BillFitzmaurice.info

ONE JACKLITE PLUS A BRIDGED LEPAI WILL SHAME ANYTHING THATS PORTABLE

How do you bridge the Lepai?

ncgrove wrote:Condolences on the Beatbox.

It works out well for her use, so I didn't mind too much. She had been complaining about the weight of the Jack for a while - I was excited when I saw the Jack Lite, but she's not patient enough to wait on me to build one

We actually took the Beatbox to the lake and connected it up to our little battery backup/jumper unit. It lasted for 9 hours out in the hot sun, I was rather surprised. Plenty loud enough for our group on the beach without bothering other families out there with their own systems. Sometimes the Jack is overkill

Israel wrote:ONE JACKLITE PLUS A BRIDGED LEPAI WILL SHAME ANYTHING THATS PORTABLE

Yeah... what ncgrove said. How?

You can NOT bridge a Lepai Tripath amp as the chip is already internally bridged.. It will die immediately if you try to bridge it..

sorry i dont knew the internal architecture of the amp or i mismatch the idea I was talking about the lepai digital the one with mp3 and fm. it says speaker impedance 4 - 8 ohms if it holds down to 4 ohms/ch it still can not be bridged?

yep, can't bridge Lepais... though there are other tripath solutions that give more output.

ryan222h wrote:I'm with her...if you want a portable boombox, go buy a boombox. They are cheap enough where its not really worth it to go and try to build one

Disagree... there's a big hole in the market for powerful quality portable sound. The Boominator design (such as the above orange box) is pretty good though it's the opposite extreme to little pocket-sized speakers. There isn't much in between, time to DIY.

I've spent a lot of time pondering portable and battery powered solutions, and if we could apply a BFM design to it - the Jack seems it'd translate well. For the Jack, you could make a wedge shaped compartment for the battery+amp which will allow it to be used on the ground angled up. That said, for something bigger an Omni12 could be bi-amped (or 2x10 tri-amped) which is something I'm going to try soon enough. The big limitation with battery powered stuff is amplifier output, hence the appeal of high efficiency horn designs.

I personally think it is time for a Jack 8 or even Jack 6 - something in the 12" x 12" range. Howz that sound to you guys? We need a quality 6" or 8" driver with a neo magnet, then add maybe 4 piezos. That would be cool as HAIL in my opionion. Throw a Lepai on it with a battery pack and/or PV cell and you are good to go.

Bill, plans for a smaller Jack -- pretty please?

I have an OTop 12 in my back yard with a lepai that I plug my phone into for the days I actually have the time to be in my back yard. Lowes had 5 watt, 12 volt solar panels ("trickle charger") on sale a while back so I picked up 2 of them thinking one I day I would put together a portable sound solution. An OTop with 10 watts is pretty dang loud for normal personal use.

I'd love a 12" cube horn loaded speaker, the size of a milk crate... who has seen wheelie bin sound systems? they're fun, but a bit big and compromised. Milk crate speaker stacks is the next step

edit: updating this post with a new idea to save double posting.
Here's something I'll share, as I'll never make money off it... one of my random ponderings:

Many Tripath amps can run from 12-24v, the more you put in the more you get out.
It's made me think laterally about a good battery supply, the first thing that comes to mind is 2x SLA batteries in series for 24v and use a 24 charger. That works... but I'm really keen to focus on lighter setups that the tripath can allow for, and started looking at NiCad and Li-* batteries.

One option could be 14.4v RC car batteries, run two in series and switch them to parallel for charging. But then it gets fiddly and you have be careful with building it all.

Another thought was to look at the batteries and chargers used by power tools - having a charging solution that doesn't require switching or modifying is a good place to start, especially if I move to post "how to" guides online. Less liability.
A bit of searching dug up a battery adapter for Makita 18v Li-Ion which allows the new slide-in batteries to fit the old big-plug tools. What this means is by modifying the adapter you could have the new Li-Ion battery slide and lock in to place in the chassis of your speaker/amp set up. It could easily slide out and slip in to the dedicated charger. A very neat solution once the chassis mount is built, no need to mod the battery or charger.

