Jennifer:
The last Gainclone I worked on was a project with my younger daughter. The chassis was a HiFi2000 Galaxy model (2U, 230mm wide by 280mm deep). The diyAudio store sells them. If I were to do it again, I'd consider a larger chassis and reserve space for a buffer or preamp; as it turned out, this chassis was just large enough for a set of chipamp.com LM3886 and power supply boards, a 300 VA toroid, an extra power supply for the LEDs, a board to handle source selection and a passive preamp. See post #1258: http://www.diyaudio.com/forums/chip-amps/79303-chip-amp-photo-gallery-63.html
Regards,
Scott
The last Gainclone I worked on was a project with my younger daughter. The chassis was a HiFi2000 Galaxy model (2U, 230mm wide by 280mm deep). The diyAudio store sells them. If I were to do it again, I'd consider a larger chassis and reserve space for a buffer or preamp; as it turned out, this chassis was just large enough for a set of chipamp.com LM3886 and power supply boards, a 300 VA toroid, an extra power supply for the LEDs, a board to handle source selection and a passive preamp. See post #1258: http://www.diyaudio.com/forums/chip-amps/79303-chip-amp-photo-gallery-63.html
Regards,
Scott
Custom Aluminum Bar Amp Enclosure
Hi, I drew up in OpenSCAD an amp design. My brother is a machinist and can buy a 6 foot long bar of 3/8" thick aluminum at a good price and cut it into 4 pieces for me.
17" long faceplate with rounded corners (5mm radius)
16 1/2" long backplate (square corners)
11.25" sides (square corners)
Assembled depth is 12"
He hasn't yet made the cuts, nor ordered the aluminum bar yet. $65 for the bar.
It's for an LM3886 amp and will be using the backplate as the heat sink with ventilation holes above it.
Here's a screenshot, what do you think?
My question for you guys is: What would be the best affordable way to add a bottom to this amplifier I've started on. Should I just put a piece of solid wood in there and screw in from sides and back? Or maybe screw a support block into each of the 4 corners and sit a metal plate on top of those four blocks?
Or could have him route (mill) out a dado on the insides of all 4 pieces and slide in a plate then screw the backplate on after that.
Need some ideas thanks! I'll worry about the top at some later date.
Hi, I drew up in OpenSCAD an amp design. My brother is a machinist and can buy a 6 foot long bar of 3/8" thick aluminum at a good price and cut it into 4 pieces for me.
17" long faceplate with rounded corners (5mm radius)
16 1/2" long backplate (square corners)
11.25" sides (square corners)
Assembled depth is 12"
He hasn't yet made the cuts, nor ordered the aluminum bar yet. $65 for the bar.
It's for an LM3886 amp and will be using the backplate as the heat sink with ventilation holes above it.
Here's a screenshot, what do you think?
An externally hosted image should be here but it was not working when we last tested it.
My question for you guys is: What would be the best affordable way to add a bottom to this amplifier I've started on. Should I just put a piece of solid wood in there and screw in from sides and back? Or maybe screw a support block into each of the 4 corners and sit a metal plate on top of those four blocks?
Or could have him route (mill) out a dado on the insides of all 4 pieces and slide in a plate then screw the backplate on after that.
Need some ideas thanks! I'll worry about the top at some later date.
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Not wood on that cool heavy build cabinet.
At least a rectangular floor made out of 1.5mm aluminum (~1/16" for you Imperial heathens ) ; it will also add rigidity to your frame , turning it into a box.
Easiest is making it the external size of the frame, and using countersunk head screws (~3 to 4 mm) to bolt it all around (at least 2 or 3 screws per side, so 8 to 12 total, even better if you add a few more) and screw them into the wall thickness, which is ample.
Or you can bend lips around that floor, in that case you can bolt to walls, screws will still be invisible from outside, or go through frame walls and screw or rivet them together.
At least a rectangular floor made out of 1.5mm aluminum (~1/16" for you Imperial heathens
) ; it will also add rigidity to your frame , turning it into a box.Easiest is making it the external size of the frame, and using countersunk head screws (~3 to 4 mm) to bolt it all around (at least 2 or 3 screws per side, so 8 to 12 total, even better if you add a few more) and screw them into the wall thickness, which is ample.
Or you can bend lips around that floor, in that case you can bolt to walls, screws will still be invisible from outside, or go through frame walls and screw or rivet them together.
Google: Metal Supermarkets Might be one in your area? affordable and a good place to buy metal (retail) they even do Online sales.
You can buy sheet cut to shape a 16 ga ali would make for good top and bottom.. maybe 15 /20$.. cut to size (free).
That bar stock piece likely to be 20/30$... Should you want it.
You can buy sheet cut to shape a 16 ga ali would make for good top and bottom.. maybe 15 /20$.. cut to size (free).
That bar stock piece likely to be 20/30$... Should you want it.
If you are going to make the effort to machine the whole case out of billet, it would be a travesty to stop short and not finish it nicely.
