Rega, AT33PTG/II, Guns N' Roses and IGD

Hi everybody.

I recently bought the Audio Technica AT33PTG/II cartridge for my Rega RP3 (with an RB-303 arm), and I've been having some problems with inner groove distortion, mostly on the two Guns N' Roses' "Use your Illusion" albums.

I have included sound clips at the end of this post. I have recorded most of the changes that I've tried.

I haven't used the cart much yet, so I've only managed to find a few more albums with inner groove distortion, one of which I've included as a sound clip (although it might just sound muffled as opposed to distorted).


Before I go into details I will state the objective of this thread:

The (online) seller has said that they could send me another unit to see if that would fix the problem, but if I can figure out a fix on my own (if the cart is not the problem), then I might as well save both me and the seller the hassle (and the postage costs).

So my question is: Can any of you suggest a fix that I haven't already tried yet (outlined below)? Maybe there's something I just didn't think of.

I've been going crazy over this for a couple of weeks now - as you can see there are a lot of details to report!


What is a bit odd about all this is that I downloaded Pbthal's rips of the two Guns N' Roses albums, and despite different equipment, the beginning of the album, "Right Next Door to Hell", sounds identical (as you will hear in the sound clips), but especially the last song on side 1 of "Illusion I", "Perfect Crime", is heavily distorted on my setup. On Pbthal's rip, there's only a slight bit of distortion. It's a loud, aggressive song, so distortion should be expected. I also downloaded a different rip done with a Zyx cartridge on a Pioneer, and that also only has very slight inner groove distortion.

The distortion is most noticeable in the part of "Perfect crime" that starts after 48 seconds.

However, on the song "My world" on "Illusion II", which is also a loud and aggressive song at the end of the side, my recording sounds the same as on Pbthal's. "So fine", also at the end of a side, also sounds identical, but that is a more mellow song. And then "Breakdown", also at the end of the side, sounds a bit more distorted, or at least muffled, on my setup. These are included in the sound clips as well.


My gut instinct tells me that the problem would be one of the following things:

* The cart is faulty.

* The alignment is off.

* The records, although looking to be in practically perfect condition, have been played with a bad cartridge, and therefore it's simply just the records that are at fault, and I can't fix it. I did try to clean the record though, with no effect.

* My tonearm (RB-303) simply can't track the inner grooves properly.

* The azimuth is off.



Before I go into further details, I should probably mention that I'm the sceptic type. I've considered buying the Mint Protractor, but despite all the glowing reviews I still haven't seen a single before/after sound clip being posted, and then the stories are essentially no different than the glowing reviews of a $5000 power cord. I have, however, found that alignment does indeed matter, and I've passed blind tests between different alignments, also blind tests of different VTA settings, on two different cartridges. On some cartridges alignment makes more difference than on others in my experience. So this is why I'm still considering buying the Mint Protractor. But I would like to see/hear more proof than just stories .



So here's what I have tried to adjust so far:


* Alignment: I have used a magnifying glass and light to get this right, and I also bought a jeweler's loupe. I have used the printable protractors from Vinyl Engine by Seb and the Conrad Hoffman printable protractors as well. I've tried Baerwald and Stevenson by Seb and Loefgren A and B by Conrad Hoffman. One thing I found out is that Stevenson by Seb actually corresponds to Loefgren A by Conrad Hoffman, and Baerwald by Seb corresponds to Loefgren B! I also found that the angle of the cartridge/cantilever on the two different protractors were markedly different. All this was quite surprising. After printing I checked both with two different rulers. But it's possible that something has gone horribly wrong while printing.

I have also tried pushing the cart all the way forward, pull it much further back, angling it a little towards the label, angling it a little more, angling it a little less, putting it completely straight in the tonearm, angling it to match the protractors, angling it a bit more or a bit less than the protractors. And lastly, I found a close-up picture of someone with an RP-8 who used the same cart, so I tried aligning the cart the same way as in that picture.
None of this seemed to change anything.

* Anti-skating: I've tried pulling it all the way out, pushing it all the way in, and many positions in-between. No effect.

* Tracking force: The recommended tracking force is 1,8 to 2,2 grams. I've tried going from around 1,3 to around 2,6 grams. No change.

