tda 7293 and tda 7294 help

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i do great soldering.so no question of dry solder.
regarding the amp let me give details.

i m using the power supply the car smps circuit of rod elliots site.it gives me perfect symmetrical +-30v i/p.i am using 10000uf per channel philips caps as filters.
signal is from computer mono out using ultra thin signal wires from a local manufacturer of high repute here in India.

i suppose power supply is the prob and the transformer(the part that i had to manufacture) is at the heart of the problem
is it possible????

a person told me that the ic i m using is altogether fake!!!!!can it be true??can ic be fake
i got ic from same source and built tda1554q and tda8560 and using them in my car with no problem at all

i make po like pcb using photo process so pcb prob also out.

any other that u can make out being culprit
 
Tda 7294 !!!!

Hi Sagar,

I have a very bad experince with these chips long time back, had 3 no: of 7294 and blew one after the other.

I suspect that the Ic must be fake. I would suggest you try with LM 3886, it is available easily in the market and high power , better specs.

Arasuk
 
thanks to all for your help
i will take the amp to my college for testing with the pro level power supplies and oscilloscopes.
arasuk.. i dunno y but i love these chips very much.i have brought lm3886 and lm3876 n will test them.but will definately work up on tda729x series.
will inform u guys soon

adhir one question to u."who r my south bound neighbours"?
 
tested the chips at my college.
used the power supply to pwer it up
eureka!!!it worked but at very low volume and heavy noise

college power supply is perfect(no noise,regulated etc etc as with every university)
so what is the noise source
signal source is computer mono out
good quality philips caps used.(original ones from authorised philips outlet)

whats the source
(i tested tda7294 from jean yves martin site pcb link is)
http://www.jeanyvesmartin.com/ampli_TDA7294.htm
 
:bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling:

i used my own power supply(a new 20-0-20) transformer as power source at home and there was SMOKE.my ic's soul disappeared in thin air(tda7293)


anyone has a nice and decent layout that worked.what is schematics?power supply.i have ten of both tda's each so ineed them to work:confused:

:smash:
 
i have now built lm3876tf based amp
it is wonderful.good power and great sound reproduction.but achilles heel is that the ic becomes very hot.load is 4ohm but the prob. continues even eith 8ohm.ihav used it in n.i mode with no cap at i/p signal.the feedback res. is 47k.voltage is very safe 26v at 5amps(power supply is totally clear with fast recifiers and adequate capacitance)
big heat sink that remains cool i.e the ic becomes very hot very soon.is it normal for it?my tda1554q and8563 remained warm during full power
but never as hot(untouchable) as it gets.one more,the ic is tf version i.e insulated version.
thanks in advance for help
 
Hi sagaverma, I have built 7294, 3886/3876/3875. I like 7294 because it reminds me of the good ol days with mini-crescendo. I would say that mosfet amps are rarely good but when they're good, they can't be matched by bipolar. In certain point between good and not-so-good, I think it's about preference. Because I like this mosfet "property", I would go the distance to get the most out of the TDA. Black Gate power supply, MUR diodes, etc.

I'm also looking for TDA7293. Problem is I don't trust my local market. I need to go out of town to buy the chip. That's because of our "south bound neighbours" hehehehe.

I'm also working with the LMs. Trying to match them with BOZ. But because I don't know electronics enough, I need to burn some chips. My objective is single supply, inverted, with common input bias. Can you help me?
 
hi Jay

southbound neighbours??:confused: who r they?chinese, etc.tell me bec u 2nd one to say so
from my knowledge i can tell u not to go for single supply app bec much of the quality will b sacrificed('remember i asking ques in another post bout a preamp,i built it and its ok ok,bec of single supply)
notice that supply of the pamp is 24v i.e double of 12volts[opamp also operates at 24v bec + -12v so total voltage envelope for swing is +12-(-12)=24v],the standard bias voltage of opamps.

the waveform given as i/p needs to swing b/w the + - voltage of the power transistors of the amp.so higher the voltage more is the swing(provided transistor soa is not exceeded)

in a single supply operation,the o/p voltage swing is limited to only +ive half of graph.thats an ineffecient way of operation bec music content has -ive gain also for certain frequencies and it would be good for it to swing in -ive portion of the power graph.in single supply operation,for +ive or -ive gain,voltage swings only in one portion of graph(+ive).that is not good nor effecient

in a nutshell,don go for single supply.use dual supply.

y inverted?do u wanna make bridged amp?
 
