Reviewing audio gear usually necessitates moving your own gear around to accommodate review samples. I recently found myself with an empty turntable shelf on my rack (something of a rarity) and decided to bring one of my rebuilt TD-150s into the system to accompany the Technics. In doing so, I encountered the inevitable frustration that comes with ownership of a suspended deck, namely the suspension itself which so often goes ‘out of tune’ as it were, especially if the deck is moved. I decided then and there that never again would a metal spring be permitted in a turntable of mine, and set out to seek a better solution.
That solution came in the form of an isolation grommet from Analogue Innovation. Three grommets in fact, designed as a direct substitute for the springs of an LP12. Though designed to work with the company’s ‘Sole’ sub chassis, the ‘In Sole Elastomer Suspension Kit‘ work effectively in any LP12, or indeed the many Thorens, Ariston and other turntables with conical springs in common.
I approached designer John Ruggles to review the kit here. A few pounds later (beer money in hi-fi terms) and the kits soon arrived. I ordered two sets with the intension of trying them in both of our TD-150 rebuild projects. John did, however, stress that these kits are primarily designed with the LP12 in mind, though at least one is In Use on a modified TD-150 with an early Sole sub chassis. In John’s own words: “This isolation kit was not developed for the Thorens TD150, but was so for the LP12, specifically fitted with Analogue innovations Sole Sub-chassis.” John was happy for the review to be “warts & all” and was happy to give me total freedom of script even if I personally felt they did not offer any improvement on the TD150. Now that is a company who are confident in their product, and rightly so.
Disclaimers out of the way and we proceed to installation. Installation couldn’t be easier. I’ve been trying a few sub chassis prototypes in the AAP12. The one seen here is a composite construction but multi-layer acrylic has been tried too.
The isolators ship with knurled nylon nuts with a machined flange designed to centralise the rubber isolator on the bolt. The top of the isolator slots into the sub chassis as would the original grommet. Washers and locknuts aren’t necessary at all, though I did install locknuts beneath once I’d levelled everything up in the hope that I can avoid the need for future adjustment. Indeed this review has been a long time in draft and the decks with these in place have been moved a time or two with no further setup needed. The setup itself is hassle free and takes five minutes or less. Simply install the isolators, adjust for height with the platter and arm installed and then level it up. No more perfecting the bounce, no more trying to centralise the sub chassis, and no more minimising unwanted lateral movement.
Our Thorens TD-150 remains as stock as ever besides the addition of a thrust bearing and damper to the motor which is now virtually silent.
The isolators offer a few notable advantages over the conical springs. Firstly, the ‘bounce’ that suspended decks are known for is gone and the whole platform becomes far more stable as a result. Movement in the sub chassis is significantly restricted which all but eradicates unwanted lateral motion caused by the sub chassis rotating on its axis.
The isolation properties are better too. Certainly better than a standard conical spring which imparts some horrible resonance peaks. Better even than the Vinyl Passion Blue springs which have an anti-vibration coating. Any disturbance in the mounting surface will usually cause the suspension of a sprung deck to go haywire. Here any such disturbance is dissipated without drama and with no ill effect on playback. I wrapped my knuckles on the table on which the decks were situated without causing so much as a thud from the speakers and certainly no skipping or wobbling from the turntable.
Sonics are vastly improved with more detail across the board, most notably in the bass which is better defined and less bloated than before. Speed stability also saw a welcome improvement owing to the increased sub chassis stability. Elastomer isolators are better at resisting the pull of the belt than a compression spring, so the relation of the motor and sub platter and thus the belt tension remain true. Rumble is reduced as are the sonic effects of any resonance in the top plate which can sometimes be heard as a kind of ‘steering’ of detail in the upper mids and highs.
All in all a terrific upgrade and tremendous value at several times the price. They are available for £25.00 currently, and will be increasing minimally to £27.50 per set on June 30th though this is inclusive of UK first class P&P. I applaud Analogue Innovation for continuing to offer reasonably priced audiophile upgrades especially for the LP12. The Analogue Innovation elastomer isolators bring considerable sonic advantages while removing most of the frustration inherent with the ownership of a suspended turntable. Highly recommended.
