Calling ARO/Prefix users

Mark,

The ARO is a little different. There is a hole in front of the arm base. A chassis mount style plug is mounted into this hole from the underside of the armboard and secured by 4 tiny woodscrews. Naim thoughtfully provide a spare with the ARO in case you lose one!. Back on top of the armboard, the lead-out wires hang out of the bottom of the unipivot bearing cap ie they do not go through the centre of the arm base as they do in fixed bearing arms. The lead out wires are terminated in a small round socket which is mated with the plug through the hole in the armboard.

The wires below the amboard are dressed in a more coiled fashion, not straight as they are with the Ekos.

Jeremy

James,

Good question, it could be inconvenient if you don't use your LP12 with the baseboard removed and you swap arm tubes regularly.

The trick is to be able to access both top and bottom of the TT at the same time, such as you do when adjusting the suspension. Then the plug and socket can be mated by pushing the socket from the top while holding the plug in place from below. You should find that it makes levelling and adjusting the bounce easier in any case since the subchassis now has very little to damp the bounce.

Jeremy

PS Listening to Rachel's Selenography on vinyl right now, absolutely unbelievable! Don't know how much it has to do with this tweak.

James,
On my LP12 the Prefix is not covering the plug, you can access it through the gap between the Prefix and the arm base. I'll try to take a pic when I install the Armageddon next week.

Jeremy

James--

The Prefix should be installed in the right front corner of the LP12, so there is plenty of space between the end of the Prefix and the location of the arm cable plug.

Jeremy--I've tried this in the past, with mixed results. My best results have come with the screws used, but not screwed in "Linn tight."

The other thing I would note is that EVERYTHING you do to an Aro will affect how it sounds. If you really want to drive yourself nuts, try changing the force you use to hold the bearing pillar in the arm collar...

Best,

Bob

Bob,

Thanks. I noticed a big difference probablt because the leads are too short while I wait for the proper lead assembly to arrive from Naim.

I agree about the things that make a difference to the sound, with th ARO it doesn't appear to be so much the conventional things like tracking weight VTA and bias. I have the collar screw so loose at the moment I don't know how it stays in place

While you're on the line, I notice a tracking distortion on a couple of records (including Antonio Forcioni & Sabina Sciubba Meet me in London on Naim's own label) right in the middle of side 2. This isn't cured by adjusting the bias. So I think I need to attend to the overhang and offset. Did a search but couldn't find any definite advice on this, do you know if this is a common problem with the ARO (and Koetsu cart).

Thanks,

Jeremy

Jeremy, great thread! This is the best advice, which I received here in 5 years and whose execution does not cost anything. I agree it extend bass and increase "flow" even further!

After removing the four screws I stated that the socket in the hole wedged. Therefore I increased the hole over for instance 3/10mm.

BTW: Before 4 years I recommended here to remove the bottom of the LP12. This brings better basses. The accesibility to the socket is then also good. The moreover I recommended here to replace the LP12 feet by wood feet. One can sand the feet off in such a way that the LP12 stands absolutely firmly. Then you have better heights and long time bouncing.

Ulrich

Just wanted to post that the Naimed LP12 with Koetsu Onyx is finally sorted. The cost is nothing if you already have a drill press, $96 + tax in US if you don't (plus you get a new toy to keep). Add $100 if you include a proper Naim counterweight.

Don't want to bore everyone with the details so please contact me privately if you're interested.

Jeremy

Jeremy

Aro/Koetsu Onyx: please let us know the details! I am very interested. How does it sound? Is it an old Onyx? Platin? Diamond?

- Jun, not bored at all!!

Jun,

I know you're just desperate to get your Onyx on the ARO! So was I! They all said it couldn't be done!

I'll post some more details soon. I do believe, though, that Naim have their ARO spec spot on - well, what else would you expect.

Meanwhile, the first thing before you get too excited is to weigh your Onyx. The next step is to measure the stylus to mounting hole distance. This can be done VERY CAREFULLY with a magnifying glass and a ruler arrangement by using a reference point like the front of the cartridge. Better is a travelling microscope. Every Koetsu cartridge seems to be different.

Jeremy

Many Thanks, Jeremy! Sorry for my English, I couln't find "spot on" in my dictionary: what does this mean?

I'll post some more details soon

Can't wait for the details! How does it sound??

- Jun

Jun,

Sorry, busy listening to the bolt mod. You haven't sold your LP12 yet have you?

So how does the ARO/Koetsu sound? Well, apart from sounding like only the Koetsu does, no problems now tracking Cat Power and side 2 track 2 of AF and SS is now rock solid. I have heard this recording many times on CD and vinyl and this is the first time I have noticed the character of Sabina' fortissimo, it is almost endless and you get the sense of that. The other big news is that the background noise is really low, it' s just like when I used an XX-2 in the ARO and there was never a dirty record.

There is really not much difference tracking a test record. Lucky thing is, not much music consists of a 300Hz modulated tone.

The overall sound is just as you'd expect - a combination of the speed, detail and dynamic range of the Koetsu and Prefix, the timing of the LP12 and the addictive flow of the ARO.


Jeremy

"spot on" = absolutely right. Similar phrases might be "bang on", "dead right", "on the button".