***Official Electronics Thread of Officialness (it starts off with lots of Nixie Tube Clock goodness

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taliesyn said:
Good one Dai, keep us updated with progress :)

Like the way you've bridged the fuse connection with wire :eek: :p
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Ha! I wondered if anyone would spot that. I blew the fuse by plugging it in before cutting some legs off :rolleyes: I did a quick bridge job to check nothing else had blown. A new fuse is on it's way from Pete at PV elec.:cool:
 
bulb66 said:
Yes that's correct, and yes you do have to print it (On transparency) but you can reused that as many time as you like in fact i reused one i made 6 months ago. :)

Some of the traces on the board i just finished drilling and fill are less than 1mm wide, i'm really happy with my <£40 UV box. Beats paying the £200 they cost from Rapid, lol.

J
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Wouldn't mind a build log for this sort of thing, including plans etc. Ive always fancied making my own PCB's, but do not know where to start!
 
I could try and take some pictures the next time I etch a PCB. It shouldn't be that long before I'm next etching one - I'm currently working on the artwork for a project so it'll probably be a couple of weeks max before the board gets etched.
 
Well my latest 'project' if you can call it that is a stock implementation of Sijosae's discrete rail splitter (well stock apart from a couple of decoupling caps which will be making an appearance once they arrive lol. They are 0.47uF metpoly ones which typically are the ones I've run out of :D).

Basically it's a simple circuit using discrete components that emulates the TI TLE2426 rail splitter but allows much greater currents to be handled, and it 'equally' splits a load into V+, V-, and a VGND (virtual ground). More current than a circuit using an op-amp for the splitter could handle too.

I have a CMOY amp that I built up from a kit ages ago, using 2 x 9v separately wired batteries (individually powering each channel of the op-amp) which could potentially discharge unevenly and cause a DC offset in the output jack, which could technically damage any headphones that happened to be plugged in at the time.

After advice from some audio gurus, I've already changed from stock it so that it has the batteries wired in series and now has a simple resistor divider circuit using a couple of hand matched 4.7K resistors, and it works fine.

But this is better and I was bored OK? :p

I've knocked up a prototype, having tested it on breadboard first of course :cool:, and it appears to work, so it's all good stuff :)
 
taliesyn said:
Well my latest 'project' if you can call it that is a stock implementation of Sijosae's discrete rail splitter (well stock apart from a couple of decoupling caps which will be making an appearance once they arrive lol. They are 0.47uF metpoly ones which typically are the ones I've run out of :D).

I've knocked up a prototype, having tested it on breadboard first of course :cool:, and it appears to work, so it's all good stuff :)
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Sounds good. I've been thinking about improving the virtual ground circuit on my CMOY from it's current 741 Op-amp to something else. Was a little put off building that Sijosae's circuit because Tangent says it's the least accurate. Surely it can't be less accurate than a resistor voltage divider ground?

Please update with pics and stuff.
 
Tealc said:
Sounds good. I've been thinking about improving the virtual ground circuit on my CMOY from it's current 741 Op-amp to something else. Was a little put off building that Sijosae's circuit because Tangent says it's the least accurate. Surely it can't be less accurate than a resistor voltage divider ground?

Please update with pics and stuff.
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I'll take a pic later if I remember!

You'd think it would be more accurate, wouldn't you. I've still got the resistor divider in place so I suppose I could test it and see :)

Mine had none implemented at all. Odd, as if I remember correctly, a resistive splitter is part of the original CMOY design.
 
I'm sure Tangent probably meant it's the least accurate of all the other vritual ground circuits apart from the voltage divider. I haven't noticed much difference though going from resistor divider to 741. The Op-amps that misbehaved before with the resistor still misbehave with the 741 but perhaps not to the same level.

Still getting a little distortion at high volume though so will be trying out some new things over the coming weeks to try and improve that, including swapping in a 24v power transformer which I just found up the attic to replace the 12v one I'm using now. Might also throw a voltage regulator circuit together to get a constant voltage.
 
Tealc said:
I'm sure Tangent probably meant it's the least accurate of all the other vritual ground circuits apart from the voltage divider. I haven't noticed much difference though going from resistor divider to 741. The Op-amps that misbehaved before with the resistor still misbehave with the 741 but perhaps not to the same level.

Still getting a little distortion at high volume though so will be trying out some new things over the coming weeks to try and improve that, including swapping in a 24v power transformer which I just found up the attic to replace the 12v one I'm using now. Might also throw a voltage regulator circuit together to get a constant voltage.
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More than likely. I would have thought the 741 would have made more of a difference though.

Which op-amp are you using in the CMOY itself? Mine is the JRC 4560D and with 2 x 9v it's stupidly loud, and surprisingly distortion free :D

Took a few days to burn it in initially, but it really sounds good now.
 
taliesyn said:
More than likely. I would have thought the 741 would have made more of a difference though.

Which op-amp are you using in the CMOY itself? Mine is the JRC 4560D and with 2 x 9v it's stupidly loud, and surprisingly distortion free :D

Took a few days to burn it in initially, but it really sounds good now.
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I went for the OPA2132 but I have tried the OPA2227 and a cheap NE5532.

I basically copied Tangent's design apart from a 0.47uF PP cap and the PCB itself, which is stripboard. I substituted the recommended potentiometer for one I could actually buy.

The NE5532 is incredibly unstable with the virtual ground in both my attempts. It oscillates really badly when anything but ultra low volume is put through it.

The OPA2132 as it stands sounds lovely until I crank it up to ear splitting volume, where it falls aparts a bit. This could be power supply issues though as I am using an unregulated 12v 500mA power supply that is putting out 18v with such a low load. Might try the CMOY with dual 9v batteries at high volume to check this actually.

For my third attempt I will proof first on breadboard and experiment with gain and the different op-amps and hopefully come up with something a little better.

Now that I have the second attempt in place I can take my time on the third.
 
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Ohh an electronics thread. Ohh with 3D printers too. Been lusting about one for ages!

Here I do quite a lot of projects too, mostly small size. Here is a USB i2c+temperature sensor.
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And my latest board; a controller for 2*5 meters LED strips to "balance" them. I use "car usb chargers" and hack them apart to get to the switching power supply in there, thats for the 5V to feed the logic.
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All done with Eagle, toner transfer, sponge to etch etc. Surface mount soldering done with a frying pan mostly.
 
Any recommendations for a soldering station? Looking to replace my soldering iron for something I can control the temperature of. Got about £120 to spend, is there anything decent out there at this sort of price?
 
Lakeland said:
Any recommendations for a soldering station? Looking to replace my soldering iron for something I can control the temperature of. Got about £120 to spend, is there anything decent out there at this sort of price?
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I almost exclusively use this nowadays with a chisel tip.

Temperature stable, LV iron, grounded iron so ESD safe, standard tips, separate iron holder, and fast warm up. Works just as well with that horrible lead free solder. Cheap as chips too.

I bought one a while ago on the offchance that it wouldn't be too bad, but it's actually excellent and does the job rather well. It's a rebranded Chinese jobbie, I think the high street electronics place does them (again rebranded but more expensive), and I think Atten rebrand them too.
 
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