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cart measurement vs quoted spec

Hi,
I'm a bit puzzled by some cart measurements performed with the ACOUSTECH test record, using HP oscilloscope and using (differential connection) through ML 326S phono-modules.

No loading (47k), measured on XLR pre-outputs. The following transpired:
Left vs. Right = *- 2dB* @ 1kHz 7cm/s lateral (mono track), *spec = <0,2dB!*
Left vs. Right = on 1kHz 7cm/s vertical out of phase track, clearly NOT EVEN CLOSE to out of phase!
1 kHz left channel only *- 16dB* leakage to right! *Spec = >28dB @ 1 kHz!*
1 kHz right channel only *-10dB* leakage to left! *Spec = >28dB @ 1 kHz!*

This seems a most disappointing showing indeed. Let me hasten to say that all variations with regards to anti-skate, VTA, VTF, Azimuth and Zenith, were attempted for any optimisation.

I shall not yet disclose the make, which is a VERY well known brand, and their TOP of the range offering.

Has any one got some explanation for how such a major variation can be the case?!

There might just be some folks out there trying there darntest by NEVER getting their apparent alignment problem fixed, please note the various threads, ---- and it might be a cart way out of quoted tolerance?

I have also noted that in this instance, MAJOR Azimuth (+/- 2 deg), VTA, VTF, changes had absolutely MINOR measured effects!
The 'biggest' in this case was 'Zenith' by some 0.5mm left turn to compensate for a 'minor' out of centre cantilever (~ 0.25mm off-set to the left).

Tonality and such is NOT really affected, BUT distortion with massed instruments/orchestra etc. i.e. as soon as things get 'busy' the problems start.

Greetings,
Axel
axelwahl
axelwahl OP
788 posts
 
Hey Dan_ed,

man, not "LOOK AT ME" ...look at these measurements. I have no noise to take care of as I explained, so ARE you reading what I put there? I NEED NO FILTER neither my buddy, somehow it feels you are busy with some other contributor. No need to get tizzy with each other, please...

You say:
>>> Now, a spectrum analyzer would be much different. <<< Well yes, I guess we can agree on this. But hey, now we are really talking $$$. Just to check a cart, well maybe, but not in my budget, sorry.

So let's agree you go use your DMM, and I wish for you it's a FLUKE of sorts, else any error will be very likely further aggravated.

Please lets just be nice, and I will say it next time more pretty like e.g.: measuring with a DMM, compared with a O'scope appears to me of a little lesser result related quality. Also no filter seems needed, given of course the particular circumstances. (I think of hiring a typist, all that for simply "sux" :-)

Love you all,
Axel
glai's avatar
glai
446 posts
 
LOL :)
axelwahl OP
788 posts
 
Hi :-)
I wish Dougdragon, and Darn_ed would join the that "LOL:)" just a little bit --- hey, now "look at me" man!
Greetings,
Axel
PS: that right man, someone thinks I'm that Beverly Hill cop dude Foley, pissing off that whole oh so serious congregation?!
axelwahl OP
788 posts
 
Hi All,
as mentioned (promised?) the Orpheus L cart measured today.
It is to spec. in all but down by ~ 1.5dB on cross-talk at -28.5dB but the same for L/R
Spec. Channel separation: Greater Than 30dB.
Listening to the cross talk Ulti. Test tracks seems to confirm it NOT being any better than the Lyra Dorian that we also measured.

Enjoy the music while you can,
Axel
PS: Any VTA and Zenith tweaks did not yield different / better results.
axelwahl OP
788 posts
 
Hi All,
it's been a couple of days, and let me share today’s status on what prompted this thread.

The the cart measured was found to have an out of spec. tracking angle (plus further test still to do...) Since it was still under warranty it will be replaced.

As I do not have 'deep enough pockets' and have not followed Doug's advice to chuck it in the bin, at least I now may get a working example.

Funny thing is, that I am now much more into the 'beauty' of MM's sound, so I might just keep it as a trophy :-)

It also shows that even the most expensive offerings by a manufacturer is no guaranty for faultlessness.

So, if anyone just can not get his cart to perform despite having done his alignments over and over confirmed --- it might be the cart actually is the cause.

Greetings,
Axel
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