The great p-mount cartridge experiment

Preface

A couple weeks ago, I mounted up an Audiotechnica TR485U p-mount cartridge on a stamped aluminum headshell with an adapter, to try it out on my Technics SL-1700Mk2 turntable, with good results. I then thought I should be able to use the same headshell/adapter combination to try out some other p-mount cartridges I had sitting around.

I then posted a question in this forum: http://www.audiokarma.org/forums/showthread.php?p=1863307

My question is, was the p-mount standard such that the tip of the needle should be in the exact same spot in relation to the end of the arm where it was mounted? In other words, should I be able to swap p-mount cartridges into the headshell/adapter I have set up, and have the overhang and alignment be correct?

Click to expand...

The answer was that this should work, that the needle position should be the same per the p-mount standard. However, this assumes that all manufacturers followed the standard exactly. This led to the current question I hope to answer with this experiment.


Question

How precisely did different manufactures follow the p-mount (TP4) standard, both for needle placement (overhang and height) and for cartridge weight (which, with the unadjustable counterweight of p-mount turntables, determined tracking weight)?


Test Subjects

The following p-mount cartridges were on hand and used in the experiment. All are older carts, and all have replacement styluses (not the one they were sold with). In addition to testing the variations in the carts as noted above, I also want to give them all a spin and see how they sound.

Audiotechnica TR485U with an ATN152LP shibata stylus
Pickering XL-28U with a DTL2 elliptical stylus
Audiotechnica DR400E with an ATN2472SE stylus
Two different variations of the Ortofon TM, both using the same aftermarket 14 stylus
* One with "TM" marked on the side, and a black base (contrasting to the off-white body) where it inserts into the adapter
* One with "TM" on one side, "14" on the other side, "Ortofon" across the top, and an off-white base to match the body


Equipment

Technics SL-1700Mk2 turntable, Pioneer SA-610 integrated amp, Pioneer CS-510 speakers
* My usual bedroom system in its usual habitat.

Shure SFG2 stylus pressure guage

Stamped aluminum headshell with p-mount adapter installed
* This was set up for my TR485U cartridge, and I didn't want to lose that setup, so I kept the adapter installed in the headshell in the same position for the experiment.

Technics overhang guage
Metric ruler marked in mm
* To determine the position of the point of the needle in three dimensions.

Mr. Clean magic eraser
AT stylus brush
ProGold contact enhancer pen
Discwasher D4+ kit
* To keep everything clean and perfroming well during the experiment

T Bone Burnett (self-titled) MCA-5809, side 1
Fine Young Cannibals (self-titled) IRS-5683, side 1
Falco ~ Weiner Blut Sire 26290, side 2
* Test recordings, all recently purchased and played recently, so I'm familiar with how they should sound. None of the three are very flat, so how well these carts track warps was also tested.


Lab notes

First I double-checked the setup on the Audiotechnica TR485U cartridge. I determined that the point of the needle was dead center for overhang and lateral position, and that it was 4mm above the end of the overhang gauge. I set the SL-1700Mk2 arm to 3 on the VTA accordingly, and left it there for the rest of the experiment. I then set the tracking weight with the SFG-2 to 1.25g (less than the 1.3g I had been running it at, but 1.25g is the TP4 standard). I double-checked this by dialing the counterweight back to zero which got me a good floating position, then back to 1.25g where I triple-checked it again with the SFG-2. I then played the first and last track on the three test recordings, and everything sounded great.

Next up was the Pickering XL-28U, which I recently rediscovered in a box of stuff from when I was in college 20 years ago. I just mailordered a replacement DTL2 stylus (a .3 x .7 mil upgrade on the original .4 x .7 DTL1 stylus, which was quite worn) and it arrived this past week, and this was the first test of the new stylus. First I measured the needle position in the headshell/adapter; it was 1mm forward in the overhang gauge, and it was 5mm above the end of the gauge. I then mounted the headshell on the arm with the counterweight at zero, and the end of the arm was high, so this cart is lighter than the TR485U. When I used the SPG-2 to set the tracking weight to 1.25g, the counterweight read 1.5g indicating that it was a quarter gram lighter. When playing the test recordings (at correct 1.25g weight but with the overhang remaining 1mm long), it lacked the some of the brightness of the TR485U but gave a good solid uncoloured performance.

