Essentially, I'm taking a guess at the correct size of speaker box. My estimates are based upon the dimensions of the original speaker enclosure, which sounded pretty awesome. I'll probably go slightly larger, to see if it has any improvement on the bass. If not, I'll try reducing the size... I've also downloaded WinISD, so I'll see how that goes. Also, my designs based the GF-777 have a small slot just above the outer speakers, which were tweeters on the original. If I don't opt to put tweeters here, I might have a go at a bass reflex speaker. (In the event I cock up, I'll just seal it off). I didn't know that piezo's wouldn't require a crossover, so thats definitely one to try! Just to confirm, is this the right type of piezo? http://cgi.ebay.co.uk/PIEZO-SPHERIC...rkparms=72:12|39:1|65:12&_trksid=p3286.c0.m14 or http://cgi.ebay.co.uk/piezo-horn-tw...rkparms=72:12|39:1|65:12&_trksid=p3286.c0.m14 I am still in two minds about the design. I could design something completely original, or I could make a replica of a classic. At the moment I'm leaning towards the latter, but I'm thinking, since mine will be a tenth of the size, certain details will have to be omitted. So essentially, I'll be picking the most unique characteristic features to duplicate. But then I thought, how about something new, with obvious inspiration from the original - sort of how the Mercedes SLR Mclaren takes obvious inspiration from the old school 300SL, but doesn't copy it. Still working on a final design... Did you build it yourself? Sounds like a lot of fun. I can't wait to get properly started And last, but not least, a request for some help. As you requested mvagusta, here is a (rather poorly taken ) take of the underside of the PCB (tell me if you need a better pic). The power lead goes into the plug on the bottom right.
It's a little out of focus but i can make it out, just! Adding a cheap elecrolytic power supply/stiffening cap, say 1000uf to the same +ve & -ve inputs i have indicated should help sound quality a bit. The tiny one that is there is probably only 100uf, so you'd have 1100uf total which is much nicer. I'd go for a tweeter like the second one you linked, as it has a spherical horn so the sound is projected in all directions, helping the boombox to sound good in different environments. Just beware, many of the cheap tweeters out there have nasty rough responses, but we can't be fussy at that price. Even if it is a little rough, you'd have to be a bit of an audiophile to complain about it, you'll be happy. It is possible that it would be a bit loud, so you might end up hooking up a ~4ohm resistor in series with it to quieten it down.
Ahh you absolute Legend! Thanks for that. Saves me scratching my head with a multimeter for a few hours I'm usually quite cautious about these things, in case I blow up a capacitor, or a transistor or something... And I'll see if I can get my hands on a few capacitors, boost up the sound quality a bit. To keep it neat, I might just swap the existing one for a larger one... I was thinking the smaller one would be better to use as well, so I suppose thats that. I'm not much of an audiophile, or indeed a -phile of anything else , though I'll be sure to try a resistor if it sounds bad. I think you've had enough cookies, you might get diabetes so here are some sugar-free Oreos:
I love the design for the Brixton Briefcase... You sure you couldn't incorporate a few logic gates or transistors to make the switching system a little simpler? I mean, my knowledge only extends as far as A-Level physics (and we didn't even study Digital Circuitry), but You could do it. I'm a little too tired to think of how right now.. but you've got me thinking, I'm gonna have a look at your circuit diagram again.
Thanks a lot. I'm glad you like it. I've postponed the custom design idea, in favour of a replica tribute at the moment, but we'll be generally seeing the same principals being used. At the moment, the circuitry is rather messed up, but hopefully, over time, these ideas will refine themselves to become much simpler. I think, to keep things easy, I won't have an LCD in this one, so thats about 3 switches gone... I suppose the thing I'm replicating had a LOT of buttons, so I'll see how I could use these switches to enable the most aesthetic set up. Working on a better a Sketchup as we speak, so I'll be posting that up asap...
Sugar-free Oreos?! Isn't that just an empty box? BTW: I to lusted over that exact boombox project. My plan was to buy an 80's boombox and modernise it (ie. a dock in place of the cassette deck). Alas, it never came into fruition, but I hope yours is more successful. http://www.pocketcalculatorshow.com/boombox/ have a history of boomboxes if you need some inspiration.
It is the sort of idea you can quickly fall in love with... I have had a good look around the Pocket Calculator Show website, and there is a lot to see there... among my favourites are the Conions, the JVCs and the Sharps...
Hey, weren't you gonna use some nice little viewsonic speakers for this mod? They had four speakers total, so it would be perfect for a beasty boombox mod, and no need to buy tweeters! And the extra cap i mentioned is more important when you are using a plugback, but even when using a battery it still has the effect of providing a nice n close, low resistance & high current reservoir. Small barely noticeable gain with small speakers, but definitely worth the tiny cost & effort. I prefer those home made style cookies you were giving cpemma btw
Here are the babies I'm ordering. They'll do the job just fine, with my current battery. (When I get an SLA battery, I'll go for a kit, osme crossovers and some high end drivers). Since these are 5W, I'll assume a pretty low current usage (<800mA), based on the idea that my larger, 12W speakers ask for 1.2A. So all in all, should make for a pretty tidy little set up to play with. Will definitely give the cap thing a go, and if I get stuck, I know where to ask for help I think you're turning into a bit of a:
