tda 7293 and tda 7294 help

[sagarverma]

i know bout this ckt.i wanted some tried and tested(like what u made).

did pcb??

class d subject to availability of chips.

 

[aman]

pcb

hi sagar
........it is the same ckt which i build,pcb also similiar. But i dont have that amp now.It would have been changed many hands now...
Yesterday i transfered the toner to the pcb and it was great transfer and tonight i m going to etch it. I m in search of a suitable plastic tub for etching process.Now i use a small plastic "dabba" used to keep buiscuits and namkeen... and use water heater (used for acquariums) I think u too use that.
any suggestions
regrds
aman

 

[sagarverma]

hi aman,

the transfer was supposed to be perfect(after following my guidelines).i suppose u followed all.

i have a plastic tub(mini rectangular box) 4 etching.
i liked your idea of mini heater rod

chemical,i suppose u will use anhydrous fecl3(with hcl if ok ok traces but without if pcb has very fine traces).
i would love to see the pcb of yours .

 

[aman]

pcb

hi sagarbhai,
yes,i followed ur guidlines strictly...... thanks,hats off to u....
i use anhydrous ferric chloride from lr mkt, Rs 75/ half kg.I never use hcl,dangerous . with fecl3,heater rod and proper amnt of water it doesnt take more than 20 minutes.
I have populated that pcb 80%,rest i will do today after matching transistors.
I dont have camera/phone to show u the karishma like pcb....
but some day i will show the pcbs

aman

 

[sagarverma]

Hi Aman,

what is the ckt that u made pcb of?

pic anyway

 

[aman]

ckt

hi sagar,
I built SymAsym5 by MikeB sounds very good with nice punch and easily available components.
U can search that in forum.
regards
Aman

 

[sagarverma]

hi Aman,

looks good amp.components::as u said genuine r difficult to get,plz tell bout the source of genuine.
+
where is the components overlay for that amp?is yours working?power supply voltage used?

 

[aman]

hi sagar,
I m building the amp with the genuine trannies i m having now.
cant get more.....
But u can use mjl21193/94(to-3) and can be get from Mehta Bros.
U can read the thread relating to sym and can know more abt it.
regrds
aman

 

[godslayer]

OH MY GOD.. PEOPLE of my location talking about the same ic as i wanted to know.. but i think you people dont logon.. if you do, i would love to know about 7294 amps.. of if any other you have made nowadays.. you are right.. my friend too made 7294 it burned without any output in 5 min... can you both help please?

 

[ashok]

Some like it , some don't care for it and some hate it as they seem to explode unpredictably when they used it. But yes it appears to be more touchy than say LM3886.
Don't ask for more posts on these . Use the 'search' button and chip name and you will get quite a LOT of threads on them. Read them all to get to grips with what people have to say about them. Then you could follow some construction threads also on this forum and make your own chip amp.

You might have noticed that you are some 5 years late on this thread !

 

[godslayer]

ofcourse i know i have bumped quite late that is why i have written if i am late by the way i have seen many chips and amps.. but right now i am still confused... there is a huge market in delhi but i donot know what parts are already available here and what not.. the place is like 25 km from my place(and no metro) so before i do unnecessary running around.. i'd rather take someones advice on making a good reliable amp

 

[Th3 uN1Qu3]

The 7294 is a fine IC but it has chances to be DOA. I built three amps using this IC. The 1st one i had some trouble with till i figured out that Vmute and Vstby have to go to the POSITIVE rail to turn on the amp. 4 years ago there was an error in the datasheet and they were referenced to the negative rail. Then it worked fine.

The 3rd one didn't go out of standby although everything was wired properly. If i would disconnect one of the power rails the amp would start (with a horribly distorted sound of course). I bought a new chip and dropped it into the same board - the amp powered up and still works to this day (3 years).

 

[mav254]

on any chip amp, it must have heatsink compound and a good heatsink, if you don't you'll have trouble. the silicone will transfer the heat to the heatsink and disapates 5-10 percent off the heatsink making it run cooler.

 

[kuldeepsingh]

i always suggest to buy samples from NS site even they are a little costlier. But you'll get a genuine chip

 

[horizonrays]

i always suggest to buy samples from NS site even they are a little costlier. But you'll get a genuine chip

ns site ? do you mean national semi conductor ?
but how to get them ? can you give the link ?

 

[AndrewT]

google National Semiconductor.

 

[horizonrays]

andrew i know about national semiconductor and their site , but i do not know how to get samples from them , i use the material available in local market and sometimes they are counterfeit .. i want to know how to get sample from national semiconductor directly .

 

[kuldeepsingh]

you have to make a login account at NS site which is free of cost and then you have access to "samples" link. Just select the IC you want , go to its samples availability and NS will tell you shipping cost that you have to bear for particular nos samples.
technically samples are free but you have to bear shipping.

 

[horizonrays]

mr kuldeep , can you tell me how much does it cost for the sample to arrive inidia , because you said it's costlier than local market !!
and also can you tell me how many chips can i buy ?

 

[kuldeepsingh]

u can just check it. it was 10$ for 5 chips some time back. i had forgotten my NS password and too lazy to retrieve it. just make login account and u can see cost urself.