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Rega planar 2 with s shaped tone arm help

A

Andyb2

New Member
Hello
I wonder if anyone out there can help me. I've just purchased a mk1 rega planar 2 with the s shaped tonearm. My question is regarding cartridge allingment. I notice that many s shaped tonearms have a way of aligning the cartridge without using a protractor by measuring a distance from the rubber gasket to stylus point once cartridge is placed straight in the headshell. Does anyone know what this measurement is for this tonearm and turntable?

I'm aware that I'll probably get many replies saying I should still use a protractor but would like to know if such a measurement exists or if someone has found a optimum measurement themselves?
 
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Hi. Welcome to AK. The gasket to tip measurement is an approximation that only works for specific turntable geometries (pivot to spindle / overhang / eff. length) like some Technics (52mm) or Pioneer (49mm) models. In those cases the mfgr guaranties that trick would get you close enough to a good alignment. It can still be tweaked for better performance with a protractor, but it's good enough to reduce the tracking error to acceptable levels. For other turntables with different geometries, you're going to have to use a protractor. If after that, by some coincidence, the cart happens to be center aligned with the headshell, you can measure the gasket to tip distance and use it in the future. Unfortunately it's uncharted waters for the Rega and "S" shaped tonearm - so you're gonna have to discover it (assuming it exists) by trial and error - using a protractor.
 
tnsilver said:
Hi. Welcome to AK. The gasket to tip measurement is an approximation that only works for specific turntable geometries (pivot to spindle / overhang / eff. length) like some Technics (52mm) or Pioneer (49mm) models. In those cases the mfgr guaranties that trick would get you close enough to a good alignment. It can still be tweaked for better performance with a protractor, but it's good enough to reduce the tracking error to acceptable levels. For other turntables with different geometries, you're going to have to use a protractor. If after that, by some coincidence, the cart happens to be center aligned with the headshell, you can measure the gasket to tip distance and use it in the future. Unfortunately it's uncharted waters for the Rega and "S" shaped tonearm - so you're gonna have to discover it by trial and error - using a protractor.
Click to expand...

Many thanks for the reply.

I have purchased a generic 2 null point protractor (coming in the post). I'll have to give that a go. I have a further question/s regarding that. I have read on these forums that with a s shaped tonearm with sme headshell such as this the cartridge should not be twisted in the headshell and only moved back and forth keeping it straight? Is this correct? I have also read if this is the case I should look to align perfectly in the 'a' position first (nearest the spindle) and then try to match with 'b'. My final question regarding this is if its not possible to do this without twisting the cartridge out of a straight position am I better off keeping it straight and in line with position 'a' and not worrying about position 'b' so much as some advise on here. Or twist the cartridge out of a straight position and attempt to match both? Many thanks in advance for any help. Really want to get this deck set up properly. It will be my first attempt at this so want to get it something like right without damaging anything.
 
By "twisting" do you mean that the two headshell screws are not inline with each other? Try to keep the two inline and parallel. Move both equidistant, to get to final protractor alignments --- both outer and inner points on your protractor. It may take a couple two, three or more tries, but you can very close with both headshell screws still being parallel with respects to the headshell slots. And the cartridge lining up properly on the protractor. :)

This video may help you. [MAN!!! it looks like every Manny, Moe, & Jack has decided to make a YouTube video on how to setup a turntable. I like Vinyl TV's, because he is easy to understand and explain things well].

Starts around 12:00 mark.

 
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Mr Boochie said:
By "twisting" do you mean that the two headshell screws are not inline with each other? Try to keep the two inline and parallel. Move both equidistant, to get to final protractor alignments --- both outer and inner points on your protractor. It may take a couple two, three or more tries, but you can very close with both headshell screws still being parallel with respects to the headshell slots. And the cartridge lining up properly on the protractor. :)

This video may help you. [MAN!!! it looks like every Manny, Moe, & Jack has decided to make a YouTube video on how to setup a turntable. I like Vinyl TV's, because he is easy to understand and explains thing well].

Starts around 12:00 mark.

Click to expand...


Thanks again. Shall give that a watch and do my best! Appreciate the response.
 
tnsilver said:
No. That's nonsense. Many original SME headshells do not provision for twisting the cart off-center b/c they only come with fixed mounting holes (as opposed to sliding slots). Alignment in such cases is performed by sliding the TA back and forth on it's mounting plate - effectively varying the pivot to spindle distance. My guess is that someone had mistaken this to be the only valid alignment method so they had the sliding of the TA on the mounting plate replaced with varying the overhang, which is what you get when you slide the cart back and fourth in the headshell. While in theory it could, coincidentally, yield the correct alignment - it depends on the specific tonearm and may not be true at all. It also makes cart alignment absurdly more difficult than it should be. FWIW most of those SME's where it's relevant - are "J" shaped tonearms so I don't know where such ideas come from.
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Hello

Thanks for the advice. I've watched the video the previous person posted so am now fairly confident I can undertake this task. Thanks for clearing that up for me.
 
I don't like that video at all. Take it with a grain of salt. The person in it seems to me like a self appointed arm chair "expert" and appears to lack the basic understanding of the procedure he's explaining. He's using a Technics clone TT where the Technics geometry applies, so he's advising about keeping the cart straight in the headshell, which is only relevant for the Technics case. He also uses some arbitrary protractor that he had downloaded for no particular reason from vinyl engine with a complete disregard to the specifics of the turntable. He says it's "confusing" but it's obvious to me he has no clue what the different protractors are used for and when. Worst of all, he has no regard for overhang while aligning. He kinda looks like that screwdriver he's using - totally inappropriate for the job. No! I'd skip that video and find a better informed presentor.
 
tnsilver said:
I don't like that video at all. Take it with a grain of salt. The person in it seems to me like a self appointed arm chair "expert" and appears to lack the basic understanding of the procedure he's explaining. He's using a Technics clone TT where the Technics geometry applies, so he's advising about keeping the cart straight in the headshell, which is only relevant for the Technics case. He also uses some arbitrary protractor that he had downloaded for no particular reason from vinyl engine with a complete disregard to the specifics of the turntable. He says it's "confusing" but it's obvious to me he has no clue what the different protractors are used for and when. Worst of all, he has no regard for overhang while aligning. He kinda looks like that screwdriver he's using - totally inappropriate for the job. No! I'd skip that video and find a better informed presentor.
Click to expand...


