Micro-Sized Subwoofer Plate Amp Idea...

[tomzarbo]

So after reading the micro-subwoofer thread from a few days ago, I got to thinking about a smaller micro-sized sub plate amp that I mentioned that doesn't exist.

I spent a few hours putting this together on a whim; it's roughly to scale-just enough to make sure things would fit. I realize that the sub section of this amp should only be used with 8 ohm bass drivers, but there are several small ones (or two 4 ohm units) that would fit the bill for something that could be considered "micro" sized. The fact that this amp also has the ability to output the L & R channels for satellite speakers is just a plus.



So, laugh if you want to... it's kind of a goofy idea I admit, but I may spend $30 and give it a go just for fun. I have lots of LED's w/resistors, several 12/v power bricks and a few 8 ohm drivers on the small side that would work with something like this. As long as the heat doesn't build up inside too much, I think it may work out okay. a bit of 1/8" sheet alum and I'm on my way! Feel free to mock and degrade to your heart's content... oh, and constructive help/ideas are also welcome. Micro-B

TomZ

[bullittstang]

Re: Micro-Sized Subwoofer Plate Amp Idea...

+1 for the idea, as I thought about something similar. I have no where close to the ability to design what you did, nor am I that creative.

Please make a thread and let us know how it goes. I am certainly interested in something exactly like this!

[Wolf]

Re: Micro-Sized Subwoofer Plate Amp Idea...

So after reading the micro-subwoofer thread from a few days ago, I got to thinking about a smaller micro-sized sub plate amp that I mentioned that doesn't exist.

I spent a few hours putting this together on a whim; it's roughly to scale-just enough to make sure things would fit. I realize that the sub section of this amp should only be used with 8 ohm bass drivers, but there are several small ones (or two 4 ohm units) that would fit the bill for something that could be considered "micro" sized. The fact that this amp also has the ability to output the L & R channels for satellite speakers is just a plus.



So, laugh if you want to... it's kind of a goofy idea I admit, but I may spend $30 and give it a go just for fun. I have lots of LED's w/resistors, several 12/v power bricks and a few 8 ohm drivers on the small side that would work with something like this. As long as the heat doesn't build up inside too much, I think it may work out okay. a bit of 1/8" sheet alum and I'm on my way! Feel free to mock and degrade to your heart's content... oh, and constructive help/ideas are also welcome.

TomZ

How does the sub volume work on that board? I didn't know it was adjustable. Is it the jumpers?
Later,
Wolf

[tomzarbo]

Re: Micro-Sized Subwoofer Plate Amp Idea...

How does the sub volume work on that board? I didn't know it was adjustable. Is it the jumpers?
Later,
Wolf

Yes, I think it hooks up to where the jumper would be:

"There is an optional 2-pin connector for adding a standby feature, and a 3-pin connector with included jumper for regulating the bass volume (wiring harnesses not included). Add a 50k potentiometer (sold separately) to the 3-pin terminal to control the subwoofer channel's volume separately from the master volume control. When the jumper is placed between the middle and right pins, the subwoofer channel is controlled by the master volume. And when the jumper is placed between the middle and left pins, the subwoofer channel is shut off."

...But I'm not sure, I'll report back on how it hooks up when I figure it out.

TomZ

[arrayed]

Re: Micro-Sized Subwoofer Plate Amp Idea...

I wondered about those pins on mine... good discovery. Curious how that turns out.

I like your sketch up, but you labeled the outputs as left outputs on both channels. Also, you can go 12v, but I recommend more. I went 16v and it works great, no issues. here is a link to a power supply like he one I used:

http://www.amazon.com/Replacement-Ad.../dp/B003QNWSQ2

8$ and free shipping is tough to beat.

Definitely micro! Good job. I think, for desktop use, it really is a great little amp so far.

[Lutkeveld]

[Mike b]

Re: Micro-Sized Subwoofer Plate Amp Idea...

Something like this for the plate.....http://www.parts-express.com/dayton-...ProductDetails

[tomzarbo]

Re: Micro-Sized Subwoofer Plate Amp Idea...

I wondered about those pins on mine... good discovery. Curious how that turns out.

I like your sketch up, but you labeled the outputs as left outputs on both channels. Also, you can go 12v, but I recommend more. I went 16v and it works great, no issues. here is a link to a power supply like he one I used:

http://www.amazon.com/Replacement-Ad.../dp/B003QNWSQ2

8$ and free shipping is tough to beat.

Definitely micro! Good job. I think, for desktop use, it really is a great little amp so far.

Yeah, I saw that goof. I have two left feet, but I still prefer a L and R output on my speakers. I'll fix it as time goes on a bit and more ideas are generated.
16v works good? I hesitated to go the full 18V but 16 should generate more output like you said, and that's a good price on the power brick! Depending on the PS used, I'll adjust the power jack size to match what's most commonly used... 2.1mm vs. 2.5mm.

What subwoofer driver are you using with it? Did you go 8 ohms or 4 and how is the output?

Thanks for the input.

TomZ

[tomzarbo]

Re: Micro-Sized Subwoofer Plate Amp Idea...

Something like this for the plate.....http://www.parts-express.com/dayton-...ProductDetails

Perfect! I was thinking there must be some kind of wall plate or something that would be thick enough to hold up... that will fit the bill nicely, it's the perfect size... and it even has the gasket tape on it already!

