KF6NFW
08-19-2010, 08:33 PM
I need a simple circuit to build a 40-60 watt mono audio amplifier for use with a PA system. This will be used for monitoring radio when outside of vehicle at a distance.
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K7JEM
08-19-2010, 08:43 PM
You could most likely buy something used for cheaper than you would be able to build something like that.
KF6NFW
08-19-2010, 09:12 PM
probably true, but still willing to build for fun, after all if you cant learn something new even if more expensive then why get out of bed in the afternoon? Consider the fact we pay high prices for higher education for little value in today's market. Not much difference in my mind!:D
I agree though it likely is more expensive to build then to buy, but why not humor me and let me do it the harder way!
I agree though it likely is more expensive to build then to buy, but why not humor me and let me do it the harder way!
K7JEM
08-19-2010, 09:27 PM
There are lots of amplifier chips available that will do what you want, all of them will require higher voltage than 12v to achieve more than just a few watts. Most of them require split supplies of +-25 to 70v.
The old school way is to use a transformer in the audio output, but it would be hard to find one today. That way you could use two heavy duty power transistors and run it right off 12v.
The old Micor mobile radios used this approach, and developed about 12 watts of great sounding audio. They were the standard for public safety for years. That radio on an external speaker could be heard a quarter mile away.
Joe
The old school way is to use a transformer in the audio output, but it would be hard to find one today. That way you could use two heavy duty power transistors and run it right off 12v.
The old Micor mobile radios used this approach, and developed about 12 watts of great sounding audio. They were the standard for public safety for years. That radio on an external speaker could be heard a quarter mile away.
Joe
KF6NFW
08-19-2010, 10:04 PM
I was thinking 40-60 watts was a bit much but was willing to try! My experience is that you dont need more then 15watts unless an EMS/EMA vehicle.
However the environment it will be used in would certainly require such a noise level, its hard to get over the noise of a few thousand people lining the streets for a parade sometimes.
However the environment it will be used in would certainly require such a noise level, its hard to get over the noise of a few thousand people lining the streets for a parade sometimes.
AG3Y
08-19-2010, 11:51 PM
One approach would be to use a horn speaker. A good re-entrant horn, fed with less than 25 watts would blow your ears out at 20 feet, and be comfortably loud at a greater distance than that!
I remember standing in front of an old Altec-Lansing "Voice of the Theater" full range horn loaded speaker system, being fed with a 25 watt amplifier. You could not stand to be within 10 feet of the thing without getting a splitting headache!
Remember 25 watts is only 3dB down from 50 watts, and when listening to music or voice, that is hardly a discernable difference in volume!
I remember standing in front of an old Altec-Lansing "Voice of the Theater" full range horn loaded speaker system, being fed with a 25 watt amplifier. You could not stand to be within 10 feet of the thing without getting a splitting headache!
Remember 25 watts is only 3dB down from 50 watts, and when listening to music or voice, that is hardly a discernable difference in volume!
N5USR
08-20-2010, 09:02 AM
I remember standing in front of an old Altec-Lansing "Voice of the Theater" full range horn loaded speaker system, being fed with a 25 watt amplifier. You could not stand to be within 10 feet of the thing without getting a splitting headache!
Heh... Reminds me of the electronics instructor I had in Vo-Tech during high school. He enjoyed telling students about his home sound system, most often in response to someone bragging about their high-watt car stereo. He had gotten a set of Altec-Lansing speakers from a theater being demoed. His favorite line, "1W in and I'm knocking paint cans off the shelf in the garage!" :D
Probably a bit of exaggeration on the 1W part, but his point was good - with the right speakers, you don't necessarily need mega-wattage!
Heh... Reminds me of the electronics instructor I had in Vo-Tech during high school. He enjoyed telling students about his home sound system, most often in response to someone bragging about their high-watt car stereo. He had gotten a set of Altec-Lansing speakers from a theater being demoed. His favorite line, "1W in and I'm knocking paint cans off the shelf in the garage!" :D
Probably a bit of exaggeration on the 1W part, but his point was good - with the right speakers, you don't necessarily need mega-wattage!
KF6NFW
08-20-2010, 12:25 PM
Heh... Reminds me of the electronics instructor I had in Vo-Tech during high school. He enjoyed telling students about his home sound system, most often in response to someone bragging about their high-watt car stereo. He had gotten a set of Altec-Lansing speakers from a theater being demoed. His favorite line, "1W in and I'm knocking paint cans off the shelf in the garage!" :D
Probably a bit of exaggeration on the 1W part, but his point was good - with the right speakers, you don't necessarily need mega-wattage!This is very true, now just convince the morons who believe more power is the answer, particularly the ones that drive down the road shaking their car apart.
I always encourage them to turn it up to max volume in hopes of finally killing it!
This project I am working on is for father in law and he does understand the concept but I think may be over shooting his goal!
Probably a bit of exaggeration on the 1W part, but his point was good - with the right speakers, you don't necessarily need mega-wattage!This is very true, now just convince the morons who believe more power is the answer, particularly the ones that drive down the road shaking their car apart.
I always encourage them to turn it up to max volume in hopes of finally killing it!
This project I am working on is for father in law and he does understand the concept but I think may be over shooting his goal!
K4EEZ
08-28-2010, 09:41 AM
Try this place:
http://www.electronickits.com/kit/complete/complete.htm?gclid=CLmD7L_w26MCFRBTagodXFL28w#Ampl ifier%20Kits%20And%20Modules
73
__________________________________________________ ______________
I need a simple circuit to build a 40-60 watt mono audio amplifier for use with a PA system. This will be used for monitoring radio when outside of vehicle at a distance.
http://www.electronickits.com/kit/complete/complete.htm?gclid=CLmD7L_w26MCFRBTagodXFL28w#Ampl ifier%20Kits%20And%20Modules
73
__________________________________________________ ______________
I need a simple circuit to build a 40-60 watt mono audio amplifier for use with a PA system. This will be used for monitoring radio when outside of vehicle at a distance.
W9GB
08-28-2010, 11:39 AM
This will be used for monitoring radio when outside of vehicle at a distance.
12 Watts of Audio (AF) output is PLENTY for your operation.
Public Safety vehicles use about 12 watts -- and you can her those at these distances !
http://www.n0ss.net/index_general.html
Tom Hammond, N0SS provides modification instructions for popular 5 watt and 12 Watt amplified Motorola speakers.
http://www.n0ss.net/motorola_amp_spkr_mods_04jul2009.pdf
Surplus Motorola speakers regularly sell on eBay.
NSN6054C and NSN6027A are two model numbers you can examine.
I did the modification of a 12 watt speaker five years ago --- PLENTY of AUDIO !!
a local club member immediately offered me $$ for it (so I sold my converted speaker).
w9gb
12 Watts of Audio (AF) output is PLENTY for your operation.
Public Safety vehicles use about 12 watts -- and you can her those at these distances !
http://www.n0ss.net/index_general.html
Tom Hammond, N0SS provides modification instructions for popular 5 watt and 12 Watt amplified Motorola speakers.
http://www.n0ss.net/motorola_amp_spkr_mods_04jul2009.pdf
Surplus Motorola speakers regularly sell on eBay.
NSN6054C and NSN6027A are two model numbers you can examine.
I did the modification of a 12 watt speaker five years ago --- PLENTY of AUDIO !!
a local club member immediately offered me $$ for it (so I sold my converted speaker).
w9gb
