nekomatic

To answer the first one, at low frequencies the capacitor in series with the HF driver will have relatively high impedance, and at high frequencies the LF driver itself will have relatively high impedance due to the inductance of its coil. So the nominal impedance of the design is still 8 ohms.

I don’t think it came with any particular specification for accuracy, but it seems ok in as much as it gives reasonable results for known components. I’m sure it’ll be using the built-in ADC of its microcontroller to do the voltage measurement, plus the tolerance of any extra components it uses to source or measure currents, but that should still be good to within a few percent I’d think. If you need serious accuracy you’d need to pay a lot more for a more serious bit of kit, but most of the time you really don’t.

The more B the softer, i.e. the more graphite. So for lubricating a nut I guess 6B would be the choice.

Get you, I just glued mine to a spare bit of plywood

Non English language songs that become hits in English speaking countries, maybe…

For electronic builds or repairs: you can get a component tester like this off eBay for fifteen quid or so that will identify the two or three terminal component (resistor, capacitor, inductor, diode, transistor/FET) that you plug in to it and tell you its parameters like resistance, capacitance, inductance, diode forward voltage, transistor gain etc and which pin is which. Absolutely invaluable for confirming that you’ve got the right part and have got it the right way round before you start soldering.

And you're not getting away without

I know it's not originally hers, but… she's Kirsty innit

Good shout on Jacques Dutronc above, too

I’ve obviously not explained correctly what I was thinking of, but you’re right that the arrangement I was thinking of would risk presenting 9 V to the amp input as you inserted or removed the plug at the instrument end, so is probably… unwise.

I wonder this too, and I’ve seen them.

Actually taking this seriously for a minute, if the active bass has battery negative wired to the jack's ring contact, expecting the mono plug to short that to the sleeve, then you should indeed be able to power it through the cable by shorting the battery connector in the bass and supplying +9V on the ring of a stereo plug instead. This seems so obvious that I must have made a mistake somewhere, otherwise why isn't it commonplace?

If Bill Fitzmaurice said it, I believe it. I think I’m probably leaning towards the front port though, if only for the benefit of the grille protecting it.

The low notes on a bass have a wavelength of over a metre though - even for their second harmonics.

The baffle is definitely glued. I’m going to glue in the bracing and a strip to block the slot port after I’ve cut the various holes and sanded the existing paint off, because there’s no point sanding the bits that I’m going to cut out anyway! Good point about rear porting - space for the port on the baffle isn’t an issue but it would mean I could stop worrying about whether to try and paint the port tube. I guess it would also improve the rigidity of the baffle? It wouldn’t have the grille to keep lost objects and mice out though.

Isn't it about time somebody mentioned Steve Swallow? Pleased to see the love for Me'shell upthread though. And does anyone else know Bob Fitzer of Universal Congress Of?

That's neat but I'd want to check what the current draw actually is - what counts as 'very low power consumption' might be a bit different between a model boat that runs for a few hours on a rechargeable pack and a bass that you expect to last for months on a PP3. Genius! With the added bonus that it would also cut out if you started pulling any of that neck-in-the-air rock star posturing 😄

Right… My first task has been to scrape, dissolve and sand off enough of the bituminised felt gunk from the rear panel to bare wood so that I can glue a couple of braces there. If I get my hands on the idiot who read somewhere to use that stuff and thought it was a good idea… oh. Meanwhile I've got all the bits now, and looking at where they'll go on the front panel it's going to be pretty tight for the horn: I don't want to fit it and then find that I've got a problem with how to fix a grille on the front - I'm thinking I may even need to cut the front of the horn down a bit along the two sides parallel to the long axis of the ellipse. So I'm going to get a grille made before I start cutting any holes. Unfortunately the front recess isn't deep enough to use a flat grille like the Basschat design, so instead Mark at speakergrills.co.uk has quoted me to make one with folded edges (in powder coated steel - he doesn't powder coat to order for small quantities any more, due to cost, but says he's got a pre-coated offcut he can use and will touch up any cracks along the folds) which is not super cheap but I think it's the right solution to both protect the speaker and look decent. I'm thinking I'll add 'ears' to the cab at each corner to effectively extend the recess and protect the grille corners, and I've got some oversize plastic corner protectors which I'm hoping will make the thing look reasonably professional. So next stop is to await the grille, make final decisions about positions and then (gulp) get sawing…

That’s obviously the right answer. Although I don’t fancy 48 volts on the end of a jack plug.

Nifty! I was thinking one could fit that in a small box with the plug bit sticking out, and secured with a nut of the same thread size as the jack plug cover. Unfortunately you can’t add a ‘power on’ LED to this design because when the bass is powered on there’s no voltage available to run the LED. The real answer to this would be a circuit in the bass that put the electronics into an ultra-low-power mode if you didn’t play anything for more than an hour or something like that. I’m sure that’s feasible but it would need to be pretty titchy, so probably a surface mount design not something one could knock up on some stripboard (unless there’s more space in an active bass than I realise)

Thing is, if you get a switch to solve the problem of forgetting to unplug the bass whats to say you won’t forget to switch the switch off? (I hasten to add, I know I would!)

The battery negative is connected to the ring contact of the jack, and the circuit ground to the sleeve. When you insert a mono plug it shorts ring to sleeve thereby connecting power to the circuit. It's certainly possible there are other ways of doing it such as an isolated switch, but I think the above method is fairly standard

Well I thought I was listening to 6 Music via the iPod thingy, and it was playing a series of good solid 6 Music type tracks… in fact I was amused to note that I probably had most of them in my own collection. Even a bit of Les Claypool in there, nice. Why is nobody talking between tracks though? Isn't it usually Shaun Keaveney now? Has someone died? 😮 Obviously, it was actually that the iPod thingy had somehow gone on to a shuffle of my library instead.

It ought to be possible to hack something together from a standard jack plug and a little diecast box or something. Maybe someone who makes custom cables could knock up a prototype.

I have a pair of these too and every word is true.