Reloop RP-4000 (SL-1200 clone) eff. mass? Which cartridge?

[aaabbcc]

Hi,

I was asked a few day ago which cartridge to recommend for a Reloop RP-4000 M3D (one of the SL-1200 OEM clones that go by different names).

I'm wondering what's the effective mass of such a clone's arm. Same as SL-1200 (12g)?

And will an overhang gauge for the SL-1200 fit?

This is what the service manual says (no value for eff. arm mass given:

Type: Static balanced S-shaped tonearm with detachable headshell
Effective Arm Length: 230.5 mm
Overhang: 16 mm
Tracking Error Angle: Less than 3 degree

Tracking Force Adjustment Range: 0-4g
Applicable Cartridge Weight: 6-10g
Anti-skating Range: 0-7g

The rest - like freq. response, output volume, channel separation and balance - obviously depends on the specific cartridge, Ortofon OM GT, which AFAIK is a cheapo DJ cartridge some of these TTs came with. The 'needle pressure range' (probably a fancy word for tracking force) given for this is 2.5g.

Does anyone have specific cartridge recommendations? Note that this is strictly for home/hi-fi use, no deejaying/scratching.

TIA

[JaS]

The gauge might fit. It's anybody's guess what the effect would be though as according to the specs the arm length and overhang are different? Personally I'd use a universal protractor rather than a tool designed for a different arm. As for effective mass, if the manufacturer doesn't state it you would need to measure it with a test record to be sure. For the cartridge, as long as you stick to moving magnet and stay away from very high/very low compliance types you should be fine?

Regards,
JaS

[aaabbcc]

Okay, I dug out the respective specs of the SL-1200/1210 arm from the official service manual:
Effective length: 230 mm
Overhang: 15 mm
Offset angle: 22° (no such spec was in the RP-4000 manual)
Tracking error angle: within 2°32'

Not sure whether this is close enough, and whether the available specs of both arms are enough to judge it.

@ JaS:

Thanks, but I'm very bad at adjusting cartridges, as I haven't done it for ages. Plus the cartridge in question atm (Ortofon OM) has a form that makes adjusting difficult. It might be another matter with a different cartidge with a more ordinary shape.

[JaS]

Not sure whether this is close enough, and whether the available specs of both arms are enough to judge it.

Reloop don't list the offset angle so the original alignment is unknown? Dialling in the wrong overhang could have adverse affects though. For example, if the offset angle is 22 degrees (as used by Technics) then using the Technics gauge to set 15mm overhang rather than the 16mm recommended by Reloop would have this affect on distortion (the blue line is 15mm).



Of course without knowing exactly what offset angle Reloop use it's just a guestimate, and whether the increase in distortion would be audible is also debatable The Technics gauge might even give better alignment!

Regards,
JaS

[aaabbcc]

Reloop don't list the offset angle so the original alignment is unknown?

They don't. The service manual is from the library here at VE.

Dialling in the wrong overhang could have adverse affects though. For example, if the offset angle is 22 degrees (as used by Technics) then using the Technics gauge to set 15mm overhang rather than the 16mm recommended by Reloop would have this affect on distortion (the blue line is 15mm).



Of course without knowing exactly what offset angle Reloop use it's just a guestimate, and whether the increase in distortion would be audible is also debatable The Technics gauge might even give better alignment!

So it might not matter anyway, and I just shouldn't worry about it?

Thinking about it, aren't all these Technics-knockoff turntables all designed to also be used with Concorde-style cartridges that don't have a headshell and can't be adjusted at all?
Then the Technics gauge should work.
Does +/- 1 mm overhang really make a practical difference?

[JaS]

I'm not sure? The Technics gauge doesn't really set overhang anyway, it sets the headshell mount to stylus tip distance. If Reloop expect you to use the same distance then it will work; if not then you'll get some other alignment which may or may not be better. If you don't want to use a protractor then you'll have to suck it and see? To be honest DJ turntable manufacturers don't take arm geometry very seriously anyway, which is why they often give no indication of how you are supposed to align a cartridge

Regards,
JaS