Third was the AT DR400E, with a two-year-old ATN3472SE stylus, a good .3 x .7 mil elliptical. This cartridge had been on my parent's Dual until I replaced it last month. Unsurprisingly, since they are both Audiotechica products, the needle position was the same as the TR485U. However, when installed on the arm and put to the zero mark from the TR485U, it also was lighter, and the SPG-2 also showed it to be a quarter gram lighter. Set to 1.25g tracking force, it gave a good performance fairly similar to the Pickering.

Next up were the Ortofon TMs, first the all-off-white one marked 14. I noticed that the aftermarket 14 stylus didn't look like the best of workmanship; the markings on it just didn't look right, particularly the red dot on top. I bought it a couple years back on eBay from Ed Saunders if I recall correctly. The needle position was 5mm up off the base, the same height as the Pickering, and just a little forward, perhaps half a mm longer on overhang. It too turned out to be 0.25g lighter than the TR485U. It sounded OK on the Fine Young Cannibals and Falco records, but had audible distortion on the T Bone Burnett record, which is an all-acoustic album recorded live to two-track digital.

Last was the Ortofon TM with the black base with no number marking, using the same 14 stylus. The needle position was the same as the other TM, but it turned out to be heavier. When the counterweight was at the zero point for the TR485U it didn't float, but it wasn't as high than the other three carts. When I set the conterweight to 1.25g on the SFG-2 for the cart, the counterweight scale read 1.35g, indicating it was a tenth of a gram lighter than the TR485U. The playing test was very much like the other TM cart, including the distortion on the T Bone Burnett record.


Conclusions

Different manufacturers didn't follow the p-mount standards in the same manner, both in needle position (which I expected) and in weight (which I didn't expect). However, the needle position seems to be close enough that for a quick performance test, using a headshell & adapter set up for one will also work for others, but a check and possible adjustment of the tracking weight is probably in order (although I did not really test this, only testing performance once I reset the weight, which is a quick and easy adjustment).

I also suspect the performance of the aftermarket Ortofon 14 stylus.

Part II

Next Question

While I don't know the p-mount standard for needle position, I do know the standard for tracking weight is 1.25 grams. Which of these cartridges would track at the standard 1.25 grams (matching the preset anti-skate) on my Technics SL-BD22 turntable?


Additional test subject

Audiotechnica LS580/LT with an ATN152LP stylus (it has its own, not the same stylus as the TR485U)


Additional equipment

Technics SL-BD22 turntable, replacing the SL-1700Mk2
DeOxit spray
Bubble level

Smithsonian Collection of Classic Jazz (1st edition), side 2
* Used in an attempt to use a mono recording to hear the mis-set antiskate on those that didn't track at 1.25 grams, which didn't really work. The left channel was slightly louder than the right on all cartridges per the power meter on my amp, probably due to a worn recording. It did give me a good excuse to listen to Jelly Roll Morton and Louis Armstrong.


Lab notes

The SL-BD22 was brought out of storage, hooked up to the system, and leveled. According to a label at the base of the arm, it was "precisely adjusted at the factory *tracking force *anti-skating" above a marked scale from 0 to 2 with an arrow at one and a quarter.

The TR485U was installed first. After some work (DeOxit into the speed control pot to fix the erratic speed problem that has happened in the past, ProGold on the cartridge pins after the first try only had the left channel), I got it up and working. Checking the tracking force with the SPG-2, it was tracking at 1.5g, a quarter gram higher than the standard.

I then tried the Pickering XL-28U as a representative of the carts that were a quarter gram lighter than the TR485U. This is the cart I purchased with the SL-BD22 about 20 years ago, so I wanted to hear the combination. Per the SPG-2 it was indeed at the correct 1.25g tracking force. It sounded good on all the test recordings, confirming my original selection of this combination.

