cart measurement vs quoted spec
This post was interesting, until I reached the part where you FINALLY mentioned the off-centre cantilever. If the cantilever is visibly off-centre, why waste time on performance measurements? The manufacturer did not quote specs from, nor would any reasonable person expect on-spec performance from, a visibly flawed sample. Measuring junk is silly - discussing those measurements is inane. ;-) I have also noted that in this instance, MAJOR Azimuth (+/- 2 deg), VTA, VTF, changes had absolutely MINOR measured effectThis is true for all cartridges. For azimuth and VTA (SRA), MAJOR changes always have MINOR effects. These two adjustments have VERY TINY target zones. Once you're outside those zones, further changes have little effect or, in the case of azimuth, even contradictory or unpredictable effects. Changes to these parameters must be made in TINY increments, lest you swing back and forth past the target zone without ever hitting it. A 2 degree azimuth change is at least 10 times larger than the target zone, so the probability of hitting it with such changes is quite low. Better sample + smaller adjustments = better results with fewer measurements. |
The full name of the test record that was used is: "Ultimate Analog Test LP" by Analog Productions. Axel Hi Dougdeacon, phew, now let ME tell you, that this particular main-line manufacturer considers that ~ 0.2 cantilever off-set within tolerance! +++ For azimuth and VTA (SRA), MAJOR changes always have MINOR effects +++ Listen! I did, as I mentioned, maybe not that it came that clear across. All of this 'tiny' stuff you can HEAR, oh yes, but IN NO WAY SEE ON THE SCOPE, right? So, I think this measuring is not exactly inane nonsense. Unless I hear from a production cart maker that a 0.2mm off-set is way out of spec. It is a problem that has been noted before by e.g. J.C. how tricky it is to get it right BY HAND, never mind by some tool, jigs or what ever in volume runs. I do not think for one moment that I'm the only one around trying to get his cart alignment right, whilst the cart itself actually confounds those hyper-tolerance attempts as e.g. preached by DerTonarm... If you can have such wide spec variations, go tell me 0.01mm starts to count!? No way for the scope, and who can tell for your ear. Greetings, Axel |
Dougdeacon afore we're all gonna ride real high on that one, a little supporting help for all those imperial/inch folks. 0.254mm or 2.5 tenth of a millimetre = 10 thousands of an inch! (I hope this will help some) I'd be little surprised if there arenÂ’t some (or more) folks that would not even trust themself to see that difference... As a trained Engineer (Mechanical) I can, thank you. But that needs some training, and then someÂ… Axel |
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. |
Hi Al, It is an MC as I surely stated, all of 3.5$ of it. We also measure it by switching channels, and stepping up and down the alignments parameters mentioned AND using an SUT just to see. NO DIFFERENCE AT ALL! There is a resonant peak ~ 12dB --- can you believe it, at between 80Hz - 120 Hz! But it does not translate into hearing it... The main issue it that whacked out channel balance. Hi Raul, I think you put your finger right on it! +++ ... 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. +++ SO, PLEASE CAN WE HAVE SOME SHOWING OF HANDS WHO MEASURED HIS CART WITH OSZILLOSCOPE AND TEST RECORD! How about Dougdeacon, who thinks it is 'inane' to measure a 10 thou out-of-centre cantilever cart?! Axel |
It is an MC as I surely stated, all of 3.5$ of it. Hi Axel -- I had looked pretty closely at the original post, but I didn't (and don't) see a reference in that post to whether it is mc or mm. In any case, as you are no doubt aware, a mc working into a very high impedance or open circuit will have a pronounced resonant peak at ultrasonic frequencies, perhaps even approaching radio frequencies (e.g., 100kHz+). So I'm wondering, considering the miniscule distance between coils, if radiation of those frequencies between coils could account for the poor channel separation numbers you measured. This may be of interest: http://www.hagtech.com/loading.html Regards, -- Al |
