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Old 23rd October 2011, 03:32 PM   #2391
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Location: Copenhagen, Denmark
Quote:
Originally Posted by bastanken View Post
If I have 8 batteries rated at 1.5 V that would be 1.5 x 8 = 12 V, right?

But how long will I be able to play at maximum volume?
I can't find any info of the capacity of the batteries but i guess they are somewhere between 12000-18000 mah.
No. Alkaline batteries drop to 1.2V under load within minutes so you'd need 10 in series.

Technically the specification for most alkaline cells reads 18Ah but that's a very moderated truth because that would be under extremely low load conditions and allowing the batteries to drop to 0.8V per cell.

Realistically you can expect 6-8 hours playing time, so actually only about 2-2.5Ah under real life use at maximum volume. But that's only for top of range brand name batteries. Expect much less for cheap ones.

If a festival don't allow SLAs then go with li-ion/LFP cells. It'll be way cheaper and better.

Last edited by Saturnus; 23rd October 2011 at 03:35 PM.
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Old 24th October 2011, 09:36 PM   #2392
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Quote:
That's not quite accurate. All you need is a passive filter. I have earlier in this thread described a passive filter that would fit.
even though i've read through the thread and searched it for the part where you have described a passive filter i haven't been able to find it... if either remember where the roundabouts of this post is or if you could tell it again, it would be appreciated

we've decided to go with the pht407 because of your expertise in a previous post where you described the cons with choosing this model from the other pht407's
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Old 25th October 2011, 04:30 PM   #2393
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Ok I guess your right! thanks!

I got 2 more questions.

1. Is this LED supposed to be like this in the picture?
What purpose does the square (GND) has where the red arrow are pointing at.
I hope you understand what I mean...
http://img811.imageshack.us/img811/4651/dsc043511.jpg

2. Can I connect this adaptor or will the amp take damage?
http://img87.imageshack.us/img87/2401/imag0447.jpg

I guess I need a heat sink for a full load with all the speakers, right?
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Old 25th October 2011, 06:41 PM   #2394
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Quote:
Originally Posted by bastanken View Post
Ok I guess your right! thanks!

I got 2 more questions.

1. Is this LED supposed to be like this in the picture?
What purpose does the square (GND) has where the red arrow are pointing at.
I hope you understand what I mean...
http://img811.imageshack.us/img811/4651/dsc043511.jpg

2. Can I connect this adaptor or will the amp take damage?
http://img87.imageshack.us/img87/2401/imag0447.jpg

I guess I need a heat sink for a full load with all the speakers, right?
1. It's to place a screw terminal for power in like those used for the speakers, or soldering directly.

2. No, but that adaptor is far from powerful enough. You need at least a 3A adaptor and preferably 5A adaptor. That's because even though average consumption is only around 350mA, peak output can easily exceed 10 times that.

It's always good to be on the safe side but the first year I went with it to Roskilde I didn't have a heat sink on it at all, and it ran fine. But that being 2007, and it being quite cold compared to recent years, I guess that's part of the reason. Another reason was probably that I the first year hadn't optimized the feedback resistor for ultra low input so it probably only ran at half maximum power at the most.
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Old 26th October 2011, 12:16 PM   #2395
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Quote:
Originally Posted by Saturnus View Post
1. It's to place a screw terminal for power in like those used for the speakers, or soldering directly.

2. No, but that adaptor is far from powerful enough. You need at least a 3A adaptor and preferably 5A adaptor. That's because even though average consumption is only around 350mA, peak output can easily exceed 10 times that.

It's always good to be on the safe side but the first year I went with it to Roskilde I didn't have a heat sink on it at all, and it ran fine. But that being 2007, and it being quite cold compared to recent years, I guess that's part of the reason. Another reason was probably that I the first year hadn't optimized the feedback resistor for ultra low input so it probably only ran at half maximum power at the most.
Okay I understand, thank you!
I think I have some old heat sink that I used to my computer so I will go with that then.

What batteries do you recommend?
Here is a link that came up earlier in this thread, BatterySpace.com/AA Portable Power Corp. Tel: 510-525-2328 - Powerizer Battery Official Site
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Old 6th November 2011, 03:19 PM   #2396
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saturnus would it be possible for you to post a diagram or picture of how you wired up the woofers and tweeters to the amp. Did you need to use a crossover bewteen the 2?
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Old 6th November 2011, 03:54 PM   #2397
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It's already posted earlier. And included in the occasional round-ups of the important posts.
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Old 6th November 2011, 08:09 PM   #2398
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Quote:
Originally Posted by johnsharpe View Post
saturnus would it be possible for you to post a diagram or picture of how you wired up the woofers and tweeters to the amp. Did you need to use a crossover bewteen the 2?
A link to where the subject was described and discussed earlier:
The Boominator - another stab at the ultimate party machine
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Old 6th November 2011, 09:54 PM   #2399
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Quote:
Originally Posted by Campino Morten View Post
A link to where the subject was described and discussed earlier:
The Boominator - another stab at the ultimate party machine
cheers have been looking through the 240 page thread for a couple of hours now
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Old 8th November 2011, 11:14 AM   #2400
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Hi togehter,
Some days ago I build my first self-designed boombox using some chassis and amp laying around for some years. It's 40x40x90cm, around 90l volume, 1x bass chassis (VXT 124, 12"), two midrange speakers (VXT 54) and two tweeters (also cheap crap). I used 19mm MDF for the box, it's pretty heavy now ;-)
Attached two (bad quality) pictures of the box.
As the first box now is definitive too heavy I'm into planning my second generation boombox and found this fantastic thread.

I've build it mainly for two reasons: First to use it inside a gym (3 fields, so quite big) for warmup, so should not make a disco in the gym but be reasonably loud. Second application would be outdoor use in summer to sound some beachvolleyball courts (background music, no big event music) or smaller party events.

So after some hours reading through this really long thread, the following idea came to my mind (didn't read something like this so far):
What, if I build up two half Boominators, each with 1x 7AH SLN battery, a AMP6 amplifier (or maybe 1 AMP9 with the new external subwoofer option) and design a kind of coupling mechanism to mechanicaly combine these thwo "half" Boominators so that I have these configuration options:
Ultra-mobile: Only one half Boominator with pure battery operation (for beachcourts, not sooo loud)
Normal: both half Boominators combined to one full Boominator (with switching power supply and battery loader included for still mobile operation with connection to mains.
Option: Maybe with the new AMP9 design it would be possible to add an additional subwoofer box?

Does that make sense to you?

BTW: What is the up to date choice for the piezos/tweeters?
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