Rega P1 + OM20 Setup Problems

 

New member
Username: Sumocomputers

Post Number: 1
Registered: Aug-08
I have a Rega P1 turntable, which I have had for about 1 year, running it with the supplied Ortofon OMB5e cartridge and the stock RB100 arm. I have been happy with the turntable, but started getting some better vinyl, so I decided to upgrade to an Ortofon Super OM cartridge, and 20 Stylus (OM20 when combined).

In any case, I ran into a few issues when trying do the proper "Advanced Setup" from http://www.audiophilia.com/features/cartridge_setup.htm, and hoped someone might be able to point me in the right direction, or just confirm my assumptions. Even though I am having issues, I will say the sound is pretty good, but of course want to make sure I am getting the most out of the unit. I found tons of info on all the setup instructions and what to listen for, but not on some visual sanity checks to do after your setup is done.


1. Using a Shure SFG-2 on a level turntable and anti-skate to 0, I set the tracking weight to 1.5 grams. But when playing records, it seems like the cantilever is almost bottoming out, at least compared to the OMB5e. It seems that with a little record warp, I should see the cantilever should move a bit, but it does not, though the arm does very nicely. The cartridge bottom has some clearance, so it never hits the vinyl. I have photo at the link below, as this is my biggest concern:

http://www.flickr.com/photos/coffeeguy/2758213196/

2. It seems like getting the right alignment using all the common protractors out there might not be possible with this arm. The biggest problem I ran into was that I simply could not get the stylus far enough forward for the inner alignment point on most protractors. I found a Stereophile article somewhere that confirms it is the headshell slots that are to blame. So I ignored this part, and followed Rega's instructions of lining up the tip of the stylus with a special hole in the headshell. Hopefully this is OK.

3. There really isn't any Azimuth adjustment, so I just ignored this part. It seems very close to parallel to the record. Hopefully this is OK.

4. There isn't really an Arm Height adjustment without shims, so I just ignored this part. It seems very close to parallel to the record. Hopefully this is OK.

I have a Hi-Fi News test record on the way, I was planning on using that to further fine-tune the anti-skate and possibly the tracking weight. Thanks for any other help or pointers.


Chris
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 12926
Registered: May-04
.

"1. Using a Shure SFG-2 on a level turntable and anti-skate to 0, I set the tracking weight to 1.5 grams. But when playing records, it seems like the cantilever is almost bottoming out, at least compared to the OMB5e. It seems that with a little record warp, I should see the cantilever should move a bit, but it does not, though the arm does very nicely. The cartridge bottom has some clearance, so it never hits the vinyl."

If you simply switched from an OM5 to an OM20, nothing about the arm set up should have changed and therefore would not have required any chnage on your part. All you really needed to do was slip in the OM20 stylus to complete the upgrade. I would suggest you double check your set up.

When a cartridge rides over a warp, the cantilever should not flex. That would indicate an improper cartridge/arm match and the stylus would change VTA on both sides of the warp. If the arm rises and falls with the warp, you are seeing what should happen in a well matched set up. As long as the cartridge never bottoms out, you need not worry though 1.5 grams is a bit on the high side of tracking force for that cartridge. Better heavier though than too light. Adjust by ear for what sounds best.

If the arm came with an OM5 installed, why can't you get the OM20 to align properly? They are the same cartrige body. You should be able to use the Rega protractor to get proper alignment of this cartridge. Rega's protractor is unlike most others.


"3. There really isn't any Azimuth adjustment, so I just ignored this part. It seems very close to parallel to the record. Hopefully this is OK"

Even budget cartridges should come from the factory with very good azimuth adjustment.


"4. There isn't really an Arm Height adjustment without shims, so I just ignored this part. It seems very close to parallel to the record. Hopefully this is OK."

There are aftermarket VTA adjusters available for the Rega arms, if you're concerned.

.
 

New member
Username: Sumocomputers

Post Number: 2
Registered: Aug-08
In fact I did not just plug the new OM20 stylus into the the old OMB cartridge, I bought a new "Super OM" cartridge to go along with the OM20 stylus, so that might explain that confusion.

Regarding the alignment, even the old stock setup (OMB/5e) did not follow the Stevenson or Baerwald Rega protractor I downloaded from the link.

Keep in mind this is an RB100 arm, which I think might have a different length?). I know this Stereophile article (http://www.stereophile.com/turntables/507rega/) also mentions the problem I have with the RB100. Here is an excerpt:

"Footnote 2: The cartridge on my sample was indeed set up perfectly, but in accordance with Rega's own alignment scheme: a double-null geometry that differs from others in that its innermost null point is closer to the lead-out groove. Prospective buyers should also note that the RB100 has shorter cartridge-alignment slots than other Rega tonearms, and does not allow quite enough overhang to achieve perfect Baerwald alignment with many cartridges."

Which Rega alignment protractor(s) should I be using?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 12929
Registered: May-04
.


What came with the table?
 

New member
Username: Sumocomputers

Post Number: 3
Registered: Aug-08
What came with the table was the RB100 arm, and the OMB cartridge, and the 5e stylus. It also came with a MDF platter, but I upgraded to the glass platter. In terms of a protractor, there was no protractor included. The "Advanced Setup" instructions simply show that the front of the stylus must be aligned with the front of the hole in the headshell. Those are advanced mind you. Here is a link to the entire 2 page manual in PDF:

http://www.rega.co.uk/downloads/P1%20instruction%20manual.pdf
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 12930
Registered: May-04
.

Since I am not familiar with the P1/RB100, I don't know if what you received is all that should have been included with the table. I find it highly unusual to provide nothing more than instructions to eyeball the stylus tip to a hole in the headshell when most styli can't be seen from above when the cartridge is properly mounted. Telling you to square the cartridge body is not very helpful either. In my experience a protractor with a reasonable amount of fine detail provided and careful alignment to the marks provided on such a protractor is essential to achieving proper LP playback.


I would call your Rega dealer or the Rega distributor here in Dallas and ask about what should be included in the packaging. Rega is idiosyncratic at times but this is just sloppy customer assistance IMO if no other alignment device has been provided. I have dealt with Rega since they first came into the US in 1975 - I bought the third Planar 3 table imported into the US and now own an Apollo - and this would surpass their legendary "just do it my way" approach to packaging.

None the less, if the table had an OM5 mounted and Rega considers that cartridge to be set up correctly, the OM20 should be a direct drop in replacement even if you remove the OM5 body. In other words, the slots should not be too short for an OM20 if they were correct for an OM5. Otherwise, the concerns you expressed in your op should have been addressed in my initial reply.

Anything else?


.
 

New member
Username: Sumocomputers

Post Number: 4
Registered: Aug-08
Regarding your statement:

"In my experience a protractor with a reasonable amount of fine detail provided and careful alignment to the marks provided on such a protractor is essential to achieving proper LP playback."

This is what I hear everywhere, and yet there is no protractor to be found. I will email my Rega dealer who has been excellent so far, and is just an hour away.

Regarding the OM20 being a drop in, I agree with that, but thought perhaps the cantilevers might be different lengths, so I just wanted to do what everyone else does for alignment -- use a protractor!!!

Appreciate the help, and I will see what my Rega dealer has to say.

Thanks

Chris
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