Along similar lines, I know that Nottingham Analogue recommends that the grub screws used to set the tonearm height (for setting the VTA) to be made only tight enough to secure their position. They specifically advise against torquing the screws too tightly, claiming that it will result in worse performance and a more strained sound quality. Of course, YMMV.
Albert Porter over on Audiogon sells these. He says it's a difference you can hear....he has a Altas (but with SME arm)...maybe he has some thoughts on the proper amount of torque...
Albert is a great guy. I bought one of his TQ screw drivers and tried it out. Totaly smothered the sound of my Koetsu MK1 Urushi on the FR66S. Way too tight IMHO. I thought I was going to strip the screws... sometimes we want a sure thing that works everywhere but magic bullets are rare in my experience.
it really has an effect on sound quality.
right amount of tork should be around 0.073Nm or 0.65lb-in.
higher tork=more dynamic and tight sound, sometimes a little bit edgy
low tork=smooth relaxed sound but loose bottom.
Richard Mak, producer of the AnalogMagik toolset, offers a Torque Driver Kit which he suggests is viable for 90% of cartridge screws. US MSRP $185
From his Web site:
In conjunction with SEM Powertrain Engineering, AnalogMagik has performed extensive research, measurement and listening tests on the effects of proper Torque on the headshell screws and the resultant sound of the cartridge.
On a microscopic level, the torque on the headshell screws affect the frequency response, resonant frequency, harmonic distortion, as well as the as well as the inter-modulation distortion levels of the generated signal.
If the torque is too tight, it will change the resonance frequency of your setup, acting as an unwanted equalizer, contaminating the audio signal. It will lead to a reduction in the high frequency response, as well as causing an increase to the level of inter-modulation distortions in the low frequency region. Sonically, this translates to a sound with smothered ambiance and "air", while instruments will be robbed of natural decay and resonance.
This is quite an old thread but I’ve only just happened upon it. There doesn’t seem to have been a conclusion so I though I’d relate my own trials.
I bought a torque driver that claims a range from 5 to 60cNm (0.05 - 0.6Nm) and even came with a calibration certificate for the points at 60, 36 and 12 cNm.
My usual cartridge is an Ortofon SPU Royal N which comes with its own screwdriver and peg wrench. Using either of these against the torque driver I couldn’t even get to 5cNm, more like somewhere between 2 and 3. Assuming Ortofon know their cartridge’s robustness I forbore to apply a grip stronger than fingers and just used what I could achieve comfortably.
I’m using a Schröder Reference arm and a brass cartridge mounting plate, the plate attaches to the wooden “head shell” of the arm with a single screw and here the tightness really matters. Too tight and though the music has a swing to it the dynamics are subdued and there’s no excitement, to get this cartridge to play rock music convincingly requires this screw and also the counterweight grub screw, which dears on a plastic sleve, to be barely tight enough to hold their positions. A bit of Dio era Black Sabbath happened to be at hand when setting this and was quite telling. The angle of an allan key and listening was the only way to gauge these in the end, the torque driver was well below its useful range.
Where the torque driver does come in handy is the screw that locks the arm height adjustment. The actual adjustment is by a hidden screw inside the pillar with a left hand thread but the setting is locked by another grud screw and 21cNm was about there and at least I’ve removed any inconsistency from this when adjusting arm height but it’s effect is quite marginal compared to the two key screws who’s torque I still can’t measure.
The Dynavector 17D3 I used while my SPU was rebuilt seemed to want a tighter setting on the mounting plate to arm screw but this was pre torque driver and just my impression. Probably every combination will be different.