I'd still be looking at ~$80 for a charger and ~$70 per battery for an 18V 3AH unit, but it's a good starting point.

bitSmasher wrote:I'd still be looking at ~$80 for a charger and ~$70 per battery for an 18V 3AH unit, but it's a good starting point.

$150 is pretty steep just to power up the amp. And 3AH might not cut it for a day at the beach or a weekend trip. The 2020A has a comes with a two amp supply. When going mobile, I have a two amp fuse on the line from the battery and haven't popped any fuses. Say it draws one amp playing at a good volume with the J10. If I understand batteries correctly (which I very well may not), that's only 3 hours of running time.

Maybe someone has a better idea of exactly what sort of current the Lepai draws. I do like the idea of using a drill battery to run the portable rig. No battery wires to accidentally get backwards, and no resulting smoke from the Lepai.

ncgrove wrote:$150 is pretty steep just to power up the amp.

Hmm, maybe where you are, but not here in Australia.
Everything is expensive here, due to a lack of population base, a broad expanse of water, rip off merchants/highwaymen/daylight robbers who can charge what they like because "it's not made here" and excise and duty and shipping costs...

ncgrove wrote:I do like the idea of using a drill battery to run the portable rig. No battery wires to accidentally get backwards, and no resulting smoke from the Lepai.

For sure, that's what I'm aiming for with this idea... simplicity. It isn't cheap to get started, but since I plan on restoring/rebuilding a few old boomboxes with modern amps + drivers having a simple, lightweight, modular battery solution is an aim - especially since the next step would be DIY guides on my blog or instructables, to take the guesswork out for others.
The boomboxes wouldn't be huge power devices a 3AH battery should last more than long enough. My own big portable rigs will probably run from SLAs with 50AH+ at 24V, but they'll be a bit silly
Oh, and on the topic of bigger batteries - dug up another idea last night. Electric bicycles and scooters use 24v Li-Ion units with 30-50AH in them. Sold as a sealed unit with charger and mount included. Can buy them cheap from China, but I'd be paranoid about strapping a potential bomb to my rig

And as Grant mentioned, prices here are exhorbitant. A premium to pay for drill batteries, but possibly worthwhile. See what a Makita battery+charger combo is worth locally and compare it to other battery options. Have a look at this Battery Adapter on ebay, that'd be what I'd hack and mount to the chassis, for a slide-on battery to clip in securely.

Anyway, before nerding on about batteries... let's talk about good cabinent designs to repurpose for portable sound.

Also off the reservation:

A friend of mine made a "Podzuma" It sounds great and has a decent battery life for a lead acid battery. It is used at the pool or at tailgates. I looked for a while into using LiPo Batteries (Lithium Polymer) like the ones I have for my RC cars and boat. Huge power, no memory and small size/weight. But the battery packs are between 80-100.00 USD. They also require a balancing charger, if a cell in the pack get more than 1.5 volts out of balance with the other cells, it can lead to catastrophic failure (ie explosion), so there is a definite risk for the newer battery types. But it would be a huge amount of power on tap. The cost/benefit just wasn't worth the headache.

The Podzuma design came from Parts Express. http://www.parts-express.com/pdf/The_Podzuma_16637.pdf

I have also been very impressed with the TDK 2 Boom box, extremely loud and sounds great. Terrible battery life though. http://www.amazon.com/TDK-Record-770000 ... =pd_cp_e_0

Just some other options.

Hi I'm just building a J10 Lite to use as a boombox and was looking for a amp. Any body got any ideas for a 100 to 250w into 8ohms with tone controls. Not looking for 12v just 240v will do and available in the UK.

Why not take an SLA (on it's side) with a built in compartment (think jack air head) for a car head unit (playing usb versus cd for extended battery life)?

This would be similar to the form factor of a boombox with the power provided by a 20w car head unit. It's already running at 12v so no power conversion and would run for hours on a battery or indefinitely with a solar charger....