P-Mount woes (crazy skipping and looping)

[RZ1]

About a week or so ago, I got myself a JVC AL-A158 P-Mount turntable with an Audio Technica 1001 cartridge. Specs wise, it was quite impressive (doubly so considering it is a cheap looking belt drive). 0.04% wow and flutter, 67db signal to noise ratio. When I tested it's speed, it was pretty much dead on perfect at both 33 1/3 and 45 rpm. It had a broken stylus though, so a new one was ordered soon after, and it arrived today (26 December). I was really exited to test it, and when it is working well it is great!

But then I found it had a glaring weakness- an arch nemesis: thin, light, mildly warped and somewhat bass heavy 1980s pressings. Amy Grant's "Unguarded" album was one such pressing, for example. When playing it, the tonearm would first skate across the first few beginning sections of the record and then eventually get stuck looping one part again and again, unable to get past it. No matter what I did (cleaning the record, reinserting the cartridge, changing the platter mat) it still skipped and looped. This frustrated me to no end. And this is on a new stylus! That said, other records, like the ones from Enoch Light's Command record label, played fine with no issues. Also, I don't think this is because of vibration. The speakers are on a mat, separate from the desk the turntable is on. Not to mention the skipping almost always happened on the same tracks in that LP, at almost the same parts.

My main turntable up to this point has been the Crosley C8, which I have moved to a different setup because I wanted to experiment with a P-Mount turntable in my main setup. It uses an Audio Technica AT3600L cartridge I set to track at 3 grams. This turntable breezed through that same Unguarded album like it did with any other record I played on it- no skips, no loops.

This got me thinking: Perhaps this is why no one makes P-Mount turntables anymore? I've heard that the T4P standard's mandated 1.25 grams of VTF and 6 gram cartridge often did poorly on warped records, but I thought it would at least do well on mildly warped records. I wasn't expecting it to perform that poorly. After all, aren't most old/vintage records at least somewhat warped to some degree? What are your thoughts?

P.S. Both cartridges (the 1001 and the AT3600L) are using a .6 mil conical stylus. I'm debating whether or not an elliptical would do better on a light VTF for the 1001. Also, I'm not using a record weight on either turntable- I don't have one.

 

[Decibel_116]

About a week or so ago, I got myself a JVC AL-A158 P-Mount turntable with an Audio Technica 1001 cartridge. Specs wise, it was quite impressive (doubly so considering it is a cheap looking belt drive). 0.04% wow and flutter, 67db signal to noise ratio. When I tested it's speed, it was pretty much dead on perfect at both 33 1/3 and 45 rpm. It had a broken stylus though, so a new one was ordered soon after, and it arrived today (26 December). I was really exited to test it, and when it is working well it is great!

But then I found it had a glaring weakness- an arch nemesis: thin, light, mildly warped and somewhat bass heavy 1980s pressings. Amy Grant's "Unguarded" album was one such pressing, for example. When playing it, the tonearm would first skate across the first few beginning sections of the record and then eventually get stuck looping one part again and again, unable to get past it. No matter what I did (cleaning the record, reinserting the cartridge, changing the platter mat) it still skipped and looped. This frustrated me to no end. And this is on a new stylus! That said, other records, like the ones from Enoch Light's Command record label, played fine with no issues. Also, I don't think this is because of vibration. The speakers are on a mat, separate from the desk the turntable is on. Not to mention the skipping almost always happened on the same tracks in that LP, at almost the same parts.

My main turntable up to this point has been the Crosley C8, which I have moved to a different setup because I wanted to experiment with a P-Mount turntable in my main setup. It uses an Audio Technica AT3600L cartridge I set to track at 3 grams. This turntable breezed through that same Unguarded album like it did with any other record I played on it- no skips, no loops.

This got me thinking: Perhaps this is why no one makes P-Mount turntables anymore? I've heard that the T4P standard's mandated 1.25 grams of VTF and 6 gram cartridge often did poorly on warped records, but I thought it would at least do well on mildly warped records. I wasn't expecting it to perform that poorly. After all, aren't most old/vintage records at least somewhat warped to some degree? What are your thoughts?

P.S. Both cartridges (the 1001 and the AT3600L) are using a .6 mil conical stylus. I'm debating whether or not an elliptical would do better on a light VTF for the 1001.

It has nothing to do with being a p-mount style. This model looks like it was made by Technics for JVC. Probably a rebadged SL-20. It is a much better turntable than the Crosley. The problems you are experiencing could be simply be related to vibrations from the bass content in the music. Proximity to the speakers could most definitely be issue. I have owned (and still own) many different p-mount style turntables. I have never had this issue with any of them. If you are having these kinds of issues, something about the location and/or setup is off. Technics sold millions of these things. This is not normal performance.