Third subject was the Ortofon TM with the black base (no number marking). It tracked at 1.4g per the SFG-2, and had the same distortion on the T Bone Burnett recording.

Then I had the idea to check the Audiotechnica LS580/LT cart installed on my Technics SL-Q5 linear tracking turntable. This cart looks the same as the TR485U and takes the same line of styluses, and the "LT" in the model name indicates it was intended for use on a linear tracking table. I had thought that it was the same cart with different model numbers, but I was surprised. It is 0.1 grams heavier than the TR485U, tracking at 1.6g on the SL-BD22 per the SFG-2.


Conclusions

The lighter of the p-mounts in my collection (Pickering XL-28U, AT DR400E, white-base Ortofon TM 14) track at the correct 1.25 grams, and the other are heavier than the standard weight.

Just because two p-mount cartridges appear the same and use the same family of styluses, they may be different weights.

If I put the SL-BD22 back in service (such as for my daughter when she gets older) I'll most likely use the the Pickering CL-28U on it.


For further investigation

Buy or get a access to a good scale to get a weight on these p-mount carts, for future reference. That way, I can look at the spec weight for a p-mount cart and know if it will track at or about 1.25 grams or not. Also, attempt to find out what the TP4 p-mount standard was for length to needle tip, to see which of these carts meet that standard and which are off.

Try out my spare 10 stylus (authentic Ortofon) on the TM carts. The 14 stylus is supposed to be run at 1.0-1.5 grams (1.25g sweet spot) while the 10 is supposed to run heavier with at 1.25-1.75g range (1.5g sweet spot). Since the heavier TM tracks at 1.4g on a p-mount arm I might as well try out the 10 stylus on it.

Swap the lighter TR485U with the LS580/LT cart on the SL-Q5 table and see if the lighter tracking weight makes a difference.

Try out the DR400E cart on the SL-BD22 before it goes back into storage to see if that combination works too, so I have a second good option for it.

Both of my Ortofon carts and all three of my Grados want to run turned in slightly (all 1/2 stds). This is like 2~3 degrees from dead on. In addition they all like to track at around 1.8 grams to get best sound.

I use initial set-up and tracking force as the starting point, but tune for best sound by ear from there, I suggest you try this with one table/shell/adapter combo and see if it makes any difference?

Almost all the distortion is gone on the Ortos. Occasionally, it will sneak in a bit on one track here or there. The Grados sound fine in this configuration. Seeing as how I change carts to find matches per LP, I'm getting quite good at noting these subtle changes. I suspect you will too soon

I can try making those changes on my SL-1700Mk2; I have more empty headshells and another p-mount adapter which I'm 99% sure is an Ortofon.

That won't work so well on my two p-mount tables, and part of this exercise turned into finding which of my p-mount cartridges would work best at the p-mount standard settings. I still think I'll try the two TM carts on the SL-BD22 p-mount arm with the 10 stylus before I store the table away again, to get an idea if the problem is with both cartridges or a sub-standard aftermarket 14 stylus. I had bought that 14 stylus in order to use it with a TM cart on a p-mount table, but it clearly failed in that role. I could also try out the 14 stylus on my OM and Concorde carts, once I swap the SL-1700Mk2 back into the system, to see how it performs there at different tracking weights.

I run my 1/2 inch mount Grado Black head on (no way to adjust the angle in the AT-MG10 headshell which it is mounted on) but I've been trying out different tracking weights and VTA settings on it. No way to change that angle on my old-school Ortofon Concorde too, but it has been sounding quite nice (on the right records) since I picked up the clue on the adjustment screw and adjusted the length out to 52mm.

I dig the thread title...experiment on, my friend.

Excellent and thorough report.

My only comments so far are that aftermarket replacement styli are not always accurate in weight, although I'm assuming that the two 152LP styli were the same. The TR475U and LS580 are, in fact, the same cartridge, but were probably manufactured in different batches and so a variation of .1g is not surprising.

