Disease8

Me and my friends that are in a semi improvised Electronic Hip hop act have this idea.
We have a friend that has kind of doe it already which is to build a portable battery powered speaker into a brief case..

Obviously everything will have to be 12v which actually makes it pretty interesting as  you could easily throw solar power into the mix to recharge/power it depending on the weather.

What makes it complex is it would have to have an extremely simple mixer with lets say 4x mic inputs with at leat gain control (of some sort), 2 line inputs and possibly a D.I . . .

Ho realistic is this? could you have 4 mic pre's powered from 12v?

I was looking at a very noob and simple way of making portable speakers using the super cheap 40watt amps you can get from China and such and then simply buying a seperate 12v battery with charger and plugging that in. It would be simple enough to break down and rebuilt some old Hi Fi speakers into a brief case or some box with the battery and amp. This is a very easy way for me to do it without any electronics experience. The difficult part is we will just have stereo line level in. As its got to be a "Jamm Box" we need all kinds of things plugged in. So would there be a simple way to perhaps use the amp and battery from China and somehow work a basic mixer into the equation? No Phantom power or anything just for dynamics..

I am really excited about this idea and cannot wait to get out on the road making beats all night in all kinds of places :-) . . .

AMP:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=280716587908&ssPageName=STRK:MEWAX:IT#ht_3979wt_1139
BATTERY:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250864527770&ssPageName=STRK:MEWAX:IT

Thanks....
Dom...





Samuel Groner

    Z├╝rich, Switzerland
  • Posts: 2935
Re: Portable Battery Powered Loud Speakers with Pre-Amps + D.I ?
« Reply #1 on: August 03, 2011, 07:12:23 AM »
Quote
Obviously everything will have to be 12 V.

This is possible (hit Googel with "single supply opamp", but I think I'd make life easier by using a DC-DC converter (e.g. Murata NDTD1212C). This will allow you to power the small-signal sections from bipolar supplies, and just the power amp directly from the battery. A bit of RC filtering might be necessary for critical circuits (e.g. the mic preamp) to reduce noise from the DC-DC converter, though.

Samuel

Disease8

Re: Portable Battery Powered Loud Speakers with Pre-Amps + D.I ?
« Reply #2 on: August 03, 2011, 07:37:37 AM »
Quote
Obviously everything will have to be 12 V.

This is possible (hit Googel with "single supply opamp", but I think I'd make life easier by using a DC-DC converter (e.g. Murata NDTD1212C). This will allow you to power the small-signal sections from bipolar supplies, and just the power amp directly from the battery. A bit of RC filtering might be necessary for critical circuits (e.g. the mic preamp) to reduce noise from the DC-DC converter, though.

Samuel

Sorrry in laymans terms what exactly would i been gaining from doing this?
Will the items I mentioned on ebay be ok? Its about 40watts in total. 20 per channel..

sahib

Re: Portable Battery Powered Loud Speakers with Pre-Amps + D.I ?
« Reply #3 on: August 03, 2011, 10:14:02 AM »

I have a four channel board that you might be interested in for the mixer.
http://www.groupdiy.com/index.php?topic=44696.0

It works on 24V (2 x 12V batteries in series would do). It has 4 channels of mic-input, on board limiter and a headphone amp. Would fit your bill perfectly.

If you want to go fancy and add some VUs I also have some small, back-lit VUs with simple single transistor stage drivers that again would fit the bill. They are obviously not as accurate as pro-level VUs but still give rough indication of level and look pretty.

For DI it depends whether you go active or passive. I have some passive ground loop eliminators
( basically a transformer).

PRR

Re: Portable Battery Powered Loud Speakers with Pre-Amps + D.I ?
« Reply #4 on: August 03, 2011, 07:33:36 PM »
> could you have 4 mic pre's powered from 12v?

You can do anything you want.

What do you REALLY want?

Ribbon mikes on harpsicord? Vanishingly low distortion?

Or $49 SM58-like dynamic mikes? Overdriven to rude sounds?

I done a lot of work (good and rude) on not much more than this:

PRR

Re: Portable Battery Powered Loud Speakers with Pre-Amps + D.I ?
« Reply #5 on: August 03, 2011, 07:58:57 PM »
I know this is a DIY forum, and you asked for four mikes, but here is a pre-made solution for a couple mikes and misc line input(s) from 12VDC for $99:

http://www.radioshack.com/product/index.jsp?productId=2103829#

Re: Portable Battery Powered Loud Speakers with Pre-Amps + D.I ?
« Reply #6 on: February 01, 2014, 04:05:56 AM »
Me and my friends that are in a semi improvised Electronic Hip hop act have this idea.
We have a friend that has kind of doe it already which is to build a portable battery powered speaker into a brief case..

Obviously everything will have to be 12v which actually makes it pretty interesting as  you could easily throw solar panel into the mix to recharge/power it depending on the weather.

What makes it complex is it would have to have an extremely simple mixer with lets say 4x mic inputs with at leat gain control (of some sort), 2 line inputs and possibly a D.I . . .

Ho realistic is this? could you have 4 mic pre's powered from 12v?

I was looking at a very noob and simple way of making portable speakers using the super cheap 40watt amps you can get from China and such and then simply buying a seperate 12v battery with charger and plugging that in. It would be simple enough to break down and rebuilt some old Hi Fi speakers into a brief case or some box with the battery and amp. This is a very easy way for me to do it without any electronics experience. The difficult part is we will just have stereo line level in. As its got to be a "Jamm Box" we need all kinds of things plugged in. So would there be a simple way to perhaps use the amp and battery from China and somehow work a basic mixer into the equation? No Phantom power or anything just for dynamics..

I am really excited about this idea and cannot wait to get out on the road making beats all night in all kinds of places :-) . . .


AMP:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=280716587908&ssPageName=STRK:MEWAX:IT#ht_3979wt_1139
BATTERY:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250864527770&ssPageName=STRK:MEWAX:IT

Thanks....
Dom...

It really seems to be very exciting idea indeed.. Have you got the system? If it is worth I would love to get similar system very soon.
« Last Edit: February 02, 2014, 09:46:13 AM by MarkHart »

barefoot

Re: Portable Battery Powered Loud Speakers with Pre-Amps + D.I ?
« Reply #7 on: February 04, 2014, 02:19:17 PM »
Your battery link no longer works.   But if you're planning on using a car or motorcycle size battery, you want a "deep-cycle"  battery.   Regular automotive batteries are optimized for short bursts of very high current, not for sustained medium to low current .  Also, frequent discharges will significantly reduce their lifetime.    Deep-cycle batteries are designed for portable equipment like you want to build.   You might also consider building an AC charger into the unit.  If so, use one designed for deep-cycle.   

Lighter battery types like lithium and NiMH are much more fussy about discharge and recharge levels.   Best to use a smart charger/controller designed for the battery.   Otherwise, you'll be replacing batteries often and possibly even have them burst into flames!  ;)     
Thomas Barefoot
Barefoot Sound


 

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