Here are a few things you can check. I assume the factory feet are still intact? These help to damp vibrations from the environment. Also, make sure the turntable is completely level (using a bubble level). Have you checked the tracking force with a scale? Make sure the tonearm tracking is within spec. Also, try removing the dust cover. Sometimes the dust cover can resonate and cause vibrations to be transferred to the base. If everything about the setup checks out, test the tonearm bearings.

All other things being equal, 3 grams of force is greater than 1.25 grams of force. It may actually be the only thing keeping that nail into the groove consistently in the current location - especially warped records. That does not mean that the P-mount design is deficient. It means you may have discovered an less than ideal location for a turntable. Regardless of whether your speakers are on mats, the bass sound is air pressure moving in the same environment as the turntable. Isolating the turntable as much as you can from the environment will help resolve resonances. I don't what else to suggest without seeing the turntable's environment.

An elliptical stylus will track better and cause less wear to your records, but will not resolve skipping issues.

 

[RZ1]

Factory feet are intact. I do see the resemblance with the Technics SL-BD20, but the BD20 has worse wow and flutter and better signal to noise ratio. Turntable seemed brand new underneath- it was quite dirty on the top (possibly from years of storage?) when I first got it but underneath the platter and inside the turntable itself was clean- and the grease hadn't dried up. It still even had the plastic sheet the 45 rpm adapter would sit on (on its holder) when it was brand new, and that adapter seemed to have never been moved from it's original position. Auto return doesn't work properly, but that's an issue I can live with- it doesn't bother me that much. I checked to make sure the tonearm wasn't rattling in place- it was as solid as the C8's, so I don't think there's anything wrong with the bearings.

I have used other turntables in that same location- the C8, a Pioneer PL-990 (AT-LP60 clone), and a Kenwood KD-291R (long gone- no longer have it. Notably, it's vibration dampening was terrible. I experienced very similar skipping issues when I was using that, despite it using an AT3600L with a factory set VTF). Out of these three the C8 was the only one that never really skipped on any records, though it did occasionally have looping issues with certain records (that vary wildly. All clean as I could make them, but I've seen looping on seemingly non bass heavy songs) that were solved by briefly switching off the anti skate. It was also the heaviest of the bunch with an MDF plinth so maybe that played some role in vibration dampening (along with the increased tracking force).

I'll see if removing the dust cover helps. I've never removed it whenever I played records- always kept it in an open position. Maybe that thing vibrating while hanging up there is causing the skipping? I don't know. This is the first really light tracking turntable I've ever got so I don't really have anything similar to compare it to. I'll check level later (what I do know is that the shelf it is on is most definitely NOT level (the wood is warped). I usually sat it on top of my Onkyo CD changer (that isn't on at the same time as the turntable but does have a smooth and level surface) for added stability, but then again that CD changer is also on that same warped shelf). Also, the stylus I'm using on the Audio Technica 1001 cartridge is still brand new, so it may need more time to break in. No I don't currently have a scale, but like I said, besides certain specific records, it tracks well most of the time and there doesn't seem to be any way of adjusting the VTF. I'll also try playing a problematic record while just using headphones. If it doesn't have any problems I will know then.

 

[lini]

(...) What are your thoughts? (...)

I'd suggest to visually check the azimuth of the needle tip - as well as whether there's sufficient clearance between the cartridge body and the record surface in playback position (and also sufficient clearance between the lift bank and the arm tube).

Greetings from Munich!

Manfred / lini

 

[j_loop]

Does it have a linear tracking tonearm? If so its belt(s) may need replacing. Loose belts on linear tracking arms can cause intermittent problems.

 

[RZ1]

I'd suggest to visually check the azimuth of the needle tip - as well as whether there's sufficient clearance between the cartridge body and the record surface in playback position (and also sufficient clearance between the lift bank and the arm tube).

Greetings from Munich!

Manfred / lini

This is not your standard 1/2" mount turntable. If it were my Crosley C8 (a more normal turntable akin to the Fluance RT82) that was having these issues I'll check that. (Granted I don't know what that is but I'll look it up). P-Mount turntables are supposed to already have correct cartridge alignment, VTF, VTA, and anti skate settings.

Does it have a linear tracking tonearm? If so its belt(s) may need replacing. Loose belts on linear tracking arms can cause intermittent problems.

Not a linear tracker. I know a lot of P-Mount turntables are linear trackers but this one isn't. For context it is much more similar to the Technics SL-BD20.

 

[Hugo65]

Did you check the VTF and make sure it's actually @1.25g?

 

[RZ1]

Did you check the VTF and make sure it's actually @1.25g?

