Nytech CTA 252XD

Nytech CTA252 Nytech’s classic ‘Calculator Tuner Amplifier’ is largely forgotten now, but made a great impression on the British hi-fi market when its star burned brightly in the late nineteen seventies. Its name was no mere whimsy – back when launched in 1972, calculators were almost the width and depth of an LP record, and plugged into the mains supply, just like the Nytech. It was an age, lest we forget, where the world was still transitioning from tube to solid-state, and electronics were nowhere near as compact as they are now. Like those supersized electric adding machines of the day, the top panel was festooned with buttons, but instead of a numeric display there were three neat panel meters for the radio tuner.

The CTA 252 was the first product to emerge from Nytech’s new factory, just outside Bristol in Chew Magna. Its designer, Richard Hay, was a talented young twenty eight year old who’d served his time in the illustrious company of Arthur Radford and Arthur Bailey, having graduated from Southampton University in 1967 with an electronics degree. Hay had always loved music, but his first passion was aerospace and had dreamed of a future with Hawker building fast jets – his boyhood hero was Barnes Wallis.

Radford Electronics was an excellent grounding for Hay, being a serious engineering company that even designed and built its own test equipment – this gave Richard a chance to put his know-how into real, commercial products. As a child he’d lived in Bangalore with his family, and acquired a taste for building hi-fi by getting Heathkits sent over from the mother country. At Radfords, he had a launch pad for his talent – The Edinburgh Wireless Tuner was one of his designs, and ended up being published in Wireless World, then an industry-wide journal of electronics design excellence.

Towards the end of his time there, as chief engineer he began working alongside Arthur Radford with the intention of progressing the company away from its fine but ageing range of tube amplifiers to new-fangled transistors. His love for valve amplifiers went on to inform his solid-state designs. His son Robert says that Nytech products were essentially, “like valve designs but executed with solid-state devices, with capacitor-coupled outputs rather than transformer-coupled ones”.

In 1972, Radford engineers Dave Alner and Paul Hamblin left to start Nytronics Ltd. with Richard Hay. Between them, they came up with the new CTA 252, originally as a custom console for a music centre chassis. That distinctive plastic top surface came from the simple requirement to fit inside a pre-existing case alongside a Dual turntable. It was called ‘CTA’ because its construction was inspired by an early Canon desktop calculator.

It was a classy piece of work, showing much of Richard Hay’s Radford DNA. Putting out a modest 25W RMS per channel into a 4 ohm load, it nevertheless drove speakers well and in the words of former Nytech test engineer Phil Balaam, “had a very unique sound”. Part of the reason for this was the AC-coupled power amp design, which made it a very safe amplifier as far as (not blowing up) loudspeakers was concerned. “It had a capacitor in the signal path, which was frowned on by many on sonic grounds”, says Balaam, “but he had some very clever ideas that got around that”.

Another interesting facet of the design was the physical construction, with several plug-in printed circuitboards, obviating the need for yards of internal wiring (common in amplifiers of the time). Also plug-in was the disc input stage, so MM or MC could easily be accommodated, and the 252 also had a sophisticated FM tuner head which also went on to appear in the A&R Cambridge (now Arcam), T21 tuner.

The CTA 252 had a litany of facilities, from the built-in tuner and phono input, to bass, midrange and treble slider controls, balance and loudness. There was a mono switch, a tape monitor and switching for two pairs of speakers. The tuner got AFC and the luxury of four presets – this was perfectly sufficient at the time because there were so few FM stations on air. Two headphone jacks completed the picture – you could see the unit’s ‘deluxe music centre’ origins…

The Nytech was launched in 1975 for the princely sum of £93. At the time, Britain was ravaged by inflation and its price rose fast, and by 1978 it was nearly twice as much – yet this didn’t stop the hi-fi press giving it rave reviews. Indeed its receiver status was often ignored, and the little Nytech was often recommended as an excellent sounding amplifier in its own right. Magazines such as Popular Hi-Fi advised readers to buy it if they couldn’t afford a Naim preamp/power amplifier combination.

The CTA was a fairly straightforward design electronically and stuck firmly to good engineering principles. Careful tweaks to both the amp and power supply were able to wring really excellent performance to make something far better than the sum of its parts. All Nytechs used the same basic design of a Class AB push-pull amplifier, running off a single supply rail with the speaker AC-coupled to the output. Clever detail design work meant the circuit was able to go down to about 15Hz with less than 1dB of insertion loss, Phil Balaam says. Sonically, even by today’s standards the amp is still good, with a bubbly and rhythmic sound and strong stereo soundstaging.

Never overly powerful, Nytechs still completely belied their low power ratings, rather in the same way the NAD 3020 did. They gave a big, ballsy sort of solid-state sound, rather than a mild and meek one. They never quite gave ‘hear through’ transparency, and lacked tonal light and shade, but Nytechs were always fun to listen to, and sung with most types of music. Needless to say, the tuner is insensitive compared to modern radios, but given a good aerial it has a beautifully rich and warm sound which is the equal of almost everything on sale today.

Recognising that the company’s future lay with audiophiles and not music centre users, Nytech began tweaking the design. First, 1977 saw a new version with some component changes, then a direct, non-switched speaker connection was added, and the phono stage was improved. This was followed in early 1978 with the CTA 252 XDII which got an improved toroidal transformer which gave the unit 25W RMS into 8 ohms, rather than 4. Later in 1979, the XDII got a slight facelift with upgraded switchgear, the DIN speaker terminals went to 6.3mm binding posts and the ‘link’ socket round the back got a higher voltage in anticipation of forthcoming Nytech products.

Richard Hay had been a member of the Active Loudspeaker Standards Organisation along with Linn, Meridian and Naim. It was a working group set up to define standards for active speakers, to provide interoperability between brands. Hay’s passion for these systems meant that it was never going to be too long before the Nytech receiver started to split up into component pieces, ready to go active…

First, the CPA 602 power amplifier was launched to provide a power upgrade for the CTA 252; it produced well over 60W RMS per channel and had a sound “to rival Naim”, says Balaam. This came out in 1979, and was soon joined by the CTP 102 tuner/preamplifier, which was basically the CTA 252 without power amplifiers. In early 1980, the EXO 102/3 electronic crossover and CXA252 crossover amplifiers were launched.

The latter was a revolutionary idea at the time, and owners of CTA 252s and ARC or Linn speakers could add the CXA252 to convert their system to a full active loudspeaker with the power amps in the CXA driving HF and LF for the left channel and the power amps in the CTA 252 doing the same for the right channel. Balaam says without equivocation, “the difference in musical quality was astounding and became the best value for money upgrade available and made Nytech/ARC active systems highly desirable”.

They did indeed prove very popular, with reports of many people eschewing Naim active systems for Nytech’s new high end components. “The CPA 602 power amp is the best thing Nytech ever did,” confides Balaam, “it’s a wonderful sounding thing. People started complaining that the CTA 252 XDII didn’t have enough power, so I remember us building up the CPA 602 which I had a hand in design and construction. My main job was to stop it blowing up every five minutes, but we got the bugs out of it pretty quickly!”

Nytechs drove active Linn Isobariks surprisingly well, but Richard Hay decided to forge a strategic partnership with the Acoustical Reproduction Company. ARC 101, 202 and 050 speakers were all convertible to run in active mode, with the passive crossover put on the back, so it was easily done. “It did a lot for ARC loudspeakers,” says Balaam, “for a fairly small upgrade price you got a system in a completely different league”. He adds that, “when the big ARC202 speaker came out in active form, a real war started, as people started to compare it very favourably to the Linn/Naim Isobarik active system – whereas the Nytech CTP102 tuner preamp, EXO102/103 crossover, and two CPA602 power amps driving ARC202s, cost about about a tenth of the price”.

Some 30,000 CTA 252s were sold over its production run, which came to an end in 1982 when the case moulds had reached the end of their useful lives. The product had come along, been slightly repurposed and extensively upgraded over a decade, and made a great name for itself and its company. Sadly though, tragedy befell the brand with its new factory flooding one winter, and various disagreements between the people running the company over its general direction. Nytech ceased trading in the early nineties. The legacy lives on with Heed, whose range shares much of the original Richard Hay DNA. These days, Nytechs surface on the second-hand market now and again for around £100 depending on condition, and although fiddly to fix, are a bargain. More recently, Nytech Audio has resurfaced under the curatorship of ex-Nytech engineer Phil Balaam, with a new range of amplification and servicing support for the classic gear.


  1. peter mackin

    I still have my xd series…perfect condition…any takers?

  2. Patrick Frawley

    Way back then, I was chief designer for a company called Jacy Plastics. I designed all the injection mould work involved in the calculator style case. We made the mould for Richard, that was before the advent of CAD design, every thing was done by hand in those days. I met Richard Hay many times when we were tooling up the mould. never did get my free amp. ha ha. Is Richard still around.
    These days I spend most of my time in China, I have Injection Moulds made for my UK clients and I am also in partnership with a Chinese company with whom I sell my specialised range of plastic plumbing products which I manufacture here in the UK. Mould making has changed so much since those days, all the skill of tool making has gone.



    • Robert Hay

      Hi Patrick,
      Stumbled upon your note today…sorry to hear you never got the amp.
      Dad passed away in 2012, after a short tussle with Pancreatic Cancer. 68 was too young, he’s still missed.

  3. andyrawlins

    I still have and regularly use my CA252 integrated amp. It sounds great in my study with my original Mission 700s .

  4. Bob

    Cta252xd still doing sterling service here

  5. Dougal Julian Hare

    Finally bought a refurbished CTA 252, some 40 years after first seeing one for sale in Carlisle and well worth the wait.

  6. Rich C.

    This is a cute little thing, Looks very much like a miniature mixing console. Could easily be incorporated into a customised DIY ‘console’-type music centre together with a period (deck-only) turntable unit, such as a Garrard SP-25, Goldring-Lenco GL-75/78, or a Pioneer PL-12D.

    Rich C.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: