Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Loudspeaker Amp schematic needed
Loudspeaker Amp schematic needed
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 2nd April 2007, 06:54 AM   #1
silentblackhat is offline silentblackhat  United States
diyAudio Member
Join Date: Jul 2004
Send a message via AIM to silentblackhat
Default Loudspeaker Amp schematic needed

I am looking for an amp that shoudl be pretty easy to build, as well as will power an 8ohm loudspeaker. Its RMS rating is 25 wats but I dont think I will need 25 watts.

I am wanting to make this an amp that will power an electret microphone, that i can switch on and off, as the input and the 8 ohm speaker as the output. This will be installed on a motor vehicle(honda civic to be exact) as a PA system.

Any help is greatly appreciated.

PS: i am very compitent in the world of electronics. Before i built a preamp(LM386 based) that has worked very well for what i needed it for so I know how to put these things together; i can follow schematics very well.
  Reply With Quote
Old 2nd April 2007, 03:13 PM   #2
jaycee is offline jaycee  United Kingdom
diyAudio Member
Join Date: Apr 2004
Location: Norwich, UK
Hmm... you want it in a car, so you will want it to run from 12V. I'd look around for some "car audio" type chips, ST make a lot of them. The example schematic in the data sheet for them should be fine. You won't get 25W into 8 ohms from 12V directly, though.

You may want to stick a preamp before this that deals with the elecret mic. This should be easy enough to do with an opamp.
  Reply With Quote
Old 3rd April 2007, 06:53 AM   #3
unclejed613 is offline unclejed613  United States
diyAudio Member
unclejed613's Avatar
Join Date: Dec 2006
there are several that will do about 25w bridged
here's one of them.....


i think NS makes a couple, and we're still talking analog..... there's a bunch of D and T amps as well.....
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 3rd April 2007, 11:32 AM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
make sure the pre-amp is insensitive to car noises, ignition, alternator, etc (=very good PSRR).
The amp similarly should have a good PSRR.
If the microphone is only for voice then maximum intelligibility can come from narrow banding the amplifier and pre-amp.
In the extreme this could be as close as 300Hz to 3kHz, but 200Hz to 5kHz will probably sound more realistic.
If the mic is used close up, then consider adding an adjustable bass cut to remove the boost that close micing gives.

What are you using for a speaker? A horn could probably manage with just a few watts. Remember the PA horns used at school sports day, running on tiny batteries.
regards Andrew T.
  Reply With Quote
Old 3rd April 2007, 05:40 PM   #5
silentblackhat is offline silentblackhat  United States
diyAudio Member
Join Date: Jul 2004
Send a message via AIM to silentblackhat
the closest pic i can find is this one, its the exact one but its halfway cut off. its an 8-ohm, 25-watt(rms) powerhorn.
Click the image to open in full size.

how many watts do you think I should need for this?

I know about the noise on the pre-amp when i built it. it picked up every noise possible. I went and got a 12v+ noise supressor and now it works like a champ

are there any really simple amp schematics out there that would work with this that would be loud enough?

Also is there any of those PA system microphones out there that the amp would only be powered on when I press the botton on the side?
  Reply With Quote
Old 7th April 2007, 05:10 AM   #6
silentblackhat is offline silentblackhat  United States
diyAudio Member
Join Date: Jul 2004
Send a message via AIM to silentblackhat
any ideas?
  Reply With Quote


Loudspeaker Amp schematic neededHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
loudspeaker help needed wizzards Multi-Way 4 20th April 2008 03:41 PM
Klang + Ton 2/2007 Nexus loudspeaker article needed supernet Multi-Way 4 31st March 2008 12:31 AM
simple loudspeaker protection needed Flavio88 Multi-Way 0 12th January 2007 12:34 AM
Loudspeaker advice needed b_online Multi-Way 7 17th October 2003 08:33 AM

New To Site? Need Help?

All times are GMT. The time now is 05:49 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio