Sony’s breathtakingly expensive TC-177SD was a bold product for 1974. Described as, “the most sophisticated cassette deck ever developed”, it boasted something that not even Yamaha’s beautiful ’ski-slope’ TC-800GL had – three heads. This had previously been the sole province of open reel, and permitted ‘off-tape monitoring’, so you could hear your recording as it was being made. It meant that it was easy to calibrate the deck to any tape, so you were no longer a prisoner of the formulation the deck had been set up for.
More than this, the big new Sony sported dual capstans – again an open reel-inspired feature – for better speed stability, and the (then) very special provision of solenoid control for the tape transport. This stopped you from going direct into fast rewind mode from play mode, and causing all the associated damage to the tape. It also had Dolby B noise reduction, but this was standard fare for serious cassette decks by then, giving an additional 9dB signal to noise ratio, taking it to near open-reel levels of quietness. A built-in 400 Hz oscillator let users calibrate different cassettes correctly for sensitivity.
Another impressive feature was the Ferrite and Ferrite record/replay and ease heads. This was an extremely hard material, and far less prone to wearing than the normally used ‘Permalloy’. The discrete record/replay head was a piece of art, with optimally tailored gaps of 0.007mm and 0.0009mm, giving a frequency range of 20Hz to 20kHz, which was remarkable back in the day. To this day, Sony F&F heads generally work just as well as when new, forty years ago.
Selling for £381 when new, the TC-177SD was breathtakingly expensive – about half the price of a Mini 850 motorcar! But you got a beautiful battleship for all those bucks; this machine is heavy and large and exquisitely finished. The solenoid transport has a sense of solidity that is only usually seen on high end open reels. The circuitry inside is very complex, and there’s a big, chunky AC synchronous motor which is largely responsible for its 50W power consumption. The vinyl, ‘wood-look’ wrap looks dated now, but was the height of fashion for the deck’s four year life.
Needless to say, it’s a superb sounding machine, head and shoulders over almost every other cassette deck of its day, with a powerful bass, clean midband and extended treble – especially with Sony’s best FerriChrome (FeCr) tape in situ. However, you’re still aware you’re listening to an early cassette machine – it doesn’t have the sparkling clarity of an early nineteen nineties decks running metal tape, for example. It’s a wonderful curio, and unjustly cheap secondhand should you be lucky enough to find one. The main issue is its condition – any unit of this age is likely to need a service, and this won’t be cheap. Good luck on your quest!