The two carts that were 1mm or so forward were also 5mm higher. Lower the arm 5mm down to the same level as the ATs and the effective arm length is reduced closer to where it would be with the AT, although admittedly by a small amount.

It would be interesting to get hold of a Technics cart, since they are the ones who developed p-mount, and see how these others compare to it.

Both 152LP styluses are genuine AT, but both of those carts would have come with a 122LP originally. I could try swapping needles around to see if it makes a difference. I also forgot I had an aftermarket 102EP stylus I could try and see if it changes the weights on the TR485U and the LS580.

The carts with the forward needles were only 1mm higher (5mm above the overhang gauge vs. 4mm) than the AT carts. Still, the higher position would shorten the overhang a smidge, since the p-mount tables have no VTA adjustment. If the needle position on the AT carts is correct (and AT used to supply Technics with OEM carts, didn't they?) going longer than the standard was probably better than going short.

SA-708 said:

Both 152LP styluses are genuine AT, but both of those carts would have come with a 122LP originally. I could try swapping needles around to see if it makes a difference. I also forgot I had an aftermarket 102EP stylus I could try and see if it changes the weights on the TR485U and the LS580.

The carts with the forward needles were only 1mm higher (5mm above the overhang gauge vs. 4mm) than the AT carts. Still, the higher position would shorten the overhang a smidge, since the p-mount tables have no VTA adjustment. If the needle position on the AT carts is correct (and AT used to supply Technics with OEM carts, didn't they?) going longer than the standard was probably better than going short.

Click to expand...

Sorry I misunderstood the height measurements. And no, Technics started the T4P standard and made their own p-mount carts, some of which are top notch, rare, and highly sought after.

Further results

More experimentation with my p-mount SL-BD22 before it goes back in storage.

I tried out all three needles on the TR485U and the LS580/LT. There were very small differences (1mm deflection on the balance pointer on the Shure SFG-2) in the tracking weights with the grey aftermarket 102EP stylus and the two black 152LP styli. There was a pretty exact tenth of a gram difference between the two cartridges, as close as the SFG-2 is able to measure, which seems like a rather exact difference for a manufacturing variation in a p-mount cartridge.

I tried out a 10 stylus on both of the TM bodies, both the 1.25g tracker and the 1.4g tracker, and there was no distortion at all. The 14 stylus is now officially suspect.

I also tried out the Audiotechnica DR400E on the records I'd been playing, as well as a sealed copy of Emotional by Falco I purchased today, and it sounded quite nice. Definitely one of my top two choices, out of the carts I have, to use on the SL-BD22.

Correct...

The only P-Mount carts that follow a standard design with a weight of 6-Grams and T4P overhang are those that are clearly marked T4P on the body. T4P carts should weigh in at 6 Grams and track at 1.25 Grams. I have seen a couple of tables that were set up for P-Mount carts that had adjustable Counterweights and Anti-Skating so those tables would allow the use of the non-T4P P-Mount carts such as GRADO. Just about ALL the Technics tables were T4P compatable as were the Audio-Technic P-Mount carts. Again, these are all marked T4P.

I know that GRADOs were not made to the T4P specs nor were SHURE (even though SHURE P-Mounts work really well in T4P arms). Panisonic/Technics came up with the P-Mount T4P system as a way to simplify the setup of cartridges and tonearms. Other manufacturers found the P-Mount to be a great way to eliminate those pesky lead wire connections...however, in the end, 1/2 inch has prevailed.

Joey

Thanks. Any idea of what the T4P overhang standard is?

I don't think any of the carts I was trying out were marked T4P on the cartridge itself. Only one I have the original literature for is the Pickering XL-28U; I'll check that out when I get home.

Ya know,

I'm not sure where you would find that as the idea behind T4P was to illiminate all of that concern for the end-usser. The T4P tonearms and cartridges were designed to be 100% compatable only requiering that you "plug-n-play". I will check my Technics manual for the SL-22 and see what it says about overhang and pivot.

