Help with vinyl frustration?


I guess it is my turn for some frustration with set up. I've read posts about it, but haven't encountered it until now.
I bought a new ScoutMaster about 4-5 months ago. I installed a brand new Dynavector 20XL which is supposedly a good match. However I have never sensed the magic that I believe this TT is capable of providing. I have checked and rechecked all calibrations. I have been up and down the scale of VTF/VTA. The problem persists.
The problem is that on certain songs on certain albums the vocals and upper mids/mid bass have a slight distortion. This might happen on one song and the next song sounds fine. This began just about the time of break in for the cartridge, maybe 50-75 hrs. As I said, I have checked and rechecked. I can find nothing wrong. I get the feeling that it is a very minor thing. Then sometimes I wonder if it is the cart itself?
I only notice this on classic rock albums which is what I play the most. I haven't heard this on classical albums. Which causes me to ask, Am I seeing to deeply into a poorly recorded record? But if so, why only certain songs on the album? And always the same place; vocals? This doesn't seem like an acceptable answer. Certainly if it is I guess I shouldn't have sold my MMF-7. However the SM kills the 7 on classical.

Anyone with any suggestions?
128x128artemus_5
That was it. Overload. That was the word that kept running through my mind when I heard it but I never thought about the phono preamp overloading. Duh! it was turned down but not enough. The Wright has 65db gain w/o the 1:10 tranny. I've got it turned down as low as it will go now and the distortion has gone. At least it has on the 2 of the songs that were leading offenders.
Thanks a bunch
it sounds like a cartridge problem to me too. an alignment issue would be the first place to check.
Distortion can also be aggravated by too little vertical tracking force (VTF). I found this to be the case with a couple of cartridges I owned. In both cases, I was using an inaccurate measuring device. Once I got a more accurate stylus force gauge I was able to clear this up significantly. Finally, skating can cause distortion, but you'll typically hear it in a single channel when that's the case. Since it seems like overloading correction has solved the issue, this post may be moot, but hopefully still useful.
Artemus, doesn't K and K have a 1:15 or 1:20 step-up? Might be your cheapest solution unless you can trade your 20XL in for a higher output cartridge. If it were me I'd try to keep the LO MC thing going since that's my preference.
Dan ed
Wouldn't a 1:15 or 20 give more output? I was thinking 1:5 would be less, but maybe I'm thinking backwards.
Nonetheless the problem seems to have gone now that i have it turned down.