High Frequency distortion / Image and audio

I have some slight distortion at certain high frequencies which I can't figure out on my Beogram 6500.    I didn't always hear it with other records but I could finally confirm it wasn't my imagination on the first track of my brand new Norah Jones 180gm LP.  I thought it might be the cartridge which was rebuilt by Benny but he and I tried a few other decks and other cartridges on the same LP track and it still seemed slightly "over driven" (but not actually distorting) on the best deck and cartridge he had.   We both agreed that my MMC3  had the best overall sound of some other ones he offered.  However, when I got home I could actually hear it distort.  Seems more prominent on the right channel.  I had it going through an AUX input with my BeoSystem3 so I ran it through my newly acquired  Beomaster 7000 (Thanks Benny!) and listened through headphones to make sure it wasn't an imbalance with the cables/EQ and it was definitely still there.

I then thought the pick up arm seemed to be pulling away from the indicator arm a bit too much and that the tension may be causing an issue but I've adjusted everything according to the service manual and have corrected for that but it unfortunately did not solve the issue.  Neither did adjusting the weight heavier or ighter.

I've cleaned the diamond as best as I can but there is still a dark discoloration on the tip which (for all I know) could be perfectly acceptable.  FYI I am very new to vinyl so I'm curious if there could be some physical limitations to some vinyl LPs and what my equipment is able to actually track.   Even Benny's equipment did seem to struggle to keep this particular track (track 1 "Dont' Know Why" from Norah Jones' Come Away With Me)  as smooth as I would expect on the high note.  Could this actually be on the LP?  The CD sounds fine on that note but obviously doesn't have the dynamic subtlety I hear on the Vinyl.

 

Would love some input from you veterans as I want to know as much about my equipment (and vinyl)as possible.  I'm happy to accept that vinyl isn't digital but I certainly don't want to except bad audio if I can avoid it.  

In the link is an audio sample with a picture of tip (as best as I could).  The audio is from my iphone but you should still be able to hear the distortion when she hits the high note.

Thanks!!

https://vimeo.com/88277537

 

 

At the risk of shamelessly bumping my topic... Here's a more simple question;)

 

Is the dark discoloration on the diamond tip usual/acceptable or a sign of too much build-up?  I haven't been able to get it off and am happy to let it be if I'm being too obsessive unless it could cause sound quality issues.  I hear a slight distortion in the high range.  Could this cause that?

Thanks!!

 

 

 

It sounds like the signal level is clipping to me. As if the signal is being over driven. I wonder if you're not having some problem with the RIAA board in the Beogram.

DMacri:

It sounds like the signal level is clipping to me. As if the signal is being over driven. I wonder if you're not having some problem with the RIAA board in the Beogram.

Thanks DMacri.  Yeah.  I feel I've narrowed it down to either the RIAA being too "hot" or (hopefully) the weight balance of the arm.  

 

After reviewing other pictures of diamond tips I believe mine is probably normal and in good condition.  I've got everything on the arm calibrated nicely except I need to confirm the pressure of the stylus.  

I also suspect that the weight adjustment on the arm is NOT accurate.  I've discovered that I actually can minimize the distortion a bit by cranking up the weight to 1.8.  So maybe I'm on to something there.

Is there a way to test the weight or zero out the weight on the BeoGram 6500?

I know it's trickier on this model than earlier models as it was designed not to loose accuracy.  Nothing in the service manual about calibration, but if it can go out of adjustment there has to be a way to put it back.  Any ideas about this or confirming accuracy? 

Mistracking can produce the kind of sound you describe if I understand your description better. Also it shows up as sibilance on high freq stuff. I can't tell much from your photo of the stylus, it's possible the black area you're seeing is due to light diffraction in . he stylus rather than something on it. Without true stereoscopic microscope it's darned difficult to actually evaluate a stylus.

I have an old Shure stylus force gauge, it's a tiny metal balance beam with a sliding weight and a notch to drop the stylus into. I have used it before but on the B&O table it's a little harder to do than with a pure manual one, as you have to get the thing to drop the arm while the table is not spinning. I had to put on a record, start the record playing, then pull power, gently raise the arm, pull the record, then gently drop the arm by hand into the gauge. Then carefully reverse the process.

If I were really interested in stylus force gauges now I'd get one of the digital scale ones where you drop the stylus onto a slightly soft rubber pad, that seems like a safer approach than the hard metal groove in my old Shure one, at least for B&O gear.

Jeff:

If I were really interested in stylus force gauges now I'd get one of the digital scale ones where you drop the stylus onto a slightly soft rubber pad, that seems like a safer approach than the hard metal groove in my old Shure one, at least for B&O gear.

An original B&O stylus weight scale actually looks like this!

So I guess it is safe, but you're right it is difficult to use in practice, and I have never dared trying it out...

Thanks Jeff.  It certainly sounds like what you are describing.  Is there a specific type of "mistracking" you are thinking.  It does seem to be only distorting in the left channel.  The Right side sounds "harsh" ( which may just be a difficult LP to track) to but does not actually distort. I can also confirm this afternoon that it does not appear to be the cartridge as I've achieved the same distorted results in the left channel with a different MMC3 that I borrowed.  

Is it OK to "over weigh" the stylus a little or can it really do damage?