Ortofon RS-309D opinions

I have the AS309-S and I had the same questions. Ortofon were happy to give an explanation - see below.

I ended up using the alignment gauge that came with the tonearm, as it was a bit difficult to get Mint to make one. Now that I have re-read this, I might try my SPU with pivot to spindle of 314mm.
Anyway, the arm sounds great and clearly more than one way to align cartridges with this or any tonearm.

BTW, I use Mint tractor for my other tonearms.

There are two schools of thought concerning this arm – the figures that are suggested by Ortofon Japan ’s engineers, versus the suggestions by our chief of cartridge engineering (in Denmark ).

The recommendation from the Japanese engineers is:
Mounting distance = 311mm
Eff. Armlength = 326mm
which gives overhang 15mm)
Cartridge parallel to headset, i.e. offset angle like the arm itself (19 deg)

Denmark’s recommendation is:
Mounting dist = 316,6mm
Eff. Armlength = 329mm
Off.set. angle = 16.5 deg

Denmark’s rec. gives Baerwald alignment.
As you see the cartridge need a slight twist with respect to headshell.The stated eff. armlength is easily achieved with Ortofon headshells and most cartridges.

Using a SPU (in G-housing) gives an eff armlength of 329mm
Off.set angle is of course determined by the arm itself, i.e. 19 deg.
A mounting distance of 314mm will then give the best result.

Best wishes,

Louis @ Ortofon

I'm using a Mint with a 309-d which is set at Denmark's recommendations (316.6) for a 309s, in Downunder's message. The cartridge is twisted in the headshell so the offset is correct.

Has anyone noticed the downforce adjustment is useless and you have to set it to zero and move the counterweight to adjust the tracking force...?

Thanks, Downunder. Interesting. As you say, more than one way to skin a cat. Maybe the Japanese Ortofon method is better, who knows.

After my message, I changed the pivot to spindle distance from 311mm to 314mm for my SPU Royal. So effective length is now 329mm.

On my SPU, I prefer the sound of the 329mm effective length. Sounds more pure and clearer. I am not going back to the Japanese 326mm for SPU.

I will next try my technics EPC100C mk4 at effective length 320mm. This will be interesting.

cheers

Sprog, I havde a 309-D and the tracking force adjustment knob works just fine for me. I do not have to move the counterweight to adjust the tracking force, just the knob.

You may want to check with Ortofon because the knob should work or it would not be on the arm.