The Boominator - another stab at the ultimate party machine

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#6,182
Yes, at a fixed voltage the current is limited by the load and power = I^2*R in a DC circuit. So if the supply can provide the needed current then increasing the current capability wil have no effect on the used power.

Speakers are complex loads and peak demands are important too. If you compare the data sheet THD vs power graphs in BTL vs PBTL (make sure you use the same supply voltages!) you will see that the THD spike is at roughly double the power output.

In practice, does it matter? I'm not sure it does. We all know the MAX amps work really well in this application at even lower power.
 
#6,183
aterren said:
You can't go wrong with thee weiners. They really are a top notch implementation of the TPA3116 amp.
http://www.diyaudio.com/forums/grou...eo-pbtl-editions-available-4.html#post4579108
Click to expand...
The Wiener card isn't really designed for low power consumption. It's got output snubbers which eat power, OSCONs with significant leakage current, a linear regulator which makes 5V for a microcontroller that runs all the time, no low battery shutdown, and in shutdown mode it still pulls appreciable current.

These things don't matter so much for a home system, but if you're chasing battery life I'd go with a cAMP card instead. Canopy should have those on sale any day now, Viktor predicted yesterday but it wouldn't be the cAMP if it wasn't delayed 😉
 
#6,185
How would you think the power consumption, sound quality and volume of the cAMP compares to the Amp9?

I guess you would have to run two of them on a signature boominator as they are 2 channel, yes? Is that going to make it impractical from a power consumption perspective?

Also they are 12v only right?
 
#6,187
Am I getting this right? The cAMP has a built in solar charge controller? So It's just a matter of plugging the battery straight into the card and then same for the solar panel and it'll charge while playing?

And how does it compare to the maxamp20 in terms of power consumption?

Like would my boominator last the entire roskilde festival if I had a 7,2ah SLA and a 10-20W amorphous solar panel? (finding these are tricky...)
 
#6,188
Yup. You can hook up a 12V solar panel straight to the cAMP's solar input. Or a 19.5V or 24V DC power supply for charging at home.

I don't know the quiescent current of the Maxamp or Tripath cards, but the cAMP idle current (switched on, no audio input) is under 20mA. I measured it a while ago but can't find the number, and my DMM has a blown current fuse :/
 
#6,190
The cAMP doesn't have signal sensing. I tried, but couldn't come up with a threshold that would pass all music and not keep the amp on due to background noise.

20mA is pretty low though, with several aH of battery supplying the thing it'll last a lot of hours if you accidentally leave it switched on.

Sent from my Nexus 4 using Tapatalk
 
#6,192
Slick. And what at which points does the LED light signal things? Would it replace the function of a LED voltmeter over the battery, or does it just blink when battery gets low or something like that?

The info on the canopy sound page is kind of sparse! Is there anywhere else you have info on it or should I read through the entire development thread? 🙂
 
#6,193
lutkeveld said:
But how is 20mA possible with the amp turned on? Or how does it know when to shut down?
Click to expand...
The TPA3118 in 1SPW mode, with a 400KHz switching frequency, pulls just under 20mA quiescent current. The opamps in front of the TPA pull a few mA all combined, but they're running from 3.3V regulated off the 5V USB switcher with a low noise LDO. Everything else that pulls power (5V USB regulator, microcontroller) is very low quiescent current.

The LED periodically blinks with a "code" of sorts:

Red: battery too low for amp to run, 5V USB is also shut off.
Orange: battery low (<30%)
Green: battery OK

Long blink: battery charging
Short blink: battery not charging (or fully charged)

Long delay between blinks: amp off
Short delay: amp on.

Sent from my Nexus 4 using Tapatalk
 
#6,194
Allright, then I guess there's really no need for a voltmeter! So I need to buy a LED light like this one?
https://www.elfa.se/sv/led-lampa-ro...er_Buyable=1&page=1&origPageSize=50&simi=99.5

Getting ready to order all parts tomorrow! Real excited 😀
made a spreadsheet of almost everything I need to buy if anyone has use of it
https://docs.google.com/spreadsheets/d/1Sl_sOQudsSV_c1SGNZ3Vzr_LCXXuMbWnrPewHOtX94g/edit?usp=sharing

Throwing in a simple question here since I know near to nothing about electronics:
I should be able to connect the solar panel (will be using an external one) to the cAMP using one of these, right?
https://www.elfa.se/sv/chassidon-mm...,+kåpa=Hona&page=79&origPageSize=50&simi=99.0

And while on the subject of solar panels, has anyone tried this one? URL says 14watt so I'm wondering where the typo is. E-mailed the store some days ago but haven't recieved an answer yet.
Solar module 19W / 12V
 
#6,195
I can't read what's on the Elfa site but it should work provided it's a common cathode LED. Common anode won't work.

That DC jack will work.

That solar panel claims 1.18A at 16V which is about 19W. Now that power number might be the "perfectly clear day, sun directly overhead, at the equator" operating point 🙂
 
#6,196
gmarsh said:
I can't read what's on the Elfa site but it should work provided it's a common cathode LED. Common anode won't work.

That DC jack will work.

That solar panel claims 1.18A at 16V which is about 19W. Now that power number might be the "perfectly clear day, sun directly overhead, at the equator" operating point 🙂
Click to expand...

Interestingly enough it didn't say at all if it was cathode or anode so I settled for another one, a red/orange + green 3-pole common cathode LED which I hope will work!

Shipping turned out to cost €110 for the solar panel. Wew. Found a 15W one from a swedish retailer instead...

Thank you so much for all the help!
 
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