The building your own portable soundsystem thread

[fractionMan]

Oh so I could just use 2 of the batteries I've got?? That sounds bit more promising than saving up for a gel battery. I'll look up the wiring process up.

I'd read that about those amps. Shame really

Don't do it with the li-ions!

Do it with lead acids. Li-ions I have no idea if they'd blow up or not.

 

[fractionMan]

can anyone recommend a decent battery to use to run one of these?

http://www.technologyinthehome.com/...upunkt-Velocity-2GO-6-Subwoofer.html#LargePic

it runs off 8AAs at about 1/3 of the power available when you run it off the AC adapter... the adapter is supplying 13v at 4.6A, so i'm thinking with the right battery i can run it a lot longer and at higher power...

maybe a motorbike battery or something similar? would it need some sort of power regulator to keep it from blowing it up, i'm thinking car and bike batteries run at about 13.8v?

that thing's a bargain at 49.50 imo. Shame about "Sorry this product is no longer available"

 

[pesh]

Car and bike batteries run at 12V, which will be fine. No need for a limiter - it will draw as much current as it needs.
Something like: http://www.batterytrader.com/delphen-7000-sealed-lead-acid-batteries-p-24233.html
Coupled something on this list: http://www.google.co.uk/search?client=opera&rls=en&q=lead acid batteries&sourceid=opera&ie=utf-8&oe=utf-8&channel=suggest#q=lead acid charger&hl=en&client=opera&hs=Haw&rls=en&channel=suggest&prmd=imvns&source=univ&tbm=shop&tbo=u&sa=X&ei=ME14TpPLBZKr8AP4z-WNDQ&ved=0CHEQrQQ&bav=on.2,or.r_gc.r_pw.&fp=4a57707260bc0b1c&biw=1254&bih=760 (choose one that can supply at least 1000mA, so that you can charge and playback at the same time)

Cheers Crispy

what would you recommend as a charger? standard 12v trickle charger or something?

FM, yep it's a great sounding box, and very very loud when running off the PSU. only real thing i can fault on it is the fact the speakers are unprotected so i know it's going to end up getting killed at some point if i'm not very careful...

 

[fractionMan]

I use the Yuasa 7ah 12v batteries and they're great. They're also cheap on ebay.

For charging you can use a car battery trickle charger if you already have one. Don't charge it at more than about 2a though.

 

[sim667]

Don't do it with the li-ions!

Do it with lead acids. Li-ions I have no idea if they'd blow up or not.

Ill bear that in mind..... Thanks for saving my eyebrows

 

[fractionMan]

Hey all,

I've come by a few bass speakers and I'm thinking of twinning them with some piezos. The last ones I had were crap and the ones I've been recommended aren't available in this country

Any recommendations?

 

[fractionMan]

I'm going to use this circuit to make it sound half decent:

( a 22 ohm resistor, and a 4-4.7 uF cap) from: http://www.burton-manor.co.uk/Audio/piezo.htm

Would a cap like this be ok? http://www.hobbytronics.co.uk/capacitor-4.7uf-63v-ev
what rating resistor do I need. Would 1w do it?

 

[fractionMan]

This guy describes building an attenuator with 2 resistors: http://reviews.ebay.co.uk/Tweeter-Attenuator-Resistor-Guide?ugid=10000000004030106

 

[fractionMan]

I has a website.

http://boomboxy.com/

Comments, opinions on pricing, offerings, web design etc welcomed.

 

[stuff_it]

I has a website.

http://boomboxy.com/

Comments, opinions on pricing, offerings, web design etc welcomed.

Lol @ the one with the speaker grills - I don't know any parks quite that rough!

 

[Crispy]

http://boomboxy.com/faq/

Typo: Peak Music POwer/Peak

Otherwise, looking very nice

 

[fractionMan]

http://boomboxy.com/faq/

Typo: Peak Music POwer/Peak

Otherwise, looking very nice

cheers, typo corrected!

