Has anyone built GC into a speaker to make a self powered monitor? - 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 26th September 2003, 01:30 PM   #1
diyAudio Member
 
e.lectronick's Avatar
 
Join Date: Feb 2002
Location: Ocean, NJ
Question Has anyone built GC into a speaker to make a self powered monitor?

Hi,
I've been toying with the idea of making self powered studio monitors for some time, since I heard of the Gainclone, I've been Wondering how small the amp can be made?

The whole cab could be pretty small. It could have an 8" fostex driver. If you needed a heatsink, you could have the whole amp mounted inside the back panel (like some crossovers are) with the heatsink integrated into it and coming out the other side.
Of course it'd have to be shielded, or use a shielded speaker.

If you're worried about long line level runs picking up noise, you could build a balanced GC and use XLR inputs for a really pro setup.

By the way, has anyone attempted a GC at +4 dBu line level?

Just some musings. I might try it once I have a good homebrew speaker cab. I'm working on that one now.

-Erik.

P.S. I just thought I'd edit this piece and add the idea that this would be the ultimate in keeping with short lead lengths the GC likes in order to sound good. It would only be inches from the speaker driver. Very little signal loss. And there's the benefit of being able to tweak the amp and speaker response together so they are matched well. Some kind of built in eq filters perhaps to account for any dips or peaks in signal response of the driver in that particular enclosure.
Lastly, the use of a Fostex driver like the FE206E or FE207E (shielded) eliminates the need for a crossover as they are relatively cheap good sounding full range drivers. Again, more clutter out of the signal path for the ultimate fidelity.
__________________
-Who put the Tribbles in the Quadrotriticale?
  Reply With Quote
Old 26th September 2003, 01:42 PM   #2
JCoffey is offline JCoffey  United States
diyAudio Member
 
Join Date: May 2003
Location: Atlanta, GA
Its been done. In fact you can get Alesis amps from www.apexjr.com for $50 each wit a LM3886 chip driving the woofer and a LM2976 chip for the tweeter.
Attached Images
File Type: jpg alesis.jpg (62.0 KB, 901 views)
  Reply With Quote
Old 26th September 2003, 01:46 PM   #3
diyAudio Member
 
e.lectronick's Avatar
 
Join Date: Feb 2002
Location: Ocean, NJ
Question Do they sound as good as the homebrew GC?

Yeah, but are they using the GC circuit? I thought that commercial use of the design would be forbidden since it's so close to the original Gain Card, no?

It's a neat little amp unit. Looking at the pic, I'm really impressed with how small it is.

I can't help but think that a homebrew unit could be made custom to suit the driver and cabinet and thus sound better.

Thanks for the link!

-Erik.
__________________
-Who put the Tribbles in the Quadrotriticale?
  Reply With Quote
Old 26th September 2003, 02:20 PM   #4
diyAudio Member
 
JOE DIRT®'s Avatar
 
Join Date: Apr 2003
Location: Brantford, ON
I have a gc running my computer speakers but its inside my case.
I was fortunate enough to have the room because it is a server tower.....I would have built the amps into the speakers otherwise

DIRT®
  Reply With Quote
Old 26th September 2003, 02:25 PM   #5
Banned
 
Join Date: Nov 2002
Location: Adelaide, Australia
Send a message via MSN to SkinnyBoy
take in one step further... amps in the speaker boxes, and the powersupply external.. or was that the idea in the first place? lol

EDIT:
actually... thats not such a bad idea... perhaps I should do it for my towers... I was gunna have to make an amp anyway... but if all I have to make a box for is a couple of transformers, it simplifies things quite abit.. and the amp shouldn't displace much space in the boxes at all, cos the heatsink would be external, and the rest would fit in the thinkness of the MDF pretty much... hmm.. it also simplifies Bi or Tri amping quite abit... hmm hmm... worth a try do you guys think? hehe
  Reply With Quote
Old 26th September 2003, 02:53 PM   #6
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
I tried GC with long cables and the very short ones and didn't notice any difference, really. But, if the drivers and crossovers are not chosen properly, the degradation of sound will be substantial. The way you mount the whole GC module inside the speaker (and possible vibrational influence) will have much bigger impact on the sound than the advanatge achieved with using short speaker cables. Although it may seem weird, the closer the PS to the amp, the better. PS wires influence the sound the same way as speaker wires

