help with selection of high power amplifier kit for dj/sound reinforcement use - 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 21st September 2001, 05:03 PM   #1
ogp is offline ogp  United States
diyAudio Member
 
Join Date: Sep 2001
Location: Ohio
Send a message via AIM to ogp
Hi, I am relatively new to the arena of diy amplifiers and such. I was looking at possibly purchasing a kit since I have never built one before. I do have some experience soldering, but not on reading schematics, although I don't think it would be very difficult to learn. So, I was looking into getting a kit for a high power amplifier that I could use for DJ/Sound reinforcement use. This would be subject to long periods of high output, so I would like something that would last. I would also like something that sounds comparable to commercial products. Does anyone have any suggestions? Most of the amps I have found seem to be class A whereas I probably need a class D amp. I have found a few things from hobbytron.com that velleman makes. The ones that caught my eye were this one http://www.hobbytron.net/vk4020.html and this one http://www.hobbytron.net/vk4010.html. Has anyone built either of these units? What about some of the kits from marchandelec.com? I need a stereo amp to drive two speakers (four would be nice) and put out at least 100 watts, although I think somewhere around 200 or 300 would be better. Any help/suggestions are greatly appreciated. Thanks.

Dave
  Reply With Quote
Old 21st September 2001, 07:58 PM   #2
paulb is offline paulb  Canada
diyAudio Member
 
Join Date: Jun 2001
Location: Calgary
Dave,
Something like the ILP modules (see http://www.audioxpress.com/bksprods/kits/ki-hy2000.htm) might be worth looking at. Note that even if it says "power supply included" you still need a transformer.
  Reply With Quote
Old 21st September 2001, 09:16 PM   #3
ogp is offline ogp  United States
diyAudio Member
 
Join Date: Sep 2001
Location: Ohio
Send a message via AIM to ogp
so if I got one of the modules that came with a power supply, would the only things I need be a transformer and a case? and then just wire up some rca inputs and speaker binding posts? Also, could you tell me exactly what the difference is between the OMP/MF modules and the ones you pointed me to? Thanks.

Dave

[Edited by ogp on 09-21-2001 at 04:20 PM]
  Reply With Quote
Old 22nd September 2001, 12:00 AM   #4
paulb is offline paulb  Canada
diyAudio Member
 
Join Date: Jun 2001
Location: Calgary
I haven't used the ILP modules from AudioXpress, so I can't say exactly what you would need. I'm sure they come with an application note; perhaps you could find the ILP web site or send an inquiry to AudioXpress.
Fuses, man, you gotta have fuses too. At least:
- one for the AC input
- one for each speaker output
- maybe one each in the + and - DC power rails
I'm not familiar with the OMP/MF modules.
  Reply With Quote
Old 22nd September 2001, 12:07 AM   #5
Helix is offline Helix  United Kingdom
diyAudio Member
 
Helix's Avatar
 
Join Date: Jul 2001
Location: UK
Default SPK output fuses

I wouldn't put any speaker output fuses, they apper to have enough output protection.
  Reply With Quote
Old 22nd September 2001, 09:41 AM   #6
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
You might like to consider an AB kit from http://www.printedelectronics.com called the AKSA.

  Reply With Quote
Old 22nd September 2001, 11:25 PM   #7
ogp is offline ogp  United States
diyAudio Member
 
Join Date: Sep 2001
Location: Ohio
Send a message via AIM to ogp
Do you think the AKSA would be powerful enough for my application?
  Reply With Quote
Old 23rd September 2001, 01:06 AM   #8
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
How much power do you need? This is a vexing question, as it is related to ego and other subjective issues.

The AKSA is 100W into 8 ohms, but is extremely punchy in the bass and sounds like about 150W when compared to many other amps, such as Rotels.

A great deal of perceived power can be gained by careful choice of bass driver, too. An 87/wattdB driver produces half the subjective bass of a 93dB/watt, and with improving driver technology it's no longer difficult finding such beasts.

