freq. responce help on mini amp

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Yes, connecting two samevalued elkos in series halfes their value.

Practical application is: if you're in need of a non polarized cap but the value is not manufactured (ex. 47 uF Cap, very expensive). In this case you connect two ends of same polarity (ex. 2 x 100uF elkos konnected on plus or minus will give a cap with 50uF).

mic
 
alright... I'm testing it right now. I noticed my output caps get warm after clipping for a little bit, is that bad? Yes, I did notice a significant bass increase! I think its due more to the output caps rather than the filter, I'll try it without the extra filter cap real quick. Btw, thanks for the help! this will turn out to be a nice 4-H project after all! :)
 
ThSpeakerDude88 said:
alright... I'm testing it right now. I noticed my output caps get warm after clipping for a little bit, is that bad?


The caps should not get warm. With the caps low working voltage and being driven to clipping that might cause them to get warm. I may sound like a broken record but I think you need 50volt caps. Make sure supply caps are wiring in parallel(you want 2000uf). You could add a .1uf as close as possible to the supply pin on the chip.
 
ThSpeakerDude88 said:
Would 10,000 uf be overkill on the outputs? what about the filter?

You can find out if it is overkill by using this

159155/(load in ohms*freq.) then you want to multiply that by four
ei. 159155/(4*15Hz)=2653 : 2653*4=10612uf.
So if you have 4ohms speaker and want a low frequecy cutoff of 15hz,it is not overkill. With 8ohms the cutoff will be around 7hz.
At some point you may want a cutoff.
ThSpeakerDude88 said:

what will the .1 uf cap do? :confused:

It will help stop oscillation and high frequecy noise.
 
oh sweet, ok. hey, I like these types of mathmatical problems :p So do I run the .1 uf cap ( I'm assuming ceramic disk 50 volt or higher?) to ground, or between the chip and supply rail? Also... forgive the stupid question...what about bipolar capacitors for the output? :confused: I don't think I've ever seen any other than regular polarized caps on an output..
 
ThSpeakerDude88 said:
So do I run the .1 uf cap ( I'm assuming ceramic disk 50 volt or higher?) to ground, or between the chip and supply rail?
Bewteen rail supply and ground. Just parallel with supply caps

Originally posted by ThSpeakerDude88 Also... forgive the stupid question...what about bipolar capacitors for the output? :confused: I don't think I've ever seen any other than regular polarized caps on an output.. [/B]

I cant recall see a 4700uf or a 10000uf bipolar cap,you have to run a bunch in parallel. Or use 10000uf polarized cap and add the highest film cap you have.

You can also two 20000uf caps Neg-----Pos Pos-----Neg or Pos-----Neg Neg-----Pos to get a Bipolar 10000uf cap
 
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?
 
ThSpeakerDude88 said:
hm ok. where do I mount it, across the output cap?

In parallel with the other output caps
ThSpeakerDude88 said:
what value would you reccomend.. because I doubt I have anything more than 1 uf at most, and I probably dont even have that.

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

ThSpeakerDude88 said:
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?

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)
 
oh ok. Well lol, with my speakers thats the case too *loves marantz* all the way down to 25 hz, although not sure how useable it is there but they will sure make your chest hurt.

Maybe the reason I'm not noticing a difference is because I'm not hooked up in stereo ? I'm only useing one channel, I've noticed with both channels the bass is double, almost tripple ( unless your an idiot one day and hook em up outa phase and it takes you 3 days and going through your amp wires and crossover before you figure out you got the woofer cables backwards..-_-)

Im not so sure about your last comment, my fisher will make my marantzes crack the walls practicly with gutteral low end bass.. peaking at only 20 watts on the meter. 5 watts is loud enough. Ive got another question. How much amperage should my psu be able to supply? does that effect the bass when you need that extra kick? My psu is 32 volts @ 940 ma, if the amperage were higher would the responce be better?
 
jaudio said:


If it's not worth the extra cap then use one but leave the film cap(If you added one)


If youre using your amp for anything other than a subwoofer amp and a film cap for high frequency. I can just heard a 20hz test signal with the volume turn all the way up but I can feel the air froml the subwoofer.

This will help

www.the12volt.com/ohm/page2.asp


I think your amperage is much too low.
 
thanks! that should be. I forgot, if you notice in the pics, the green cap just in front of the blue filter one is my hf supressor cap, it goes between + and neg. rails. I have a question though: Should I install the power in jack before the capacitors ( ie, caps between the amp and power supply stage) or should I leave it like it is , the power comes in and goes to 2 rails on the pcb, the caps are at the back of it, as you can see in my pictures the red wire coming from pin 2 is the power supply pin. the jack towards the front of the amp ( volume controll side of the amp) is the power in, and the one with the two capacitors immediatly behind it is the speaker outs, and the 3 gang one is my input ( just to clarify things) So should I move the power jack to the other end of the board just behind the blue cap?

An externally hosted image should be here but it was not working when we last tested it.
 
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