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In Reply to: Help with VTA on a Thorens TD-125MkII posted by rmchew@adelphia.net on August 1, 2005 at 07:39:48:
There's a reason so many people like the Thorens around here -- they sound great, and they are really not SO hard to tweak. It can be frustrating if you don't know what's wrong, but with some patience and some willingness to "dig in" to them, you can figure out how to make them sing. You can certainly learn a lot about turntables by working on them.I would follow the advice already given and make absolutely sure that you are turning the right two setscrews. It's an easy mistake to make, especially if you have one of the TP16s with the rotating "collar" that hides the screws. It's possible that the arm is snug in there, but I don't see how it could be "frozen". The shaft is stainless steel. Assuming you have loosened the correct screws, you should be able to (gently) get a little rotation on the pivot. If it's snug, this may help you to adjust it down.
How much steel do you see showing along the tonearm shaft? Is it possible that the VTA is already all the way down? If this is the case, then mats or spacers may be the only way to go. I would doubt this, however -- my Stanton 681 has a lot more overhang than an 0M20 (from what I remeber of the OM series), and I was certainly able to get the correct VTA for those.
Also, you mentioned that this is a new cart. I doubt you'd have quality control issues, although this is a possiblilty. Be sure to check that the stylus is fully seated on the cartridge housing and that the cart has no play in the headshell.
There is sometimes a break-in period associated with new carts. Do you have a spare headshell for your Technics with which you can test?
Other things to check --
azimuth: Is the cart perfectly level side-to-side? The TP60 shells can be tilted one way or the other.
arm bearings: does the travel both side-to-side and up and down feel nice and free? With a 30-year-old table, it's possible the tension on the bearings can become misadjusted, but Thorens can be easily readjusted.
VTF: A too-low VTF can cause the kinds of problems you are describing. Have you tried setting the VTF for the higher end of the recommended range? Are you using the settings on the arm adjustment to determine the VTF you are using? Does the increase in apparent weight increase properly as you increase the setting? Just last week, I got a 126 MkII with a TP16 Mk II arm and could not get the arm to show any reaction to the VTF adjustment until I got it up to 1.5 grams. I took off the top bearing screw (counting the rotations so I could replace it the exact same way) and loosened ever-so-slightly the screw that holds the adjuster in place -- it had been binding and the tiny tension wire was not in play at the low end of the range. This simple turn-of-the-screw fixed all of that.
Keep at it -- eventually you'll find out how to get it to perform well. I have felt your pain trying to tweak a Thorens, but this is usually replaced by a "duh" when I figure out I just wasn't adjusting it properly.
Follow Ups:
Thanks for all the suggestions. Ashamed to admit it, but I was using the antiskate adjusting screws and didn't realize the tonearm height screws were under the rotating collar. I didn't have time tonight to see how it sounds, but will report back tomorrow night. I'm going to start with the arm high in the rear and work downwards. I'll also recheck the alignment & azimuth. I thought maybe the OM20 was a poor match, but others have said they use it (or OM30) on a Thorens with good results.
Let us know how it goes. All the best.
Thanks Chris,
Much, much better; not quite perfect, but a great improvement; maybe there's hope yet. Think I may have messed up the antiskate though as when you turn the knob the change is erratic or the gauge doesn't move at all. That's minor and I think I can fix it. Thanks again.
Rob C.
Hello Rob
My antiskate did that too. I'm not sure what happened but plan to eventually figure it out. It has a sticking point. For now I lift up on the knob to get it past the "sticking" point. You can see the magnet cylinder move in response to the knob on the inner part of the arm near the pivot. I'll let you know if I figure out how to get it back to how it was(start a topic at the top of the page) or you do the same.It really is satisfying to figure these things out and I'm pleased with the music produced for having not spent much money.
Regards
Chris
You seem to have lots of experience with the Thorens. What have you noticed about the antiskate device? Mine seems to be off. I have to over apply it. Sometimes I'm not sure if it's doing anything. Do these things get weak over time? It's the magnetic one on the TP16 Mkl. I'm using the HiFi news test record to help set the antiskate adjustment. Thanks
I imagine they could get weak over time, but I don't know for sure. I can't personally attest to any knowledge of the magnetic properties of the material (ferrite?) in question. That said, anti-skate settings aren't quite as critical as azimuth, alignment, VTF, or VTA. If you're getting a good idea of where to be with a test record, I'd just leave it at that.I kinda wish that Thorens had used the TP11s more than the 16s -- I think both the VTF and anti-skate settings are more "true" on the 11s. But I'm not about to transplant a TP11 on my 160 or my 126.
Yes, you're right. My VTF adjustment is not accurate. I just set it using the counter weights. To the other guy, who started this thread, make sure you have a scale to check the VTF.
One other note -- the tension on the wire for the VTF setting can be adjusted. The little tube over the counterweight has a hole in the back of it. Look in there and you should see a threaded sleeve. In that sleeve is a threaded nylon screw that can be moved to increase or decrease tension (the crimped end of the wire sits in the middle of the screw, so you may have to rig something to move it -- I used a pair of tweezers).So if you have a scale (assuming your tension line isn't binding anywhere as mine had been), you could adjust the VTF setting so that it reads accurately.
Again, this is why I love the Thorens -- it's as if they knew their tables would still be running in 30+ years, so everything can be easily recalibrated if need be.
Yeah, I just bought one of those little digital scales on Ebay (I think it was ~$22 with shipping). I've been futzing around too long trying to guesstimtate 4-5 grams for 78RPM carts on tonearms that don't adjust above 3 grams.
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