Hi Al, THAT particular cart actually has no such an issue, as for example a 'Dorian' would have BIG TIME! But now we'd get close to a make disclosure, which I would not like to do at this point. I'm in touch with the manufacturer to see what they have to say. I can EASILY use this cart with 47k due to it's damping arrangement, in fact it is rather happy with 1k. (NO MORE CLUE NOW). You might be aware that these days there some are actually some quite fine with 47K. Next I also mentioned the testing with SUT, which is using as low as 13ohms loading on primary. Results were NOT AT ALL influenced (I'm not talking of scope's beam-width variations here!) There has been a lengthy discussion on that SUT subject on some other thread, say no more... If a resonance would influence the channel balance being out by a factor of 10 (compared to spec.) we would see this BIG TIME on the scope. The only res. as mentioned (~100 Hz!)is VERY visible on the scope. Axel |
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. |
Hi All, well, I'll keep you posted on this one. IÂ’d love to know if some other folk could share some related example(s), good OR bad, just so as to learn something from it. You can tweak-align you sweet hind off, and NEVER come right if that happens, distortion is programmed for you right in the cart. Note: an e.g. relatively cheap cart, the DV 20X-L STILL includes a measurement diagram of the cart you bought --- WELL DONE I SAY! Thanks, Axel |
"...characteristic initials in gold, which decorate the sides of the cartridge housing, stand as a signal to the outside world that this technologically advanced cartridge is ******** the finest, most accurate and in our own opinion also best-sounding design." The above is quoted from the manufacturers sales material which goes on to state; "...with a newly developed, state-of-the-art, moving coil cartridge in the absolute high-end class. In terms of design technology, the ********** is of course based on many of the most important innovations and patents that ********* secured for ******** in the course of his work stretching back more than 30 years." Apparently, the substantial cantilever offset is a technological achievement. Based on the manufacturers statements there should be no need to actually test the cartridge. |
:-) Wow Commcat, maybe there is no need to test a Ferrari either. Well, I guess we do know it's more fun to drive with correct wheel-alignment, handles the corners just a bit better. That said, would they ever agree that an incorrect aligned one ever left their premises? Mistakes can happen on all sides --- as long as they are not too many and too often. Axel PS: But then also, who actually has the gear available to question a factory setting? |
You can tweak-align you sweet hind off, and NEVER come right if that happens, distortion is programmed for you right in the cart.True! Just what I was trying say in my first response. By way of sharing experiences, I once owned an ABC model DEF with an off-line and twisted cantilever. With test record, notch filter and multi-meter in hand, I proceeded to measure channel (im)balance and crosstalk. Adjust as I would, I couldn't get anything remotely close to decent numbers. No surprise, you can't make a silk purse from a sow's ear, and I STILL say I'm inane for discussing it. :-) I've also measured multiple samples of my current reference cartridge using the same tools and methodology. On all but one, channel balance was within 0.2db (usually less) and crosstalk was < 0.1 db (below the resolution of the meter, even when measured at the POWER amp outputs). The one sample that measured higher was replaced under manufacturer's warranty, no questions asked. |
Axelwahl, If the cartridge in question is the Ortofon PW, is this the same cartridge that you praised as the best cartridge you have heard apart from the Transfiguration Orpheus, or is this another iteration? I agree that your measurements are disappointing, but, I am trying to understand the correlation between the poor measurement and sound quality. |
Axel, Have you verified your measurement procedure with another cartridge? If I had captured those numbers, they would seem to be suspect to me. I'm not saying that they are but I'd sure want to know that I can at least verify the results/technique with a different cartridge to be sure it's not a measurement error. Dre |
Hi all, Dave, that res. ~ 100Hz showed a 'lift' of 2.25 times signal level compared to the rest of the measured band level. I would NOT think it is a faulty test record... And as I stated, it is not audible with normal listening. Why? I have no idea, other than at ~ 40Hz I have some 'room lift/lock' --- and it might just all fit together. Who knows. Dre_j, in being proper and decently scientific what you suggest aught to be done. Alas I have not another cart of same make and build to do this. THEREFORE, in all fairness my measurements are not 'valid' according to scientific method. What is valid is that I get distortion at high vinyl levels with massed instruments / orchestra / fortissimo, and it *seems* to tie in with the