Calling all OC9 users

Posted by: woodface on 20 November 2001

I have an OC9 in a full spec LP12 set up (Lingo/ekos /circus) and thought I had it set up optimally. I have it on 1.75 tracking and 1.75 bias. Everything was hunky dory until I played REM 'New adventures in HiFi'; at first it sounded awesome but then began to sound a little thick and heavy. This set me to thinking about my tracking weight - is it too heavy? The OC9 frequency graph is based upon 1.5 gm but I fear this may be too light. Before I delve into tweaking hell I would be grateful if those using the same cartridge could report on their findings so I have some kind of average to work to.

Posted on: 20 November 2001 by Eric Barry

I have an OC9 and I track it a tad over 1.5, certainly not 1.7. To get in the ballpark, you should get the Hi Fi News test record and set it so you can track the +16db track, and set bias for even breakup in both channels, and then possibly back it off a tad (as the antiskating is higher on the inner groove than the outside of the record). You can also set by ear on something difficult to track, like loud orchestral bells, sibilant sounds, fem. vox., etc. The OC9 is a superb tracker, so don't worry about tracking at 1.5, it should handle it.

--Eri

Posted on: 20 November 2001 by Craig B

I've no direct experience setting up/using the OC9, however ambient room temperature is an oft overlooked operating condition that affects phono cartridge performance. This eventually becomes all too clear to the avid vinyl enthusiast during the change of the seasons.

Linn are one of the few manufacturers to recognise this and do mention it in their 'Tonearms and Phono Cartridges Manual' (does anyone have the PDF they can send to me?).

Linn recommend 1.7g VTF for their cartridges as optimal at 20C and suggest increasing by .1g for every decrease of ? degrees C or alternatively reducing VTF by the same ratio for temp increases above 20C (all within a reasonable range of course).

Me, I just adjust it until it sounds best to my ears, however, with Linn arms I usually end up pretty close to having AS set ~20% less than VTF with any reasonably good tracking cartridge that I have tried. I have also found that during the course of a listening session records start out sounding best at a higher VTF value and end up sounding best at a slightly lower VTF as the fest continues. I usually leave it set at the latter value and just ignore the first record side during the next session.

Given the season and ATs suggested values, I would leave VTF roughly where it is now and drop AS a bit, however if you have your home heating cranked up you may wish to experiment with lower VTF (and AS).

Of course, the REM disk might just sound 'progressively' worse relative to some of their other releases.

Craig

Posted on: 21 November 2001 by woodface

I had a bit of a play last night and settled on a tarcking force of just above 1.5gm (the next notch along on the ekos) and this seemed to bring about a deal more separation. I was surprised that the apparent level of detail increased as the tracking force was reduced. I will monitor it over the next couple of weeks and adjust the bias as required.