LAST Record-Preservation Treatment

LAST (Liquid Archival Sound Treatment) is a record treatment developed by one Dr. Catalano, which promises to retard dramatically the wear of vinyl discs. I don't feel that the advent of true digital discs will diminish the importance of LAST; on the contrary, as this century comes to a close many stereo records will be in their 30s and 40s and in need of as much preservation as possible, if the sounds and performances we treasure are to be preserved.

After perusing the reprints of reviews in other under-grounders, supplied by LAST at their CES booth (all raves, needless to say), I was impressed by how fuddled were their explanations of the LAST-discovered wear mechanisms and cures. In this, my presumably correct explanation, I will draw from information found in an excellent pamphlet entitled "The LAST Word," available from the manufacturer (footnote 1). The explanation therein is worthwhile reading, not only for the technical information and the fascinating Scanning Electron Microscope photographs, but also simply for its point of view on stylus/record interaction.

Dr. Catalano's analysis begins by dismissing the relative importance of our most cherished model of record wear; that is, inelastic deformation of the record groove, brought about by repeated playings.

While conceding that earlier stylus forces of 5 to 15 grams—and those figures were typical some years ago—could accomplish record wear in this manner, mode n stylus loadings of up to 2.5 grams, according to Dr. Catalano's investigations, do not result in groove deformation. Instead, LAST concludes from their scanning-electron-microscope (SEM) photographs that most record wear is of a type they call conchoidal fracturing (conchoidal means shaped like a cone with helical patterning), with some additional wear caused by the stylus tearing vinyl from the groove walls as they attempt to adhere during the stylus's journey through the groove. Although the full range of SEM photographs from which these deductions were made was not available to me, it is clear from those in the pamphlet that the two types of wear are quite different.


The conchoidal fractures most resemble the scars on the face of a person who had severe acne; the torn portions of the record groove resemble the sides of a canyon in the Southwest which has been extensively eroded by water. Accompanying both forms of wear, and perhaps the most annoying evidence of wear, are numerous irregular pieces of vinyl which, having been popped or torn out of the groove wall, are subsequently welded to it further down the groove by the heat generated by the passing stylus. To my knowledge, there has been no research into why different areas of the record are subject to the two different wear mechanisms.

The difference between the played and unplayed records in the SEM photographs is truly shocking. Another interesting observation is that one record, Kotekan by Reference Recordings, shows markedly less wear (say 80% less) than another record, Holst's The Planets (no manufacturer specified), though neither untreated record came through the initial 50-play test unscathed. It seems certain that this is due to differences in the quality and composition of vinyl in the two records. Perhaps the most interesting observation is that conchoidal fracturing occurs in silent grooves as well as modulated ones.


Fig.1 Playback distortion from virgin record, untreated (0–20kHz, 5dB/large vertical div.).


Fig.2 Playback distortion from virgin record, treated with LAST (0–20kHz, 5dB/large vertical div.).

Dr. Catalano's model of what happens in disc playback goes something like this: As the stylus moves along the groove, it sets up shockwaves in the vinyl. The energy comprising these can only be ultimately dissipated in the form of heat. These shockwaves are reflected many times, greatly reinforcing one another, and causing high concentrations of energy at certain spots, such as imperfections in the vinyl. Above a certain threshold, the energy of the shockwave and its reflections is great enough to overcome the cohesive forces holding the polymer together and pieces of vinyl literally pop out of the surface. This is called conchoidal fracture because the ejected pieces resemble the chips removed when a piece of flint is shaped into an arrowhead.

Dr. Catalano also found that this conchoidal fracturing does not abate after a few plays, but occurs with every play of the record.

How then does LAST combat this fracturing? LAST effects a change in the surface of the vinyl to a depth of ten molecules which has the effect of reducing the "surface free energy" (footnote 2) of the vinyl. We find from the field of thermodynamics that reducing the surface free energy of a substance increases its stability and therefore its resistance to change. In the case of LAST this increase in stability is sufficient to resist the conchoidal fracturing referred to above. The energy of the shock waves is not so great as to pop the pieces of vinyl out of the surface and we see in the "after" (after LAST treatment and 200 plays of the record) SEM photographs that little or no fracturing has taken place and there is a remarkable absence of welded on pieces of vinyl in the record groove.

This is not to say that it would be impossible to observe conchoidal fracturing in a LAST-treated record: if either the vinyl was originally unstable enough (because of many imperfections, say) or the shockwave great enough (because of unusually high stylus loading, for example), conchoidal fracturing could still take place.