channel imbalance. At medium level, and less complex music it can not be easily noted, if at all. Larryi, it sounds contradictory and you noted that correctly. Yet --- if I compared the two carts, not factoring in the problem area of the one, it is my finding. Since at the time of comparing I was still assuming that 'some' as yet un-detected alignment issue was causing this distortion with massed instruments, fortissimo, etc. It is NOT affecting tonality, detail, and such at more normal levels. So, the 'assumed to be defective' cart still sounded a good second to what I had listened to. The Orpheus is yet more detailed, yet a bit clearer, yet a bit more balanced, simply better. I incidentally also had the lesser "Transfiguration AXIA" in my system and of course given taste and all such it was not my preference, with a type of slightly more refined Dorian sound i.e. it has a slight edge on a Dorian - AND if you like that sound presentation. It is VERY open sounding and a bit tilted towards the top i.e. not at all as neutral as the Orpheus. The point is, that the cart under question is NOT breaking up all over the place!! It might just be yet so much better if it were in spec. --- an assumption of course. Part of this enquiry was to get some feedback on similar 'encounters' AND NOT to categorically insist on a scope beams width measurement finding. There is e.g. one track that puts left to right channel out of phase so as to cancel them. All being at it's best next to nothing should be heard during play-back. I instead get 1kHz 'screaming' at me. A pretty clear indication that the preceding measurements of channel leakage and imbalance found were correct. Greetings, Axel |
Hi Dave, some dB correction. I just veryfied the 100Hz res. level. It was 2.5 times signal level. BUT that makes it ~ 7dB and NOT 12dB. Sorry, for this misstatement. It appears to fill in the upper bass 'floor bounce' related dip in that area of the speaker, and is therefore not actually noticable. Axel |
I meaured channel match + crosstalk on PC1, ultraeminent and titan I. All performed to spec. L & R less 1db difference (assuming phono stage gain is matched). Titan I was best in channel separation with 34db crosstalk on both channels tested with Analogue test LP (track 2 and 3) while mounted on the Phantom. On the Davinci with no Azimuth adjustment, still a manageble 29-30db. The azimuth sweet zone is tiny and easy to jump thru. I did not measure the frequency response of the cartridge. |
Thanks Glai, just the sort of feedback, type=good, I hoped for. Now,+++ The azimuth sweet zone is tiny and easy to jump thru. +++ On a 3 point cart mount i.e. not flat-top mounting, and in a fixed Azimuth arm like a SME V, I come to think the ~ 2 deg. stated Azimuth-test-tilt, might be a bit out-of-whack. So let's say it's more like +/- 1 deg. at best. Suffice to say I NEVER ever would tilt it that much, that the cart-body outer rim touch the head-shell, the max. that was tested. A perceivable air-gap would always be still there i.e. left and right top between cart main body top and head-shell bottom. In your experience could an Azimuth-tilt, as actually in use, of between ~ 1/4 to 1/2 deg account for a 10 times! greater channel mismatch, AND a 12dB(L)to 18dB(R) out of spec cross-talk?! I have a hard time to figure that to be so. My suspicion is further, that the gummy / suspension settled (funny enough, always to the left in these type carts) creating this 10 thou out-of-centre cantilever. In your experience, would such 'smallish' cantilever off-set be able to create these out of spec. measurements? Again, I find this hard to swallow, since cantilever off-set is a 'fact of life' even with some more pricy carts --- according to what I hear. +++ (assuming phono stage gain is matched) +++ this point HAD to come up, which is good. On the oscilloscope measurement the amplitude mismatch was perfectly replicated by swapping channels left to right. Next argument could be some out-of-balance cable connection. Again, no measurable difference in resistance could be noted, BUT about 0.1 ohm difference in DC cart-coil resistance between left and right! Could this explain the (10x higher then spec) 2dB left-to-right mismatch (spec= >0.2dB)? And also the *different* L/R cross-talk of 12dB and 18db? But surely NOT the 12/18dB *higher* crosstalk of -16dB and -10dB vs. spec. = >-28dB! I'd really appreciate your take on this. Thanks, Axel |
Dre, I was thinking the same thing. Axel has a habit of sensationalizing things so I think we should question his technique. But he could also be questioning the results of a particular cartridge that really does have an issue. If that is the case, this thread loses impact. Much like Axel's other threads. ;-) Be well, Axelwahl. |
Axel, I've done these measurements numerous times and have never seen this kind of a result, so that's why I'm cautious about condemning the cartridge at this point. I think it would be very educational for you to test another cartridge so you can get a better handle on the likelihood of the measurements being reliable. There are a few things that could possibly cause your numbers to be off that have nothing to do with the cartridge. The errors could also be cumulative. Again I'm not saying they are just that it deserves consideration. - Please provide the model number of the O'scope you are using. - Are you using the 10x probes? - Have you verified the O'scope inputs track each other by tracing the same input signal? - Where are you taking these measurements? (What output of your audio system are you using to feed your scope?) there is the possibility of additive and induced error... - 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? - are you using a different amplitude settings on the O'scope to take amplitude measurements before you convert the output to dB? these amplitude settings can be off relative to higher settings which could contribute to an error in measurement. - If this is a modern o-scope, are you using the cursors to take amplitude values OR are you using the measurement features to get amplitude values from the scope numerically? (I ask because these time based measurements can be misleading by containing more than the frequency of interest.) - Are the gains settings for the phonostage set to the same level? - Is the cartridge loading the same on both channels? 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. 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 phonostage by using a Y-connector. I hope this all makes sense, Dre |
What is valid is that I get distortion at high vinyl levels with massed instruments / orchestra / fortissimo, and it *seems* to tie in with the channel imbalance. At medium level, and less complex music it can not be easily noted, if at all.AHA! Finally we get to the core of this thread, which I've tried to drive at from the beginning - namely, why are you measuring channel balance and crosstalk? I've heard exactly the distortions you describe in at least 50 systems, and I've eliminated it in at least one or two. ;-) 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. |
Axelwahl, Thanks for the further information. I think there is a good possibility that your cartridge is "slightly" defective. The "buzz" on Ortofon is that quality control is not one of their strong points. A misalignment of any of the generating components could account for the channel imbalance (not necessarily related to the cantilever being canted slightly to one side). An audio shop once leant me a table while mine was in for service. The table had the then top of the line Dynavector. At first, nothing seemed amiss. It was smooth, extended, beautiful sounding, with a huge soundstage. But, to me, it sounded phasey and the images, while large, were quite diffused. I don't have your kind of test gear, but I did experiment. I have a Yamaha DSP-1 ambience synthesizer/recovery system which feeds four channels of ambient information (in addition to the two unprocessed stereo main speakers). One setting recovers out of phase information (Hafler circuit). Playing mono records, this Dynavector had massive amounts of out of phase information where my Lyra cartridge put out virtually none. A cartridge can have "problems" which are not immediately evident. I wonder if your problem with orchestral crescendi has to do with your channel imbalance issue. It seems like you have correlated these variables because this was the "problem" for which you have a measurement. It sounds more like a mistracking or resonance issue more than anything else. If it is somehow directly related to channel imbalance, I would expect it to be more of an issue with stereo records than mono records. Has that been the case? |
Yep, and there is a legitimate method for measuring crosstalk while taking into account the channel imbalance. I haven't read all of the details on what Axel is doing here. Having been through a few such discussions with him I know it is just not worth the effort. :-) No offense Axel, just please find another way to interact with the other inmates. |
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 whoÂ’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 |