I don't have a scale. Even if I did I don't see a way to adjust VTF on this turntable (yes it has a counterweight). From what I heard, Audio Technica P-Mount cartridges that have the AT81CP style body (which is the case with the 1001) are T4P compliant (6 gram cart, 1.25g tracking force + or - 0.5g)

 

[RZ1]

As far as I can tell it doesn't skip and loop on every record. For example it is unaffected by Enoch Light records like "Persuasive Percussion Vol. 4". Like I said I'll check level later and will update on the result

 

[lini]

This is not your standard 1/2" mount turntable. (...)

I'm aware, that were talking about a T4P turntable in your case. Nevertheless needle azimuth can be not ok, if one happens to get a needle with slightly rotated cantilever assembly. And cartridge bottom to record surface clearance can get marginal, if one happens to get a needle with faulty cantilever suspension - and as that JVC isn't the youngest anymore, it's also possible, that the lift bank might not reach its originally intended lowest/playback position anymore, if the lubricant has become sticky. Another reason for insufficient lift bank to arm tube clearance can be, that the lift bank sports a glued-in rubber inlay, that isn't properly held in place by the glue anymore, so that the ends tend to "curl up", hence causing playback-radius-dependent problems. None of these problems being limited to non-T4P-tables - hence my suggestion to check for these.

Greetings from Munich!

Manfred / lini

 

[RZ1]

Lift bank is ok. Stylus cantilever is fine (not bent or resting too low), and alignment does not appear to be off. The stylus needle itself points straight down when in playing position. These were things I had checked initially when I was trying to figure out what was causing the issue (along with things like changing the platter mat since what I was using before was too high- needless to say the issue persisted)

 

[RZ1]

I feel like I've narrowed down the issue to one of two things:
1. There was a reddit post that complained about this specific model skipping when walking past it on a non-isolated surface (poor vibration damping?)
2. The turntable may not be level (it sits on top of a CD changer which itself sits on a wooden shelf that is warped in a mild U shape)
It could also be both, along with other factors like playing with the dust cover on (and in an open position)

 

[RZ1]

Turntable was horizontally level but not vertically level (it was tipping a bit downward). Don't worry about that speaker on the shelf, it isn't hooked up. Now I'm gonna have to figure out how to correct this. That said, when records were playing they didn't skip towards the edge but rather towards the center.

 

[RZ1]

Correcting the level didn't do anything. Removing the dust cover didn't help either. Also, I tried to listen to Amy Grant's Unguarded record again with this turntable through headphones to minimize the vibrations caused by the speakers. It still skipped and looped, but I also discovered something else. As it turns out, while playing on the very first track, "Love of Another Kind", all the bass drum thumps were heavily distorted. Instead of the expected thump I get a splatter effect like as if a fruit just exploded. The background synths also sounded quite distorted. Seems like I may have to get a scale after all...

 

[RZ1]

I played another similar bass heavy record as well- in this case Ray Parker Jr.'s "The Other Woman". This one tracked better (it is a bit less warped- in fact it was basically flat), but the splatter effect still very occasionally showed up (the drums were also quite distorted), and I noticed a bit more sibilance than when I played it on the C8. There was also somewhat more surface noise. Whomever suggested testing VTF might be on to something here...

 

[RZ1]

Apparently P mount cartridges are secured by both a screw and a nut. I have the screw, but not the nut. Considering these both help to set VTF correctly on a P-mount, I'm starting to suspect that this turntable is tracking too lightly.

Update: It seems the nut is only for LP Gear's own P-Mount to 1/2" mount adapter. I'll still probably have to get a scale to figure out what is happening though...

 

[revox-b77]

Are you sure the stylus is in good condition?

 

[RZ1]

Are you sure the stylus is in good condition?

It is a new stylus. I just installed it two days ago. I'm not fully ruling out the possibility of a defective stylus so I'm waiting on a scale because I don't have one right now. If the VTF is good that means the stylus is defective.

The new stylus is a Phansteihl aftermarket one. That's why I'm not ruling out this possibility.

 

[TConnelly]

I’m wondering, why can’t you just tape a penny to the “headshell” and see if it helps? (A time honored tradition!) Also I might suggest you tape a penny (or two) to the counterweight in such a way that the tone arm balances and check to make sure the gimbal bearings are free and the arm returns to level when deflected. I have a Yamaha P-750 that developed problems with that. It exhibited symptoms similar to what you describe. Good luck!

Cheers………………..Todd

 

[RZ1]

Finally got a scale and DAMN that VTF is way too high for that cartridge (The scale reads 1.88 grams. That cart isn't designed for more than 1.5).
Also checked the C8, and it was correctly tracking at 3 grams