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

Showing 2 responses by rauliruegas

Dear Axel: That's why I " love " those vintage MM/MC cartridges and maybe one or two of today cartridges that come with real test diagrams of some of its specs even some of them comes with a " certificate " for its specs.

Other that your recording maybe is not right on its specs what you find it is no surprise at all. It is easy to write specs on product manuals/brochures where we read it and almost never we ask for a test on it that can validate those specs: we trust on it.

That happen not only on products like cartridges or TT but in electronics/speakers too.
Any one can read through Stereophile reviews the manufacturer specs and the real measurements that JA makes where you can read that almost always are " differences " , sometimes and more often that we like " severe " differences.

Regards and enjoy the music.
Raul.
Dear Axel: Well, it will be interesting the Winfeld ( I assume is this one ) manufacturer answer and how they validate its specs on each cartridge sample.

Of course that could be really useful and appreciated that other cartridge manufacturers can share with us their " thoughts " about.

Regards and enjoy the music.
Raul.