Hi gents
Finally got a chance to have a check / adjust of my setup yesterday and today (best-laid plans and all that). So, to recap (save you re-reading my "war & peace" first post, but be aware I'm creating another one)...
- I'm finding excessive sibilance on LP replay. Trying to work out why, given that the cartridge alignment / setup looked OK on initial measurement.
- It's a 3-motor Voyd with Origin Live Onyx arm and Goldring 1042 MM, into a Tube Technology M.A.C. phono stage. The arm is the 9.5" version so uses the same geometry as Rega.
- Phono stage does not have adjustable capacitance for MM, specs quote it as 150pF (plus tonearm cable - I have the OL upgrade cable fitted so not sure if that's different to the 50pF John mentioned). I have also noticed that I have different valves fitted to those described in the specs, which is different again to what's printed on the actual board inside (12AT7 / 12AX7 vs 12AU7 / 12AT7 vs 12AX7 / 12AX7, respectively). The valves are the ones fitted when I bought it (Second hand) so no idea if it was supplied like this from the factory or a previous owner changed them. Photos shown below.
- The quoted input sensitivity for the phono stage is an (unbelievable?) 0.8mA for MM and (also unbelievable?) 0.08mA for MC - see the spec sheet that I downloaded from the website (Tube Tech stopped production many years ago I believe, but the website is still active).
I adjusted the VTF and, heeding the advice I was given here, re-checked it by bringing the weighing scales down to the heigh of the platter + LP. I did this twice, once to align with a thicker (180g) LP and again slightly lower to align with a thinner pressing. Before doing this I used the supplied 5g weight to calibrate the scales (of course this assumes the weight itself is accurate!) The difference in VTF was small - 1.93g at the lower height vs 1.97g at the upper height. I found an old set of the Ortofon balance scales and checked the weight with these against the electronic scales, it seems that the scales are fairly accurate, as far as my knackered old eyes can see. It looks like the Ortofon is recording 2g at the upper height, not sure I could discern the difference between 1.97 and 2 on those balance scales...
I checked (with a ruler, so not 100% accurate) the pivot to spindle distance and it's 223mm I think, which is within the 1mm tolerance that Origin Live quote so I believe the armboard has been drilled accurately. The cartridge overhang is approximately 18mm.
I reduced the side bias by moving the clamped ball back close to the pivot. It's now about 8.5mm from the centre of the upright as far as I can tell. I also re-checked the cartridge's zenith and it seems to be aligned correctly (sighting the cantilever along the lines of the gauge, not using the cartridge body).
The VTA is set so that the armtube is parallel with the platter.
I should have mentioned before that the LP I noticed the big problems with is Texas - The Conversation. Perhaps this is just a particularly cr*p production / pressing (no comments on musical taste, thank you!)
but although there may be a slight improvement I can still hear the sibilance quite obviously. Just for clarity, and in case I've been using the wrong term, by that I mean that the vocal sound "S" (as-in "Speak") sounds distorted and exaggerated as if you're trying to hiss like a snake, the "Sh" ("Shove") sound can also sound shrill. Crash cymbals also sound, well, too "crashy"! I can hear this effect on other LPs too although not to the same extent. A recent 180g pressing of David Bowie "Let's Dance" has a slight tendency towards this effect, and a few older LPs have also exhibited it. I'm not unconvinced that I can also now detect a tiny bit of mistracking distortion on some louder passages, during "Ricochet" for example.
I'm going to experiment some more with that side bias as I can say that the imaging is not good, and from what I understand, getting the bias correct does make a significant difference to this. My digital setup runs rings around LP in this regard at the moment.
I've still not tried swapping the stylus over with the one from my other turntable yet, which I will do, but for the moment I'm going to persevere with the current one while I seem to be making small improvements. If anyone can think of any other possible reason for the problems, please let me know!
I need to get this right because in the not-too-distant future I need to repeat the exercise with John's OL Encounter! Best make sure I know what I'm doing....
Thank god for Ikea Groggys! Not too clear from the photo but the centre point on the measuring platform is near-as-damnit the same height as the HFN test LP:
Readout in this position
Double-check with the Ortofon balance scales - again not too clear (excuse my awful photography with an iPhone) - the stylus appears to be on or almost on the 2.0g mark:
Checking again at the slightly lower LP height:
Side bias adjusted to give 8.5mm distance from the upright part of the bias hanger to the centre of the clamped ball: