Nothing In Particular

[jack]

Not to say I wouldn't like one of these to play the precision game, but it would be just the collector of test kit impulse

http://www.keysight.com/en/pd-100000129 ... =GB&lc=eng

If you bide your time, who knows what will turn up...

I sold all of my older test kit when I moved out here, except the Tek 2465A and a couple of other bits... cathartic.

Someone was selling off Keithley 6.5 digit 2015THD DMMs for under 300 quid (notice went up on the EEVBLOG forum) - got one of those. Still a current model, selling at USD 5,000...

They are now around at 350 quid - all are ex-ATE, so previously rackmounted thus minus their tilting bail, but otherwise perfect.

Mine was still in calibration. Overkill for most folk, but I do mainly micropower IoT stuff these days, so for me it made sense - the MSP430 uP boards I use idle at about 13uA - every tiny bit of current saved extends the life of the CR2032s that drive them and the 2015 has 10nA resolution - perfect for this task.

That beast you referenced has ONE PICO AMP resolution. Insane!

[Michael L]

I was thinking about a Fluke 8842A which can be had for under £150. Currently I have a Robin AR4011 and a cheap RS meter recommended on this forum a while back. (https://www.industrialcalibration.co.uk ... 0Sheet.pdf )
I don't have anything that measures true rms.

[jack]

Have a look at the Aneng AN8008. Astonishing value for money and genuine TrueRMS - many reviews out there including eevblog and detailed ones from Mark Henessey, a BBC lecturer. The 8002 is also worth considering and has slightly different characteristics.

Paid about 14 quid for mine on Banggood - turned up a few days ago and good enough for 95% of what I need.

Being so cheap, has the advantage of being sacrificial, though in destruction testing they have proved to be amazingly resilient...

[Nick]

Those Flukes look like a good deal if you want a bench DVM. I do have doubt just how accurate true RMS meters actually are at anything above 50Hz. But they could be better than I think now.

I would think if true RMS was the goal, a HP3400A would be worth looking for.

[Michael L]

Have a look at the Aneng AN8008. Astonishing value for money and genuine TrueRMS - many reviews out there including eevblog and detailed ones from Mark Henessey, a BBC lecturer. The 8002 is also worth considering and has slightly different characteristics.

Paid about 14 quid for mine on Banggood - turned up a few days ago and good enough for 95% of what I need.

Being so cheap, has the advantage of being sacrificial, though in destruction testing they have proved to be amazingly resilient...

This was an interesting read Jack. The Fluke I mentioned was being sold by the same seller I bought my super clean lab psu from and was snapped up while I was deliberating.

[Michael L]

Who would believe it. A group of grown men getting together with their toys



Reminds me of the fun I had with the PE Minisonic I built in the 70s. It was full of 741s

http://www.timstinchcombe.co.uk/synth/p ... nov_74.pdf

[andrew Ivimey]

PE, Elektor. Maplin and a few others. The 8038 chip, fabulous but getting stable log oscillators was nigh on impossible. I built a small wall of modules and linked them together with a patch board just like the synthi AKS. The best unit was a sample & hold voltage driver - versatile and fab!!!

[Nick]

I forget which it was now, but someone made a series of log control chips that included a oscillator and filters. I remember building a third oscillator for a mini Moog, that had the problem of being more stable than the internal ones.

[Mike H]

I remember making most of the Practical Electronics one. All 741 op-amps. Learned a lot about the 741 doing that, mostly about what it can't do.

748 was better at doing some things faster but then you have to start getting into learning slew rates and compensation capacitors to keep it stable in the HF, all got a bit too complicated for me at the time.

[Michael L]

I would have loved a keyboard but as a poor BT apprentice couldn't stretch to it. I used a stylophone type interface which was the default for the Minisonic.
My favourite thing was the ring modulator. The Dalek effects, amplified nicely startled our neighbours.

[Mike H]

Log law oscillator - just remembered, shortly after that was another PE project to do that, based on the behaviour of a diode junction.

The diode junctions were the base-emitters of 3 transistors of a CA3046 array (so you could have up to THREE oscillators!), a fourth transistor was used to heat the chip, and the fifth acted as a temperature sensor. The heating and sensing was done by an op-amp, using a thermal negative feedback loop principle. Interesting but not quite as good as it promised. It was charmingly called a "transistor oven".

[andrew Ivimey]

DAm's just lost my post....anyway, it was amazing just what a 741 could do.... 2x 741s in one package! and by the time I got a job with Electro Harmonic some genius had invented operational transconductance amps.

Going back a bit - Keyboards! Such fun (not) wiring up double contacts under a five octaver- one set a ladder of resistors and one for envelope shapers - maplin sold me a 49 er that I took to Goldsmiths' so I could read a little bit more Marx, Freud and economics while making bigger and bigger unstable synths. I used a modified stylophone through a Watkins copycat(valve) right from the earliest days of the band.

[andrew Ivimey]

Yep Mike - done it but it was still not reliable 'on stage.

I dreamed of Moogs, EMSsynths were horribly unstable too. As the band continued after Goldsmiths I bought a Korg 700s, still couldnt afford Moog, Arp or Roland.

Crap filter but rock solid tuning that Korg was good.

[ed]

aww you boys, i dunno

I bought a yamaha sy77 back in the day...super reliable as I remember...could fiddle and shape with the oscillators and make any kind of rude noise you wanted...also could dial in the piano for standard stage use...not a soldering iron in sight. It didn't teach me much about electronics though.

When I sold it I got nearly as much as I paid for it....some guys from an African band came and picked it up.

[andrew Ivimey]

Had one too but then they brought out the SY99 and I could import samples..... Bloody heavy but very reliable. I still have an SY55 keyboard in the attic-half an SY77 (?)