Discussion in 'Electronics & Electrics' started by rainwulf, Mar 8, 2009.
haha can't wait.
So what is all this going into?
Ive found the rack-mount cases that Jaycar sell are good for a project of this size.
http://dh.mwp.id.au/audio/2004-06-16 DAC2 (1U)
http://dh.mwp.id.au/audio/2004-09-08 DAC-Amp4 (3U)
The amp will be going into a stained pine cabinet that im also making myself.
Making as much as i can by myself.
Surround enclosures are nearly done, all that is needed is speaker sealant and mounting, and the hole for the speaker wires, and of course surface finish.
How the drivers sit. Nice and snug.
Im going to be air tight sealing them to the enclosure, there is absolutely no resonance with these enclosures, rock solid.
4 done. Cant do the last one, i have run out of speaker cable.
I powered one of them up on my home stereo amp, it packs a punch!
Typically, low bass response, but i expected that. They sound quite nice actually. Cheap driver thats for sure, so one day i might get splits, or better quality drivers.
update, 5 speakers are all finished.
Tomorrow, if i get time, its time to start assembling the amp, and designing the sub enclosure.
Looking forward to pics.
any updates mate its looking good so far
Been a busy lately, but i have painted one of the speakers, and assembled the amplifier modules onto the baseboard.
Painting has been on hold due to the weather we have been having, but hopefully today i can get the rest painted, and the first sand down.
Now the amp modules are assembled, i just have to make the amp enclosure and buy some test loads, and see how it goes.
I had to use the MDF i was planning to use for the sub enclosure for some benches, but thats ok, as it was only 12mm.
Going to buy some thick ass sheets today, 16mm should be fine with internal bracing.
Im going for sealed enclosure, but im going to run the T/S params of the woofer drivers into some software and see if its going to be better building an infinite baffle. I think the Vas is too high though.
44 litre box coming up!
Sounds ghood looking forward to an update.
Lets hope you dont get any ground loop issues, they can be a big PITA to fix.
Aren't those fans noisy?
A couple of big 120mm fans might be better, move more air and are a lot quieter.
I gather there are holes in the wood under the heatsinks to let air move through?
I cant see any under the big black heatsinks though...
Your power supply is way way overkill
Must have had a few nervous moments before turning it on for the first time.
Did the lights in your house dim?
The mounting bolts for the Transformers really should have mains earth attached via a lung. Just in case the insulation breaks down and makes the bolts live
Are the input and out jacks all gonna go through those small holes? Can't see any jacks in you pictures yet. Would there be any chance of the heatsinks scolding the wood?
Input is directly wired from the pc with a triple channel stereo cable.
outputs are at the back, will get some more pics for that.
No chance of the heatsinks burning wood, the chips are hard limited to 135 degrees C, and the sub amp is protected as well, along with a temp sensor mounted on the heatsink.
If the heatsink gets too hot, those fans at the top spin up to full speed, and they will nearly levitate at full speed.
They are 12 volt fans running at about 3.9 volts. You can hardly hear them, and dont hear them at all over any music, and my main pc.
Nice job to bad we can't hear it for ourselves.
I have finished the amp totally now, i just inserted its "brains" which is the timer unit for the amps internals.
Soft turn on, de thump, speaker protection, fan turn on etc.
Its all now controlled in the right sequence, and will also stay off for about 2 seconds if there is any interruption in the power to stave off surges.
I may increase that a bit, see how it goes.
this thread =
VERY impressive build.. keep it up.
are you going to fully doc after build (ie: list full parts / build cost / how much blood you lost / etc ??)
I created a 5 channel amp of my computer a few years back, based on the LM3886, for a tafe project. Every thing on one PCB.
If you use a cap on the mute line, there is no on or off bang, and get the insulated version of the LM3886. I had some "Unpleasantness" with the non insulated version.
I like the gear solution for the volume pots, but when you are running it from a computer its not all that necessary, i had a front channels, front channels balance, rear, rear balance, center and sub, 6 total.
The Sub amp is a 350W kit going to a 12" car sub in a closed box.
The speakers are small hifi ones from various other systems, Pioneer, Kenwood.
With your speakers you should think about adding a tweeter for the high end, and making the sub cutoff as high as you can, 200Hz ??
The kenwood 4 inch is a good single driver solution thou.
My current project is a stereo TriAmp setup, outputting about 500W total, I will take some Photo soon and post them with more info.
Oh for the cooling, you can get Thermal Circuit Breaker from altronics for turning on the fan, or killing the power.