Retro activities today:
- Washed an ASUS Radeon x600Pro and Ensoniq AudioPCI 3000 cards. They didn't come out as clean as I'd like, but good enough. The Ensoniq sound card looks as if black dust / sooth has burned onto the PCB and just won't wash off with regular dish detergent and water. But it's cleaner than it was. I might try IPA later on. As for the x600 Pro, it looks OK. I missed a spot between a few of the capacitors and there's a ton of dirt there, but will see if it's worth re-washing the board. Might try it like this first (later tonight or tomorrow when it dries), just to see if it works, and then go from there. Both of these cards were picked up as e-scrap boards at the fleamarket sale last weekend. I paid less than $3 for the two of these (about $2.50, actually), so don't have any real expectations. The x600 Pro also had a zip-tied 50 mm fan on top of its cooler and the original fan removed (likely because it failed.) But whoever did this did a terrible job and warped the heatsink like crazy on the bottom. So not sure if the core was contacting the heatsink surface that well with the mod. There's always a chance it could have burned out. We will see, I suppose.
- Washed some vinyl records and CDs/DVDs that I also picked up off the ground at the fleemarket last weekend. Haven't tested the records yet, but they don't look too scratched, and at least they are not warped (which is rare for that flea market.) As for the CDs/DVDs, there's an Office 2007 Ultimate PE DVD (PE=Pirate Edition 🤣), a bunch of CDs with music, and a few blank DVDs and CDs that I picked up off the ground specifically because they looked like they were blank. Oh, and there was also a CD labeled "pictures : ) ". Decided to snoop in it just for shits and giggles. Apparently it was from a group of high school kids from some years back. Then there was one picture with the ID cards of 4 of the people from that class, which revealed they are all just 1 year younger than me. Looking at the date of the pictures, I suppose that makes sense, with most of them being taken 2005-2006 and the CD burned around 2007 or 2008, IIRC. And for those who are wondering... yes there were a few "saucy" pictures in there 🤣. I was genuinly more interested to see the interiors and/or surrounding of their houses or where the pictures were taken, though. And as a bonus, I found a few "desk setup" pictures, which were quite cool to see IMO, showing the average teenager's computer setup back in those days - yup, good old silver/beige desktops with CRT monitors. COOL Maybe I'll post them in the "show your work area" thread later this week. Just need to inspect the pictures again to make sure there isn't any sensitive info that might leak out.
- Brought some rocks from the local river bed for a project my father is working in the yard. No modern equipment was used for carrying the rocks 🤣 - just 100% manual labor, carrying the rocks in a century-old wooden wheel barrow. I suppose that qualifies as retro activity too, right? 😁
PD2JK wrote on 2024-09-05, 05:59:
So we have a 120 Watt (PMPO) speaker set, equipped with 15 W woofers + 3 W tweeters, and the amplifier is capable of giving 2.1 Watt. Per channel I hope. 🤣
Hehe, typical cheap desktop speakers of the time. 🤣
Though if we have to be honest, these aren't that bad at all. The woofers are quite alright and shielded, which is nice. And you got real tweeters too... so there's that.
Now as for the amp... 2.1 Watts /ch is the nominal value the manufacturer gives with 9V Vcc (with an ugly 10% THD 🤣). If you look a little closer at the AN7148 datasheet, the IC is rated for 24V absolute maximum (well, you probably don't want to go that high, being an absolute max. rating), and rated for 6-18V nominal operation. So depending on the voltage that the transformer/power adapter for these speakers is outputting (and the current it can supply - 1 Amp should be minimum), you may actually be able to get higher power output. For example, with 18V Vcc for the IC and 4-Ohm drivers, I think you should be able to get about 6 Watts of output power per channel... which isn't too shabby for close-range listening. Of course, that power will only do any good if the speaker boxes are up to snuff (which I'm not that sure about, as they look like typical thin ABS plastic that'll resonate like a can.) Also, I'm not sure the heatsink on the IC will be able to handle the P_d for that kind of output output power, at least continuously. With short "thump" bass notes spaced apart, it won't be a problem. But any music content with continuous low-freq. bass notes will likely make the heatsink toasty. Also, I see the speaker ports have quite the rough edge. I doubt the drivers will be moving that much air to cause any port chaffing noises, but still that's something to keep an eye on too. I suppose if you really want to improve these speakers, you could do that by reinforcing the walls + add some damping on the "cabinets" (more like, cans?), and replacing the output coupling caps with bigger ones (along with the feedback and RF rejection cap), that might improve the sound a little. But it will probably be more work than it's worth.
On a related note, I have somewhat similarly-built speakers from the late 90's (similar arrangement with a larger-than-cheapo-speakers woofer and a real tweeter like yours), and I have to say that I think they sound quite decent. With the Bass knob turned all the way up, they actually pump out some decent low-end bass down to 45-50-ish Hz, which is not bad at all considering their size and build quality.
