Sanwu 2.1 ch 2x50w+100w hiss noise (boombox)

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NotExist

Member
Joined 2017
Hello
Its my first project, my knowledge about amplifier and sound is very low, ill be glad for some help.

I made solar powered boombox, powered by 24x 18650 battery's.

The sanwu amplifer make hiss noise, i hear it when i turn the amplifer volume up and the Bluetooth volume down.
Same thing happen when i use sd card or disk on key.

Ill be glad to solve this problem, but if its impossible, this hiss sound can damage the speakers?

I saw the hiss sound post of the tpa 3116, i used search but i couldn't find the solution to my amplifer.

My second problem is the solar power charger,
I add to the amplifier on/off switch.
When i switch it on, the solar charger disconnect the load, than after 30 sec it connect the load automatic.

There is solution for this or my only way is to connect the loads directly to the battery section on the charger?

Links:
Amplifer SANWU[emoji768] SW-HF41
SANWU(R) SW-HF41 Wireless Bluetooth Digital 2.1 Channel Amplifier Board 50W+50W Stereo Output 100W Bass Output USB TF Card Decoding Play 12-26V DC Sale - Banggood.com

Speaker:
Amazon.com: Rockford Fosgate R165X3 Prime 6.5-Inch Full-Range 3-Way Coaxial Speaker - Set of 2: Car Electronics

Subwoofer:
Amazon.com: AUDIOPIPE TS-AR6 6" 150W Car Audio Power Subwoofer Sub TSAR6: Sports & Outdoors

Solar charger:
24V 12V Auto Solar Panel Battery Charge Controller 30A 20A 10A PWM LCD Display Solar Collector Regulator with Dual USB Output -in Solar Controllers from Home Improvement on Aliexpress.com | Alibaba Group to Clipboard


P.s
The buck module is for 12v loads
It give power to future cooling solution and intex 12v pump.

Thank you very much,
Alex 20180219_223648.jpg View attachment 664680 View attachment 664681 20180210_183745.jpg
 
N

NotExist

Member
Joined 2017
Think said:
The hiss won't damage your speakers and connection directly to the battery is fine. A BMS should protect against undervoltage, if not; make sure you don't run your cells below 3V. Seems like you use 6 in series so don't go below 18V.
Click to expand...
Thank you very much.
Yes its 6 in series, 25.2v.
I dont connect it directly to battery because the solar charger have undevolatge protection, i think the bms can go lower than 18v, dident test it tho.

The hiss is bothering me, right now im thinking to buy other amplifier, maby car amplifier, the problem is that it wouldn't work with 16.8v pack.

There is any car amplifier projects with 18650 battery pack in this fourm?
 
T

Think

Banned
Joined 2017
With my boards, I had a little (noise floor /high gain) hiss with some very sensitive horn tweeters (eminence apt150) but none with the planar tweeters. see Tube system for bike

Are there any 2.1 car amps with crossover? You could reconfigure your battery pack to 3 in series (max 12.6V) but I would not go that way.
Do the drivers have their own boxes internally? Did you calculate volumes with Winisd or other software?
 
T

Think

Banned
Joined 2017
Yes, and in the manual of your sub there would be some volume recommendations.
From the comments on the Amazon link for your sub:

"In the product manual, they recommend a minimum 7-liter box. (Check the manual on the manufacturer's page). I suggest that you put foam like that of teddy bear (about 50%) to that box, for a clearer sound."

Maybe you can make it a ported box which will give more bass, but is bigger; check the manual and the volume of your box.

"sounds great to my ears. " is the most important :)
 
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H

horst303

Member
Joined 2009
NotExist said:
No and no, everything done by eye.

Shuld i make saperate wall between the drivers and sabwoofer?

Right now, sounds great to my ears.
Click to expand...

Well you can't argue with that, if it sounds good to you then it sounds good.

But in principle different sized drivers sharing the same volume is a really bad idea, because they do interact, problems could be anywhere between smearing the sound, losing efficiency because they work against each other, one could even destroy the other.

PS: really like your plywood, do you know what timber it is?
 
N

NotExist

Member
Joined 2017
horst303 said:
Well you can't argue with that, if it sounds good to you then it sounds good.

But in principle different sized drivers sharing the same volume is a really bad idea, because they do interact, problems could be anywhere between smearing the sound, losing efficiency because they work against each other, one could even destroy the other.

PS: really like your plywood, do you know what timber it is?
Click to expand...
Thank you!

I guess you talking about the coloring coat on the plywood itself.
Its paper, i choes it when i bought it from factory verry cheap.
There is same color formica, now im really disappointed that i dident choice the formica coat solution.
The paper will be damged easy.
 
W

wrybread

Member
Joined 2018
Awesome project!

How many watts is your solar panel?

Any problems charging those lithium batteries with that PWM charge controller that (I'm guessing) was designed for lead acid batteries?

If you accidentally leave the power on and the batteries go completely dead, are they ruined?

As far as using a conventional car amplifier, I'd guess it would draw a lot more power than these Class D amps, but I certainly could be wrong about that.

Please keep the thread posted with your project, this is fantastic work.
 
W

wrybread

Member
Joined 2018
And to charge lithium batteries, don't you need a very regulated power supply? In other words, it's not like lead acid where you gradually raise the battery voltage?

I'm not sure about that, but it's what I've always understood. I suppose it's solvable by adding a voltage regulator to your charging circuit.
 
C

cacao ambiance

Member
Joined 2015
aross.me
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