The other effects of LAST, ones not predicted by Dr. Catalano's model, are reduced record wear due to tearing (the stick-slip phenome™ non) and a marked improvement in the sound of new, unplayed records. The reduction of tearing wear is also attributed to the reduction of surface free energy, so that the surface free energies of the stylus and the record groove are more closely matched. I do not understand the importance of this matching; perhaps Dr. Catalano will respond to this review and therein explain.

The improvement in sound of new, unplayed records, which we have verified in limited tests and which is the most salient feature reported in reviews by others, remains somewhat of a mystery. Dr. Catalano speculates that the stylus-induced shock wave, travelling at roughly 37 inches/millisecond, speeds ahead of the stylus and damages the record groove prior to the stylus's arrival. While this may be true, it does not explain why treatment of a record groove already damaged in this mann- er, but not enormously (as in the second playing of a high-quality vinyl record), would result in a drastic improvement, unless the secret lies in a radical dampening of the shockwave so that there is significantly less interaction be™ tween the energy of the shockwave and the stylus itself, a possibility not mentioned by Dr. Catalano.

The application of LAST is a two-step process which takes about 2½ minutes per side—2 minutes of which is waiting. First the record is cleaned with a product similar, perhaps identical, to Discwasher D4, using a supplied narrow velvet-like applicator. After the record is dry, a small amount of the preservative is applied using a similar (but gold-colored) applicator. It is allegedly impossible to use too much except from the standpoint of economy (the instructions are nicely honest by encouraging this economy). One is aware of the smell of the vehicle, Freon TF, which is highly volatile—great care should be used to cap the bottle tightly, again in the interests of economy.

Our tests attempted to eliminate other variables, such as the cleaning process that precedes a LAST treatment. We played sections of Professor Johnson's Astounding Sound Show (Reference Recordings RR-7) before any treatment other than dust removal. We played it again after cleaning with the Keith Monks machine, and then a third time after cleaning and LAST treatment.

The Keith Monks cleaning made a significant difference, in terms of lowering surface noise and improving openness and cleanness of sound; in some passages this effect was greater than that achieved by the LAST treatment. (Why a simple wet cleaning would improve the sound of a new, unplayed record is not clear, but it has been suggested that it removes a slight waxy deposit of mould-release agent—a substance which helps the vinyl to separate from the stamper surface—from the surface of the disc.)

As I imply, there were passages where no observable effect of LAST was noted; however, in others the difference was astonishing. Most remarkable was the passage for harp, where prior to LAST treatment, the sound of the harp was intermixed so extensively with what sounded like tape modulation noise that one had to consciously separate the noise from the notes. After the LAST treatment some noise was audible but had to be consciously sought out rather than ignored.

Without access to our own Electron Scanning Microscope, we have no way of confirming Dr. Catalano's observations about the conchoidal fracturing and whether or not LAST prevents it. There is no question though about LAST'S ability to improve the sound of discs; as J. Gordon Holt described it, the sound becomes less mechanical and more like original tape—evidence enough that something did change when LAST was applied. The effect sounded as though the treated grooves were indeed damping out HF stylus resonances, which would seem to imply enhanced absorption of energy. We have no way of verifying the preservative effect of LAST, its greatest claimed benefit; but neither have we reason to doubt the authenticity of Dr. Catalano's SEM photos, which do offer dramatic evidence. Even if the preservative effect were to be less than claimed, the immedi™ ate sound improvement makes the product well worth the investment.

After having plowed through all this, the fatigued reader might wonder why so much time and space were devoted to this product. Primarily, the reasons are our love of records and our fascination with groove-level interactions. Certainly if this treatment (our LAST treatment of the subject, so to speak) is too verbose, or unclear, we welcome our readers' response.

Footnote 1: Gamma Omega Associates, Livermore, CA 94550 (1982); The LAST Factory, 2011 Research Drive, Livermore, CA 94550-3803. Tel: (925) 449-9449. Fax: (925) 447-0662 (2015). Web:

Footnote 2: Surface free energy is defined as the total energy minus the product of temperature and entropy, a definition which should be sufficiently opaque to all but thermodynamicists.

The LAST Factory
2011 Research Drive
Livermore, CA 94550-3803
(925) 449-9449

Allen Fant's picture

Interesting- LA.
is there a similar product for CD ?

corrective_unconscious's picture

Sure, there are these green magic markers....

leok's picture

After using Last 2 (record-preservation treatment) I find the amount of anti-skate force required to maintain right-left stylus force balance is significantly reduced. Anti-skate on my Graham 1.5 is set to almost minimum. Without the Last treatment, mid-range anti-skate was required. I interpret this as indication of reduced stylus/record friction.

I also find record sound improves as described in the above article.