* Azimuth: When looking at the cantilever it seems straight, but it's difficult to tell (I've seen bent cantilevers before). I did, however, notice that the cantilever bends a little to one side when it touches down on the record. The only way I could get it not to bend was to put a lot of paper washers on top of the cartridge on one side or under one of the screws that attaches the arm to the plinth. But it looked completely crazy. So, I think this makes it more likely that the cart is the culprit rather than the azimuth. I increased the numbers of paper washers gradually and then listened. I tried this on both sides of the cart. I also tried putting the paper washers under each of the three screws between the arm and the plinth. I also used a bubble level on top of the headshell as well as on the plinth and platter, and the level was completely perfect.

Here's a picture that I took while playing that actual GN'R record:




* VTA: I've tried raising the arm with thin metal washers and bolts (around 1, 2, 3 and 6 mm), and I've "lowered" the arm by putting another record or two under the record mat. My experience tells me that VTA gives more more or less treble, so it wouldn't affect distortion, and not surprisingly it didn't get rid of the distortion.

* As for my tonearm, this could be a possibility, although the arm has a great reputation. It should be noted that Pbthal uses a linear arm, which should lower IGD. However, the rip with the Zyx cartridge was done on a Pioneer PL-7L, which also has a pivoted arm.
Last year I tried out a different cart, which didn't sound like I expected (lack of treble), and I then put it on an acquaintance's old Thorens TD-321 with a Mørch DP-6 arm. It sounded more or less identical on that one, but slightly better on my setup (I made a recording). Also, this cart was actually an older model, and the shop let me do recordings of the new model on their setup (and they set it up), and I liked the newer model even less (even greater lack of treble). They said that the new model sounded exactly like it was supposed to.
So I think my tonearm is okay .



And finally, here's a link to the sound clips:

MEGA


All suggestions are welcome !

Thanks!

 

Number one: If the records are used and the previous owner shaved the inner grooves off with their cart there is nothing you can do. This is much more common than most people know.

Do you own a test record? If so, which one?

Re: alignment, I would use the Conrad Hoffman program to generate a Stevenson protractor. Try both the DIN and IEC groove spacing. I believe one or the other is optimized for narrower inner grooves. Use that one. Can't vouch for "Seb's Stevenson" but it sounds way off if you are finding it matches some sort of Lofgren alignment.

Re: the tonearm, do a simple test. You'll want to remove records from the TT and put the stylus guard on first. Float the tonearm to zero balance with zero antiskate. Gently tap the tonearm towards the spindle. Do you encounter any resistance whatsoever? Wiggle the arm back and forth and see if you can feel anything binding. If so, it may be the tonearm wiring in which case you'll have to try to adjust it.

Re: azimuth, I would not rely on listening tests. Either use a test record to set it up or get a mirror and use the reflection method. For a brand new cartridge, unless the integrated headshell portion of your arm is bent or manufactured improperly *, very little adjustment should be required.

Re: VTA, factory spec is 23 degrees for that cartridge. You can use an acrylic block to get that dialed in.

*Believe it or not, I've heard of this happening occasionally with Rega arms. You can remove the cart and everything then place your level on top to see if the integrated headshell itself is level - it may not be.

 

Can we get a TLDR version?

 

I have that cart on my VPI Scout. I can tell you that I ONLY get noticeable IGD when the record is worn (most common) or it's a pressing issue (I've only encountered this on one or two new LPs including a Yes album that others on this forum noted the same issue with). This isn't what you asked, but you really shouldn't be experiencing this problem with that cart unless the record is the cause.

 

Did you receive a REGA protractor with your table ?
I would align it to Rega standard first.

VTA should not cause distortion, I used 2mm spacer with the AT33PTGII but without spacer I did not experience distortion.
Anti skate also should not cause distortion.

Have you tried other records ? Do you have distortion on those ?

If distortion is on all records, the culprit can be the arm or the cart.

Do you have another cart ? You could purchase a cheap at95 and check if you experience distortion.

1) Eliminate the record by testing other records
2) Eliminate the cart or arm by testing another cart
3) You will have the culprit

 

I have a at33ptgii myself mounted on a td160, I have one record that appears flawless but the at cart cant play due to a locked groove type situation, on my other tables no problem whatsoever. No IGD type observation sorry. I also have another player and cart with another observed record that skips on a spot that my other setups just breeze over.