Your suggestion to have a dado milled out is the way I would go. You can easily have a plate burned with ventilation slots that will fit in the relief perfectly and will complement your case nicely.
You are going to have the front and back switch, power and connector locations machined, so the small added effort to program and mill the top and bottom covers relieves is incidental.
My 2c anyway.
Your suggestion to have a dado milled out is the way I would go. You can easily have a plate burned with ventilation slots that will fit in the relief perfectly and will complement your case nicely.
You are going to have the front and back switch, power and connector locations machined, so the small added effort to program and mill the top and bottom covers relieves is incidental.
My 2c anyway.
Many possibilities to make it unique. No point leaving it plain and boring.
I agree about the dado, or possible recess the inside edges so the top fits into the remaining space.
Run some groves along the sides and front matching up at the corners, coinciding with the buttons etc. Carve your initials on the front etc.
I would love to have the facilities do do work like this.
I agree about the dado, or possible recess the inside edges so the top fits into the remaining space.
Run some groves along the sides and front matching up at the corners, coinciding with the buttons etc. Carve your initials on the front etc.
I would love to have the facilities do do work like this.
Dissipante 3U for LM3886 amp?
I am thinking about the following chassis for amp, just to make things easy:
Dissipante 3U – diyAudio Store (BETA)
I'd get their baseplate as well for the extra $12.
This case has heatsinks on each side but I'd like to keep the AC part of the amp far away from the LM3886 boards.
So would it make sense to put the 300VA antek in the front left corner and BOTH of the channels of the LM3886 on the back right side, together? -- they'd be sharing the same heatsink. The left heat sink wouldn't be used for anything but I guess I don't really care... the AC power lines would be far away from the LM3886.
I could also build an internal compartment to separate the antek from the dc supply (front left of case) and the amp boards. I could even build a compartment for the dc supply if that would help.
Well let me know what ya think thanks!
I am thinking about the following chassis for amp, just to make things easy:
Dissipante 3U – diyAudio Store (BETA)
I'd get their baseplate as well for the extra $12.
This case has heatsinks on each side but I'd like to keep the AC part of the amp far away from the LM3886 boards.
So would it make sense to put the 300VA antek in the front left corner and BOTH of the channels of the LM3886 on the back right side, together? -- they'd be sharing the same heatsink. The left heat sink wouldn't be used for anything but I guess I don't really care... the AC power lines would be far away from the LM3886.
I could also build an internal compartment to separate the antek from the dc supply (front left of case) and the amp boards. I could even build a compartment for the dc supply if that would help.
Well let me know what ya think thanks!
Toroids are not really a problem in close proximity as long as you don't allow them to saturate. Lead dress and proper internal layout are what is important. I'd place the toroid front/middle and the amps one on each sink with rectifiers and capacitors behind the transformer and away from the amps. Short direct wiring from the filter caps to the amps. Input wiring far away from the transformer and rectifier. Primary AC wiring can be enclosed in metal tubing (commonly done in the tube era) to avoid electrostatic coupling to nearby circuitry. Make sure chassis is connected to safety earth ground.
Does it matter if the metal screening/shielding tube touches the chassis along it's length?
I know that a drain wire touching the braided screen/shield ruins the shielding and should never be used.
Just want to update this thread and say that I've finished my LM3886 amplifier. All the details with lots of photos in the following thread:
http://www.diyaudio.com/forums/chip-amps/291371-flea-market-bargain-enclosure-my-lm3886.html
http://www.diyaudio.com/forums/chip-amps/291371-flea-market-bargain-enclosure-my-lm3886.html
Some photos (which appear in the above linked thread):
Above case was reclaimed from a 1980's commercial tape player (vent was printed on 3d printer) :
Before DC supply and speaker wire upgrade:
3D Printed Feet:
AC Inlet Label (still need to make a back label for the rest -- rca's and speaker outs) :
An externally hosted image should be here but it was not working when we last tested it.
Above case was reclaimed from a 1980's commercial tape player (vent was printed on 3d printer) :
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Before DC supply and speaker wire upgrade:
An externally hosted image should be here but it was not working when we last tested it.
3D Printed Feet:
An externally hosted image should be here but it was not working when we last tested it.
AC Inlet Label (still need to make a back label for the rest -- rca's and speaker outs) :
An externally hosted image should be here but it was not working when we last tested it.
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Thanks AndrewT, only because you've helped me so much along the way!
I really appreciate it! And the help from everyone else as well.By the way I hear no noise whatsoever now, with the volume turned up all the way and ear next to the tweeter. It was the FIIO D3 V1 DAC I was using before I upgraded to the SMSL M8. So that noise I thought might of been coming from the amplifier was really just from the old DAC -- although it wasn't really bad because that was only at max amp volume with ear 2 inches away from tweeter, and I play at about 1/2 that.
Good news I guess I don't need to try and isolate/shield things anymore inside the case? e.g. a plate between the amp boards and the dc supply board.
Good news
I guess I don't need to try and isolate/shield things anymore inside the case? e.g. a plate between the amp boards and the dc supply board.- Status
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