Hmmmm... I don't have the answer sagarverma. I just follow intuitions ;) BOZ is single supply remember? Well I can make it dual but not yet, not before I'm failed with single supply schenario. 60V is a minimum for a BOZ. Not minimum I think, it should be more, but that's the available transformer. And the LM can withstand 84V (too risky of course) and efficiency is never an issue with me. If I can make the LM3875 single ended 3W, I will :D

I don't know about the theory sagarverma, so I just build and listen. If I hear better sound coming from the single supply, I will trust my ears. With single supply I have some opportunities with gain/feedback resistors and coupling capacitors. Why inverted? Hmmm... I think it's cleaner. No, bridging for power is not my style, I'm also working with TDA2615 6 Watt.
 
tda7294

Hi sagar,
I too have built several amplifiers using tda7294 with a bass boost ckt using tl072 to get punchy bass.U can ask any help from me.Actually i want pcb for photo transfer but i couldnt find them in delhi.I use paint to make my pcb.It would be great if u tell me the place where i can get them.I have built the symasym amp of mikeB using my home made pcb and i want photo transfer pcbs to make the job easy. Please help...................
regards
Aman
 
hi aman

plz help me with a bass boost circuit
i need bass boost.
plz post the ckt and pcb layout
have u built tda7293?
tda7294 working great.

pcb:::::::::
it took me a total investment of Rs7000 to set up equipments for photographic process.i discovered later bout toner transfer method which is more than enough for DIy.so go for it.i will give u more advise if u need the same bec the conditions for toner transfer in India(delhi particularly) r totally different from rest of the world.
 
Jay said:
Hmmmm... I don't have the answer sagarverma. I just follow intuitions ;) BOZ is single supply remember? Well I can make it dual but not yet, not before I'm failed with single supply schenario. 60V is a minimum for a BOZ. Not minimum I think, it should be more, but that's the available transformer. And the LM can withstand 84V (too risky of course) and efficiency is never an issue with me. If I can make the LM3875 single ended 3W, I will :D

I don't know about the theory sagarverma, so I just build and listen. If I hear better sound coming from the single supply, I will trust my ears. With single supply I have some opportunities with gain/feedback resistors and coupling capacitors. Why inverted? Hmmm... I think it's cleaner. No, bridging for power is not my style, I'm also working with TDA2615 6 Watt.

hi jay
u seem to be a go-get-it person who is out for experimentation.
good.its nice to have people like u on this forum who don fear but do it jus bec they love it.
what bout your single supply plans?done anything?
 
bass ckt

Hi sagar
i will search bass boost ckt at home today and will send u the name of website.I built that ckt on a veroboard.Its very easy and good ckt.I didnt use tda7293 coz i couldnt get it in LR market .TDA7294 was available for abt 100Rs and lm3886 was abt 350Rs.However plz tell me abt toner transfer which i can do at home.I also used permanent marker to make pcb but the tracks were very bad and broken after i etch that and after that i never used that and used paint and results were very good but too much hard/art work needed.....
:)
regards
aman_4g@yahoo.com
 
Re: bass ckt

aman said:
Hi sagar
i will search bass boost ckt at home today and will send u the name of website.I built that ckt on a veroboard.Its very easy and good ckt.I didnt use tda7293 coz i couldnt get it in LR market .TDA7294 was available for abt 100Rs and lm3886 was abt 350Rs.However plz tell me abt toner transfer which i can do at home.I also used permanent marker to make pcb but the tracks were very bad and broken after i etch that and after that i never used that and used paint and results were very good but too much hard/art work needed.....
:)
regards
aman_4g@yahoo.com

hi aman
Rs350 for lm!!!!
hey man go to shop 220.i got lm for Rs100 there.
tda also there for 130
where u got tda for Rs100.plz tell me.

search on toner transfer method on internet,u will get 100's of links.

i have done too much of experimentation on pcb making.every process of diy pcb making.i use photo method but toner transfer is more than enough for diy.


India specific points on toner transfer method r::::

1)most of the laser printers at the printout shops r refilled toners.i.e the spent cartridges that r original,after they get empty r refilled by toners by the shopkeeper.these refilled toners r inferior quality an r not transferred well to pcb.infact they rarely get transferred to pcb.so see to it that the laser printer that u use uses genuine cartridges and not the refilled ones.

2)do not buy neelgagan or de-smat photopapers that come very cheap.no cheapos here.buy only good quality photopapers.hp is the best but very costly.kodak is the best compromise between price and quality.

3)acetone that is used to clean pcb before the transfer ,in India,its very costly to get branded and good one.cheap ones that r available r of no use.so to clean the pcbs ,use SCOTCH BRITE cleaning pad.scrub the pcb until its color changes.i.e it begins to shine.noo need for any cleaner then.use a liquid KIWI KLEEN to clean the scrubbed pcb.finally wash pcb with bathing soap and not detergent bar.the transfer will then b perfect.even thinnest traces will get transferred seamlessly.

4)acid used for toner transfer is FECL3 ONLY.best use anhydrous version but dont put hcl in it.anhydrous will take hours but no undercuts at all.use sufficient quantities.

these r all to keep in mind

y u use paint:confused: use nail enamel.dries very soon!right!!!!

plz guide me with bass booster

i also need help with woofers,tweetres and speakers.good ones that r available in Delhi.

do u know bout a torroid transformer source
where do u get your transformers?


where do u live???????

too many questions:D
 
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