I have gone crazy chasing these things down with no progress.

My lesson learned, have multiple turntables!

 

The idea of the Mint Best Tractor is that you are aligning precisely the cantilever to the null points and the arc provides positive feedback that the stylus is precisely set at the correct overhang. The protractor is built to the geometry of the tonearm placement to the platter spindle. The mirror is an aid to ensure your eyes are aligned to the null point hatch markings. I own a Wally Tractor which Mint pretty much just copied. It's slightly different than the Mint, but the concept is the same. On P5, the Wally Tractor made short work of aligning the finicky Micro Ridge stylus on my Benz-Micro Glider. Since you can't get Wally Tractors, I would highly recommend getting the Mint. They are on the expensive side. They are probably no better in theory than one that you can print out. But the grooved arc and the mirrored background do have benefits over a paper one. Are they worth $130? I don't know. I think so. I didn't pay that much for my Wally Tractor. But considering a Fieckert is $250 and doesn't rely on you finding the tonearm pivot, I think its the better option.

 

Used records–even that appear NM–can be damaged by previous play with a worn stylus. It is very common. My guess? If you found a sealed copy of this record and played the same track it would sound better.

It could also be the way the record was cut, or another hardware issue, but I wouldn’t fret over a record that wasn’t at least new before you played it.

 

Don’t know about AT, but many carts need spacers on Rega decks. Otherwise the Rega should be pretty much plug n play. Kt88 is your Rega guy here.
Have you tried other albums ? I forget but isn’t the GNR rather long ?

 

Before I respond to anything else:
Did anyone think about how the cantilever bends a little bit to one side when touching down on the record?

 

Do you mean when the record is spinning? It is a fairly high compliance cartridge at over 20cu so will easily show the effects of skating force, and that makes it pretty easy to lock in the best anti-skate setting for minimal deflection in either direction. If you mean it leans when lowering on a stationary record with anti-skate set to zero, then that's not good. Below is mine with anti-skate set to zero, no change as it settles on the stationary record ...

 

If the problem is only on this record, then the record is probably at fault. It sounds like the Op has tried just about everything humanly possible with one cartridge and one record.

The problem here is that this approach does not do anything to rule out the record as a possible source of the problem if only one record is being tested. The other problem is that in the extremely unlikely event that the cartridge is at fault here, something else which has not been done is to swap-out this cartridge for another cartridge. By this I mean ANY cartridge, not a another new sample of this cartridge. If the second cartridge has the same issue, then you can be nearly 100% certain that the record is at fault.

Used records are a craps shoot. Even some vinyl which looks beautiful which was played with a badly-worn stylus a few times may have been irreparably damaged. So again, the record would be the first thing I would suspect here, not the last.

 

I agree the Mint Tractor worked very well and the genius of the mirror ensures your sight perspective. If you look close at my avatar you can see how it works. The lighter black bars in front of the cantilever are the reflection and if you move ever so slightly to either side you can see it become misaligned with the darker null point hatch markings.

After I learned how to precisely align my rig using the Best Tractor many records that had subtle distortions sounded smooth don't know if it was IGD but they improved none the less. One thing about the Mint it is made for your TT and arm configuration change either it will likely not be a correct alignment.

Also using this type of tractor you align the cantilever not the cartridge body. My XX2 is bent to the left a little but has always sounded good.

 

Yes, that's exactly what I mean .
I didn't manage to take a proper picture of my cartridge, but it bends a little bit to the side when it touches down on a stationary record (or protractor) when the anti-skating is set to zero. I was wondering if this means the suspension is broken. I haven't had any accidents with the cart, so I'm assuming that it was that way from new, if the cart itself has a problem.

 

Thanks for your suggestions. I tried both the azimuth suggestion and the tonearm suggestion.
First the azimuth suggestion:
I removed the cart and counterweight and lowered the arm with the lever. The bubble level on top would of course be un-leveled when the arm was lowered enough, so I held the arm to the correct level with my hands, and it was completely level, just like the picture I posted in my original post:






As for the test where I float the tonearm, I made a video, which I thought would be the best idea. The micophone on my camera is a bit noisy, and I mumble a bit too much, but I hope you can hear what I'm saying. As I say in the video, I think this behaviour from the arm is normal for Rega arms. I tried turning the tracking force to more than 3 grams, which I've read is supposed to disable the spring, but that yielded the same result, so I didn't make a video of that.

