My fave review of the LP12 from Basik through Valhalla to Lingo was Corey Greenberg's. I couldn't find it online but I have it somewhere in hard copy. This is what I got from Stereophile's review archives (John Atkinson):
In its various incarnations, the Sondek LP12 turntable has been reviewed a number of times in Stereophile: first by Larry Greenhill in February 1984 (Vol.7 No.2), then by Martin Colloms in March 1990 (Vol.13 No.3), then by Corey Greenberg in December 1991 (Vol.16 No.12). The effect of the Lingo power supply was first described by me in January 1991 (Vol.14 No.1), with a Follow-Up by Wes Phillips as part of his report on the Naim ARO tonearm and Armageddon LP12 power supply in February 1996 (Vol.19 No.2). Robert Deutsch also commented on the improvement wrought by the Cirkus base in May 1997 (Vol.17 No.5).
My reaction to the external Lingo supply, comparing it back in late 1990 with the older Valhalla board, was very positive. In particular, I felt the low frequencies were reproduced with considerably better extension and definition. I performed some basic measurements on the combination of the Lingo-driven Sondek with the Ekos and a Linn Troika cartridge in my 1990 review, which are reproduced in the Web reprint. In comparison both with the LP12 Valhalla and an Australian Aura turntable fitted with an early Graham tonearm, the LP12 Lingo had slightly better speed stability, evinced by the slightly narrower "skirt" around the spectral peak representing a 1003Hz tone from the Denon Test LP. However, low-level sidebands were visible both at the 11Hz frequency of the tonearm-cartridge suspension resonance and at ±50Hz, the latter not uncoincidentally the frequency of the Lingo's synthesized sinewave supply. Rumble was very low.