Tandberg 3015A CD player Laser Pickups

Sidebar 2: Laser Pickups

In a three-beam laser system (fig.1, left), the first and third beams are directed at the disc ahead of and behind the signal beam, at opposite edges of the pit track. Their reflections are picked up by photo cells that are physically separated from the main-signal pickup cell. When both tracking cells "see" the same proportion of the total track width, their equal-but-antiphase outputs cancel. When they are displaced to either side of the signal track, their outputs are of different amplitude, cancellation is incomplete, and the resulting + or – offset voltage is fed to the head servo to get it back on center-track. Focus-correction information in the three-beam system is derived from the distribution of the main signal beam between the quadrants of a third photocell, which also receives the signal data. Perfect focus throws a circular beam; imperfect focus throws an elliptical beam in either of two directions depending on the direction of the focus error (lens too close or too far from the disc surface).


In a single-beam system (fig.1, right), tracking, focus, and signal information are all gleaned from the shape and size of a single reflected laser beam thrown onto a pair of side-by-side dual photocells. Tracking errors shift the beam toward one side pair or the other. Focus errors narrow or spread the beam between the two pairs, depending on the direction of the error.—J. Gordon Holt

Tandberg of America, Inc.
Plainview, NY 11803 (1988)
Company no longer in existence (2020)

georgehifi's picture

Good old TDA1541 equipped converter player, certainly more "musical" than the Sony's of the same era.

Cheers George

Ortofan's picture

... used the "good old" TDA1541 DAC chip.


volvic's picture

It was a sad day when Tandberg exited the hi-fi world in the mid to late '80s. Their products were built to a standard people pay thousands for today. True, this CD player and their Taiwanese built receiver weren't their best products and in some cases marked the beginning of the end of the company in North America. But their other products were magnificent. Still kicking myself for not buying a pristine pre-amp/power amp at a local HiFi store a few years ago. Might never get a chance like that again. Tandberg is the one company I still miss after all these years. Never selling my TR-2060.

georgehifi's picture

Yes, I've still got a Tandberg 5001 FM tuner somewhere, when aligned it's just as good as any Kenwood, Marantz or Dynalab ect

Cheers George

Ortofan's picture

... Tandberg model 5001 FM tuner?

georgehifi's picture

Ooops!! 3001, old age

tonykaz's picture

it was typical of the post 33.3 demise of 1985ish.

AHC was probably the best reviewer of that era, I purchased his recommended items which never lived up to his endorsements.

As CD mania overwhelmed the market in 1985, I shuttered all my Audio Industry businesses and returned to General Motors, never looking back until I happened to run into Tyll Herstens & Steve G. at RMAF11. They introduced me to Schiit & Sennheiser, god bless em !

Reading this old review refreshes the anxiety I felt about all things audio in the post 33.3 era. It felt like a Train Wreck finale for a promising Era. I still feel like: after all we'd been thru it has to end like that! ouch, hurt & whoa is me. .

Back to the Salt Mines.

Tony in Nevada ( which is even more corporate confining and entrapping than evah !!! )

ps. Gordon Rankin ( it had to be someone ) brought Redbook Greatness to Everyman, sealing 33.3's fate as a niche Collector/Hoarder endeavor

T-NYC's picture

The audio part of the company shut down Dec 31, 2000. However, a new company licensing the Tandberg name was formed by the service team who in addition to supporting existing products, released additional new Tandberg products that had been designed but not manufactured by the original firm. The other divisions went on to variously become the leading data backup supplier, a data router company, the world's largest language lab provider, plus one more I do not remember. They eventually were all sold for several billion dollars, which amply justifies the Tandberg Group's management decision to exit high-fidelity, although much missed and still greatly admired.

volvic's picture

Wow, in my neck of the woods by the late '80s the one store that carried them for decades, had pulled the plug on their products citing cheapening quality and no support. I have to be honest I never saw another of their products after that so surprised they were still around up until the late '90s. A crying shame all the same, one of the best hi-fi companies ever in my opinion.