OK. I was wondering about overhang? I've read so many places though that if you get the protractor right then the overhang should be right as well? Apparently the overhang for my arm should be 15mm.

Hypothetically if I get the overhang right by measuring off the center of spindal to the stylus would my cartridge not be aligned?
 
Andyb2 said:
Hypothetically if I get the overhang right by measuring off the center of spindal to the stylus would my cartridge not be aligned?
Click to expand...
We don't care about the spindle to stylus distance. We care about the tonearm pivot to the turntable spindle (P2S) distance (aka "mounting distance") and the effective length of the tonearm (which is the pivot to spindle distance plus the overhang). In theory, under the assumption that we've got the right mounting distance and taking the offset angle into account with the correct overhang - would assure a tolerable tracking error. Unfortunately this is seldom the case.

If you're using an arc protractor printed for your tonearm's P2S or effective length (which includes the overhang) and your stylus tip follows the arc, then you're done and your overhang is set b/c following the arc can happen only for a singular geometry. That's easier said than done b/c arc protractors are tougher to work with.

However, if you're using a "stupid" or two null points generic protractor you need to be aware of what it means. Your tonearm's geometry was designed for a specific pair of null points. Those are the points were supposedly the arc of the tonearm intersects the cutting head's linear path or radius. There are several methods to calculate these null points (i.e 'Baerwald', 'Stevenson', 'Lofgren' and what's in between that's a proprietary set up) each with it's own set of pros and cons. The tonearm mfgr may, or may not publish those specifications but the fact is the offset angle, the overhang and the P2S will not come together to align the cart for minimal tracking error unless you use those exact null points.

The bottom line is when you use a stupid protractor - you are responsible for setting the overhang and you may be required to skew the cart in the headshell. I've said it three times already. Yes, carts get skewed in the headshell for proper alignment - unless, coincidentally, they don't have to be.

What sort of tonearm is this anyway? Planars usually have a 222mm P2S parameter and they ususally come with some Rega RB tonearm. What do you have there?
 
tnsilver said:
We don't care about the spindle to stylus distance. We care about the tonearm pivot to the turntable spindle (P2S) distance (aka "mounting distance") and the effective length of the tonearm (which is the pivot to spindle distance plus the overhang). In theory, under the assumption that we've got the right mounting distance and taking the offset angle into account with the correct overhang - would assure a tolerable tracking error. Unfortunately this is seldom the case.

If you're using an arc protractor printed for your tonearm's P2S or effective length (which includes the overhang) and your stylus tip follows the arc, then you're done and your overhang is set b/c following the arc can happen only for a singular geometry. That's easier said than done b/c arc protractors are tougher to work with.

However, if you're using a "stupid" or two null points generic protractor you need to be aware of what it means. Your tonearm's geometry was designed for a specific pair of null points. Those are the points were supposedly the arc of the tonearm intersects the cutting head's linear path or radius. There are several methods to calculate these null points (i.e 'Baerwald', 'Stevenson', 'Lofgren' and what's in between that's a proprietary set up) each with it's own set of pros and cons. The tonearm mfgr may, or may not publish those specifications but the fact is the offset angle, the overhang and the P2S will not come together to align the cart for minimal tracking error unless you use those exact null points.

The bottom line is when you use a stupid protractor - you are responsible for setting the overhang and you may be required to skew the cart in the headshell. I've said it three times already. Yes, carts get skewed in the headshell for proper alignment - unless, coincidentally, they don't have to be.

What sort of tonearm is this anyway? Planars usually have a 222mm P2S parameter and they ususally come with some Rega RB tonearm. What do you have there?
Click to expand...


It's a Mk1 deck with a r200 s shaped arm. Every guide I see for setting up the planar 2 refers to a straight arm. I think from what I have researched on the deck that the arm that came with mine had a limited run and they moved over to a straight arm.

If I could find a specific guide for mine that would be great but I've had no luck yet.

I must admit I'm quite confused by everything. I've seen many guides which state to set overhang first by measuring from centre of spindal to stylus tip when arm is held directly over it and then use 2 point protractor to align . That certainly seems like the easiest method for me to get to grips with. It seems that there is various ways to do this. As I've never set up a cartridge before I'm really looking for a beginners way and move on from there.

All help is much appreciated
 
Oh, I see what you mean now. If you can place your TA directly over the spindle - all you have to do is measure an additional 15mm past it to the tip - to set the overhang correctly. Then align the cart with a protractor trying to keep the overhang settings as closely as you can.
 
tnsilver said:
Oh, I see what you mean. If you can place your TA directly over the spindle - all you have to do is measure an additional 15mm past it to the tip - to set the overhang correctly. Then align the cart with a protractor trying to keep the settings.
Click to expand...

Yes. Would that work?
 
Dandy said:
Your tonearm is an Acos Lustre GST-1 tonearm.
Click to expand...
That makes sense as VE lists the eff. length as 237mm. With the 15mm overhang this calls for a 222mm mounting distance and makes this compatible with the later RB tonearms installed on the planar. Thanks for that info. It is a nice arm.
 
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