Subwoofer amp: 2 plates or a professional 2 channel unit - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 29th November 2015, 01:56 AM   #1
Egindin is offline Egindin  United States
diyAudio Member
 
Join Date: Jan 2005
Location: Los Angeles
Default Subwoofer amp: 2 plates or a professional 2 channel unit

I'm going to use two subs. Now, I could go with two plate amps built in each sub, or I could use an external, professional 2 channel amp. I noticed that there's a ton of used professional 2 ch amps, notably by QSC, that sell on ebay for not much money. Those were used for PA's and such. I don't need much in terms of controls as I'm going to use external Richter scale equalizer. So, question for folks with experience - which is better?

Last edited by Egindin; 29th November 2015 at 01:59 AM.
  Reply With Quote
Old 29th November 2015, 02:14 AM   #2
diyAudio Member
 
Join Date: Jan 2008
Having two separate amps is better in terms of "fail safe" operation.
QSC makes some good amps and some amps that don't perform well for sub use, plate amps go from crap to very good examples like those from SpeakerPower. Brian Oppegaard, president of SpeakerPower spent 11 years as Director of Engineering at QSC Audio Products.
  Reply With Quote
Old 29th November 2015, 02:29 AM   #3
Egindin is offline Egindin  United States
diyAudio Member
 
Join Date: Jan 2005
Location: Los Angeles
Quote:
Originally Posted by weltersys View Post
Having two separate amps is better in terms of "fail safe" operation.
QSC makes some good amps and some amps that don't perform well for sub use, plate amps go from crap to very good examples like those from SpeakerPower. Brian Oppegaard, president of SpeakerPower spent 11 years as Director of Engineering at QSC Audio Products.
In the past, I used Dayton Audio plate amps with good results. But now that I got the Richter scale, I don't need all the controls and equalization. Plus Daytons rarely come used and the new ones cost about $265 a pop. QSC's looked pretty good and simple so I'm tempted... Speaking of good vs amps that don't perform well, which QSC model would you recommend for home subwoofer application?
  Reply With Quote
Old 29th November 2015, 10:05 AM   #4
diyAudio Member
 
RobWells's Avatar
 
Join Date: Aug 2002
Location: UK
One thing to consider is the noise from the QSCs cooling fans. I use 4 QSC RMX series amps and they are far too loud to have in the listening room. (Also if you consider used amps check the gain pots haven't gone scratchy - all of mine have)
  Reply With Quote
Old 29th November 2015, 12:09 PM   #5
diyAudio Member
 
chris661's Avatar
 
Join Date: Feb 2008
Location: Sheffield
That's a problem specific to the RMX line. So far as I know, none of their other amps suffer from the same problem.

I use a QSC USA-850 for my home stereo, which is an install amp, class AB with 425w/ch@4ohm, will drive 2ohm for slightly more power, or 8ohm for half the 4ohm rating. Bridgable for more voltage swing.
Fan isn't particularly loud, but can go into hairdryer mode if you bridge it into a low impedance and then hammer away for a while.


I'd consider either an old Crown/Crest/QSC amp, or one of Behringer's iNuke amps if you're willing to change the fan - there's a lot of cheap power there.

Chris
  Reply With Quote
Old 29th November 2015, 03:48 PM   #6
Egindin is offline Egindin  United States
diyAudio Member
 
Join Date: Jan 2005
Location: Los Angeles
Quote:
Originally Posted by RobWells View Post
One thing to consider is the noise from the QSCs cooling fans. I use 4 QSC RMX series amps and they are far too loud to have in the listening room. (Also if you consider used amps check the gain pots haven't gone scratchy - all of mine have)
What about replacing noisy fans with quiet computer grade ones? And I would remove all gain pots altogether - just the power! All controls would be effected from Richter scale.
  Reply With Quote
Old 29th November 2015, 06:34 PM   #7
diyAudio Member
 
chris661's Avatar
 
Join Date: Feb 2008
Location: Sheffield
You really want to keep the gain pots. RMX amps do very well on resale. Removing the pots will give the amp exactly two settings: off, or full-power. Useless for troubleshooting things or if you ever want to connect another source, and will also kill the resale value almost entirely.

You can replace the fan quite comfortably without any problem. Just check operating voltages - it might be a 24v fan.

Chris
  Reply With Quote
Old 30th November 2015, 04:58 AM   #8
Egindin is offline Egindin  United States
diyAudio Member
 
Join Date: Jan 2005
Location: Los Angeles
Quote:
Originally Posted by chris661 View Post
You really want to keep the gain pots. RMX amps do very well on resale. Removing the pots will give the amp exactly two settings: off, or full-power. Useless for troubleshooting things or if you ever want to connect another source, and will also kill the resale value almost entirely.

You can replace the fan quite comfortably without any problem. Just check operating voltages - it might be a 24v fan.

Chris
What you said about the gain pots makes good sense. After all I can always have them all the way up. Thanks.
  Reply With Quote
Old 30th November 2015, 05:13 PM   #9
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by Egindin View Post
What you said about the gain pots makes good sense. After all I can always have them all the way up. Thanks.
Or turn them down to optimize system signal to noise ratio.
  Reply With Quote
Old 30th November 2015, 06:46 PM   #10
Egindin is offline Egindin  United States
diyAudio Member
 
Join Date: Jan 2005
Location: Los Angeles
Quote:
Originally Posted by chris661 View Post
That's a problem specific to the RMX line. So far as I know, none of their other amps suffer from the same problem.

I use a QSC USA-850 for my home stereo, which is an install amp, class AB with 425w/ch@4ohm, will drive 2ohm for slightly more power, or 8ohm for half the 4ohm rating. Bridgable for more voltage swing.
Fan isn't particularly loud, but can go into hairdryer mode if you bridge it into a low impedance and then hammer away for a while.


I'd consider either an old Crown/Crest/QSC amp, or one of Behringer's iNuke amps if you're willing to change the fan - there's a lot of cheap power there.

Chris
Thanks again. I just saw fully refurbished QSC USA-900 being offered on ebay for 99.99 right here in so. Cal. Maybe it's my lucky day...
  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
MetroSound Professional Hornloaded Subwoofer Designs DemoMan Subwoofers 47 4th June 2015 02:57 PM
Amplifier terminal plates (rear plates) source? JonesySA Parts 0 8th November 2014 07:26 AM
Professional subwoofer manoli337 Subwoofers 96 20th September 2014 03:59 PM
LM3885 BPA200 200W Mono Subwoofer or Stereo Amp ASSEMBLED & TESTED w/heatsink! Travis Clarke Swap Meet 8 21st November 2010 05:52 PM
Using a subwoofer with a stereo amp Jmater Subwoofers 5 25th September 2007 03:46 PM


New To Site? Need Help?

All times are GMT. The time now is 11:58 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki