MRA : Myth or Menace?
"..Wanna see somethin' really scary....?" I don't mind straying off-subject in this instance. Does anyone else find John's azimuth research mildly alarming? http://db.audioasylum.com/mhtml/m.html?forum=vinyl&n=974192&highlight=&search_url= Not that I'm advocating that folk should stop setting azimuth "by ear" to obtain a satisfactory result. It does cast measured readings in a different light, however... |
The information here is a result of my own research done for a review of Audio Intelligent cleaning products a few years back. I am not a scientist. My understanding is that the ingredients in record vinyl have changed multiple times over the years. When we talk about what's in or on a record, we're talking about a moving target across time. Furthermore, there are no standards or practices followed by all pressing plants. However, there are not that many customized vinyl pellet offerings at any given time. Part of the changes in formulation have come from efforts to avoid actual or purportedly hazardous chemicals. At various times in the history of vinyl records, dibasic lead stearate or cadmium or other esters of stearic acid have made up as much as 2 percent of the vinyl compound. These additives provide thermal buffering for the vinyl during pressing, prevent oxidation on the newly minted record, and for some purposes, aid the platter’s release from the mold. Once these so-called mold-release agents have served their function and to the extent they are on the vinyl surface, they are (or turn into) foreign substances between stylus and groove, where they remain and attract dirt. Depending on what is put into the vinyl, these compounds may maintain their percentage as part of the vinyl formulation or they may continually work their way to the record's surface over time or they may reside primarily on the vinyl surface. I have read that chemical analyses of 50-year-old used records reveal such agents still in the groove. So I don't think there is a "once and for all" settlement of the question posed by the OP. It depends on the record you have in your hand. My practice is that no uncleaned record goes on my 'table for play and that includes new records. That seems to work okay for me. |
Dear Timothy, Many thanks for that extremely enlightening contribution. I guess, to an extent, I’ve been trying to establish a relationship between low “quiescent” noise and the acceptable cleanliness/playability of the groove. Also at the opposite end of the scale, establish MRAs effects on trackability, since the stylus is more likely to disconnect altogether during the more “energetic” sections of the programme if there is harmful interference. One would think that if you “aced” both of these it would be Happy Hour(!) however, summarising what we’ve seen so far, Doug has cautioned that celebrating low noise performance may be a naïve view with his assertion that noise is lowered progressively with less imperfect cleaning that rears its ugly head again at the “quantum” level when one has achieved a cleaning regime with the highest possible degree of perfection. For those who see cleaning as a “non-negotiable” option, we seem to have adopted the mindset or perception that MRA is “alien” to the vinyl and should be removed at all costs (and that “once it’s gone it’s gone”) even though we’ve firmly established it as a component which (most likely) makes an appearance whenever the vinyl is heated i.e. I’ve been inviting conjecture as to whether this could also apply to the effect of the stylus itself when it melts the groove during the playback process. No one has responded to that prospect yet ;^).
Let’s theorise for a moment and assume that Occam’s Razor isn’t as straightforward as it appears (extreme cleaning = fresh low-level noise =end of story). Suppose the vinyl is not melting and reforming during replay but the MRA itself is and this MRA acts as a thermal interface and a thermal barrier to the vinyl. Therefore it’s possible Doug has succeeded in ultimately cleaning the groove only to find that the groove goes through a partial regeneration of MRA on the first play – because this time the stylus is in contact with the vinyl and not the MRA, which creates noise as a by-product from more “intimate” clean groove contact rather than the LP “enjoying” existing MRA as an interface and not feeling the need to create much additional MRA… But what happens then? Doug puts the album back on the shelf content in the knowledge that the first play was satisfactory (but slightly noisy) until the second play finds the MRA partially restored to its former glory….? I’ve never cleaned new records to the depth that Doug has so I can’t say how that second replay would pan out.... ;^)
Of course this is an aside to the rumoured possibility that MRA is continuously exuded for years afterwards! (But did they consider that the stylus temperature might be the reason if MRA isn’t as much of a barrier as I’ve just suggested???)
So, in the end, it’s not so much the inevitability of MRA existing but whether cleaning can help in situations where there is, perish the thought, too much of it or the chemistry of the LP is flawed i.e. to the extent that such material interferes with peak level tracking? My suspicion is that there can occasionally be too much of it (bad chemistry) and the answer to that may be yes but I’m not hearing any examples in the current batches as yet. Enter your text ... |
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The curse of the Twilight Zone has struck again....JTA wrote a response (Post no 56) which I thought was rather good and now it's disappeared..... :( Even though it is no longer visible I will briefly reach into that alternate Dimension and formulate an answer. ;^) Post no 57 : Exactly, couldn't have put it better! I fully subscribe to the "Ellington Axiom" i.e. if it sounds good it is good. :) All the best and a Merry Christmas to all (...and please try not to think too much about MRA as it only causes indigestion ;^) |