Axel, My attempt to help was more to do with your questions that you asked about your measurements and your results. Many of the questions I asked were because the translation of your posts were unclear to me. There are a number of things that still puzzle me that may be the cause of some of your measurement results. I'm not saying they are flawed but the results are puzzling nonetheless. Thanks for the response on who did the measurements and what happened. Knowing that the measurements will not be redone any time soon or that another cartridge cannot be checked using the same measurement technique, it may not be helpful to continue discussions on the technical aspects of what may be contributing to the results you asked about in the original posting. This is simply because you are not currently able to double check anything or test any new procedures. I mistakenly thought that you wanted to run more tests and find out if the procedure was solid and you were confident with your results. Hopefully when you have a chance to try this again, you can post about it. I do know what cartridge you are speaking of. If I had one, I'd be able to help you out by checking it out specifically. But I'm not sure those results would be helpful to you since it would be a physically different cartridge. To answer your question to me about one of my suggestions. The reason for the Y-connector usage suggestion is because this test eliminates the cartridge inter-channel interaction completely. By doing so, the procedure will only be feeding the same signal into the phono inputs along with any subsequent amplification so you will know the contribution of error/offset of the electronics. I know you said your consultant is away so you can probably answer this later if you choose to. How did you guys get differential measurements from the XLR output with a ground referenced scope? (did you use differential probes? 2 pairs of single ended scope probes (4 probes) in differential mode?) I wish you much success in searching for what you are asking. I hope you can find the answers you seek. Dre |
Thanks Dre, I will follow up on the Y-connector suggestion, some time next week the earliest. We used: 2 pairs of single ended scope probes (4 probe/clamps) in differential mode. The scope was quite recently calibrated I might mention also. I have posted a bit earlier today my assumption that the cross-talk's lowish level, PLUS the 6dB variance L/R could explain an increased 'smearing' problem at higher accelerations / output. Would this assumption (all things considered equal for the moment) make some sense in your experience? I actually think it could be a clue to the massed instrument high level distortion / smearing. I further assume the 2dB channel imbalance is not nice, but the lesser of the related issues. It would mostly pull images more to the higher output side, AND produce some image 'fluffing' i.e. the opposite of a 'carved-out-ness'? Lastly, could you give some indication if this 0.15ohm DCR diff. between the L/R coils is unusual, or is this of no import within your range of testing carried out? I'm much obliged for your constructive engagement and it might just serve more than only my curiosity. Many thanks, Axel |
Hi Dre, as my consultant is back from Munich, please find the rest of the pending answers :(+++) - Please provide the model number of the O'scope you are using. +++ Hitachi Model V-212 Megahertz Scope - Are you using the 10x probes? +++ NO, we used the pre-amp (326S) XLR output, assumed to be more correct then 10x probe. - Have you verified the O'scope inputs track each other by tracing the same input signal? +++ Yes, using 5V square-wave signal to verify both channels are still calibrated. - Where are you taking these measurements? (What output of your audio system are you using to feed your scope?) there is the possibility of additive and induced error... +++ ML326S pre-amp XLR out-put, but using the probes between PLUS and GROUND pin. - 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? +++ We will follow up with measurement of another cart, and I'll be in touch. Damping with the arm's silicone trough had no influence on the 100Hz ~ 7dB resonance at all. - are you using a different amplitude settings on the O'scope to take amplitude measurements before you convert the output to dB? these amplitude settings can be off relative to higher settings which could contribute to an error in measurement. +++ We convert to dB by calculation and value derived from amplitude measurements of scope's screen grid. - If this is a modern o-scope, are you using the cursors to take amplitude values OR are you using the measurement features to get amplitude values from the scope numerically? (I ask because these time based measurements can be misleading by containing more than the frequency of interest.) +++ No numerical output, but amplitude calibrated to screen-grid. - Are the gains settings for the phono-stage set to the same level? +++ Yes. - Is the cartridge loading the same on both channels? +++ Yes. 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. +++ Having discussed this suggestion, I'm told this was highly unlikely as there were no indications noted that would have supported such. 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. +++ As mentioned already, we will use this suggestion for additional verification and I'll keep you posted. Thank you again for all these valuable inputs, Axel |
