Build Poweramp 4ohm high power - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 19th November 2003, 11:48 AM   #1
Account Disabled
 
Join Date: Jul 2003
Location: Adelaide
Send a message via MSN to da_madaxeman
Question Build Poweramp 4ohm high power

Is it possible to from scratch build a home power amp which could deliver 250 watts RMS into 4 Ohms? This of course without explosive amps, million dollar budgets or 50%THD levels...

I know this is asking ALOT. All power figures are ideal and may vary.

It would run from 240VAC outlet, with line outs from my stereo. The only other needed components would be an on/off switch (i do know how to put those in...) and a volume knob. I may put in a switch for bass/treble filter, if i find it needed, but I can manage that.

-Eli, willing to be yelled at if its relevant.
PS just making sure of something. If for example i wired 400 watts RMS at 2 ohms, into two 4ohm subs in parallel, would they each get 400 watts rms?
  Reply With Quote
Old 19th November 2003, 10:47 PM   #2
PRR is offline PRR  United States
diyAudio Member
 
PRR's Avatar
 
Join Date: Jun 2003
Location: USA
> Is it possible to from scratch build a home power amp which could deliver 250 watts RMS into 4 Ohms? This of course without explosive amps, million dollar budgets or 50%THD levels...

You can scratch-build anything you want. Egyptian Pyramid, the InterNet, the 1903 Oldsmobile: all built from scratch. (And Mr Olds did it in a barn.)

However... 250W in 4Ω is a VERY common rating for rock-n-roll PA amplifiers. Most of these have impecable specs, sound that does not suck, and the prices are super-competitive. It works right out of the box, no flames, or if not they will give you another one on warranty. Unless you have an unusual spare-parts box, the price of a complete assembled warranteed PA amp is little more than the price of your parts, and people have been known to work months or years to assemble large power amps from scratch (and many abandon the effort). That's months of un-paid labor, some of it pretty dull (chasing back-ordered parts), and you need a pretty spiffy test-bench to smoke-test and verify a big power amp safely and meaninfully.

There are lots of things that DO make sense as DIY scratch-built. But you need a pretty specific reason to justify building high-power amplifiers in a range where commercial competition makes fine low-price power-monsters.

> If for example i wired 400 watts RMS at 2 ohms, into two 4ohm subs in parallel, would they each get 400 watts rms?

Each would get 200 watts.
  Reply With Quote
Old 20th November 2003, 12:37 AM   #3
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
Yes you can. As an example the Opti-MOS kit from www.sealelectronics con probably be configured to do that with double-die L-MOSFETs.

I think there is aqn outfit called AssieAmps that has something on that order.
H*o*w*e*v*e*r that is biting off a major, major project if this is a first amp project. The currents would most definately be lethal! The guage of the power supply and output wiring woulds have to be scaled up from what one finds in more modest amps. PCB traces would need to be made large enough to hanle the current. Even power on/off would need some additional circuitry.
  Reply With Quote
Old 20th November 2003, 01:14 AM   #4
DUG is offline DUG  Canada
diyAudio Member
 
Join Date: Jan 2003
Location: mississauga ontario canada
My first power amp was 200W / 2Ohms

Do your math with respect to current supply from your power supply and current supply through your output devices. Control your bias well with temperature tracking and limit the closed loop gain to less than 20. Yes, use thicker wire / copper on circuit boards and watch your ground circuit for high current in signal paths. Analog amplifiers cannot be greater than 70.7% efficient, so make sure your heat sink is large enough. All the usual safety features when powering up...a variac for first time or a 100Watt bulb in series with the line...fuses can save components going into thermal runaway.

have fun
__________________
Doug We are all learning...we can all help
"You can't stop the signal, Mal. Everything goes somewhere..."
  Reply With Quote
Old 20th November 2003, 05:42 AM   #5
Damosan is offline Damosan  Australia
diyAudio Member
 
Join Date: Feb 2003
Location: Perth
Default Available in Aus

Mad,

Try this one from Jaycar

URL=http://www1.jaycar.com.au/productView.asp?ID=KA1760&CATID=&keywords=ka1760&S PECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=xxxxxx xxxx&Keyword2=xxxxxxxxxx&pageNumber=&priceMin=&pri ceMax=&SUBCATID=]Jaycar KA1760[/URL]

I have built one or two and they perform really well. Just a big inrush current at turn on.
  Reply With Quote
Old 20th November 2003, 05:58 AM   #6
Banned
 
Join Date: Nov 2002
Location: Adelaide, Australia
Send a message via MSN to SkinnyBoy
I'm making a power amp... like 100watts per channels... 8 channels.. you can't buy anything like it.. lol

I already have the filter capacitors.. sixteen 100volt, 4700uF chasis mount capacitors.. and I have most of the other capacitors I need too..
  Reply With Quote
Old 20th November 2003, 07:13 AM   #7
Account Disabled
 
Join Date: Jul 2003
Location: Adelaide
Send a message via MSN to da_madaxeman
I do like the sound of one or two of those kit amps on www.seaelectronics.com as they have very nice power levels, though I also like the idea of simply buying one. I will enquire at the big PA places and see what I'll be up for. Thanks!
  Reply With Quote
Old 20th November 2003, 03:16 PM   #8
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
If you go the PA amp route, rember that many include a fan. You may find the fan noise unacceptable for home use. Some also have fans that come on only when the temperature rises to a certain level which may not happen too often.
  Reply With Quote
Old 21st November 2003, 08:04 PM   #9
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
ive just built slones amp design of 11.8 in his high power amp book 250watt 4 ohm, cost me about 150 for EVERTHING (two monoblocs), yes I bought the caps and sinks of ebay but there is no reason you cant either. They sound fabulous driving my dads speakers better then a Quad 77 and a musical fidelity A1. Anyway, building these is really simple it took me less then a week and I had university to attend at the same time.

If you choose to build them good luck.

Matt
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  Reply With Quote
Old 21st November 2003, 09:41 PM   #10
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
Default Q for 5th element

Did the one week build time include the enclosure. Just asking since that is where I'm the most awkward.

Also did you use Slone's artwork to make the PCB's or did you layout your own? Just curious.
  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
what poweramp is realy the best to build? prorms Solid State 60 13th February 2012 08:07 PM
is this poweramp ready to build???? prorms Solid State 19 28th April 2008 06:49 PM
I Want To Build A 100+Watt per/channel Tube Poweramp ak_47_boy Tubes / Valves 29 17th October 2007 11:16 PM
How to build a +/- 60VDC high amp power supply audiobahnkid592 Power Supplies 4 18th March 2007 03:09 AM
Quick question - possible to build high-power current-source Class D amp? 454Casull Class D 2 24th November 2006 10:48 PM


New To Site? Need Help?

All times are GMT. The time now is 11:50 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