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The building your own portable soundsystem thread

I like the look of this tripath TK2050 amp as it's optomised for 8ohm loads: http://cgi.ebay.co.uk/Hifimediy-T1-...ultDomain_0&hash=item1e6262a96f#ht_1427wt_950

But it's 40 quid. The SURE amps I've been talking about are optimised for 4 ohm loads.

So I'm looking for cheaper options such as the 17 quid TDA8920 2x100w based amps, but I can't work out how they fare with different impedance loads. This amp can also be bridged into a 200w monoblock!
http://cgi.ebay.co.uk/Mini-2x100W-T..._Amplifiers&hash=item2eb42dfb83#ht_4563wt_716

A new cheap TA2020 amp is on the market and it's much nicer looking than the 13 quid lepai. It's unblemished by logos or words and suitable for mounting so that the face place is external, meaning people can change vol and turn it on and off easily. http://cgi.ebay.co.uk/New-Tripath-T...Amplifiers&hash=item3a63f13e68#ht_4148wt_1051
 
I really want to build a portabl soundsystem (as cheap as poss), and was discussing it with a mate over the weekend....

Does this sound about right for a list of items:
Suitcase (cabinet)
Amp with input
Speakers (obv)
leisure battery
inverter


If we used a car amp and speakers we probably wouldnt need an inverter though would we?
 
Yeah, get a 12v or 24v amp. Inverters mean you end up wasting a shed load of power plus many 240v amps just convert it back down to DC or lower voltage AC meaning further losses, which all have to come from your battery. You'd end up using twice the power.

The one I linked to above is pretty good for the right kind of speakers, although you'll need to solder the inputs in and it has no case. And it's 24v :D

Battery size etc depends on how portable/loud you want it. Leisure batteries are fucking heavy!
 
The key thing is the T-class amplifier. This lets you get high-quality sound with very low power requirements. 10 years ago, you'd need a car/leisure battery and a car amplifier. Now you can get away with 8-10 AA for 6-8 hours of playback (speaker size depending) or use a li-ion battery.
 
Just to clarify here, the 6-8 hours is not at top volume, as I discovered on saturday. It's at medium volume. Top volume will work for less than an hour before you have to start turning it down to avoid the amp clipping.

The hifimediy 2050 T1 amp I just ordered is a tripath amp btw :) I'll be powering it with 2x7ah 12v lead acids wired up into a 24v configuration, which is about 7kg of batteries. Suitable for bigger things with wheels. You wouldn't want to carry it around!
 
RE li-ion batteries

Chinese cctv batteries seem to be the best bargains capacity (ah) to price wise, but they're falsely advertised with higher ratings than they've actually got imo. Like 2x overstated.
 
Cheers for the info....... Im gonna look into where I can get all this stuff cheapish and decide exactly what I want/need.

Good to know about the batterie.........any suggestions between the low AA and the leisure battery that are a good compromise?
 
sim667 said:
Cheers for the info....... Im gonna look into where I can get all this stuff cheapish and decide exactly what I want/need.

Good to know about the batterie.........any suggestions between the low AA and the leisure battery that are a good compromise?
Click to expand...

The 7ah lead acids are 13 quid: http://www.urban75.net/vbulletin/th...tem-thread?p=11632871&viewfull=1#post11632871 and 3.5kg (for comparison my lesiure batteries are 115ah, 80-100 quid and weigh a fucking ton)

But it really depends on what amp you're going to use, how portable you want it, space considerations, battery life you want, volume etc

Have a read through the thread and you'll find some links to the cheapest tripath 2020 amp and some reasonable yet cheap full range 6.5" speakers.
 
I've been looking for 4 ohm drivers as you get much more oomph out of them on the tripath 2020 (25w compared to 13w). It turns out QTX do a range of 4 ohm speakers at reasonable prices with reasonable SPL levels.

8" woofer, 4 ohm, 93db spl, 15 quid: http://www.yourspares.co.uk/manufac...m-8in-driver-for-qr8a-178202uk-902.528UK.aspx

10" version is 95spl and only 19 quid from this vendor: http://www.commsandsound.com/qtx-sound-4-ohm-10in-driver-for-qr10a-178-203uk.html I'm pretty sure that's the loudest speaker you'll get for the money.

Can't vouch for the quality - these are used in the cheaper end of the range QTX active speakers. I think I'm going to get a couple of the 8" ones for my latest case (and some piezos) and see how it goes, although I'll have to check the 9cm deep thing won't be an issue.
 
Just reading up on changing input resistance to increase gain so that the amps sound loud even from phones. It looks like you can double the gain and not harm the amp at all. Which is awesome. I'm looking re my new tp2050 based amp, but I'm going to look into modding my other amps too.

The soldering looks well fiddly - the existing resistors are tiny and the easiest way to up the gain appears to be to parallel a 20k resistor with r1 and r4 on the board.
 
How portable?

449d1147480264-rig-porn-1328579234wc.jpg


overland_to_oz.1175625780.truck.jpg
 
Christ. I don't even want to start thinking about the running costs for that beast of a truck...

I have searched 8 charity shops and turned up no decent cases :(
But the random tat shop down the road does a nice little hand-luggage sized wheelie suitcase, which I think is just right for a festival campsite/picnic in the park. £25.
 
Dunno but this one...

9180_700w.jpg


Got to Bristol and back (from Milton Keynes) for under £100, which isn't bad with today's fuel prices
 
If it's any compensation FM, I was around a table in a certain Brixton institution and an certain urbanite mentioned you and your sound system at the March. Before you know it some near random* was approaching and waxing lyrical about 'his mate' and the very same little rig. So the word has spread, well amongst the dregs of Brixton's drinkers anyway.


*He's an Electrician and his name begins with S fwiw
 
What about this idea then?

One of these
An amp like fractionMan

Two of these:
Speakers

Then make a box to put it in, and power it with a battery like fractionMans; The idea being to run my bass though it as a busking amp sort of thing for bbq singalongs and the like. Any advice welcomed.
 
like I said before i strongly suspect running a bass through one of those amps will blow it up. you need a purpose built bass amp and speaker.
 
junglevip said:
What about this idea then?

One of these
An amp like fractionMan

Two of these:
Speakers

Then make a box to put it in, and power it with a battery like fractionMans; The idea being to run my bass though it as a busking amp sort of thing for bbq singalongs and the like. Any advice welcomed.
Click to expand...

Sorry, but those speakers are terrible. They might sound ok (I've no idea) but they're only 84dB SPL, which means they'll be really quiet. Look for speakers with SPL in the nineties. The higher the better. 94dB spl will be twice as loud for the same power.

I can't comment on the suitability as a bass amp as I've not tried using it as one. I might have a go with one of mine tomorrow night and see what happens.
 
Crispy said:
Airport security wouldn't like one of these coming on a plane would they? :(
Click to expand...

No reason why not that I know of. I've been on planes with all sorts of bits of gear on me and in my bags.

To protect it you could put it inside a larger case with a load of clothes to act as padding.
 
I'm thinking more the random bits of homebrew electronics/batteries knocking around inside it :D

I've got my eye on a hand luggage sized wheelie case in a local shop, and plan to cannibalise my home speakers (2 out of 4 drivers got broke during moving house so they don't sound right any more).

I guess for planes, I could just unconnect everything and put the parts in checked luggage.

Will have to think about fabrication method for grilles - I have access to a full workshop, so can get fancy.
 
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