40hrs. on my boheme cartridge. I'm sure the suspension is broken in by now. I am going to fabricate a shim out of a delrin blank. I will also try to increase my VTF a bit and see how it all plays out.

Andy

AndyPrice44's picture

I got off work this afternoon and made the tapered spacer from a scrap piece of delrin they had at the machine shop. At first, the spacer was too big. I then reduced the height a bit and got it to fit. With the spacer installed I am now having problems with the clearance between the record surface and the cartridge body. I can increase the height of the tonearm but, then I am defeating the purpose of the tapered spacer anyway. If I increase the height I move furthur away from 92 degrees. As it is now, there is just a fraction of space between the record and the cart body. This is with the tonearm level with the record surface and VTF set at 1.35g with a shure guage. If I try to lower the tonearm to get closer to 92 degrees, the cart body makes contact with the record. I will say it does sound a little bit better this way.This may also be a placebo effect. More listening is called for. I think I am out of options at this point. I might request a retip and hope to get a stylus/cantilever assembly that is closer to spec. Thank you to everyone for their insight and suggestions.

pulling my hair out ( what's left of it)

Andy

jjgr's picture

Peter repaired and retipped my Sumiko Blackbird with his top of the line retip option, and it has been one of the best hifi investments I have ever made.  I've been very happy with the sound for several years now.  Also, as has been widely reported on this and other sites - Peter really takes care of his customers and stands behind his work.  I know, because when I originally received my repaired Sumiko, and had it all set up, I noticed a problem with the tip.  Peter graciously agreed to "make it right" for me (unlike Saab for Mr. Fremer) - I suspect simply (or precisely) because that was the right thing to do.  

ianm0's picture

I refer to the photo at the top of this thread. The SRA line is that joining the tips of the two triangles and that usually is not the diamond's line of symmetry. Peter confirmed this in one the threads in Audioasylum forum. Are you guys using this line for measurement?

The angle between the SRA line and the cantilever is 100° in the above photo. If the SRA is at 2° (with the vertical), the cantilever is then at (100 + 2 - 90)° = 12° with the horizontal.

Provided one can take a photo as the one shown, setting the SRA using the the cantilever is a lot easier. One may still wonder if change in VTF will change the cantilever angle. It won't - I have observed the microsope image on screen while I gently pressed down the cartridge body. The body is lowered while the cantilever angle hardly changes.

Another question is how constant is the aforementioned 100° angle? My observation is not very. I have two cartridges Peter worked on - both with Ruby cantilever and OC-CL stylus: 119° (edit 109°) vs 106°. I can see very different cantilever angles on my two cartridges (edit: see Edit 2012-8-30 below). So I think Peter must have taken this difference into account when he mounted the cantilevers. It would be nice if Peter in the future will specify this piece of info with every job.

Edit 2012-8-30: The angle 119° should be 109° - still a 3 deg difference between samples. For this rebuilt, the vast difference in cantilver angles is greatly reduced from 31 deg to 21.5 deg by lowering the arm by ~4 mm, contravening the geometric rule of 4 mm = 1deg. (I still have the photos to verify, so not a mis-reading error.) I took the pain to main the same VTF throughout since it affects VTA too. Don't have the slight inkling why. Possible explanation: the suspension is too old or some other reason.

Retipper's picture

Dear Andy;

Thanks for posting here. As was said above; we take great pains to make sure every piece that leaves here is accurate. I personally do not build the Boheme, but leave it to my very accomplished staff to do that.

In the birth of any manufactured item, there can be any number of things that go wrong; this is especially true of miniature items. Suppliers can make errors, as can assembly folks. I like to think that the huge amount of time I have spent with my employees training them is a plus, and that as a result, they do fine work. That said, in manufacturing it only takes one error to make a prdoduct that is less than absolutely perfect. In making cartridges, one tiny error. We rely on many companies, people, fixtures and processes in the dynamic chain of events - all which must go perfectly to replicate phono cartridges from their manufacturing master samples.  

As was said above - I take great pleasure in taking care of my customers should any issue arise, almost more so than personally building cartridges and my other products. Please arrange to ship this cartridge back to me using our website link on the top of our page ("Retipping")  - you need to register once - and we will take some measurements here, and correct it if need be.  Please include in the box all documentation from this blog. 

It was said you were getting extended top end - please see if the booklet with your cartridge indicates if this is an UNCOMPENSATED cartridge, which requires 300-600 pf loading to smooth out the top end. That could be one of the major contributing factors for a peaked top end. I can also measure that here when it arrives. I am travelling till Sept 5th, but will address it immediately (as I normally do with returned Soundsmith products) upon my return. 

Peter Ledermann / Soundsmith 

AndyPrice44's picture

Peter

Thank you for your detailed response. As was indicated in our previous e-mails, I will be sending my cartridge back to you when you return. I do understand that complications can arise when dealing with manufacturing on a microscopic level. I know that in reality there will be slight inconsistencies in any product this small. In all honesty, I have enjoyed my boheme cartridge over the past year I have owned it. I wasn't the person who described the brightness in the top end. My cart is an 100pf internally compensated model. The boheme sounds fairly neutral and clean to my ear when I have my phono stage set to 47k loading. I have no complaints about the sound. I have enjoyed our past conversations and your help along the way. I will be in touch when you return. Thanks for good customer service.

