gofar99 Messages: 1955 Registered: May 2010 Location: Southern Arizona
Illuminati (5th Degree)
Hi Wayne, Quite interesting. I suspect the problems arise because of the UC202. I have one plus a few others and found the one that gives the best results is a SIIG HD7.1Box. An older unit, but native 24/96 resolution. I feed it to a Velleman PCSGU250 PC scope. Also an older dual trace unit. It can provide many of the measurements at the same time you were having trouble with. Together with the test LP and using a Simaudio Moon phono preamp which is not my most favorite to listen to, but is extremely accurate and quiet (they say over -100 db in MM) I get what I feel are accurate and consistent measurements. My findings have been that cartridges are not as accurate as many folks think....at least none the average person can afford. I use ones as lowly as an AT F7 to as high as a Dynavector Karat 23MR-RS with a middle ground of a Grado Sonata II. Channel balance in amplitude is often quite good. Things like separation of channels and cross talk are almost always not symmetrical. One channel will tend to bleed onto the other in a unsymmetrical manner (L-R one values R-L slightly different) Even the high end ones are prone to this. As price goes up (usually) the performance gets better up to a point. A parameter you didn't address is tracking. As long as a cartridge is nicely nestled in the groove all is well. The moment the amplitude of the modulation exceeds some value performance goes down the tube.
All this is good stuff...but in a perverse manner it doesn't tell you how a particular turntable, arm and cartridge will sound. I have a number that measure rather closely, and sound quite different. A lowish end AT and a higher one measure nearly identically, but sound worlds apart. I guess this is what makes our hobby fun to pursue. BTW, the screen captures are quite good.