Mini Speaker/Amp project

[Braden]

Hi there,
I am pretty knew when it comes to circuitry, but wanted to make a speaker/amp that would fit in an altoids tin. I used this Amp chip

http://www.ebay.com/itm/PAM8403-5V-DC-Audio-Amplifier-Board-2-Channel-3W-2-Volume-Control-USB-Power-New-/390966036363?pt=LH_DefaultDomain_0&hash=item5b0764478

and speakers similar to these

http://www.aliexpress.com/snapshot/6549360196.html?orderId=66287542784183

But the output is terribly quiet, even more so than simple DIY videos of simply stripping headphone speaker cones and connecting them to a 3.5mm jack. Any ideas on why it could be so quiet? Thanks for your patience in helping a new guy!

Braden

 

[Braden]

the board is powered by a 2032 3v coin battery

 

[davenn]

Hi Branden,
welcome to EP

one of those batteries wouldn't last long ... if it could even power it properly at all, since it requires 5V and is capable of 3W per channel

Dave

 

[Braden]

Thanks a lot for the reply Dave
The one I got said operating voltage 2.5V - 5.5V, maybe the low voltage is the issue then? Any suggestions on a different, portable power supply (i.e. not USB)?

 

[davenn]

OK then voltage shouldn't be a problem, just the lack of power from a 2032 .... they are not designed to supply the current needed for this amplifier. .... if I was you I would be looking at 3 x AA NiCad or NiMH type batteries in a pack of 3 or 4

 

[Braden]

Do you think something less bulky like this 6v might work?
http://www.ebay.com/itm/Pack-of-10-...411?pt=LH_DefaultDomain_0&hash=item4ae455c60b

 

[davenn]

Do you think something less bulky like this 6v might work?
http://www.ebay.com/itm/Pack-of-10-4LR44-476A-PX28A-A544-K28A-L1325-Dog-Collar-Remote-6V-Batteries-/321658406411?pt=LH_DefaultDomain_0&hash=item4ae455c60b

no, no good too low a current capability
Battery Specifications:

• Model #: L1325/4LR44
• Brand: Vinnic
• Voltage: 6 Volts
• Chemistry: Alkaline
• Dimension: 13.0 mm Dia x 25.2 mm H
• Capacity: 165 mAh <------- not likely to even power the unit
• Weight: 9.57g (0.34oz)
• Chemical System: Zinc-Manganese Dioxide (Zn/MnO 2)

you need a supply that is capable of at least 500mA which is why I suggested 3 x AA NiCad or NiMH type batteries. and if you use the 2500mAh ones, you should get an hour or so of use between charges

Dave

 

[Braden]

Oh I see, thanks. I guess I will have to go with the three AA NiCad's then. I guess there is no way to fit this board to support 9V rather than 5.5V? Sorry, I know so little, thought it would be a lot more simple to attempt to make something like this https://www.etsy.com/listing/71329841/portable-mint-tin-guitar-amp-headphone?ref=shop_home_active_1
But thanks a lot for your help Dave

 

[davenn]

don't be sorry ... its all cool ... just things you learn as time goes bye

those small 9V batteries don't have the current capability either, they are only around 350mA
and you would further waste power dropping that to the ~ 5V needed

would be interesting to know what amp IC they are using in that project

Dave

 

[Braden]

what about a using a 123A (16340) Battery? They are 3.7V and about 1000mA. Surely would be interesting to see what is used in there, but i still have a lot of learning before i would even understand what is on the PCB

 

[davenn]

what about a using a 123A (16340) Battery? They are 3.7V and about 1000mA.

it would be worth experimenting with one of those batteries for a start and see how much user time you get from it
Then consider their cost and how often you want to spend $xx on them


ohhh just found a rechargeable version of them .... that would be the way to go
http://www.batteryjunction.com/rcr123a.html

along with the appropriate charger
http://www.ebay.com.au/itm/123A-LR123A-CR123A-16340-rechargerable-battery-charger-/170491676045



Dave

 

[Braden]

Thanks, I will try that out and see how it is. Do you know much about speakers? (surely more than I do haha), I thought the ones I got should be fairly loud, but they are quieter than some videos I have seen where people just use junk headphone speakers.

 

[davenn]

The output from such a small, low powered amplifier isn't going to be much 1 W at the most
Loud isn't really an option

 

[Braden]

hmm, ok. I guess I will try it and see how it sounds
a different question, similar to the first on battery power: Is it possible to retro fit this to run off of battery somehow rather than USB? http://www.ebay.com/itm/3-5mm-USB-B...926?pt=LH_DefaultDomain_0&hash=item3ce7151f4e

 

[BobK]

You could run that off any of the 5V power banks that have become popular for recharging cell phones. Like this, for example:

http://www.ebay.com/itm/5600mAh-5V-...t=LH_DefaultDomain_0&var=&hash=item3cf0bceecd


Not recommending this particular product, have no knowledge of it, and the capacity seems impossibly high.

Okay, I see now that it uses 2 18650 batteries (not included) this make more sense. The batteries will cost about $10 a piece. You can pay less, but they will probably be counterfeits like the set that I bought, which were useless.

Bob

 

[Braden]

Dang, maybe at that price i would be better off just finding one that already has a chargeable battery in it. I have seen a lot of 18650 UltraFire's on ebay for about $1 per piece for 10, but maybe they are knock off's then and no good huh?

 

[BobK]

Dang, maybe at that price i would be better off just finding one that already has a chargeable battery in it. I have seen a lot of 18650 UltraFire's on ebay for about $1 per piece for 10, but maybe they are knock off's then and no good huh?

Yes, I would beware of them. I bought some cheap ones, supposedly 3000mAH. Two of the 4 were basically DOA, the others ran down in less than 2 hours at 100mA draw, so more like 200mAH.

Bob