festival speaker?

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hi im thinking off making a speaker for festival use.
i have read about the SONIC IMPACT T-AMP and would like to use it with this box
http://www.thansen.dk/product.asp?c=958793389&n=1200267971&pn=1220481800

will that be posible??
i would use a 12V car battery for power suply

what about the the "41Hz amp32-PS" is that better for this type of speaker.

i dont know much about hifi. hope you will help.

thanks lars
 
Hi there.

Yeah, that'd work great. I suggest the 41hz amp6-basic though since it's easier to solder. It also is less critical with voltage than the t-amp. Same price too, actually.

Knowing from experience, since I lugged this one:

An externally hosted image should be here but it was not working when we last tested it.


to Roskilde Festival last year with a t-amp installed in it. I had 2x 12 volts 7Ah SLAs inside, and they lasted roughly 40 hours at extremely high volume.

Some of my idiot friends fried my t-amp though by putting it up for recharge without disconnecting the amp first. So I'd suggest going with the amp6-basic, just as I am this year.

Btw, I have improved the monster by adding some solar panels and a slight redesign.

Anyways, see you at Roskilde. Cheers.
 
No no, amp6-basic is practically identical to both the t-amp and the amp3s. The only difference is the type of housing for the chip. So all 3 types runs on the same base voltage, around 12 volts.

T-amp and the amp3s use almost exclusively SMD (surface mount devices) and if you're not experienced in soldering those, I strongly suggest you get the amp6-basic (or buy a t-amp off course).

They all have the same voltage rating, except that because of the different housings, the amp3s take a little higher maximum voltage than the t-amp, and the amp6s take a little more than the amp3s.

See the problem is that a fully charged car, or SLA (sealed lead acid), battery has an output voltage of about 13.8 volts, which is higher than the recommended maximum voltage of the t-amp. Another problem is that a common car battery charger can output up to 14.4 volts when charging. This is (slightly) above the maximum rating of the amp3s, and certainly enough to fry a t-amp.

The amp6-basic can take up to 16 volts, though the recommended maximum voltage is 14.6 volts. This means you'll have more headroom.

In any case, if you do connect a charger, make sure it's an electronically controlled one. Don't just go for the cheapest one, as they are likely to just being a transformer with a rectifier bridge, and they'll likely fry even the amp6s.

If you buy a t-amp, I strongly suggest adding a diode from the battery to get a 0.6 volts voltage drop (and protection from reverse voltage). Also make aboslute sure you cannot charge and play at the same time, at all. Trust me, when people are drunk and stoned they'll try anything stupid, no matter how many times you tell them to do it one specific way.

That's also the problem with car batteries and festivals. Car batteries cannot under any circumstances be turned on it's side, or flipped upside down. The acid will pour out, and likely ruin your speaker, and/or clothes, whatever. That's why I strongly suggest you get SLAs. They can be turned any way you like, though it's recommendable that standing correctly while charging.

On a final note, I'd like to point out that those aren't really "bassboxes", they got a tweeter so they should be full range, just don't expect super high quality sound or sound pressure from such cheap speakers.

Good luck. And don't hesistate to ask more questions. Cheers.
 
Good choice!

You sure didn't miss a detail Saturnus! Indeed a diode or rectifier bridge can drop the voltage just enough to run a T-amp safely.

I built AMP32 and AMP9, right now busy with a Truepath. I have never been disappointed with 41hz quality. Impossible to beat the bang for the buck...
 
v-bro said:
You sure didn't miss a detail Saturnus!

Making festival speakers are my pet peevee. I've built a new one every year for 9 years straight. I love to see the jaw dropping effect those have. This year, it's possible to run it the whole festival (8 days) provided we get some sunshine because of the solar panels.

I am though already planning next years completely over the top version with better drivers, an amp9 (hopefully by then in a BASIC version), and ... fuel cell powered.

I've struck a deal with some of people at IRD (http://www.ird.dk/) that they provide me with a free direct methanol fuel cell pack if I just print their logo on the speaker. IRD makes the only, as far as I know, commercially available fuel cells.
 
Panomaniac: Since I'm going all out, I might as well get a switch mode DC-DC converter to bring the 6V output up to the 24V I need for the amp9.

V-bro: Smaller standard caps is simply not enough for power storage. It's fine just before the amp but I'm putting 6 2.7V 5F (that's full Farads, not microfarads) in series/parallel for power storage before the DC-DC converter because I have them lying around from another project. I might even get more. You can't beat those ultracaps when it comes to power storage in a small package (the 5F ones are ø10x20mm), and at a very very reasonable price too.
 
Saturnus said:
V-bro: Smaller standard caps is simply not enough for power storage. It's fine just before the amp but I'm putting 6 2.7V 5F (that's full Farads, not microfarads) in series/parallel for power storage before the DC-DC converter because I have them lying around from another project.

You probably already know this, but, depending on the type of ultracap you have they may only reliably supply ~100 microamps. I've only looked at the Panasonic ultracaps, and, while they can handle amps of charging current, they can only source micro to milliamps of current. The smaller (physical size) ultracaps are designed to replace batteries for memory backup('non-volatile' RAM), surviving short blackouts for servers, or things like clock chips(think microwaves or vcrs that remember the time over power outages). Ones that can source large numbers of amps are much more expensive and physically larger. You REALLY want to look at the product sheets for your particular caps, they'll also talk about topologies for serializing them (equalisation resistors or something like that...) for higher voltages.

Tom.
 
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Renfrow is right about the caps. Those ultracaps have been around for decades. They keep getting bigger and bigger in value.

But as he states, they have a very high series resistance. That's good for memory chips that need tiny currents to store information, but not for audio amps.

The big caps for audio use are the giant stiffener caps the car sound guys use. They come in 0.5, 1 and 2F ratings. Maybe more. They are large and expensive, but can supply massive amounts of current.
 
well. damn that was a wet festival....

must say that the speaker had "the jaw dropping effect"
it played for some 10 hours allmost full effect with the 7A cell brought 2 though...

unfortunetly it stoped working after 2 days. think maybe it got dropped or maybe there was to much mousture in the air. i dont know?? i will try to fix it if posible.....for next year

but again....thanks alot for the help....sure was worth the time and money....

greets.. the rooster
 
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