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In Reply to: Re: need help with nott horizon/rb250 setup (overhang) posted by imrer on October 31, 2004 at 10:57:05:
As I recall Professor Elison determined that the Clearaudio alignment tool is correct only for the stock Rega 222mm distance. If you change the arm's mounting distance to anything other than 222mm than the Clearaudio tool will not give you correct alignment.
I don't quite understand what you mean by "ends up angling the arm such that the headshell is much too close to the platter edge". I've never seen a Horizon except in photos but I do own a Spacedeck. Judging from pictures it looks like the arm is attached to the Horizon by one or more allen screws pressing on the arm's pillar. If that's right then you should be able to loosen the arm mount and rotate it horizontally until it clears the platter.
You just said the magic words. I had previously set the vta and had forgotten that by loosening that bolt, I could rotate the arm mount. Now I can loosen the one bolt to put the pivot point at 222 (or 219), and loosen the other bolt to put the headshell at a proper location and avoid being too close to the platter's edge.
Things make more sense to me now. I think I'm ready to try setting the overhang and aligning the cartridge. Though I still would love to know what the measurements should be (spindle/pivot, spindle/needle, overhang) for a properly set up Horizon.
Thanks so much.
Sorry if this seems overly picky but you're asking the wriong question. There are no measurements for a "properly set up Horizon", it all depends on the tonearm you've selected. For a Rega you have several choices. If you use the one point protractor supplied with the arm which yields Stevenson alignment then you end up with an overhang less than 17.24mm. The problem with Stevenson alignment is that it is generally considered to sound worse than Baerwald alignment due to a different distribution of distortion across the record surface.
If you mount the arm at Rega's specified 222mm then the arm's effective length is 240mm and the overhang should be 17.24 mm for Baerwald alignment. The problem with 240mm effective length is that some cartridges will end up at the extreme end of the headshell slots. But many don't. If you run into that problem then changing the effective length to 237mm by changing the mounting distance to 219.5 or 219mm will put the cartridge closer to the middle of the headshell slots. It's very difficult to measure overhang with most alignment tools (my preferred Wallytractor is the exception) so it's not really a useful number.
If you search the VA archives for postings with "Rega" and "alignment" written by "Garth" you'll find a lot of good information on this subject.
Thanks for the continued help. What I meant by asking about a properly set up Horizon is based on using the RB250 that comes with the table.
It's been befuddling, but fascinating to read about all the issues swirling around with proper alignment in general and dealing with the clearaudio tool specifically.
I got confirmation from the Nott importer that the spindle/pivot distance is 222mm. So fine. I put tool on the spindle, set the clearaudio slide arm to read 222mm and arrange the arm so that the pivot point coincides with the little dropdown needle on the clearaudio arm.
However, even with my cartridge extended to the very end of the headshell screw grooves, the stylus was still a tiny bit short of the indent in the circle. Is this because the cartridge (Dynavector karat 17d2) is small? Or is the arm or armboard incorrectly made?
As you suggested, I changed the distance to 19.5mm (approx) and was able to get it into the bullseye (so what does that make my overhang?). Just finished trying to align the stylus to the grid, and re-set the VTA and VTF and put the anti-skate to a little less than 2 to match my vtf of about 1.9grams.
Will spin some records tonight to see how it goes. I'm hoping I didn't screw up the needle with all this tweeking.
BTW, I'm in Seattle. Don't imagine that's where you are? Maybe I'll go to the local Nott' dealer (I bought the table while in a different state) and beg for a lesson in setup.
> > even with my cartridge extended to the very end of the headshell screw grooves, the stylus was still a tiny bit short of the indent in the circle < <
I haven't used that cartridge but I have a hazy recollection that it's a bit shorter than average. A search of the VA archives might confirm that. If my memory is correct then that would explain why you couldn't get the Dynavector to align at 222mm. Of course you could always take a small round file available at any hobby shop and file the slots a bit longer.
> > As you suggested, I changed the distance to 19.5mm (approx) and was able to get it into the bullseye (so what does that make my overhang?) < <
Hmm...I hope you were using a two point protractor and not the Clearaudio. It's only correct for one effective length, most likely a Rega mounted at 222mm. I don't know what the overhang is for a Rega at 219.5mm (and as I noted its tough to measure overhang anyway) but if you really want to know there's a spreadsheet downloadable from the Asylum FAQ page that will help you calculate the number. You might also want to take a look at some of the other links on the FAQ page; there are several excelent articles about cartridge set up and alignment.
> > I'm in Seattle. Don't imagine that's where you are? < <
The dynavector is smaller than typical, which is why it wouldn't work with the 222mm mounting length.
I've been reading alot of the threads in the archives and the FAQ. I'm not really a math person, so much of the discussion goes beyond me, but from what I gather, the clearaudio alignment tool, while perhaps optimized for 222, seems reasonably safe to use with tonearms that can be mounted from I think it was 210mm to 224mm distance.
I didn't use a 2point protractor because the only one I have is the one that I downloaded from enjoythemusic, and given that I had to make the spindle hole, and worry about proper printer scaling and such, I thought I was better off with the clearaudio.
At some point perhaps I will get better alignment tools, but I know that when I can, I will be upgrading certainly the arm, but probably the table, too -- so I will make due with the clearaudio until I have settled down with my long-term choice for turntable. The horizon/250 combo is awesome and I am totally happy with it at the price I got it, but I'll want to move up to a Spacedeck (or a Hyperspace if at all possible)and then I will invest in the tools necessary to have it nailed down on setup.
This has been a very interesting experience and I again thank you for your help. I finally got to spin some vinyl last night and it sounded quite good. I didn't hear the buzzing that I was getting from certain high piano notes before I began playing with the overhang. Though I haven't played through very many LPs just yet. I need to get a loupe so that I can better see and align the stylus, but I think I eyeballed it pretty close.
Now you'll forgive me if I admit that I am a former New Yorker and still a Yankee fan (though I do now also root for the Mariners). I do congratulate the Red Sox for finally winning the series. And with perhaps a few sour grapes lodged in mouth allow me to say that the one great thing about the red sox finally winning is that now, the team with the second highest payroll in baseball can stop acting like the "blue collar working man" team that keeps getting beaten by the unfairly wealthy team. Sort of like Paul Allen complaining that Bill Gates keeps outbidding him at the auction.
But seriously, I went to college outside of Boston (was there in 1986!) and I can imagine just how excited the area is.
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