2. analog
  3. 1081893118

TT setup woes

I am having some difficulties in setting up a new (for me) analogue front end (Nottingham Hyperspace TT, OL Illustrious arm, Shelter 90X cart.). Intially I set the VTF to 1.9g; dialed in the overhang with DB protractor; and set the anti-skating bias at what the mft. of the arm said was a good starting point. The VTA looked and sounded a little off; but since the arm was as low as I could set it and it would be a week before I could get the collett machined so I could set the arm lower, I went ahead and tried it. It sounded wonderful. I listened to records all weekend. It tracked everything I played. Floated images out in space like I had never heard. Here's the problem. The next week I had another 0.100" machined off the outside of the collett. In my hurry to set the arm back up, I didn't notice that the wire cradle that holds the anti-skating bias bob weight had moved. The result was too much compensation. This was made apparent by the bad break-up, misstracking in the left channel on the inner tracks of one of my favorite albums. The anti-skating problem was corrected, but the buzzing on the albums played while it was off is still there. Records not played when there was a problem, seem to do OK. Also, the damaged (?) LPs seem to play OK on my old rig (MMF7, Clearaudio Vert. Wood). Both cart. have elliptical stylis. The sound now seems to be less satisfying. Female vocals have a slightly glazed or metalic sound to them and the imaging is not quite what I remember from my first sessions. How much of this is psychological due to my hearing it break-up; are the LPs in question damaged or is it still having problems with the TT setup; I don't know. Any help or suggetions will be appreciated. -JT
john_tracy
john_tracy OP
341 posts
 
Thanks for all your help. Patrick, I did use HiFi News test record to reset the anti-skating bias. Tom, since the inside of the collett was fitted to a mandrel that was cut to fit on the lathe, the machining to the outside SHOULD be perp. to the pivot. Doug, I did reclean the records. I will say that when the problem first occured that the anti-skating bias was so out of whack that the arm would travel very rapidly to the outside of the record. I doubt if there was much force at all on the inside groove wall. I have noticed that small changes to the VTF do make a difference. After the tracking problem I set the VTF to 2.0g. I also rechecked the overhang with my protractor. I have since reset it to 1.85g. I have also noticed that amount of torgue (sp?) on the two set skrews for the pivot collett does affect the sound. Since machining the collett to allow the arm to sit lower does affect where the set skrews bite into the collett (and their leverage on it) I'm starting to wonder if this might be a factor also. Also, even with the 0.100" I had machined off, the cart. still appears to the eye to be slightly high in the ass. Should I have some more taken off? I guess I could blow all this headache off and go back to listening to those little silver M_F_ers.
dougdeacon
3,338 posts
 
John,
The 901 likes to be very slightly down at the back. It sounds a trifle shrill set up the way you describe. Again, I don't know about the 90X but it's a fair assumption that it might prefer a similar orientation. At the very least you should have the ability to try it. I'd find a way to get the arm a bit lower.

Just my $.001.
john_tracy OP
341 posts
 
That's where I am heading. In the initial setup I had the cart. loaded with 300 ohms. Probably to kill some of that shrillness. Last night I was listening to the new Peggy Lee release, Latin A'la Lee and switched to 100 ohms. Bang! Peggy Lee started to sound like Peggy Lee. Imaging and focas improved. Tried some more records and noted that there was still some of that shrillness. Removed the adjuster to lower the arm by another 0.060". Better, but still not there. I am going to take the collett back to my machinist (how I wish I were still a chemistry grad student at Stanford with access to a machine shop) and have as much as I can removed. Dropping the arm 0.100" doesn't change things much. Also, I find that there is a VERY fine line between too loose and too tight with the two set skrews that fix the arm to the table. Thanks again for everyones input.
4yanx
1,576 posts
 
John - I am distressed that you are having such difficulties with the Illustrious/Hyperspace combo. On my Spacedeck w/Mat 1 the VTA was a snap. (maybe try a thicker mat of some sort to see how it changes things). Have you considered contacting 'Not with respect to the issue? Hard to imagine there would be that much difference in pods. Know you probably don't want to spend more for a different pod - but maybe they'd have suggestions. It just doesn't seem right.

Yes, the two grub screws make a difference with respect to tightening. JUST enough to hold in place and equal if possible. I spoke to Tom Fletcher once and he told me, and has told others, that all "bits" on the 'Nots should be just snugged so that if all were loosened just a tad, the table would fall apart. I went through and followed this advice and things opened up tremendously when compared to when I had everything cinched down pretty firm.
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