TDA7293 amplifier alive

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Hello all!

I have now built a test amplifier around the TDA7293 chip and it seems to work. Im gonna buy boards for two paralell mono amplifiers with these IC:s and run the sub. I´ll upload pics of this test as soon as i have installed the ftp proggy.
nice. Isn't it amazing how small stuff like this has gotten since the first tube amp was built? I have a 50 watt stereo amp that fits in my portable cd player case for gosh sakes. lol.

dude thats humongal tranny you got there!:eek: what in the world is it off of?

btw, are those el84's or kt88's laying beside it? :cool:
The transformer is from a yamaha home cinema receiver and is about 425VA, the rectifier is from a computer power supply.

The amp (just a test to see if it works) works very good with subs so i gonna boy two boards for two paralell mono amps to drive the subs drivers.

The tubes laying around there is 6L6GC:s;)
ahh. That musta been when electronics were electronics. Nice big transformers and tons of heat producing darlingtons! I love my fishers solid design, its built like a rock. I blew a channel the other day, popped it open and replaced the fuse and was good to go. Can't abuse modern stuff like that anymore! ;)
The RX-V592 is from 1998 so it's not that old, only 1 year older than my NAD T770 which is a beast. You can still get loads of quality electronics today that is built to be able to take a beating, but you have to pay for it. Take a look at Bryston amps, they are rediculously expensive, but worth every penny if you can afford it.

Sorry to get off topic here, that is a decent looking amp you have there. I would have layed the components out on a perfboard personally for something quick like that, but that's just me. I'm happy to see that the 4 working TDA7293s that are left from my Logitech Z-560 computer speakers can be put to some good use one day.
Power and Dynamic Range:
Total power output: 400 watts RMS
- Satellite speaker power output: 212 watts RMS (53w + 53w + 53w + 53w)
- Subwoofer power output: 188 watts RMS
System frequency response 35Hz - 20kHz
Signal To Noise Ratio: 100dB
Maximum SPL (Sound Pressure Level): 114dB

wow! I wonder, is that the chip they use in the new z5500's? *wants that system very badly*


the chip says 100w @10% THD so maybe that RMS rating isnt too off. Still, the z680's say 53 watts RMS per sat @ 10% THD.. Im so confused. I hate cheap ratings :confused:

off topic: yeah I know theres a lot out there thats sturdy, but your right it has a price. My fisher was probably pretty expensive in its day, but then again it was a consumer stereo system, not something hi-fi. I will say though that unless your pumping a ton of bass into it that thing will still peak out at 120 watts a channel( on the meter at least) with no distortion, even though its RMS rating is 100 watts per....@ less than 0.09% THD- LOVE IT! :D I've even used it as a mains amp in our band running my Marantz's- its very very loud lol. nice, cheap ( cuz it had 2 transistors that came loose on the first stage (old solder I guess) when I got it) and powerful.
wow! I wonder, is that the chip they use in the new z5500's?
LOL, Logitech's speaker specifications are the biggest load of ..... you will ever see. You forgot to mention the THD of 10% they also rate them at haha. The specs they show you are simply the specs of the TDA7293 amplifier IC's, which they do not use to their full potential in that speaker system. It is a 4.1 system consisting of TangBand drivers. 1 amp IC for each satelite, and 2 amp IC's for the subwoofer. The satellites are rated at 15W RMS, and the sub is rated at 100W RMS. 160W seems a far way off from 400W doesn't it? They still manage to make a lot of noise, but the subwoofer is easily destroyed because the bass boost knob has far more gain than it should. The satellites are crossed over fairly high so that the system can play so loud without a lot of distortion, so you miss out on a lot of midbass information. All in all it is a very nice set of speakers as far as computer speakers go, but someone at Logitech should be shot for marketing their speakers with such false specifications.
:confused: that cant be right. I will say that 15 watts RMS should be nice- thats enough to make you go deaf with mid and high end. Heck, try running that much power through my marantzes and you start to shake stuff off the walls. As for a 100 watt RMS sub, well into a 10 inch speaker ANYTHING is better than my peice inspire's sub. 22 watts peak into a 5 inch woofer...woo-hoo..hey I thought SUBwoofer meant BELOW woofer range? lol. Anyways, heres some data from review on the aformentioned z560's

"Getting back to the transformer, though - it's a little smaller than any 300VA transformer I've previously seen, but it could be 300VA, and could power a high efficiency amp of close to 300 watts. I'd be surprised if the Z-560's amp module outputs more than 300 watts, though, and I wouldn't be surprised at all if it was actually 250 or 200."

hmm... 20 watts x 4 + 120 watt sub maybe?
I know the z5500's have improved a lot. Maybe they use diff. chips and/or transformer? hey does anyone own a set they could look into?
Tekko said:
There were no darlingtons in the yammy, just regular transistors and it never got hot either, barely even warm.

My fisher gets hot after a while. Don't leave anything on top of it if you dont wanna kill the amp. I installed two Antec 80mm case fans on the back and am running them off of an adjustable voltage wall wart. keeps 'er running real cool, peak the amp out for several hours on end and that heat sink hardly gets warm ( still feels cool) do it without the fans and well.. you might as well expect to say goodbye to the amp sometime soon. I've got my computer monitor sitting on top of it right now and theres still good cooling. Hey by the way, when I turn on my amp the left side of my screen has a flicker ( kind of like a low refresh rate ) Is this caused by the magnetic interferance of the huge transformer in the amp? It goes away somewhat if I stack my tuner on top of the amp and then put the monitor on top of that with aluminum foil underneath.. is there any other better solution? ( The amp looks pretty cool sitting under my monitor like that and its easily accessable)
My amps dont have any heat problems, they stay cool. Perhaps your fisher has a underdimentioned heatsink.

I have fried this tda chip a few days ago running it in 4 ohms with +-50 volts psu, this is not reccomended in the datasheet so during a loud bass line the chip cracked with a flame and burned off one of the psu pins and the output pin.
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