Any chip-amps more powerful than LM3875? - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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
Reply
 
Thread Tools Search this Thread
Old 5th February 2004, 02:40 AM   #1
DeonC is offline DeonC  South Africa
diyAudio Member
 
DeonC's Avatar
 
Join Date: May 2002
Location: Kimberley, South-Africa
Question Any chip-amps more powerful than LM3875?

Hi guys

Are there any chips than give more power than the LM3875. I'm sure there are, but I don't really know where to go. These will be for subwoofer duty.

Thanks,
Deon
__________________
I don't suffer from insanity. I enjoy every minute of it.
Have a look at my favorite thread: Interesting YouTube video clips
  Reply With Quote
Old 5th February 2004, 02:50 AM   #2
diyAudio Member
 
xplod1236's Avatar
 
Join Date: Dec 2003
Location: On the couch
Send a message via AIM to xplod1236
Yes. There are the LM3886s, which deliver 68w into a 4 ohm load, or 38w into an 8 ohm load. I have bridged 2 LM3886s, but I'm still not satisfied. I want more power. I have some samples of the LM4651/LM4652 170w class d amp, but I don't have time to get the parts for it and/or put it together. Does anybody know of a simple, high-power amp? I like free samples.
  Reply With Quote
Old 5th February 2004, 02:58 AM   #3
diyAudio Member
 
Join Date: Dec 2001
Location: SIUE, Illinois, USA
read the app notes and all. you have after the lm3875:
lm3886 - single IC, adds mute function DO NOT CONNECT MUTE DIRECTLY TO Vee!
LM4651/LM4652 - classD driver and FETs. 170W @ 4ohm, not full range.

then:
dual lm38xx bridge - 2 ICs to give double the voltage output, you can get about 120W @ 8ohm. 4ohm is no longer a good idea.
dual lm38xx parallel - 2 ICs to give extra current drive @ 4ohms, more difficult to build as well

quad lm38xx bridge-parallel - 4 ICs, 2 sets of paralleled amps that are then bridged. gives most power into 4ohm bridged.

and of course you can get a 50x2 or 60x2 IC in the lm4732 and lm4780 27 pin packages, the 27 pins are pretty close, though it is possible to bend them to fit in 100mil spacings like a typical board has.

I would like to see if the lm4651 could be used with alternative FETs to get more power.
__________________
if only it could be used for good, not evil...
  Reply With Quote
Old 5th February 2004, 03:04 AM   #4
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Default Re: Any chip-amps more powerful than LM3875?

Quote:
Originally posted by DeonC
Are there any chips than give more power than the LM3875. I'm sure there are, but I don't really know where to go. These will be for subwoofer duty.
Want a chip with some REAL balls? Try this guy:

Click the image to open in full size.

It'll take up to a +/- 75 volt supply and can deliver +/-30 amps of current.

Only $492.19 a pop!

se
  Reply With Quote
Old 5th February 2004, 03:48 AM   #5
diyAudio Member
 
Join Date: Jan 2004
Location: Buffalo, NY
Send a message via AIM to geolemon
I've got the same question...

I'm wondering a couple things:
1) how much power CAN you squeeze out of a chip amp - using the commonly discussed chips on this forum (that one above looks like a beast! - no fair! ) - can you get high power?
2) what's the minimum impedance load that you can run one of these at - and I don't even mean that in the sense of "power keeps doubling as you cut the impedance"... I mean, could you even design your 50 watt amp to make it's 50 watts at 1 ohm, for example.

In reviewing the documentation for the AN-1192 chip, it seems like the answer to both of these is "yes", although I've gathered mostly "no" impressions around here so far...

So let me quote the document, and I'm anxious to hear what people think:

Quote:
quoted from AN-1192:
The parallel amplifier is another configuration that can be used to obtain higher output power levels...
...the parallel topology provides a great way of achieving higher power levels while keeping within IC power dissipation limits by driving low impedance loads...
In fact, any number of IC's can be used in a parallell design, and when configured the same will share the power dissipation equally.
For example, using four IC's to drive a 1 ohm load means that each IC dissipates 1/4 of the total power dissipation. In other words, the load to each IC looks like a 4 ohm load (Number of IC's in parallel * load impedance = load impedance seen by each individual IC).

If the bridged and parallel configurations are combined, the outcome is a very high-power amplifier solution that far exceeds the capabilities of one IC alone...
This application note seems to indicate that this parallelling technique can be used to increase the power level seemingly without limit, and/or to create chip amps that are low-impedance compatable.

Opinions?
  Reply With Quote
Old 5th February 2004, 04:46 AM   #6
diyAudio Member
 
Join Date: May 2003
Location: Winnipeg
Whut up Geo!

1) how much power CAN you squeeze out of a chip amp

Well, that description you quoted is a good one. You can keep paralleling chips for higher output current but there are maximum supply voltages that shouldn't be exceeded. So the supply voltage is the limiting factor with chips. If you still want to get more power out of your amp, you'll need to parallel more chips. Double them if you want to cut the impedence in half.

2) what's the minimum impedance load

I couldn't tell ya. If I were to build one, I don't think I'd strive for anything less than 2 ohms. I think you may have stability issues as a result dunno for sure. I'd make sure your voltage rails are as high as possible to maximize the output power.
  Reply With Quote
Old 5th February 2004, 01:03 PM   #7
matjans is offline matjans  Netherlands
diyAudio Member
 
matjans's Avatar
 
Join Date: Aug 2003
Location: Utrecht, NL
Send a message via MSN to matjans
i just finished building a lm4780 based chip amp on veroboard (yes, it is doable) and it should pump out about 100-120W as per the datasheet (parallel config).

Man i went through hell trying to get one in NL. I had an american friend of mine send one via mail.
  Reply With Quote
Old 5th February 2004, 02:02 PM   #8
diyAudio Member
 
JOE DIRT®'s Avatar
 
Join Date: Apr 2003
Location: Brantford, ON
Steve....I bet you never seen one like this..LMAO
Attached Images
File Type: jpg ok3.jpg (12.9 KB, 943 views)
  Reply With Quote
Old 5th February 2004, 05:43 PM   #9
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by JOE DIRT®
Steve....I bet you never seen one like this..LMAO
Hehehe. Nope. Appears to be about the same size as the PA-03 (which is 2.3" x 1.63").

Only found one reference to it on the web which says it's a linear regulator.

se
  Reply With Quote
Old 5th February 2004, 06:58 PM   #10
diyAudio Member
 
tlmadsen's Avatar
 
Join Date: Aug 2003
Location: Roskilde - The vikingships
Default Power to the people

To all you power hungry peolpe

Have a look at

200 watts Gäjnklon (Gainclone) - BPA200

It will give you more than 200W in 8 ohm, 350 W in 4 ohm and if you use (paralleling) enought af "Das Modul" you get (teoritical)close to 1000 W in 1 ohm............

Have fun

Thomas
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
powerful Chip - audio digital amplifier olzon Chip Amps 1 14th November 2008 08:25 PM
Is LM3875 chip waterproof? Peter Daniel Chip Amps 236 19th January 2006 05:56 PM
Has anyone compared GC amps(LM3875/3886/4780) with other DIY SS amps(Leach,ESP) ? percy Chip Amps 31 13th January 2006 02:33 AM
I'm looking for LM3875 chip??? thomgun_lc Chip Amps 5 3rd January 2006 08:26 AM


New To Site? Need Help?

All times are GMT. The time now is 01:16 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2