INNER GROOVE DISTORTION


Seasons greetings! I have a VPI Prime Sig. with a Soundsmith " The Voice " cart. and am having an issue with inner groove distortion. I don't use anti-skating, just twisting the cable going to the junction box. I will be upgrading the arm to a Fatboy soon and when the tech comes to set it up we will address the issue. On some records I can't listen to the last song! Frustrating, any feedback will be appreciated. Also, have Pass XP-25, ARC Ref 3 and 75 with ML ESL11A's. Thanks.
joeyfed55
Ct, You wrote, ""anything" that is going to impede the stylus travel, be it tonearm setup, alignment, antiskate, condition of record - will be heard more readily at the end. Another challenge for the vinyl audiophiles."
Can you be more clear about what you wanted to say here? Because in some sense, none of the factors you list, maybe apart from dirt in the grooves, would be expected to impede stylus travel.  I believe the traditional meaning of the term "Inner Groove Distortion" refers to the fact that, as you mention, the LP has to crowd musical information into an increasingly shorter linear path, as the LP runs out of grooves. (Plus there is usually more tracking angle error on the innermost grooves, unless you're using Stevenson alignment.) There are analogies to this phenomenon in tape and digital reproduction as well.  Tape running at 15 ips and using half a track would be expected to provide much higher fidelity than the same tape running at 7.5 ips an using only one-quarter of a track, etc. And this is also why in theory 45 rpm sounds better than 33 rpm.  I'm sure you know this, which is why I wonder what you are saying above.
I must confess to have been very proud when I succeeded to
get 90 microns ''pure'' (without any buzz) with my (then) Ortofon
MC 20 with the help of my test record. The part about ''tracking
ability'' test. But then I come across the warning by Van den Hul:
''no antiskate is better than too much antiskate''. To get those
''impressieve'' 90 microns I needed to increase antiskate force.
So whenever ''buzz'' appeared in the right channel I increased the
anti skate. But thanks to Van den Hul I still have no idea how
much anti-skate is ''allowed''. So I use 0,5 g force for each cart. 
Almarg
Hopefully you will then be able to find an amount of twist that results in minimal or no deflection at all positions on the record.

@almarg

Hi Al - there are not multiple twisting increments permitted with the design. It’s more like .....are you going to do One twist or nothing.
To explain. If you look at the wire loop in the attached pic link. my former VPI JMW 12 tonearm.

https://photos.app.goo.gl/M2KjNpVbyxNCbbHM6

imo - Unless VPI has changed the materials used (wire and teflon coating type) in later wire loops.... then there is not a lot of twisting that can be done here. The wire loop is of a "construction" that provides for push back when "not" twisted. So anti-skate is there without any twisting. In addition to this, the springing action of the wiring provides for increased anti skate action as the loop is "closed" towards the end of the record.

I assume, when VPI added in an anti skate mechanism in later years, the amount of AS needed, would be below minimal, due to the anti skate action of the wiring itself.

From what I recall adding in even one twist of the wire for me - produced problems as other posters on this thread indicated. I also wonder how many of those taking shots at this tonearm / wiring technique - ever owned a VPI uni pivot tonearm ?

Cheers Chris

Joey's problem is probably due to several factors conspiring against inner groove tracking.
It does appear people tend to underestimate the skating force. If you think you are going to counter it with twisted 24 gauge wire at the fulcrum of a 9 to 12 inch lever arm you might as well try to stop a car rolling down hill by standing in front of it. Defeat your anti skating device and try playing a blank side. I would suggest putting an old worn out cartridge in first. Play a record and gently defeat your anti skating device by lifting it up and watch carefully to what happens to the cantilever. It will deviate a millimeter or two to the outside as the stylus leans heavily on the left channel unloading the right channel. Play a Hi Fi News anti skating set up groove and listen to what happens to the distortion in the right channel when you defeat the anti skating device. I might further add that in regards to vinyl playback distortion = record wear. 
Simonmoon, I highly recommend getting the new 3D printed 12" gimbal tonearm with anti skating by VPI. I do think this would make more than a trivial improvement in your vinyl playback given your current situation.

Mike
lewm - Because in some sense, none of the factors you list, maybe apart from dirt in the grooves, would be expected to impede stylus travel.


@lewm

"some sense" ??

ok here we go - hang on ....

In "some sense", when a record is cut, one spiraling, varying, groove gets created.

In "some sense" the best vinyl re-play design we can re-create, is to duplicate the record cutting process, but in play mode ,with a stylus that resembles the cutting stylus.

In "some sense" - we cannot eliminate the friction created by the play stylus against the groove walls as this is needed to start production of the signal. We do know that laser vinyl playing never took off.

So "some sense" therefore says...

Anything, and all things, that affect the travel through this groove in a way different from the way it was cut...... that creates more friction.... than the friction the stylus produces, if it was travelling the groove AS CUT........ will impede stylus travel.

In "some sense" this includes an improperly setup and or bad design linear tracker tonearm.

In "some sense" this includes the extra friction caused by a pivot tonearm’s behavior to push inside due to the cocked cartridge position.

Hey
I have talked to Peter at Soundsmith about uneven wear on carts that get sent to him for repair. This is real. Now imagine test driving a brand new car down a very narrow road, and the car had one bad design feature..... it constantly pulls to the right. 8^0

In "some sense" this includes the use of anti skate to fight off this inward tendency thus producing a constant tug of war. This impedes stylus travel.

Empirical observation based on ^^^^.

If you had ever heard a properly set up air bearing linear tracker play the inner grooves cleanly in your own space, then you would of heard this Pivot tonearm "tug of war".

In "some sense" there are times in this audio hobby, when it is not until you "remove" a problem to understand, it was there to begin with.

In "some sense " the record sounds better at the beginning than the end" (famous saying by any owner of a Pivot arm which includes me)

"some sense."