My 2+1 project; FAILED!

[Dxvideo]

Yes in every condition i will make a GC... Last weekend i purchased a pair of LM3886TF free samples from National Semiconductors. My old orders was rejected from NS everytime.. But now they said "Your devices will ship from our warehouse in Singapore as soon as possible." I'm surprised!
Anyway, it was a problem to buy first class chips from local market in Turkey. Because there are many fake chips in Turkey.. In this case my big problem is solved.
As i calculated on Overture Design Guide;
- With symmetrical 24v power supply, i can get 53,15W each LM3886TF, and needs only 2,11CW heatsink.. (Does a P4 heatsink without fan enough?) If enough, that means my enclouse will be tiny size..
- With 27K - 1K NFB resistors i get ~29dB gain and for full output power, input sensivity will be 0,736Vrms.
Everything looks preety, for now. What do you say that drawing? I wont add a preamp that...

 

[AndrewT]

Hi,
too late for this advice now but

A mains light bulb in series with the input from the mains would have prevented the explosion and probably saved most of the components as well.

Next time!!

 

[-_nando-_]

Fake components... Old problem here in Brazil.

If you go to brazil's center city, you will NOT find ANY genuine components. Is so incredible, they ONLY sell fake components.

So I buy everything from Farnell Newark In One. They are installed here in Brazil, here their customer care is a pain, but they are the one that sell only genuine parts.


Why don't you do the same thing? Instead pray for TI send you samples, buy it directly from farnell, it's cheap.

http://export.farnell.com/jsp/home/exportHome.jsp;jsessionid=KOXBJ5MDTBH3VQFIAEXEOSQ


Anything that don't have in farnell, buy from Digi-Key. www.digikey.com, they have a great customer support, with online help and everything.


Best Regards !

 

[Dxvideo]

A mains light bulb in serial .... Its exteremely late for my dead LM1876s and my damned night.. But thank you for remind.

And for now it seems i solved the component problem (at least for LM3886) I asked two LM3886TF free samples from National Semiconductors and they sent me already. I hope they will come soon.

But what do you say about my new project? Please give some comments.. PLSSSS

 

[Nenola]

I notice that this is a bit old thread, but anyway.

I'm also trying to design a 2.1 amplifier with two lm1876.
Dxvideo, do you still have the schematics for your design? Then I could see what kind of components I would need etc.

I'm a newbie in these things so I need a little help

 

[stahlight]

If you can't afford to blow it up, you can't afford to use it...

Sorry I am not very helpful, but drunk circuits usually cause me physical injury

 

[tangmonster]

This just solved my problem. I have been using two old
(early 80's sanyo speakers) up till Very recently.

I had about two glasses of brandy when i hooked up my latest design and the +35V touched the output pin on the lm3886 . GRRRRRRRRRRRRRRRRRRRRRRRRRRRRPOP

there goes a speaker and a lm3886 chip.

Two good things came from it.

One i found an EXcelent bargain on MUCH better new floorstanders the next day. And i resoldered a new lm chip and all is well now.

I newer new that two glasses of brandy was to blame.....

 

[Nordic]

yep, and being from Cape Town, I have to add for your benefit, this aslo applies to anything green....

 

[tangmonster]

 

[Paswa]

Hey, DxVideo, why made just 2.1, Join with me, I'm building a 5.1 channel amplifier

 

[tangmonster]

2.1 = music

5.1 = movies

 

[ratza]

I'd say that 2.0 = music.

 

[Dxvideo]

Its an old project. And now I prefer to make stereo projects for HIFI.

 

[tangmonster]

I'd say that 2.0 = music.

agreed!

I see 2.1 as a second best choice for music.

Actually the simple rule is play it with the channels it was recorded.

 

[danielwritesbac]

. . . Actually the simple rule is play it with the channels it was recorded.

Well, if you're talking popular music, counting the number of channels is going to take a while. There's some on the mixerboard that can't be precisely duplicated by two speakers. Plus, there's remarkably different field depths. And, then you could count the number of prosound speakers at a concert too. That doesn't fit most homes. Where is the answer; but, its more of a question of when, isn't it?

Hey, glad to hear your amp survived, and especially glad to hear about the floorstanders. Ah, real speakers--love those!

 

[ttan98]

Nando,

You got mail, please answer.

 

[TheMG]

I'd say that 2.0 = music.

Totally agree. Unless you have a PERFECTLY tuned system with a good active crossover and well you know, all that stuff, with smaller speakers and using a subwoofer for the bass, there tends to be this "void" in the soundstage.

Listen to a satellite+subwoofer (2.1) speaker system with music, next listen to a 2.0 system with speakers that have proper woofers (10"+), mids, and tweeters. You'll be shocked at the difference.

Granted, for some genres of music, a 2.1 setup is better. Rap would be one of those.

 

[tangmonster]

Well, if you're talking popular music, counting the number of channels is going to take a while. There's some on the mixerboard that can't be precisely duplicated by two speakers. Plus, there's remarkably different field depths. And, then you could count the number of prosound speakers at a concert too. That doesn't fit most homes. Where is the answer; but, its more of a question of when, isn't it?

Hey, glad to hear your amp survived, and especially glad to hear about the floorstanders. Ah, real speakers--love those!

Dude , I meant , most cd's are stereo , and most movie dvd's are 5.1.