What is head?

[Andy Hall]

Oh yes. This was the thing that assumed zero rise time for the active components......

[Tony Bryer]

I couldn't wait, so Google turned up

commentary on each product such as "The Z-50 amplifier was added to the Project 60 range in June 1970. The Z-30 was rated at 30 watts, so Sinclair decided to advertise the Z-50 as rated at 50 watts. However, the device expired at between 37-40 watts, so their designer suggested 30 watts as a rating; the final compromise was 40 watts. Perhaps not surprisingly, the Z-50 was not a particularly reliable device."

and

"Although it[Z12] was claimed to achieve "laboratory standards of performance", whatever those may be, its performance and reliability were questionable. It reportedly only achieved a maximum output of three watts, despite being advertised as being capable of 12 (hence the name). Its lifetime was also problematic - if run continuously at full output, as little as 12 hours (presumably not alluded to by the name). The problem probably lay in the fact that, like many Sinclair products of the time, it was built with cheap transistors that had been discarded by other manufacturers as rejects."

Lots more in similar vein!

[Dave Plowman (News)]

PWM - pulse width modulated. I know a couple of people that made them, but failed to get them to work. The principle is around today, though.

[Clive Summerfield]

Gah! He produced a whole raft of them, the Executive (plus Memory version), the Cambridge (plus Memory, Universal and Programmable versions), the Scientific, the Oxford series and the Sovereign series (which looked more like a modern TV remote control than a calculator). Pretty sure the last Sinclair calculator came out in about 1979. Didn't he do a kit to make a calculator designed to be worn around the wrist as well?

The ZX80 had 2K of memory, but to be honest was pretty useless as the display broke up every time a command was executed. This survived in the ZX81 as FAST mode.

The QL worked (eventually), but completely missed the boat. The Z88 was actually a good product, but once again was incompatible and arrived too late to ever be a success

Don't forget the Zike, an electric bike from the early 90's. Or the Zeta which was a bolt-on electric motor for push bikes, power being transmitted via friction drive to the rear tyre. Like that's a sound concept.

Did anyone ever use any of the Sinclair Digital Multimeters? The impression I got was that they were pretty competant bits of kit, most likely as a result of Clive Sinclair having no involvement (or interest).

Cheers Clive

[Tony Bryer]

That's the opinion of

[The Natural Philosopher]

Mm. Actally the X-12 power amp worked if you didn';t mind 15% distortion...

Yes. Clive didin;t design those , and teh bettest of all, the 4000. which Richard Torrens designed (he's still around) Clive scrapped becase he hadn't had anything to do with it.

Trying to do the undoable with crap technology on the cheap.

No.

One in ten sort of worked.

Ypu have forgotten the project I worked on - the pocket television.

After taking ten years of advance orders, he shipped just enough rubbish to avoid being sued, and it vanished wiothout trace.

I left because i told him it wouldn't work, and he wouldn't believe me, and his current shagbunny called me names, and I told her what to do.

Complete tosser, con artist and self publicist. No wonder maggie knighted him

>

[The Natural Philosopher]

No. That was the 4000, a halfway decent amp, if a bit cheap.

The PWM amp was trying to do with germanium transistors what is just about achieveable with current switching MOSFETS, but no one does, becuse its hard to get the quality.

[Andy Wade]

There were two PWM amplifier products, IIRC, the X-10 and the X-20. These were 10 and 20 'watt' (that's Sinclair watts, not SI watts) supposedly hi-fi amps. They came as kits - just a bare PCB and handful of components - no housing of any kind.

I had an X-10 and also failed to make it work in any meaningful fashion. There was no filtering of any kind on the output, so the RFI generated was considerable: enough to wipe out LW and MW radio reception for a considerable radius. I did get some audio o/p - into a Goodmans Axiette

8 (more nostalgia) - but hi-fi it certainly wasn't, more like 50% THD. I gave up on it and never bought another Sinclair product, ever. In contrast the Mullard 3-3 valve amp design I'd built a year or so before worked very nicely for several years, eventually being replaced by the Bailey 30W transistor design published in the Wireless World (~ 1968).

I've still got the X-10 in its original box somewhere in the loft. I wonder if it's a valuable collector's item by now?

[Eiron]

He should be Lord Sinclair by now. He did as much for electronics as Jeffrey did for literature.

[IMM]

Did it work?

That is understandable.

Did she do it? Did she do what they do at the snotty unis's?

No taste in clothes or haircuts.

She was a such a loser, and no taste in clothes either, and always backed the losers too. She even backed Archer too, who claimed to have been to snotty uni, but nver and no doubt did what they did. Maggie probably did what all the others do at the snotty uni's and that was why she was like that.

I'd burn 'em all.

[The Natural Philosopher]

He did as much for wife swapping as Tony has done for iresponsible lying. That place was a complete shagshack.

>

[The Natural Philosopher]

no.

no, she was already doing it with Clive.

or chldren, if rumour is to be believed.

forced to agree with you, as long as we can use Bliar and prescott as firelighters, and that revolting little squinter.

[Dave Plowman (News)]

Still using a Linsey Hood - listening to it at the minute driving a pair of LS3/5a off FreeView radio.

[Eiron]

Which one? One of the class A designs or the AB 75 watt jobbie?

Details? vintage, manufacturer?

[Dave Plowman (News)]

75 watt.

Ah. A real oddity. Chartwell kits sold to BBC staff.

Got another pair in the kitchen - made by Rogers.

[Andy Wade]

[LS3/5A]

[Eiron]

speakers as all LS3/5a's sound the same. :-)

[Dave Plowman (News)]

I doubt any two speakers sound exactly the same if you were to measure accurately enough. However, my Chartwell pair have adjustable crossovers so I set them to match the Rogers as closely as possible. One of each used as a pair but switched to mono gives a pretty stable central image.