Andy

schrickwarren's picture

I read with great interest about a problem , I was unaware that I had, and now haveing checked..  I appears the the SRA is in the neighborhood of 96 degrees.  This is on my Ortophon X1-MC, that has the ruby cantilever and fine line stylus, installed by Peter Ledermann.

So I tried Peter's recommmendation of business cards.  I started with 3 thicknesses, but that was too much.  I then went to 2 card layers, and that was the "Goldie-locks" factor..  But, as many have related the back of the cartridge now hit the record.  Hmmm, What to do!!  The cartridge material semmed soft (not titanium), so I tried filing the back of the cartridge body with a diamond nail file.(make sure you put on the stylus guard, if you have one) .  It filed very easily and with care and polishing, it looked as if it were made that way.  When re-installed in the arm, I had more clearance than before shimming, and it played perfectly.

So, did I notice a difference??? Trying to cancel any placebo effect in my mind,  I heard a general overall improved clarity, and air around the instruments.  Improved highs??  I can't tell as my ears are 76 years old.  But, the work involved, was justified, as there was a significant improvement.

If anyone is willing to try this .  Start with 2 thicknesses, even if it is not exactly 92 degrees, it is very close

Warren Schrick

AndyPrice44's picture

I would like to add that I have also noticed a slight but, noticeable improvement in sound. I took a different approach than warren and chose to make a tapered spacer instead of altering my cartridge body. I still couldn't get a 92 degree SRA but, it is alot closer than the 96 degree rake I had.  After several more hours of listening. I can hear a slight increase in clarity and overall detail. It also seems as if the bass is more defined as well. Getting correct SRA with a contact line stylii is definately worth spending the time to fine tune it. Thanks to mikey and the other members here for making me more aware of this.

Andy

audiof001's picture

Thank you, Peter, for teh informative response. I enjoyed meeting you at the NY Audio Show - your room's sound was truly memorable. It was an inspired choice on my part to have had you rebuild my Benz Glider cartridge with yoru best offering. What a nice sound that cartridge has with your cantilever. Even if I can't reach the target angle on my Well Tempered Turntable that MF suggests, the cartridge sound quite nice.

avrcguy's picture

So I've had my VPI Classic 3 with 3D arm, and Soundsmith Aida cartridge for just over 3 months. The table was setup by a reputable dealer, so I really haven't messed with the setup much. Now that I have some hours on it, I figured the cartridge had probably adequately settled to start fine tuning everything. I set the the VTF to the recommended 1.3g, and setup the digital microscope. My software didn't allow me to draw the measurements on the photo, but I came up with a SRA of approximately 115°! Will someone please tell me I'm seeing this wrong, or I've made some stupid mistake. Because I think I'm going to be sick.

EDIT: So I figured I should try the suggestions above before I get scolded. I lowered VTA, and increased VTF to 3.25g. This is more than I'm comfortable with, and the cartridge is fairly close to bottoming out. Even with those extremes, 106° was the best I could achieve. I sure hope I'm looking at this wrong.

Any thoughts?

Michael Fremer's picture

Yes, you are missing something. This is a Geiger/Replicant type stylus. The contact area is the back of the stylus, not a line drawn through the center of the stylus as it would be were it a line contact stylus. Draw the software line down from the BACK of the stylus to the record and then across. It looks like you're pretty close to correct.

avrcguy's picture

So my paranoia led me to remove the arm from the table so that I could get closer shots of the stylus. This picture obviously confirms your assessment.

It does however make me wonder if I'm misunderstanding something else. On Soundsmith's specs for this cartridge it states that the stylus is a "Contact Line Nude, 0.100mm SQ". So is the "Geiger/Replicant" you mention just a style of "Contact Line", or was this cartridge just built wrong and/or different? I guess ultimately I'm just concerned if this is somehow inferior to the seemingly more popular contact line, and if I should be raising an issue over this.

Thanks a lot for your help Michael. It is much appreciated!

jjgr's picture

I think i have the same type of stylus as avrcguy, but am also not sure whether i should be measuring down the center or the angle down the "front" (i.e. right side of the stylus as shown in this picture)? Any tips would be appreciated. Thanks!
/Users/jjgr/Desktop/Jason/12-25-14 PM - clean best.jpg

jjgr's picture
Michael Fremer's picture
The angle is that made by the stylus rear vertical line and the record surface (on this particular stylus profile)...not the center of the stylus...
jjgr's picture

Not to be an idiot - but this stuff is tricky (at least for me) - is the line to measure the line on the "face" of the stylus that "sees" the vinyl groove as it spins. In other words, in the picture linked below - is it the angle on the right hand side of the image of the stylus tip? (Which is approximately 76 degrees - indicating i would need to raise my tonearm somewhat considerably to hit 92 degrees!)

http://www.analogplanet.com/content/stylus-12-25-14

This is a fun project - thanks for all of the help and information!
Best,
Jason

Michael Fremer's picture
http://www.analogplanet.com/content/measuring-sra However, I can't tell if your stylus is identical to the Replicant/Geiger. It may have an additional cut angle at the bottom....
jjgr's picture

Mine is a "Optimized Contour Contact Line Diamond" installed by Peter at Sound-Smith. Would that be measured the same way as the Replicant/Geiger?

I raised the tonearm quite a bit higher than what i've been listening to for years (about 8mm) - to try to get close to 92 degrees:
http://www.analogplanet.com/content/optimized-contour-contact-line-diamond

This looks to be about 82 degrees, measured like a Replicant/Geiger. First impressions were that the sound wasn't as "full", the highs seemed a bit hashed and the lower end was definitely thinner sounding. I may see how much higher my Pro-Ject tonearm (older one-piece aluminum style) can go before I top out of the two grub screws that hold it in to see if i can get that last 10 degrees. Seems quite steep though. Maybe i'm measuring the wrong angle - or need a better image to measure?

jjgr's picture

http://www.analogplanet.com/content/sra-max-tonearm-height

I measure 87 degrees - ?

The photo's a beauty - if i do say so myself - even for a $39 USB microscope.

jjgr's picture

So, after tooling around quite a bit on this, it looks like for my set-up i can achieve 92 degree SRA by shimming the cartridge or a combination of shimming and raising the tonearm height (tonearm height isn't sufficient alone to reach 92 SRA). However, increasing SRA causes the stylus tip to move closer to the tonearm base - thus reducing the effective length/overhang setting. Effective length/overhang is adjusted for by "pulling" the cartridge forward in the tonearm slots. However, in my setup, when SRA is at 92 and the cartridge is pulled as far forward as possible, my effective length/overhang is too short (verified using the arc provided on my Mint Best Tractor). I've returned the tonearm height to be parallel with the turntable, pulled the cartridge as far forward as possible, and shimmed to 92 SRA (i think, see picture link below). I would say the deviation from correct effective length is about 2 mm on average across the arc of the record. I've listened to a few test tracks with this set-up and like the sound - but am wondering whether incorrect effective length/overhang will damage my stylus and/or records.

countvinyl's picture

Looks like this bit bout adding shims in the head-shell is because this cartridge stylus can't get close to the target 92 degree (2 degrees left of vertical?) in a Vpi arm even when lowered all the way at the back. That seems crazy and I don't imagine Vpi expected the arm to be used that way. I use a Sound smith Vpi zephyr with elliptical stylus in JMW 9. I met Peter of Soundsmith once at show in LA and asked where the arm tube should be compared to level and he said slightly raised at the back but to experiment and make my own assessment. The elliptical stylus is more foregiving of SRA I find.

It would be great if cartridge and turntable makers could provide general guidelines for beyond VTF for popular tonearms like Vpi, Rega etc. Grado has always said that when the front face of the body is 90 degree vertical on all their cartridges, that is the correct SRA. Let's hope their stylus mounting supports that. From Ortofon to Benz that I have had there were no guidelines. For Sumiko Blackbird (still my fav but it is out of service do to age) their excellent manual said to start with arm lowered at the back and raise a bit at a time to dial-in. Most of us won't buy a digital microscope and will want to do the best we can by eye and ear.

countvinyl's picture

Looks like this bit bout adding shims in the head-shell is because this cartridge stylus can't get close to the target 92 degree (2 degrees left of vertical?) in a Vpi arm even when lowered all the way at the back. That seems crazy and I don't imagine Vpi expected the arm to be used that way. I use a Sound smith Vpi zephyr with elliptical stylus in JMW 9. I met Peter of Soundsmith once at show in LA and asked where the arm tube should be compared to level and he said slightly raised at the back but to experiment and make my own assessment. The elliptical stylus is more foregiving of SRA I find.

It would be great if cartridge and turntable makers could provide general guidelines for beyond VTF for popular tonearms like Vpi, Rega etc. Grado has always said that when the front face of the body is 90 degree vertical on all their cartridges, that is the correct SRA. Let's hope their stylus mounting supports that. From Ortofon to Benz that I have had there were no guidelines. For Sumiko Blackbird (still my fav but it is out of service do to age) their excellent manual said to start with arm lowered at the back and raise a bit at a time to dial-in. Most of us won't buy a digital microscope and will want to do the best we can by eye and ear.

countvinyl's picture

Sorry last comment got duped, so I will ask another question. My challenge with vinyl is surface noise, even and sometimes particularly on pricey audiophile pressings. Doug McCloed Come to Find case in point. Great record and recording but disappointingly noisy after I have played It maybe 30-40 times. My new policy is to digitally rip expensive records after the 1st couple of plays. Never understood If SRA, offset angle, or azimuth had greater impact on surface noise rejection?

orangeaudio's picture

I was worried too, but the problem is to see the correct edge.
Both pictures show the same needle.


http://orangeaudio.de/temp/mimc2.jpg
http://orangeaudio.de/temp/mimc_sra.jpg

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