 

[fractionMan]

Lol @ the one with the speaker grills - I don't know any parks quite that rough!

which one?

I have a feeling I need to sort the front page out as i'm guessing nobody ever sees more than the first four.

 

[Crispy]

An autoscroll woudl be better than mouseovers IMO.

 

[stuff_it]

which one?

I have a feeling I need to sort the front page out as i'm guessing nobody ever sees more than the first four.

Not unless they start clicking on the bottom links to the other pages, no. It should show all of them in a long strip on the front page - well obvs not all if you keep on getting orders or it would get silly.

That autoscroll thingy. Or maybe that one where if people mouseover a long strip the pic is blown up - that seems quite popular these days.

 

[fractionMan]

I think you're right tbh.

looks like I'm gonna have to delve into the code then.

 

[sim667]

Nice site, i quite like it just the way it is tbh.

Where the fuck do you find cases from all the time? My mate wants me to build her a little one, but I cant find decent 2nd hand cases anywhere!

 

[fractionMan]

Junk shops, car boots etc. Trade secret lol.

 

[sim667]

Charity shops never have them, might check out a car boot if I can drag myself out of bed one morning.....

Im thinking about doing a woodwork course, so I can learn proper joins to make some speaker cabs...... I've been asked if i fancy helping make some proper loud big ones.

 

[stuff_it]

Ebay?

Making speaker cabs out of wood is pretty easy to learn, if even my woodwork can hold up in subs then you're laughing really.

 

[sim667]

i dont even know where to start..... I was unbelievably lazy when it came to design tech at school lol.

 

[fractionMan]

i dont even know where to start..... I was unbelievably lazy when it came to design tech at school lol.

I picked up 5 cases at an average price of 9 quid each yesterday from a second hand vintage clothes shop. Some are a bit messy but I think I can clean em up.

So check vintage/second hand clothes shops and be prepared to haggle. They've probably had them in stock for years and cant shift em.

Ebay can also be good but the postage often double the price, making it a shit option value wise. If you search for stuff near you then collecting them becomes and option.

 

[sim667]

Anyone ever built an active sub for a car? I'm weighing up the pros and cons of building one versus buying one??

 

[fractionMan]

they're always going cheap on ebay tbh.

 

[sim667]

they're always going cheap on ebay tbh.

I shall go forth and look.

 

[Crispy]

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.

The ones I just bought are the same shitty knockoffs The model name is LP-V3 and it's "reviewed" here: http://www.oldschoolstereo.com/2011/12/700-watt-mini-amp-lepai-lp-v3-tested.html nowhere near the power output and efficiency of a proper T-class amp.

The product description and photos on the ebay page are of the LP-2020 (the Lepai model number. the chip itself is called TA2020). The seller says they do returns so back on the slow boat to Hong Kong they go, hopefully. Grrr. I will have to shop more carefully, maybe find a UK supplier.

 

[Crispy]

Although the situation appears a little more complex than that, having read some of this humungous thread: http://www.diyaudio.com/forums/class-d/90500-lepai-t-amp-ta2020-112.html

I don't think I have the LP-V3, but the "new" LP-2020A+
I will have to borrow a multimeter and see what sort of current it draws.

 

[Crispy]

I might also make some of these mods: http://techtalk.parts-express.com/showthread.php?t=226235

 

[Crispy]

Question: My amps are rated 4-8 ohm. It seems to me from my basic physics knowledge that lower impedance is better, because it allows for more power. So I should try and get some 4 ohm full-range drivers?

 

[fractionMan]

Question: My amps are rated 4-8 ohm. It seems to me from my basic physics knowledge that lower impedance is better, because it allows for more power. So I should try and get some 4 ohm full-range drivers?

Yes, 4ohm drivers will draw twice the power, so will be louder (but not twice as loud).

Alternatively you can run two 8ohm drivers per channel for a 4ohm load.