Solid Base or Trampolin: which base board your LP12 wants

The base board is the plate that closes the bottom of the plinth. It is the least glamorous part of an LP12 and one of the cheapest, and it is also one of the few decisions where the right answer depends on your furniture rather than your budget. Linn makes two: the Solid Base, $247, and the Trampolin, $346. Here is what each one is, how they came about, and how to choose.

How Linn got here

For its first two decades the LP12 was closed with a thin sheet of hardboard, the Masonite-like fiberboard of the day, screwed to the bottom of the plinth. It kept the dust out and did little else; on an older deck it is often warped, and it adds nothing to the stiffness of a plinth that could use some. In 1991 Linn replaced it on new decks with a solid base board, a rigid plate that ties the four sides of the plinth together, and offered the first Trampolin alongside it: the same idea on isolating feet, a plate with rubber-damped feet under it, so the whole deck sat on a second, softer suspension beneath the one inside.

In November 2006, the year of the Keel and the Ekos SE, Linn introduced the Trampolin 2, which is the Trampolin sold today: an aluminum plate in place of the original’s plastic one, on suspended feet with acoustic damping material, fixed to the plinth with ten screws so that plate and plinth move as one. Linn quotes about 20 dB less floor-borne vibration reaching the deck at 100 Hz. The Solid Base sold today is the same aluminum plate on fixed feet that screw straight into the four corners of the plinth, and it has been the standard base on the Majik LP12 since Linn introduced that package. Aluminum is the right material for the job: it is stiff for its weight, it is machined flat and stays flat, where hardboard and composite boards move with humidity and age, and bolted to the plinth it turns the four wooden sides into one rigid box. That stiffness is what the springs push against, so a stiffer plinth means a cleaner-behaving suspension, which is why the base board earns a place in the upgrade order at all.

What each one does

On an older deck still wearing its hardboard, either board is a real step: the plinth becomes a stiffer box, and a stiffer box gives the suspension something firmer to work against. That is the part people underestimate. The question between the two is only whether the deck needs isolating from what it sits on.

The Trampolin’s feet are a low-pass filter between the shelf and the plinth. On ordinary furniture, a sideboard, a bookshelf, or anything standing on a suspended wooden floor, footfall and the loudspeakers’ own output reach the deck through the shelf, and the Trampolin takes the edge off them before the internal suspension has to. In that setting it is Linn’s simplest performance upgrade, and it is where we reach for it first.

On a rack or platform that already isolates the deck, the Trampolin is doing a job that has already been done, and two soft suspensions in series are not better than one. An HRS isolation platform, or better still a full HRS rack, is built to drain and damp exactly the vibration the Trampolin’s feet are there to filter. On a shelf like that the Solid Base is the better choice: the deck sits rigidly on a surface that is itself quiet, the internal suspension does its work against a firm foundation, and the result is cleaner than the same deck on a Trampolin. We hear this on our own floor, and it is the one case where the cheaper board is the superior one.

The Urika rule

There is one situation where the choice is made for you. Linn’s internal phono stages, the Urika and the Urika II, mount inside the plinth on the Trampolin, which has the mounting point built into it. A Urika deck is a Trampolin deck, whatever it sits on, and the Trampolin comes in the box when you order either Urika, so there is nothing extra to buy. On an isolating rack we simply set the deck up with that in mind.

Choosing

So: hardboard on an older deck, replace it either way. Deck on furniture or a wooden floor, Trampolin. Deck on an HRS platform or rack, or another shelf that is truly isolated, Solid Base. Deck with a Urika or Urika II, Trampolin, and it is supplied. If you are not sure what your shelf is doing, tell us what the deck sits on and whether footsteps reach the stylus, and we can usually say which board you want before you come in.

Start with a call

Either board is fitted in a short visit and the suspension is set up again afterward. Call (503) 222-2599 or write to sales@pearlaudio.com, and if the deck has other needs, Bringing an older LP12 up to date puts the base board in its place in the order of things.

— John Loranger, Pearl Audio

See also: Solid Base · Trampolin · Bringing an older LP12 up to date · Why the Karousel is the best value in Linn’s LP12 catalog.