 

As for the Mint Best Tractor, I also get the impression that it's the best protractor around, which is why I'm considering buying it.

And yes, the record might be the culprit, as I suggested in my original post. A local hi-fi shop has been helpful before, so I was considering asking them if I could play the record, and perhaps mount the cartridge, on one of their turntables.

Thanks everybody for your comments and suggestions - I hope we can keep this thread going and hopefully find a solution .

 

A different stylus might touch the grooves in different places and avoid a possible damage made by the previous owner.
However, you don't have a removable headshell and I wouldn't substitute the cartridge, which is well regarded, because of these records, which I suppose are commonly available. If the problem is only with these records, I'd keep the cartridge and try to substitute the records.

 

Did you actually test other records ?

 

Just a short spot-listen to one track and a first impression, I like pbthal's rip of "Breakdown" It's clean and has depth of image, can listen into the music effortlessly. "My rip" of "Breakdown" sounds alright, very listenable but I do hear some IGD going on. The image is more two dimensional... more later.

My setup is near field, my own built monitors (modified Celestion as I am a speaker builder) powered by a modest Pioneer SA-500 (good sounding little amp) so- I have more of a sound engineer's presentation.

I feel initially that perhaps your turntable setup may not be up to spec, (not hearing any channel imbalance, nor any glaring fault... maybe nothing wrong) -or- simply your expectations require an equipment upgrade. Guns N Roses by nature of the music is very bright, and will be challenging to track, especially at the inner groove. It takes a really good rig to play bright and loud program at the inner groove. I do believe many (not all) vinyl lovers/ audiophiles have not experienced what vinyl sounds like when tracked well. When everything is just right, it's out of this world!

 

Thanks for listening, Fringe. If you listen to "Right next door to hell" you'll hear that my rip sounds like Pbthal's, whereas "Perfect Crime" is very distorted on my setup.
At the moment I think the most likely answer is that the record is ruined or that the cart is faulty, since the cantilever bends a bit when touching down on a record (as mentioned earlier).

 

As mentioned in my original post, I have already tried lowering and raising VTA.

 

Test record: I only have the Ortofon Pickup Test Record (catalogue numbre 0002), but I doubt that one would be useful here.

Alignment: I would actually say that it was the other way around: The Conrad Hoffman protractor seems to be off, as Baerwald (Loefgren A) matches Stevenson on Seb's protractor. But it's possible that I've made a mistake when printing the Conrad Hoffman one. I was in touch with a forum member who said that he had to push the cart almost all the way forward for a Baerwald alignment, which was my experience with Seb's protractor as well, whereas on the Conrad Hoffman one it was further back.

 

The Conrad Hoffman program is very accurate but it's garbage in, garbage out. If you input the wrong numbers it won't work. Likewise, print to scale wrong and it won't work.

 

Of course .
Did you by any chance have a look at the video about my tonearm that I posted for you above?

As for the protractor, it looks like this, and I checked with two different rulers afterwards, and I also measured the pivot to spindle distance as best as I could.
I tried to insert the photo a million times but it didn't work (I don't know why), so here's the link instead (this is Baerwald/Loefgren A):

Imgur

 

I tend to agree with others that it may well be worn vinyl that is causing IGD issues here.

Words of caution if you are still considering the Mint Best protractor -

• You need to measure actual P to S very accurately and give that measurement to Mr Yip, not just 'Rega 222mm' (on an old RP6 of mine, it measured 221.5mm and therefore that is what I specified, plus exact measurements of the spindle using a vernier gauge). With Rega arms you also need to 'find' the exact arm pivot point & the Mint needs these levels of precision prior to manufacture if you are going to get the true benefit (a Feickert is much more versatile and easier to find the unmarked pivot point on a Rega arm).
• If you plan on upgrading your turntable in future then this may not be a wise investment as it will only be accurate to your current Rega model, maybe not even to another within the same brand given slight manufacturing variances.