freq. responce help on mini amp

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ThSpeakerDude88 said:
you said to use a poly cap of the highest value i have between + and ground. the circuit already includes one.

No The highest value poly cap should be in parallel with the output cap.



ThSpeakerDude88 said:
And I was asking if the power jack should be where it is or should it be closer to the capacitors?

Do you have a problem with hum or noise? If not leave it the way it is.
 
jaudio said:


Removes high frequency oscillations




No but I would add the Highest value film cap that I have. It will help high frequency response.


ThSpeakerDude88 said:
hm ok. where do I mount it, across the output cap? what value would you reccomend.. because I doubt I have anything more than 1 uf at most, and I probably dont even have that. Hmm.. I'm not noticing enough of a bass boost to warrant huge output caps, theres a little difference. I wired the 2 4700 uf caps in paralell to make 9400uf and tryed one channel, theres some difference but not much. Could it be anything else?


jaudio said:


In parallel with the other output caps


Use what ever you have. I would use the largest I have. IF it 1uf use it and see if high frequency improves



No once you go low enough bass is more felt than heard. If it's not worth the extra cap then use one but leave the film cap(If you added one)
 
ThSpeakerDude88 said:
ohh ok. Well theres already a poly cap .1 uf mounted as you sugguested, is there a difference between that an an electrolytic for the purpose you sugguested?

Im only talking about the output caps. Have you ever notice,when people talk about crossover cap it alway suggested " use film caps for tweeters and midranges". There is almost alway a better frequency response. When I dont have large film cap,I use a electroytic and a film in parallel and it is always better than an elctroytic alone.
 
hmm ok. Gee., they dont list a chart for distortion vs. freq. in the datasheet. I know THD @ output power 2 watts is approx 0.03%

I think stable at the 1khz mark up to 17 watts @ +/- 20 volts. I think its around 0.07 or 0.08 % am I right? its hard to read their diagrams. 15 khz is considerably more distorted. Try .5 % up to 18 watts before climbing up to the 10% mark on the given psu.
 
I'm thinking of building a single rail amp with the TDA7264 and I winder if the experts here could help answer a few questions?

There is no single supply application note in the data sheet, but there is one for the TDA7265 which seems like basically the same amp with external feedback. Since there will be DC on the output the feedback network is tied to ground via a capacitor in that application. However the network is internal on the TDA7264 so I can't do that, does this rule out running single rail?

The data sheet says +/- 22v supply Max. If running single rail am I limited to a single +22v or can I double it as presumably the internal ciruitry is running biased to the supply mid point (I guess this is automatically handled inside the IC because the application doesn't show any bias network on the input).

Thanks!

Actually one final question. I'm looking at this amp as an alternative to my TDA7492 class D board because I've found this has noticeable third harmonic above about 1khz making my good tweeter somewhat wasted. It seems a common aspect of all low cost class D chips. Can anybody comment on if the TDA7264 is better in this regard? I expect it is given class A/B design. I know the TDA7294 is nice.
An externally hosted image should be here but it was not working when we last tested it.
 
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