>>Yeah, but are they using the GC circuit? I thought that commercial use of the design would be forbidden since it's so close to the original Gain Card, no?<<

This is not a proprietary design, but comes out of National's application notes, so anybody is free to use it, without infringing any copy rights and patents. The only issue may be with a similar case design, but even here, it's still questionable.
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 26th September 2003, 03:39 PM   #7
ronc is offline ronc  United States
diyAudio Member
 
Join Date: Mar 2003
And you thought you had vibration problems before?
I am trying to see the advantages to this set up. It will regardless still take long leads from a pre or some sort of controlling unit.I believe any advantages would be lost in the greater vibration unless some sort of super isolaton method could be developed.
OK lets look at some methods.
Either an IR or RF controller.RF would be better.It would take a dual P/S.Or make the whole thing RF controlled with a central transmitter with the sources going into it and have the output of the central transmitting to 2 recievers(each channel) that way no wires.But then you would be subject to stray RF signals.
ron
OK as an after thought an optical cable?I have used them in the past but strictly as a low state/high state controller, i have no idea as to how well they would transmit an analog signal.
  Reply With Quote
Old 26th September 2003, 05:56 PM   #8
diyAudio Member
 
e.lectronick's Avatar
 
Join Date: Feb 2002
Location: Ocean, NJ
Default It must work or it wouldn't've been done before, right?

Quote:
Originally posted by ron clarke
And you thought you had vibration problems before?
I am trying to see the advantages to this set up. It will regardless still take long leads from a pre or some sort of controlling unit.I believe any advantages would be lost in the greater vibration unless some sort of super isolaton method could be developed.
OK lets look at some methods.
Either an IR or RF controller.RF would be better.It would take a dual P/S.Or make the whole thing RF controlled with a central transmitter with the sources going into it and have the output of the central transmitting to 2 recievers(each channel) that way no wires.But then you would be subject to stray RF signals.
ron
OK as an after thought an optical cable?I have used them in the past but strictly as a low state/high state controller, i have no idea as to how well they would transmit an analog signal.


Wow.
That's some pretty hardcore engineering. None of that was necessary for the Alesis.

Is all the isolation necessary because of the Gainclone's sensitivity to vibration in particular? Or is any amp going to be this way?

It begs the question how did Alesis achieve a working amplifier as depicted in JCoffey's post -second from the top?

I had envisioned a high output current balanced preamp or a distribution amplifier as the device which would drive the line to the powered monitor. That would be consistent with a pro studio setup.
__________________
-Who put the Tribbles in the Quadrotriticale?
  Reply With Quote
Old 26th September 2003, 06:20 PM   #9
usekgb is offline usekgb  United States
diyAudio Member
 
usekgb's Avatar
 
Join Date: Feb 2003
Location: Salt Lake City, UT, USA
The Alesis M1 amp boards really don't sound that great. They don't have much punch, and the sound stage and depth of field is lacking. If you want to check out a better implementation of the "chip amp in a monitor," check out the JBL JSR25P's. They use a single LM3886 for the tweeter, and two LM3886's for the woofer. They sound much better than the Alesis amps and the circuitry is much simpler. here is a link to the schematics:

http://www.jblproservice.com/pdf/LSR...ies/LSR25P.pdf

I hope this helps.

Cheers,
Zach
  Reply With Quote
Old 26th September 2003, 06:26 PM   #10
diyAudio Member
 
e.lectronick's Avatar
 
Join Date: Feb 2002
Location: Ocean, NJ
Default JBL/Alesis: What isolation?

OK, so I've looked at the JBL and the Alesis Schematics, now, and I don't see any super duper isolation techniques implemented, and no optical cable interface or the like. Just your standard fare: solidly mounted, XLR connected goodness.

So, why all the concerns with vibration etc...?

Am I missing something? These are chip amps just like the GC circuit.

-Erik.
__________________
-Who put the Tribbles in the Quadrotriticale?
  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
Hafler Powered Studio Monitor rwb_music Solid State 5 5th March 2008 09:38 PM
USB powered NOS USB DAC with built-in headphone amp dsavitsk Digital Source 15 10th August 2006 07:11 AM
Line array for HT with built in powered woofs elambert Multi-Way 0 27th April 2005 02:44 PM
Built my battery powered headphone amp. mig-ru Headphone Systems 0 5th March 2004 12:43 AM


New To Site? Need Help?

All times are GMT. The time now is 01:27 PM.


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