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The building your own portable soundsystem thread

The sure 2050 comes highly recommended http://cgi.ebay.co.uk/2-100w-TK2050...ultDomain_0&hash=item3367b99ee8#ht_4846wt_957. Also the hifimediy amps. I had one and it was great, then I blew it up :(

8ohm version: http://cgi.ebay.co.uk/Hifimediy-T1-...ltDomain_0&hash=item20b7fbfcfc#ht_1287wt_1141

4/8ohm version: http://cgi.ebay.co.uk/Hifimediy-T2-...ltDomain_0&hash=item1e62122008#ht_1539wt_1141

the TDA8920 based amps http://cgi.ebay.co.uk/ws/eBayISAPI....418108&ssPageName=STRK:MEWAX:IT#ht_2856wt_907 are supposed to be ok too, and a fair bit cheaper.
these need symmetric power supply, whatever that is. So not suitable. Apparently that means "where it says ±24v that means you have to supply it with +24v as well as -24v (& ground obviously)" - although I can't see why you can't do it from one set of batteries.

Of all of them I'd probably go with the sure as that has the best rep, although it's only 40w into 8 ohms (100w into 4 ohms)
 
Oops! Was that user error or a malfunction do you think? Personally I find it easy to break stuff, just changed the battery in my Ipod; what a bollock! I have a few bits left over and loads of green plastic shavings between the case and the screen.
 
fractionMan said:
not sure really. I worked fine first time, failed the second, caught fire the third :D
Click to expand...

That sound more like an undocumented feature than an actual fault. 'Under the right conditions marshmallows may be toasted; turning the amp into a handy flare and BBQ '
;)
 
The closest we can get from 12 volts input, is an output of 24 volts at 2.5 amps which is only 60 watts (HDD60-12S24-T £41.63), not enough for your application and we are out of stock until the end of June
Click to expand...

DC - DC Boost converter

For all you power hungry peeps out there that need a higher voltage for the more powerful amps. It is possible(at a price). One per channel? This spec from a different vendor? Wound to spec by one of our Chinese friends?

Thanks to Martin from Relec
 
Boominator finished! Problem is now one of the channels is blown:( We think its either a loose connection or a power mosfet (whatever that means). Bit depressed now:(:(:(
 
The front
IMG000015.jpg
 
FractionMan, When we get the amp fixed, we might be able to fix your amp thats busted. I cant promise and I have loads on for the next few weeks but it would be good to get the thing working again...
 
My dodgy cabling was at fault. We go the oscilloscope on it and the output on both channels matched. Then we thought Hhhmmm! That's odd, connected the speakers to the board itself and rather embarrassingly it worked. So it was really more of a bench test and getting to know class D circuitry.

We thought that the speaker inductor had blown. The class D amps are quite well protected; If one channel is working then the odds are that the chip is ok. They look a bugger to replace because of the mounting and the heat sink (The chip is about a fiver).

If it is the inductor then a new one will be a couple of quid IIRC. I am more than happy to PM my details and we can have a chat about fixing it. I have a few things going on at the moment though but at least we can get some ideas as to how we may be able to get it working (I'd rather tell you about that in private:)) That's of course if you want to... .. .
 
No problemo! Try the big components first the diodes, resistors etc a quite stable (so I am told) so maybe start with them. If one of the channels is working it makes it a lot easier because you compare one side with the other.... ... .. .
 
Please please please dont take this the wrong way; I would like to buy it off you if you cannot get it working:)
 
I want longer lasting batteries. Like, a weekend's festival's worth. AAs run out too quick and they're a pain to keep changing them. Also it's hardly green. So what are my options? Car battery seems too big and heavy. Fractionman, I know that eBay li-ion one you got was rubbish.
 
I've got another different type of li-ion but I've not tested it yet. 7ah yuassa (or something) lead acids last forever :) 13 quid of ebay.
 
P(in watts) = V*A

12 * 7 = 84w p/h battery power

about 40w for the Lepai means that should run for 2hrs contiuous (at max volume) A car battery is heavier but is more likley to give you about 20hrs turned up to eleven

I think this is right anyway
 
The thing about amp ratings is they're rated for peaks. They're nowhere near 25w/channel continuous. More like 2.5w iirc. You can get a weekend out of a 7ah battery ime. Well, I've had it on for 4 or 5 nights @ 6hours or so now and it's not dead yet.
 
Ahah! An old UPS that's been gathering dust at work has a 12V lead acid in it. Given that it's never been discharged (ie, kept plugged in for a few years, then unplugged and left alone), is it still going to hold a decent charge? It's rated at 9Ah at 12V, 1.4A
 
Should be good. Note that UPS batteries are usually designed to retain their charge for long periods, but not to be cycled (as in drained/charged) that often.
 
Thought I'd decorate the latest.

281297_10150728238890246_772200245_19842667_6140738_n.jpg


198752_10150728239350246_772200245_19842674_6182945_n.jpg


281687_10150728245460246_772200245_19842743_795476_n.jpg


On a related note, I've noticed a massive difference between two types of lepai TA2020+.

The earlier ones (without the tone/direct switch) sound much bassier. They're not as loud but much more controlled and have a way better overall sound. The newer ones seem to have had the gain turned right up - I can't use em at much more than half volume without heavy distortion and even at lower levels the treble sounds really harsh and the bass underpowered. I'm thinking the new ones are knock offs and not real tripaths as they sound fairly similar to the other crappy Chinese amps I've got. They're fucking loud though.
 
My free battery done good. A whole weekend's worth of loud music, no problem :)
Looking forward to "playing the campsite stage" with it at Boomtown Fair!

Also, stuck some bigger wheels on it for all-terrain use
 
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