Generally, with amps, the more power they produce, the tighter must be the stability margins, since stability is intimately related to rail voltage. Ensuring an amp is stable generally means throwing it in irons to slow it down, and this has marked effect on the sonics across the entire music spectrum. Very large (cf. 500W and up) amps run high rail voltages - I have seen 125V rails on some Pro audio types - and ensuring stability at this levels is a horrendous challenge, usually resulting in a powerful but leaden sound. (One can hardly expect a Jumbo jet to exhibit the dynamics of a military fighter!!)

Thus there are rewards in keeping the rail voltage as low as possible, and this is the reason less power will sound better than more, so long as the drivers can generate the SPL.

Hugh
  Reply With Quote
Old 23rd September 2001, 06:17 AM   #9
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
The amps and speakers need to be examined as a system.But let us look at an amp first.The Velleman kit was examined by Audio Amateur and found to have oscillation problems.The most common amps for DJ/PA in the USA over the last 20 years or so are of the Peavey CS800/BGW 750 variety.Class AB output stages with five pair of outputs running on +/- 80V and capable of 400 watts at 4 ohms.If you bi-amp your speakers two amps powered with +/- 40V will be able to play the same volume level.Each amp will need only one pair of outputs and be much easier as a DIY project.An electronic crossover will be needed.The system should take the form of a pair of two way satellites and a subwoofer.The mid-high box can be quite small as it need only respond down to 100hz and are generally mounted on a tripod type stand.A pair of 10s or 12s and a horn are what you need here.The subwoofer will be quite large and go on the floor.A single 15 in a bandpass box will work here.Buy three of these amp cards http://sound.westhost.com/project3a.htm and two of these crossover cards http://sound.westhost.com/project09.htm The total cost delivered in USA is $82.80 for all five boards and documentation http://sound.westhost.com/purchase.htm One amp card will drive the mid and high for the left channel and another for the right channel.The third card will be bridged and drive the subwoofer.The two crossover cards are to be configured with 100h and 1.2khz for the crossover points.Two 30+30 (60VCT) 200~400VA transformers will be required.The crossover will 'steal' its power from one of these.Suggested drivers are all Eminence: four Alpha 10, two per box will give 103dB/2.83V and go down to 100hz.A pair of MD2001 will be 105dB/2.83V and go down to 1.2Khz on the correct horn.A single Kappa 15LF (not the pro series) will be 101dB/2.83V and go down to 40hz in a bandpass box.All the drivers and horns should cost less than $300.The bass should play 101dB + 23dB (amplifier power rating) = 124dB, the mids 103dB + 17dB = 120dB for one side + 3dB for stereo = 123dB, and the highs 105dB + 17dB = 122dB .This is for single tone sine wave.On program material expect another 8~10dB, or about 130dB .At a typical listening distance of 30 feet this will be about 110dB on peaks.With dynamic program material this will be about 95dB average before clipping (loud) and with some compression could be able to reach 105dB (very loud).
  Reply With Quote
Old 23rd September 2001, 07:42 PM   #10
ogp is offline ogp  United States
diyAudio Member
 
Join Date: Sep 2001
Location: Ohio
Send a message via AIM to ogp
wow, djk, that was an extremely detailed post. Thanks a lot. Would the amplifiers and crossovers be difficult to build for someone who doesn't really have any experience? You sound as if you have built this very system. If so, do you have any documentation or anything as to your speaker designs? Also, I was looking around on partsexpress for the drivers and they seem to be much more than the stated $300. And I couldn't find a MD2001, is the MD2001S-8 the same thing? Has it been a while since you bought these speakers, or do you have a cheaper place to purchase them? Thanks again for all your help.

Dave
  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
Sound reinforcement 'line arrays' BassAwdyO Multi-Way 21 18th November 2006 12:40 AM
Newbie Q: Amp selection for high power/low Z AtomicDog Pass Labs 12 26th July 2005 09:33 AM
Sound Reinforcement amplifier design Tim Farrant Solid State 1 15th December 2004 12:58 AM
DIY JBL 4 Way Sound Reinforcement Dave Goodhew Multi-Way 16 16th June 2002 03:27 PM
DJ/Sound Reinforcement Subwoofer Type? ogp Subwoofers 15 17th November 2001 01:28 AM


New To Site? Need Help?

All times are GMT. The time now is 03:19 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