cart measurement vs quoted spec

Hi All,

Please! I truly do NOT want to sensationalize anything here, and I'm asking the sort of feed back that I'm now getting, so as to see if there is some reason to believe that the measurements do not tell the correct story.

Dre_j
my Electronic Engineering Consultant who’s Scope and measuring expertise was used, has just this afternoon hopped on his plain to the Munich Hi-End, so your scope related info will have to wait a couple of days, if that's OK.

+++ What output of your audio system are you using to feed your scope? +++
We used the XLR output of the ML326S, I stated that before, as well as having used the build-in 326S phono-modules.

+++ there is the possibility of additive and induced error... +++
That was my first question when seeing the results. Switching L vs R gave the exact reversed results, as I stated before as well.

+++ - The area of resonance could also be possibly due to the tonearm resonance (or somewhere else in the system which is why it would be good to test another cartridge) on that note, does adding damping to your arm change your measurements? +++
Very well, I did try the SME V silicon-trough arm-damping and it had NO! influence at all. I did not mention this so far, since we are now getting into the detail of a two page report that came about during the measuring session. (Very labour intensive job, me doing the setting variations, the Consultant doing the scope work right next to me and writing his report.

+++ If this is a modern o-scope, are you using the cursors to take amplitude values ... +++
Using amplitude values, calibrated to scope's screen grid, no digital read-out.

+++ - Are the gains settings for the phono-stage set to the same level? +++
Yes, and right now I have lots more trust in the ML R/L correct gain (check J.A.'s report on that pre if it helps).
http://www.stereophile.com/solidpreamps/106ml/index3.html
Having exactly reversed results after channel switching confirmed this also.

+++ - Is the cartridge loading the same on both channels? +++
Again, as I said before. First used with ML 47k input impedance, second run with SUT using 13ohm Tantalum Shinkoh 1/2watt 2% (actually better then spec). Also L/R reverse gave exactly reversed results. (I wish that cart be a balanced as that XF-1 trannie)

+++ Depending on how you are gathering the numbers, there could be an entire spectrum of cumulative amplitude which is not exclusive to the frequency intended to be measured and this can also effect your results. +++
Now, why would that only affect one channel?!

+++ There are a number of variables that can stack up and add errors to the measured results. Some other thoughts are the crosstalk introduced by the system itself- this can be checked by sending the output of one cartridge channel into the both input (L&R) of the phono-stage by using a Y-connector. +++
That we did not do, also since the left-to-right out-of-phase-track LISTENING result confirmed the poor results. Next question then is how much that Y connector is going to add to the issue...

+++ I hope this all makes sense +++
It absolutely makes sense, even though some items are inclusive of each other, but better double check, right?

Hi Dougdeacon
just give this here guy at least the time of day, man :-)

+++ It would not occur to me to tackle this common problem by o'scoping a cartridge to check channel balance and/or crosstalk. These distortions are vastly more likely to be caused by resonance behaviors, distortions in the amplification stages and/or speaker problems than by crosstalk or channel imbalance in a cartridge.

99% chance this was a wasted effort, IMO. +++

I have tried EVERY trick, down to machining off 20 thou from mounting screws so as to get more zenith. Please, don't think me being some measuring freak. I'm more the other way inclined i.e. don't trust measurements only and rather use my ears.
This must be more seen as a last resort and as I said: "trying to get to the bottom of it."
Alignment-tweaks are 'peanuts' if you have such discrepancies!
All that stuff you are talking about does not even SHOW on the scope! With the exception of a 6:00 to 6:03 turn of the cart to compensate for its 10 thou cantilever off-set.
Just tell us how you are going to find -12dB to -18dB less cross-talk! or -2dB less channel imbalance! your suggested way. That's like moving the deck-chairs on a listing boat!

Also, why would I get into all this pain with no reason? Just to give you guys some entertainment?
I'm plenty more rational then that, and can think of better ways to pass my time i.e. listening to music :-)

Thanks in any case for all the valuable feedback and detailed questioning.