Hey Axel, Do you have the Cardas Test Record and if so, can you guys try this approach? (It may be similar to what you are doing but I'm not sure, so here goes). I probe from the phono stage output to keep other unknowns to a minimum, but probing from the preamp out should work. Also, I don't use my o-scope. Instead I use a DMM with MAX feature and at least 3 decimal place accuracy. There are two, 1kHz test tone tracks. One is for the left channel and one is for the right channel. Play the track for the left channel and record the peak voltage at the left output. That is V1. Play the track for the right channel and record the peak voltage at the LEFT channel output. That is V2. And, naturally: dB = 20 * log(V2/V1) Now reverse the process for the right channel measurements. I don't get the published -30dB specs, probably only about 1/2 of that, for my XV-1s but I'm sure cartridge manufacturers have a better way to measure all of this without putting stylus to vinyl. However, I do get 1.0 to 1.3 dB of crosstalk which is very close to the published 1 dB spec from Dynavector. IIRC, I was getting -15dB on the right and -14dB on the left. Or something like that, which doesn't sound far from your original numbers. HTH |
Howdy Dan_ed ha, ha, :-) >>> ... but I'm sure cartridge manufacturers have a better way to measure all of this without putting stylus to vinyl. <<< As we say over here: "my foot in a fish can..." I asked them about the value of the induction of that cart uH..., was busy with figuring out primary SUT loading and the right RC for resonance damping ---- they do not even measure it or know! I think they make a well working lot of samples by hand and then run production, no measurements no more. How else can you get such variations to happen, correct me if I'm wrong. Output's the name of the game, even for the more pricy stuff. Next, I unfortunately have no "Cardas Test Record" and if I can find one it's quite expensive I guess. The one I used "The Ultimate Analog Test LP" we bought at the RMAF. Next thing is, that this cart has now been recalled, so we'll see what 'non-vinyl measurements' they will quote --- my best guess is non. They'll rework it and send it back in 3 month time, that's how it's done. It's not my first issue with them, you see. Now, we have planned to do some follow-up measurements (same method, same rig, getting scientific...:-) using a Lyra Dorian and maybe some other cart, I'll keep you posted. The joke of today is (for me) that I picked up a Garrott (A&R) P-77, MM for NOTHING! It sound better than that... well you know what. It's not funny actually 3500$ MC getting whacked by a 40 year old MM for nothing! Words fail me, and Raul will giggle quietly, saying I told you so... :-) Your XV-1s is some fine item, I heard it at the RMAF and my take was, it to be superior to, well you know what. Now your: "I do get 1.0 to 1.3 dB of crosstalk.." doesn't compute with me, it should <-28 or -30dB compared to the opposite channel when ONLY the opposed channel has information i.e. either lateral or vertical as is done with that test record from Analog Productions. Maybe you can help me to get a handle on how this cross-talk measurement of yours compares. Greetings, Axel |
I also used the Ulti. Analog test LP. With titan i, phantom 2, tw raven ac, tricon phono cable into Allnic phono. I played track 2 and 3 and measured the output of the phono with PAA3 meter. I also tried using the Einstein TT choice and results are not sig. diff.. Playing the L track: Recorded 1V output at L channel, 15-25mV ( fluctuating) R channel PLaying the R track: Recorded 1.1V output at R channel, 15-25mV ( fluctuating) L channel I took the average value of the crosstalk so approx. 