One big transformer is always cheaper than 2 little ones.
(You just don't know where to find them.)

That said, I guess it's time to do an energy budget.
Name every part you intend to power and the voltage it needs, and the current it needs, and whether it needs a negative voltage in addition to a positive voltage...and part numbers wouldn't hurt.

Does that 5.1 kit come with its own transformer? How much power is it going to deliver to the speakers...all totaled up?

I'm getting to the place where I don't trust you to know how much you don't know. I don't want to play 20 questions so, spill the beans. What's the plan? Put everything on the table and this will go faster.

In case you haven't noticed, I don't give a hoot about what you want to do. Your interests, your curiosity, your money...that's your choice. I'm just here to help you get it done and not fry yourself.

 

ha ha. alright. That is kinda why i'm posting anyway. just to make sure i know what i'm doing not to fry myself. I'm going though the parts now to see about power requirements.

 

When you get that done, I can whip up a power supply in an hour or two. I did this for a living at one time in my life. I know math you haven't heard of...yet, and details about parts that you are just beginning with. Get this all in one pile and we'll get it running.

 

Hi,
about the power supply way cant u use the Computer SMPS as it has
3.3V ; 5.0V ; +12V; -12V and can make 6.0V from 7806 if required
as he wanted to drive the HDD for his CKT. (may be for MP3) and +/- 12 V dc can be directly use for TDA-2030A power amplifier on the rectifier
hope this may solve the problem

 

Because he has an amplifier board that needs 24 VAC, center tapped. A computer supply does not have that output.

 

as per his link it state that it required +/- 12 v (you can see two IC's 78xx next to 6800μf/25v ) and TDA 2030 need ±06v Min to ±22V MAX

sir,
there is nowere mention that it required ±24v/CT

or explain in brief ...???

Symbol Parameter Test Conditions Min. Typ. Max. Unit
Vs Supply Voltage ± 6 ± 22 V

http://www.datasheetcatalog.org/datasheet/stmicroelectronics/1459.pdf

http://www.goodluckbuy.com/2-1ch-tda2030a-amp-pcb-board-components-kit-for-diy-power-amplifier-.html

2.1CH TDA2030A AMP PCB Board Components Kit for DIY Power Amplifier

TDA2030A circuit using a total of 4 blocks, 2 of which is responsible for left and right channels, the other two connected in BTL circuit used for the subwoofer. Board materials used: 1% metal film resistors, monolithic non-polar capacitors, filter capacitors feature two 6800U/25V, on the other using chemical, Panasonic and other brands. The entire circuit board design is reasonable, nice, low noise, high performance-cost ratio , very suitable for DIY starters.
Potentiometer from left to right are: subwoofer volume, treble adjustment, the total volume.
Specifications:
- Operating voltage: 12V AC double
- Maximum output power: left and right channel 18Wx2, subwoofer 36Wx1
- Output Impedance :4-8 ohms
- PCB size is about: 60 x 117 x 35mm (L x W x H)
NOTE: DIY kit installation requires some basic electronic production and practical ability, there is the risk of damage during the process of installing, once the parts are installed we are not responsible for the components. thank you for your understanding.
Previous: 2.1CH TDA2030A Assembled Module for DIY Audio Power Amplifier AMP
Next: BTL Stereo Speaker Protector Finished PCB for DIY Power Amplifier

 

parallax propeller x2(two chips) = 3.3Vdc 75mA(each chip)
cirrus CS4334 = 5.0Vdc 19mA
ghi alfat-sc-340 = 3.3Vdc 38mA
adafruit 2.8" tft lcd = 3.3Vdc 150mA
some wd laptop hdd = 5.0Vdc 500mA (mfg page states only a 5V rail)
sata to usb adapter = 5.0Vdc 500mA (going by the USB 2.0 spec here 500mA is overkill)
pic24f mtouch sensor = 3.3Vdc 300mA
Si4730 am/fm/lw/sw ic = 3.3Vdc 20mA
st013 mp3 decoder = 3.3Vdc 10uA (can't imagine it is this low, but that is what i got from the datasheet)
2.1CH TDA2030A = +-12Vac 3A max (no way do i want the speakers loud enough to draw 3A)

 

dear #12
its +-12V but not 24v

 

Dear embed68k
is it the same CKT for the TDA2030A as in my last post?#26


if its the same CKT. u can use the Computer SMPS

 

yes. but i'm basing the 3A max rating on a similiar kit. I don't know how to tell without building it first. I am putting this in a custom enclosure and want to use a figure 8 mains as the only external power connection. I am planning on how to do this project, but I won't be able to start cobbling parts until my 2500 mile move about a week away. all my circuit boards and parts are already there.

 

mkbutan: All of the information is available now. Please post your schematic of the power supply.

 

embed68k:
http://www.pjrc.com/mp3/sta013.html

Is this the MP3 decoder you are using?
Yes, 10 ua is absurd. Let's use the rating of 85 milliwatts at 2.7 volts = 32 ma.

ps, you want all the power available for the speakers because audio content contains peaks that are 10 times the average power value. You can run the speakers at .3 amps and not clip the 3 amp peaks, just turn the volume control down. and don't get picky with me about units. This is just an illustration.

ps, what is a "figure 8 main"?

 

There are zero 12VDC requirements in your inventory. True? For sure?

What's your plan for parts? Digikey? Mouser? Radio Shack? Other?

Gotta go do family stuff for a couple of hours.

 

yes that is the correct sta013 chip. the parts are coming from all over. I have the mp3 decoder already. but the ghi usb i2c chip, the si am/fm radio ic, and most others are coming from the manufacturer. i can probably get the propeller chips from mouser or digi, but most of them aren't even listed on either site. figure 8 mains is a 2 prong ac jack.

 

my radio chip is obsolete. can only buy tape reel. Si4840/44 will be used. but same power rating.

 

Here's what I'm coming up with now.
It just doesn't make sense to use a 24 volt transformer for a 5 volt supply, so there should be 2 transformers to minimize price and wasted wattage. This could also be done with switching supplies, but this is way simple to build.

546-164H12 $13.26
546-185E24 $27.75
852-PQ05RD21J00H $1.73 = 5V 2A (1/2 volt dropout)
511-LD1117AV33 85 cents = 3.3V 1A
(This one takes a lot less capacitor.)

 

and.......
the first capacitor is: 647-UVZ1C472MHD @ $1.13
that's 4700 uf @ 16V

you have the right to find mistakes and bring them to my attention.
You have the right to buy these someplace besides www.mouser.com
You have the right to find a better price.
You have the right to read the datasheets and find out what they want for the second and third capacitor.

 

thanks a bunch. this whole process was very helpful and informative. And it is clear to me now what I must do not to start fires or zap myself.

 

You're supposed to find the grounds I left off the drawing of the regulator chips and feel proud of yourself.

and don't forget you'll need some heat sinks attached to the regulators.

 

thanks again. I've wired up a bunch of regulators before. It was the ac and the whole supply amp business coming of the AC mains that troubled me and now I have a clear understanding of this. So excited to start building my radio, but I have to wait a week to move. but right now i'm reading up on all the datasheets for the chips.