When I checked the overhang with the SHURE protractor that came with the V-15VxMR and M97xE, the inner most null point was DEAD ON with an AT331LP T4P cart and a Technics SL-22 turntable so...not sure if that is any help.

I can tell you that the GRADO is WAYYYYYYYYY off for T4P compatability. It may have a P-Mount plug, but the weight of the cart is to light and the tracking force of 1.5g is incorrect! Rule of thumb...as long as the weight is 6 grams and tracking force is 1.25 grams, marked T4P or not, it should work OK. I know that the Ortofon X1-MCP works GREAT on T4P tonearms but is NOT marked T4P. Also, the ORTO OM P-Mounts tend to work best on the Linear Arms V's the Pivot arms...from my experience.

joey

Wow....it seems you've done some really extensive research on the p-mount issue. Same conclusions I would have reached having owned (and still own) several p-mount cartridges. Some weigh 5.9 grams and others weigh 6 grams.

As for the whole tracking force debate, I NEVER use the 1.25 gram tracking force. I always go heavier. For me, with a tracking force of 1.25 grams, I don't get the sense that the stylus would be sitting properly in the groove. As a rule, regardless of the make and model of cartridge, I always use a tracking force of 1.4 grams...a seemingly small increase, but enough to make me feel more secure about the stylus sitting more securely in the groove. It is always better to track a little on the heavier side than it is to track a little on the light side.

iLUVanalog said:

Wow....it seems you've done some really extensive research on the p-mount issue. Same conclusions I would have reached having owned (and still own) several p-mount cartridges. Some weigh 5.9 grams and others weigh 6 grams.

As for the whole tracking force debate, I NEVER use the 1.25 gram tracking force. I always go heavier. For me, with a tracking force of 1.25 grams, I don't get the sense that the stylus would be sitting properly in the groove. As a rule, regardless of the make and model of cartridge, I always use a tracking force of 1.4 grams...a seemingly small increase, but enough to make me feel more secure about the stylus sitting more securely in the groove. It is always better to track a little on the heavier side than it is to track a little on the light side.

Click to expand...

If the cartridge is designed for HI COMPLIANCE such as the T4P carts, you would not need more than 1.25g. All T4P carts are 6 grams with a tracking force of 1.25 grams. P-Mount carts in general very in weight. However, you'll notice that carts NOT weighing 6 grams tracking at 1.25 grams are not labled T4P, they are just P-Mounts. I know some of the good Technics Linears allowed minor tracking force adjustments... I beleive it was between 1 - 1.5 grams that could be adjusted...

joey

Joey1127 said:

Correct...

The only P-Mount carts that follow a standard design with a weight of 6-Grams and T4P overhang are those that are clearly marked T4P on the body. T4P carts should weigh in at 6 Grams and track at 1.25 Grams. I have seen a couple of tables that were set up for P-Mount carts that had adjustable Counterweights and Anti-Skating so those tables would allow the use of the non-T4P P-Mount carts such as GRADO. Just about ALL the Technics tables were T4P compatable as were the Audio-Technic P-Mount carts. Again, these are all marked T4P.

I know that GRADOs were not made to the T4P specs nor were SHURE (even though SHURE P-Mounts work really well in T4P arms). Panisonic/Technics came up with the P-Mount T4P system as a way to simplify the setup of cartridges and tonearms. Other manufacturers found the P-Mount to be a great way to eliminate those pesky lead wire connections...however, in the end, 1/2 inch has prevailed.

Joey

Click to expand...

I've always wondered about this. I have an AT cartridge and needle on my Technics TT (which I really should replace). I never assumed that the weight would be standard on them, since there is a counterweight adjustment on my TT, or at least I didn't until I got my spare JVC TT, that I recently gave away. That one had a T4P cartridge mount, but no counterweight adjustment.

My Technics TT does have counterweight adjustment AND anti-skating adjustment. In my manual, it says that the counterweight adjustment should exactly match the anti-skating, which on my TT, it does, with 1.25 grams each.

I never exactly understood why P-mount never caught on. It makes things very simple if you need to remove the cartridge for some reason, or replace it.