20mV. I was told to take the lower value because the higher value indicated noise in the cart.. If my wife tried to annoy me and turn on the washer & dryer, the cart puts out additional random 5-10mV. For more accuracy, you can use a filter to get rid of noise. I should apply the output ratio to the crosstalk measurement to be more precise. I am just too lazy and want to get the azimuth in the ballpark. Crosstalk: 20log 0.02/1= -33.9db for one channel; 20log 0.02/1.1= -35.6db Channel matching 20 log 1.1V/1V = 0.82db This is not that accurate because I assumed the gain of the phono stage is perfectly matched. I should reverse the channel on the phono to idenfy the gain mismatch in the phono. The tracks itself may not be perfectly matched too. My math is crude and I am not an engineer. Please correct me as needed. Always love to learn. What's surprising to me in this exercise, I can get the most channel separation on the Phantom, second on the triplanar, no azimuth adjustment on the Davinci. Both the triplanar and Davicni throws a wider soundstage than the Graham. When optimize, Graham arm sounds very focused like some SS gear. I cannot contribute to using an oscilloscope. Have not used one since college. I think -15db crosstalk at 1Khz is poor. Once you lose it, you are not getting it back. I would interested in how the numbers compare at 10Khz, 15Khz and 20Hz. The window for the >25db azimuth is small, it is easy to jump right pass it. If I make big adjustment, it never went < 20db As the numbers improve, make smaller and smaller adjustments until your back, neck, eyes gives out or reached equal and minimized crosstalk. With the my sonic lab ultraeminent on the davinci with no adjustment, I managed a -28 to 29db crosstalk on both channels. I was either lucky to have a near vertical stylus or QC is very good. Same goes for airtight and Lyra. I will check out the dynavector next week. After this exercise, most will see that adjusting azimuth to minimize summed output amplitude of the L & R channel playing opposing phase recording do exactly just that. It compensate for channel mismatch anywhere along the sound reproduction chain: cart, phono, pre, amp, speaker, rm acoustics ( unequal dist. to speakers). It does nothing to put the needle in the middle of the groove. |
Hi Dan_ed, that's fine, now we could be on your page... B U T a 1dB channel separation (balance variance, left vs right) would still be nothing to right home about. With your kind of cart (and mine for that matter) we are talking smaller then 0.2dB spec --- now have I a feeling we might still not speak about the same thing... As I mentioned: 1) channel balance (L to R imbalance) spec smaller then 0.2dB, mine was a dismal 2dB. 2) cross-talk (L or R leaking its info into the opposed channel) spec better then -28dB or -30dB, again mine was another dismal -16dB leak to right and **-10dB** (even worse)leak to the left. I'm trying to put your DMM measurements against this, if possible. Greetings, Axel |
Axel, Glai hit on the keys to why our measurements are off, and this was confirmed to me by Dre. He'll be posting when he gets some time, but the short answer is we are not getting the noise floor low enough with our crude methodology. When I use my DMM on MAX for example, I am only capturing the peaks and these are probably combined harmonics from extraneous noise. This is a problem when measuring the channel output with the test tone playing through that channel, but it is an even bigger problem when trying to measure that very small signal when the tone is playing in the opposite channel. We need a 1kHz notch filter. ;-) That's one way to do it. |
Unless you guys include a notch filter to attenuate frequencies above/below the test tone, you're wasting your time using a multi-meter. Surface noise, intra-vinyl resonances and warp wow will muddy the signal you're trying to measure with random noise. That's why Glai's measurements were "fluctuating" (aside from the washing machine). Been there, did that... |
Oh! So now you show up with the answer! Thanks Doug. :-) Now we know why Wally was charging what he does/did for the Analog Shop(?). Yes, there was something about all of this that didn't quite add up in my head. See what 15 years of working in the software lab instead of the hardware lab can do to your skill set. I think that for AZ not having the filter isn't such a big deal as you can still get very close, then finish by ear. As you well know. ;-) |
I like watchin' ya'll suffer fer a bit. Drives the lesson home! Wally's price musta bin based on the cost o' them filters. It shore weren't based on the quality of th' box or th' terminals. One of 'em darn near gouged up a connector on a $3K pair of speaker cables. We had to file a big spur off'n it. |
