Portable Boombox help

[Silas K]

Hello everybody!

I have searched and read a lot on this forum and i want to try and build myself a portable boombox based on the lepai 2020a+ Amp

As i am a student i dont have a 1000$ to fund and build the boominator (unfortunately)
my budget is more or less 200$ more if its justifiable to meet my needs .
I am not expecting this thing to entertain 200 people - but would like it to be able to entertain 8-12 people if you understand what i mean.

I have bought the amp on ebay and expect it to arrive in a month or so.
I would therefore like to have all other parts sorted out before that.

I have 2 decent car speakers laying around that i was thinking about using those. I will attach a picture so you can see what i am talking about.
If those speakers are stupid to use i would love if somebody could give me advice for what to use then.

Battery wise i was thinking about one or 2 of these - the 12v 12Ah weighing 4,39kg
Gel-batterier til motorcykel og scooter - Biltema

I would love to be able to install a solar panel but they seem a little pricy and would proably exceed my budget to much

If it would be possible to install a iphone charger somehow aswell it would be neet! i was thinking about the 12v car charger but im not entirely sure how to do it.

As far as casing wise i would build a case out of plywood and mount everything in there. I dont have any particular layout at this moment but one cannot be inspired of the boominater or Mini versions design.

What else should i take into consideration?

Thank you for your time

Silas

 

[lexer98]

For the iphone charger , use a LM7805 voltage regulator ... but the iphone need 2v in D+ and D- to be detected as charger ...

Circuit

How ever u can tweak the resistor to convert in to a "wall-charger" (1A)

Sauce: Apple and other USB charger secrets |

 

[DUG]

Battery power source:

Use one of these:

digi-key

http://www.cui.com/product/resource/v78-1000.pdf

Somewhere between 88% and 93% efficient.

Either way put a switch on the circuit so if you don't need it is not a drain at all.

 

[Saturnus]

Have you tried contacting Canopy Sound kontakt@canopysound.dk and ask if they still have the Aura NS525 driver for the Boominator MINI? If not do so quickly as they're only DKK89 each so you can easily build a MINI for around $200. They ship to all nordic countries.

 

[lutkeveld]

If you want anything sounding good you'd have to dump the carspeakers idea. It's possible if you just want sound for not that much money. You'd have to have a battery, amp and speakers. That's it. USB charger can be made with a simple car cigarette lighter 12->5v usb converter. You want one that is as efficient as possible.

If you want anything sounding good you could build a halfinator, mini boominator or wait untill Saturnus releases the Micro design next week.

@lexer. A 7805 would be a waste of energy, it's much better to get a step down converter like the one DUG recommends.

 

[Silas K]

Wow thanks for all the answers!

Those were some very detailed answers!
I did Think about using a 12 car charger myself, and that seems like the easiest plan.. So I think ill stick to that!

@saturnus no I haven't contacted them yet! It looks like they still have them tho! What else would I need from their webshop if I decide to skip the car speakers idea..


It sounds interesting with the mini design next week

 

[Silas K]

Oh micro design sorry! But i dont want to go too small so i Think mini is better !

 

[lexer98]

@lexer. A 7805 would be a waste of energy, it's much better to get a step down converter like the one DUG recommends.

thanks for the info DUG and lutkeveld

 

[lexer98]

Update circuit with the step-down regulator recomended by DUG and resistor for 1A charging (like a wall-charger)

 

[Silas K]

Okay..

Decided to build the Boominator mini as i feel it meets my requirement, and is fairly cheap to build actually...

I got the amp ordered, and decided to scrap the idea of the car speakers..

At canopysound.dk they have the Aurasound ns525 Drivers pretty cheap but what else should i order. I need a shopping list

4 - ns525 drivers
4 - Tweeters ?
Filter components?
Battery - will the previous one i linked work?

Im pretty much a noob at this so it would really be appreciated if somebody would helo me out

i have soldered a lot of led lamps before and looking at pictures of the filter tells me its not the most high precision job.


Thanks in advance

Silas

 

[lexer98]

What amp you ordered ? ... because those Aurasound have a impedance of 8ohms

 

[Silas K]

The lepai lp2020a+

Aurasound was saturnus idea so i Think im deffonitely gonna order those!

 

[Saturnus]

The Boominator MINI development thread is here. Read it all. That'll give you all the info you need.

Boominator MINI (development thread) - Speakerplans.com Forums - Page 1

Not the amp I would chosen but ok.

 

[lexer98]

Keep in mind with 8 ohms impedance only get less than 10w per channel but for those speakers are enough and the amplifier are more efficency with 8-ohms speakers (consume less current) that's good since you'll use batteries

 

[Saturnus]

Keep in mind with 8 ohms impedance only get less than 10w per channel but for those speakers are enough and the amplifier are more efficency with 8-ohms speakers (consume less current) that's good since you'll use batteries

There's 4 of them total. 2 in parallel per side so they'll be 4 ohm. Check link to build thread.

 

[Silas K]

Thanks saturnus! I read the whole thing a couple of times but I still can't see where you put the parts list for the filters? I'm a total newb when it comes to those...
Maybe I'm just missing it?

I know it's not the recommended amp but I kinda bought it by mistake and I guess I can always upgrade it later

 

[Sm1thson]

If it would be possible to install a iphone charger somehow aswell it would be neet! i was thinking about the 12v car charger but im not entirely sure how to do it.

as above the 7805 isnt the best way, its a linear regulator which means it will burn off more power in heat than what it transfers to your phone.

also as you want to keep it simple, Id just go for one of these:

DC 6~24V to USB DC 5V Car Voltage Step Down DC Converter Module - Black + Red - Free Shipping - DealExtreme (or a similar one off ebay)

 

[Silas K]

Thanks i just bought one of those!

now i just need the aura speakers and dayton tweeters!

And im still trying to figure out which filter components (and where) to order!

 

[lexer98]

as above the 7805 isnt the best way, its a linear regulator which means it will burn off more power in heat than what it transfers to your phone.

also as you want to keep it simple, Id just go for one of these:

DC 6~24V to USB DC 5V Car Voltage Step Down DC Converter Module - Black + Red - Free Shipping - DealExtreme (or a similar one off ebay)

That step down module don't works for iDevices because need a specific voltage in D+ and D- pins to detect the charger

 

[Silas K]

Really???