Greetings,
Axel
PS: Anyone have an idea what a ~ 0.1ohm difference in coil DCR L/R could produce in terms of that issue?!

Hi Larryi,
you say:
+++ I wonder if your problem with orchestral crescendi has to do with your channel imbalance issue. +++
Right now I think it has much to do with it, lots! But even more so, the out-of-whack L/R cross-talk!
Firstly it is much less than spec. and secondly it is 6dB in difference between L/R! If things get busy the channel info starts to 'smear' across, the louder the more noticeable, wouldn't it?
And what else would that be but distortion I ask?

Next, you say:
... initially all seemed quite fine. (When listening to this lend out cart)
Most folk can't even hear a 1dB difference in SPL for a start! (Mono) ---- BUT most folk can hear the DISTORTION caused by such an imbalance,(stereo) yes?
If not getting to the bottom of it (as I called it), you go on and on, with your alignment tweaks to no avail!

Now, let's have some more low down on this quality issue. In an off-line email exchange we/I have a case with a Jubilee owner, who just for the life of it can't get rid of the same kind of symptoms I seem to hear, hallo --- that brand you mentioned.
Next, same brand, also Jubilee with a 3 time factory return! And still not right, plus a split open body side of about 15 thou! And never addressed during the various returns! You mentioned quality issues, now that sound like one.
Pictures are right here by me, if that should sound like an 'overstatement', it is not, as it finally was taken back after plenty PT of prove it on my side.

OK, again my intend is not to blacken any name. --- I still have NOT disclosed the make showing these measurement problems, there where some guesses I did not confirm.

It truly makes me think, how many reticent alignment issues are actually based in an out-of-balance spec cart.
Let's see if we can get a bit closer to THAT part of the issue.

As Raul has stated: We ALL seem to trust those quoted measurements --- and what helps is, that it is nigh impossible for a lot of users to set-up a proper test. Not everyone has acquaintances prepared to spend hours on your gear, if the have an oscilloscope for a start.

Thank you for sharing,
Axel

All that stuff you are talking about does not even SHOW on the scope!

My point exactly. If the tool doesn't suit the task, stop using it and find one that does.

I have tried EVERY trick, ... Alignment-tweaks are 'peanuts' if you have such discrepancies!

Agreed, and I never suggested any alignment tweaks. I did and still do suggest that the audible distortions, horrible measurements and visible defect combine to indicate that this cartridge is beyond hope. Why not just admit it and move on?

[/quote]... why would I get into all this pain with no reason? [/quote]An excellent and serious question, to which only you can provide the answer.

Hi Dan_ed,
why is it that some of you folk make me feel like having root-channel?

Having insinuations of lacking integrity, lacking general understanding of the basic issues, using inane approaches to problem solving, and the like is not warming ones cockles, now would it?

Like just read your own fine stuff here please:
"Having been through a few such discussions with him I know it is just not worth the effort. :-)"

So far I always tried my very best to answer queries, and if some of the opposed party finds it not to their liking, they just put the "phono down"? Hm...

Putting an agenda like this is leaning pretty far out of the bus! It takes courage, for me it does!
I also don't want to come over like some fool, I am simply looking for civilised discourse, --- though I am known to get a bit enthusiastic at times, it is NEVER meant to be unkind --- and all say, AMEN :-)

Greetings,
Axel
PS: Ever heard of EST? Erhard Seminars Training? Well it might help to get a handle on some interactions, as long as I'm not called an EST-hole :-)

Doug,

if a manufacturer would only share that easily your trash it and dump it approach.
10 thou out of centre, since you seem to refer here to optical inspection, is not to my current knowledge a reject criteria in THAT industry.

Now if it helps, I worked over 30 years in the electronics industry and most of that time in Semiconductor Manufacturing, so I do have some idea about quality issues, if you please. And in the spirit we like to get to the bottom of things...

Axel