Howdy guys, as long as you're have some fun here, I say. Now my few pennies if you don't mind. Glai says: >>> ... or QC is very good. ...Same goes for airtight and Lyra <<< Now guess WHAT? I put in my consultant's stock Lyra Dorian. NO sibilants, no massed instruments distortion, sailing through the most difficult of my tracks. For an answers --- see Glai's comment. I think Doug, who wants us to suffer is doing real good... I had that Windfeld (yes, OK) out, it goes back to the factory. Looking from below it looks VERY much more off then I realised checking from the front. Yes, Doug was right to suggest to trash it, and get a life, hm :-) Next please, Dan_ed, you say: >>> When I use my DMM on MAX for example... <<< Dear Sir, you must READ my statements properly and sink them in. I AM USING A SCOPE! This multi-meter measurement stuff sux, period. On a scope you can see what going on, like noise etc. but not every one has one to play with as I mentioned also. So I'm lucky in this regard. Next, there is NO household appliance running when I measure, period. I also have a SEPERATE, audio only, circuit from the distribution box --- I'm told that helps :-) So in closing, I'll have some follow up measurements comming on, with SCOPE and EVERYTHING the same as the Windfeld exercise was done, but now on a Lyra Dorian. J.C. beware :-) The cart is already set-up and running in my rig. If we screwed up I'll also tell you, and also if we know why --- if we did (actually I'm confident we didn't). Ortofon recalled the cart, and I hope we get to some amicable agreement. If not, we'll see what to do next. Thank you for your lively interest in this subject and it may yet prove to be of more educational value also, if Doug comes out of his corner and stops smirking at us. Greetings, Axel |
Hi All, as promised some more measurements information. First the good news: A well used Lyra Dorian that did perform much better than that first measured cart (PW) showed the following: Loading with 1k, AND 10nF capacitance, measured on XLR pre-outputs: Left vs. Right = -0.6dB @ 1kHz 7cm/s lateral (mono track), spec = <1dB (So that was a pass) Left vs. Right = on 1kHz 7cm/s vertical out of phase track, pretty CLOSE to out of phase, (about 12dB better on listening then PW, pretty good) 1 kHz left channel -28.5dB leakage to right! Spec = >30dB @ 1 kHz! (Only marginally less then spec. and can be attributed to it's aging, or measurement variation(s)...) 1 kHz right channel -28.5dB also, leakage to left! Spec = >30dB @ 1 kHz! (comment as above) Cart roll-off @ 20kHz -3db (much better then PW rolling off at -6dB) Resonance at 29Hz at -20dB, high Q for about 3sec. during the sweep track. The measurements confirmed that the set-up is pretty much OK. Now, what was NOT OK, was my consultants 'R.O.T.' initial db conversion on some PW dB results. Still the figures show a big problem yet. Here the revised figures: No loading i.e. 47k: Left vs. Right = -1.6dB @ 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! (no change as done by listening) 1 kHz left channel only -18dB leakage to right! Spec = >28dB @ 1 kHz! (only a smallish convertion error of 2 dB) 1 kHz right channel only -27dB leakage to left! Spec = >28dB @ 1 kHz! (now this was pretty way out, not in voltage measurement but in the dB conversion! :-( The end-result is still bad enough though. There are plenty more measurements on this test record, which where done, but those above tell most of the story. Track ten for example should produce a clean sine-wave and in the case of the Dorian it does, the PW looked rather distorted leaning to one side and dented in, plus more of such, all supporting that something is not right. So there you have it... Next up will be a Transfiguration Orpheus, I'll keep you posted and hope it will not be getting too boring. As Doug would have it, if its 'broken' why bother to measure it :-) Both the Dorian and Orpheus are not 'broken' so I guess we may have his blessing :-) Greetings, Axel |
Look numb nuts, Dear Sir, you must READ my statements properly and sink them in. I AM USING A SCOPE! This multi-meter measurement stuff sux, period. If you saw the damn noise why didn't you and your buddy think to filter that out? This is all mildly interesting to me because I do need to learn better measurement techniques. But for you this all seems to be just a "hey look at me". Comments like this are exactly why I just knew coming back to your thread was going to bite me in the ass. I know you are using your friends scope. I own a scope myself but I chose not to use the scope for several reasons. There is NO benefit to doing this with an o-scope. Now, a spectrum analyzer would be much different. I took a chance and it didn't pay off. I'm done here. |
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 |
