Ah, duh. I should have known the VDD.
Anyway, I thank you once again for your help - one LAST question (I hope, desperately...) the shutdown can just be left completely alone, right? I don't HAVE to use it or anything, and if I do nothing with it, nothing bad will happen? You said to disable it, connect it to the vdd - so when I connect it to the vdd, it becomes completely obsolete, and I don't need to worry about it?
Anyway, that should be all I need. I'll probably be designing a circuit board for this with eagle, so I may come back later for some more help.
Oh, wait! One more thing! I still don't know what speaker to use. Any suggestions? Once again, I want to keep it from digikey, mostly to save on shipping. I suppose I could do 2 speakers, a semi-sub-woofer (is that the right terminology?
) and a tweeter, if you think that would still be small enough. And then, I still don't understand how to "cap" the lower limit so I don't damage the speaker by trying to drive it too low - is there a component I could just put in place (Like a transistor or something)?
Anyway, I thank you once again for your help - one LAST question (I hope, desperately...) the shutdown can just be left completely alone, right? I don't HAVE to use it or anything, and if I do nothing with it, nothing bad will happen? You said to disable it, connect it to the vdd - so when I connect it to the vdd, it becomes completely obsolete, and I don't need to worry about it?
Anyway, that should be all I need. I'll probably be designing a circuit board for this with eagle, so I may come back later for some more help.
Oh, wait! One more thing! I still don't know what speaker to use. Any suggestions? Once again, I want to keep it from digikey, mostly to save on shipping. I suppose I could do 2 speakers, a semi-sub-woofer (is that the right terminology?
) and a tweeter, if you think that would still be small enough. And then, I still don't understand how to "cap" the lower limit so I don't damage the speaker by trying to drive it too low - is there a component I could just put in place (Like a transistor or something)?Maybe slow down a bit. I guarantee that what you will need to do to pull this off is not at all compatible with a jumpy personality.
Be sure to tie the shutdown pin to the the rail (VDD). Digital inputs left hanging open can decide to switch states when someone in Siberia farts. You don't want that. Even worse things can happen when they don't really switch states, like drawing excessive current from the supply.
Are you going to photoetch a board? That will keep you from having to mess with little wire.
I will calculate the input filter component values for you, but I'm having a bugger of a time picking a speaker. What I like is not available. What's available doesn't have response curves available, or do and look scary. The probably nice sounding stuff doesn't have any efficiency. No free lunch with this one. I'll try to find all the parts at Digikey then.
Be sure to tie the shutdown pin to the the rail (VDD). Digital inputs left hanging open can decide to switch states when someone in Siberia farts. You don't want that. Even worse things can happen when they don't really switch states, like drawing excessive current from the supply.
Are you going to photoetch a board? That will keep you from having to mess with little wire.
I will calculate the input filter component values for you, but I'm having a bugger of a time picking a speaker. What I like is not available. What's available doesn't have response curves available, or do and look scary. The probably nice sounding stuff doesn't have any efficiency. No free lunch with this one. I'll try to find all the parts at Digikey then.
Okay I put together a little circuit for this. Not very fancy, just a couple notes. The input filter has no particular classical response. The first RC has a corner frequency around 195Hz and the second formed with the input impedance of the amp is around 220. Below 190Hz you should be losing response at 12dB/oct. The gain is set to 6dB. The circuit should work whether you chose 3 or 4.5V supply. The voltage divider used to bias the shutdown pin through the input connector switch might not be able to pull it low enough to enter shutdown with 3 fresh batteries and the 1M resistor. You could substitute an 820k and it should work in any case. The shutdown diasable state trips at something over a volt so it should take a few seconds for the unit to turn on once the signal cable is plugged in. Shutdown current will mainly flow through the 10M resistor at less than .5uA, which should allow you close to the shelf life of the battery.
Ya ever think of these for 2 for $6 shipped? You would double your output power and only need 5vdc for rails.
http://www.sure-electronics.net/rf,audio/AA-AB008.pdf
http://www.sure-electronics.net/rf,audio/AA-AB008.pdf
Hey guys, I'm back again, my computer was wacky for a long while, but I still need some help - I'm thinking that PCB is the way to go with this, and I had originally intended to make my own, but that won't be an option anymore, just because they're my first boards, and I don't want to screw them up. Where's an inexpensive place to get boards?
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