A while ago at work I noticed that some Compaq computers have an internal speaker that has quite a nice sound. Not HiFi but kinda nice. So... I took a few out of them (they where old and not going to be used anymore) and decided to try them for guitar.
Here's two pictures and a sound sample:
http://www.hut.fi/~pjunno/temp/kompshall/
The box is plastic hammond box. I dont remember the model number but the dimensions are 12cm x 12cm x 9cm.
It has a preamp with four fets (BF256A). Gain control is after the first stage and tone control is Big Muff -Style and it is between 3rd and 4th stage. Poweramp is LM386N-4.
The soundsample is recorded with a dynamic mic (electrovoice CO4) placed in front of the speaker. It has three tracks and my playing sucks as usual. :)
-Petri Junno
A "computer recycling" place near me regularly receives palettes of older MacIntoshes for rendering, and has a huge bin of the speakers pulled from them. These are a little over 2" in diameter, but they have rubber or foam surrounds on the cone, like a much larger high quality speaker would, and a huge magnet. Unfortunately, they are 32ohms, but 4 of them in a tiny "Marshall stack" configuration with an 8ohm overall impedance, and a couple of watts to drive them, might be interesting. These are certainly NOT the same sort of quality one sees in the "beeper speakers" found in desktop PC's. Much, much wider usable frequency range than just about anything else in that size.
Hmmm... Any chance that someone out there might be able to source these speakers for those of us unable to scavenge them?
BTW, nice amp. The enclosure looks about the size of a computer power supply, so that would really complete the theme! What power is it running on?
Ben
Quote from: Mark HammerUnfortunately, they are 32ohms, but 4 of them in a tiny "Marshall stack" configuration with an 8ohm overall impedance, and a couple of watts to drive them, might be interesting.
These are 8ohm I think... Or at least my DMM shows around 8 ohms DC resistance but that may not be the whole truth (as it usually is not with speakers). They aren't like those ordinary small PC-beepers either. The magnet assembly is quite big... That's partly because magnetic protection though. But hey... these will not hurt monitors or TV's. :)
Quote from: Ben NHmmm... Any chance that someone out there might be able to source these speakers for those of us unable to scavenge them?
Well... I don't really have that big supply and I don't think mailing them around the world would probably cost more than they are worth.
Some information I can give though: I've found these from Compaq's computers that are a something like 2-5 years old. The ones that I have found these speakers where something like Compaq Deskpro EP and EX or EXM series. The cases of those computers look like the picture on this (http://h200006.www2.hp.com/bc/docs/support/UCR/SupportManual/TPM_107a0498/TPM_107a0498.pdf) pdf. Only the ones that were suplied with soundcard or built in sounchip had a speaker like this.
The speaker itself looks like this: http://www.hut.fi/~pjunno/temp/kompshall/speaker.jpg
And after sayin that, I'd like to say thet there are probably many kinds different speakers to be scavenged that have a some kind of cool sound. This will not be the last one I will try. :)
Quote
BTW, nice amp. The enclosure looks about the size of a computer power supply, so that would really complete the theme! What power is it running on?
Thanks! Now that you mentioned it... Its not too far from the size of a typical computer power supply... Maybe I should try to buold an amp in a broken power supply... They have a bit too many holes though...
Oh.. It is powered by 6 AA-size (LR6) batteries. I think it could be made to work with less batteries but I originally intended it to work on 9v battery but started thinking it might suck those a bit too fast. AA-Cells are cheaper also) so the circuit was almost complete and I needed 9v.
Wow, those are odd-looking--kinda like a horn, but not really, with a huge (relatively) magnet. I'll look out for them, thanks.
Ben