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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 6th Nov 2019, 11:31 am   #1
TonyDuell
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Default ZN414 -- Where used?

I am sure many people here remember the ZN414 radio IC. Originally in a
TO18 package, there was a later vesion in a plastic TO92 one. It made a
simple AM radio receiver of so-so performance and seems to have been
in production for around 20 years.

At one point in the early 1970s it appears that every magazine contained at
least one radio based on this IC.

But where _else_ was it used? Was it used in any commercial products, if so
what? I've never seen it in a commercial unit, but I can't believe an IC was
designed and produced for the benefit of home constructors.
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Old 6th Nov 2019, 12:05 pm   #2
Bill
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Default Re: ZN414 -- Where used?

I left Ferranti Gem Mill in 1974, at the time we were making quite a lot of 414s. Once the device per wafer yield was satisfactory, these became very cheap to make, comparable to small signal transistors. By comparison, eline plastic eg ZTX300 could be made for a penny each. I'm not sure what the applications for 414s were aimed at, may have been military, the data sheet mentions radio control receiver with very low power consumption which may have use in some sort of shell or missile? We would not be party to that information.
On the other hand, there were a lot of electronics enthusiasts at Ferranti at all levels so they may have developed it for hobbyists initially!
There was an "Applications Department" whose sole job was finding uses for new devices and publishing construction details. There were some very good HiFi transistor amp designs from there.
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Old 6th Nov 2019, 12:12 pm   #3
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Default Re: ZN414 -- Where used?

I have a couple of commercially made earphone radios using the 414. In later years it became almost mandatory for those taking the test for Radio Amateurs to make their own demonstration receiver following the printing of an article somewhere, and for a decade or two after manufacture ceased people were desperately trying to buy these on eBay
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Old 6th Nov 2019, 12:15 pm   #4
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Default Re: ZN414 -- Where used?

That one had puzzled me too- it was so often presented as something of a toy/novelty and it wasn't really the era of a manufacturer producing an IC just for the hell of it (though intensely irritating bleeping greetings cards later changed that...).

Could there have been a serious application for something that had minimal power requirements like, say, a 200kHz (as was) carrier monitor reference or a standby LF beacon receiver?
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Old 6th Nov 2019, 12:47 pm   #5
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Default Re: ZN414 -- Where used?

On reflection, I was thinking of the auto-tuning FM earphone radios (Philips device?)
The 414 used a variable capacitor to tune, but the datasheets never showed any 'professional' application
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Old 6th Nov 2019, 3:24 pm   #6
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Default Re: ZN414 -- Where used?

I have seen them used for telimetery over power on CCTV cameras. It brings back memories of the early 1980s.
They were run at 1 to 2 Mhz and had to share the cable with 10Mhz for video.
There was housing temperature and voltage sensing one way and PTZ the other.
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Old 6th Nov 2019, 5:51 pm   #7
Paul Stenning
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Default Re: ZN414 -- Where used?

I used to have a couple of cheap-and-nasty pocket radios which used the MK484 IC which is equivalent to ZN414 (along with a battery-flattening class A audio amplifier).

See http://vintage-radio.com/manufacture...t-trannie.html just before half way down where there are photos of the insides of two sets. Unfortunately I don't have better photos and no longer have the sets.
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Old 6th Nov 2019, 6:45 pm   #8
G6Tanuki
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Default Re: ZN414 -- Where used?

Quote:
Originally Posted by turretslug View Post
Could there have been a serious application for something that had minimal power requirements like, say, a 200kHz (as was) carrier monitor reference or a standby LF beacon receiver?
From memory, the ZN414's internal coupling-capacitors had values that meant the gain was significantly less on LW than on MW.

And the phase-modulation on Radio4 that's used for the old 'economy-7' electricity-meters for swtching between rates wouldn't be resolved by the AM detector in the 414...

TBH I can't really think of any 'professional' applications that the ZN414 would have been appropriate for.
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Old 6th Nov 2019, 7:20 pm   #9
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Default Re: ZN414 -- Where used?

I also had one of the cheap pocket radios using a MK484 and class A audio amp, the battery drain was made worse than usual as the on off switch only disconnected the final audio stage. I also have a Sinclair Z1 which used a similar device.

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Old 6th Nov 2019, 7:32 pm   #10
Ian - G4JQT
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Default Re: ZN414 -- Where used?

I think I vaguely remember mention that the ZN414 was for use in developing countries where a very basic AM radio was necessary to listen to health and agricultural guidance programmes, and where a receiver with economical battery life was desirable. But with hindsight that sounds like promotional publicity. I guess it was a could have been a precursor to Baylis's wind-up radios for the same reason.

I have no idea if there were any made and marketed (or distributed free by NGOs) to such countries. It probably assumes they'd be used in urban environments (where such radios would be needed least) where strongish AM stations are more likely than out in the bush where they'd be more use.
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Old 6th Nov 2019, 8:35 pm   #11
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Default Re: ZN414 -- Where used?

I found one at work https://www.vintage-radio.net/forum/...d.php?t=159546 and will see if it is a) on the stock list and b) where used on (if ever) tomorrow.
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Old 6th Nov 2019, 8:52 pm   #12
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Default Re: ZN414 -- Where used?

I seem to remember a radio designed by I think R. Penfold, it might have been in either one of the many Electronics mags of the 80's or in one of his many books published by Babani.
Anyway he used a ZN414 but not in the usual way to make a radio as you would normally use this device, but rather as a novel IF amplifier/stage.
Now I would never have thought of doing that, and I can't ever recall seeing it used that way since either.
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Old 6th Nov 2019, 9:12 pm   #13
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Default Re: ZN414 -- Where used?

In a SWM of the 70s there was a circuit used to "SSB/AM-ize" one of the cheap Daiwa "Search-9" and MARC "NR-56" VHF radios that were popular back then.

The circuit used a ZN414 as a 455KHz AM IF-amp/detector, with a single-transistor BFO.

I built it - it wasnt too successful, firstly because the free-running VHF local-oscillator was really drifty, secondly because the 455KHz signal was tapped off _after_ the FM limiter-stage had done its thing, and thirdly because there was no way to vary the RF/IF gain - so if you set things up to work on weak AM/SSB signals the ratio of BFO-to-signal went non-sensible on stronger signals.
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Old 7th Nov 2019, 9:26 am   #14
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Default Re: ZN414 -- Where used?

Quote:
Originally Posted by Red to black View Post
I seem to remember a radio designed by I think R. Penfold... he used a ZN414 but not in the usual way to make a radio as you would normally use this device, but rather as a novel IF amplifier/stage.

Now I would never have thought of doing that, and I can't ever recall seeing it used that way since either.
I have an idea that Ferranti suggested its use as an IF amplifier stage in the data sheet or application notes for the device. At 465kHz it should work well.

But the subject of this thread... no I have never come across a piece of Production equipment which used the ZN414 either!

I have of course made a couple of radios - one fairly small, matchbox-type, and another, loudspeaker output, which I mounted on my bicycle (incidentally, mounting INSIDE the triangular frame really killed the sensitivity due to it making a large shorted turn right around the ferrite aerial, so it had to go OUTSIDE).
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Old 7th Nov 2019, 9:50 am   #15
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Default Re: ZN414 -- Where used?

I did see one used in a kid's plastic sun-visor/radio/headphones type of product - it also had a solar cell on it to power the whole thing...

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Old 7th Nov 2019, 1:10 pm   #16
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Default Re: ZN414 -- Where used?

I have never come across this in a commercial product and the hobby mags were certainly full of projects at one time. I did wonder if it was originally developed for some sort of military contract which never proceeded to anything, leaving Ferranti with thousands of the things to dispose of.
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Old 7th Nov 2019, 1:53 pm   #17
Martin G7MRV
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Default Re: ZN414 -- Where used?

Some time ago I did find one in a commercial product, and was very much surprised by it, trouble is, thats all I can remember!

If I managed to drag the details out of the far reaches of my mind i''l let you know.

Aparently all these MK484,YS414,TA7642,UTC7642,LMF501T,LA1050 are equivalents! Its almost incredible that a device could have been in production for so long, in so many forms, and yet not have many commercial uses!

Perhaps someone knows someone at a suppliers who could identify a manufacturer who is getting through large quantities, and ask them what they are making?
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Old 7th Nov 2019, 2:05 pm   #18
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Default Re: ZN414 -- Where used?

40 years ago I worked for a component retailer. After the 1978 frequency changes, BBC
schools programmes were broadcast daytime on R4FM, with the standard programmes on
LW. A lot of imported tuners/tuner-amps had no LW, so I made and sold a batch of
LW-FM converters, with the ZN414 audio modulating a 2 transistor FM bug tuned to
about 104 FM. 30 were made, my first "product". A while after this R4 was also
transmitted on 720kHz MW in London, and demand ceased.
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Old 7th Nov 2019, 3:06 pm   #19
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Default Re: ZN414 -- Where used?

This radio kit https://www.banggood.com/DIY-Portabl...r_warehouse=CN
uses a TA7642 for the AM radio section.
'Paeansonic' badged build blog here :- https://goughlui.com/2016/09/07/proj...mfm-radio-kit/

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Old 7th Nov 2019, 5:27 pm   #20
TonyDuell
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Default Re: ZN414 -- Where used?

Quote:
Originally Posted by Martin G7MRV View Post

Aparently all these MK484,YS414,TA7642,UTC7642,LMF501T,LA1050 are equivalents! Its almost incredible that a device could have been in production for so long, in so many forms, and yet not have many commercial uses!

Perhaps someone knows someone at a suppliers who could identify a manufacturer who is getting through large quantities, and ask them what they are making?
Yes, that was my thought that prompted me to start this thread. I was looking up some ICs in a 1990 Maplin catalogue and noticed that they sold a ZN414-like thing then. I remember it in magazine projects in, say, 1973. Keeping an IC in production for 17+ years for the benefit of home constuctors seems very unlikely!
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