Tonearm mounting on Rega cutout question

Hey Everybody,

I'm a little confused and was hoping somebody could set me straight. I just bought a SOTA Comet III with a RB-250 tonearm. I got he 250 figuring that I would do the regular mods, structural and cable amd so on. Then I saw an add for the Hadcock GH228 on the 'gon last week. The add stated that the 228 would work in most Rega applications. I have also seen a review of the GH228 mounted on a P9 in What is confusing me is the effective lengths and spindle to pivot distances of these arms are not the same. Is it possible to mount the Hadcock in a standard Rega post mount cutout without modifications and still be able to get the cartridge to align correctly? Thanks for any input.

The Hadcock 228 is a 9" arm and can replace any 9" Rega tonearm with one tiny modification. Since the Rega mounting hole is 1" and the Hadcock is 5/8", we sell a brass reduction ring to make the mounting a snap. It fits neatly between the tonearm and turntable. They are available in two sizes, a 1" for Rega arms and 1.5" for arms consistent with that size mounting hole.
I hope that helps.

Disclaimer: I sell Hadcock tonearms.
Desmondjim, I own a hadcock 228 and it was not a drop in replacement for an rb250 I replaced. You are right about the different pivot to spindle distances for the rega (222 mm) vs the Hadcock 228 (212 mm). Even though you can move the hadcock closer to the spindle in a rega cutout because the hadcock base is smaller, the pivot will be too far away from the spindle, by at least 5 mm by my reckoning. For that reason, even though the hadcock 228 can physically fit into the rega cutout, the 228 is not a drop in replacement for the rega, IMO.

Check out the spreadsheet at, and you can see that the 228 can not be aligned using baerwald, when mounted at 217 mm pivot to stylus distance, using 23 degree offset, 228.6 mm effective lenght and resultant 10.8 mm overhang.

Actually, the 242 is closer to a drop in replacement candidate, with a spindle to pivot distance of 226 mm. If you can offset the base of the 242 in the rega cutout by 4 mm, the 242 is a perfect drop in replacement for the rb300.

Audiofeil and Msiebers,

Thank you for your responses. This gives me something to look into and study. I think I will like being back into vinyl. So much to play with while enjoying such involving music.