[john trials]

Re: Micro-Sized Subwoofer Plate Amp Idea...

Mock and degrade this idea? I was thinking you should go into production with it. Sounds like a nice little product. I am definitely interested in how this goes together (please add build photos), and how it sounds.

Also, Erse Audio has blank terminal plates. 3x5" and 5x7". ABS

http://www.erseaudio.com/Products/TerminalCups

[Gordy]

Re: Micro-Sized Subwoofer Plate Amp Idea...

I have used the metal blank dishes on builds and they work very well. Very tedious to drill larger holes without scratching the surface. You have to use the right drill bits and speed. One thing to take into consideration is power and signal.

On the metal plate you will have 12v ground and the ground of the pots connected. This could and will probably give some feedback and create a ground loop. I used to use the PE 3.5mm line-in but use an insulated one now - Philmore 75-534. Cleaner appearence and no ground loop issues. I really like the 3x5 abs plastic plate. I have been looking for these for a long long time. Thanks John. This would solve the ground loop issue.

I think this is a great idea. It would not be hard to find a decent quality 50K mini pot. Also it looks like the white plugs are possibly JST connectors. You can find pigtails for these 2-3-4 wire all over eBay. I know the sub crosses at 150 but is there a way to possibly cross the signal input with something like an FMOD or is this just a bad idea?

I really think you are on to something. This might work well with 4" woofer. Yeah maybe not a true subwoofer but could be a dedicated low end driver to fill in. Since I only think bomb box thoughts a sealed set up for 2 3" full range drivers and ported for a the woofer. it would keep the box size down and be a pretty neat little set up.

[djg]

Re: Micro-Sized Subwoofer Plate Amp Idea...

Plastic sheet would be much easier to work.

[Kevin K.]

Re: Micro-Sized Subwoofer Plate Amp Idea...

Tom, if you could give me a drawing with dimensions for where you want all of the holes I could CNC cut some of these plates for you out of ABS. We carry ABS here at my shop and have plenty of scraps that are not big enough for us to do anything with, but would be more than big enough for these plates. Even if you decide you want to do these out of some other material, you could at least proof out your design this way.

[tomzarbo]

Re: Micro-Sized Subwoofer Plate Amp Idea...

Mock and degrade this idea? I was thinking you should go into production with it. Sounds like a nice little product. I am definitely interested in how this goes together (please add build photos), and how it sounds.

Also, Erse Audio has blank terminal plates. 3x5" and 5x7". ABS

http://www.erseaudio.com/Products/TerminalCups

Thanks for the link John. I'm just concerned though with the real estate they take up. At 1" thick they use up some space. A normal plate amp can deduct the volume taken up by the panel cut-out before adding any components...I was hoping for about a net zero gain/loss of internal volume with 1/2" material. I'll think about those terminal plates, it would make things easier.

I have used the metal blank dishes on builds and they work very well. Very tedious to drill larger holes without scratching the surface. You have to use the right drill bits and speed. One thing to take into consideration is power and signal.

On the metal plate you will have 12v ground and the ground of the pots connected. This could and will probably give some feedback and create a ground loop. I used to use the PE 3.5mm line-in but use an insulated one now - Philmore 75-534. Cleaner appearence and no ground loop issues. I really like the 3x5 abs plastic plate. I have been looking for these for a long long time. Thanks John. This would solve the ground loop issue.

I think this is a great idea. It would not be hard to find a decent quality 50K mini pot. Also it looks like the white plugs are possibly JST connectors. You can find pigtails for these 2-3-4 wire all over eBay. I know the sub crosses at 150 but is there a way to possibly cross the signal input with something like an FMOD or is this just a bad idea?

I really think you are on to something. This might work well with 4" woofer. Yeah maybe not a true subwoofer but could be a dedicated low end driver to fill in. Since I only think bomb box thoughts a sealed set up for 2 3" full range drivers and ported for a the woofer. it would keep the box size down and be a pretty neat little set up.

Plastic sheet would be much easier to work.

Tom, if you could give me a drawing with dimensions for where you want all of the holes I could CNC cut some of these plates for you out of ABS. We carry ABS here at my shop and have plenty of scraps that are not big enough for us to do anything with, but would be more than big enough for these plates. Even if you decide you want to do these out of some other material, you could at least proof out your design this way.

Gordy, thanks for your input. I was thinking about issues with signal as components connect through the common chassis. The speaker terminals should be okay, but the power input and the 1/8" signal input jack will both mount to metal as you mentioned, which could be an issue. Once I start messing around with this, I'll have a look at the connectors you mentioned.

DJG and Kevin, I see that plastic will be much easier to work with due to being non-conductive. I have a thing for brushed aluminum, I think it's good looking stuff and very stiff, but I'm not married to the idea if it means a lot of problems elsewhere with signal issues.

Thanks for the offer Kevin. Let me ask you... Do you think common 1/8" stuff would be thick enough to resist vibration in a sealed enclosure that may have as much as a 5 or 6" subwoofer in it?

PE carries this stuff: http://www.parts-express.com/abs-tex...-x-24--265-948
Looking at some of the reviews it seems some have used it to mount speakers in with decent success. It looks pretty nice as well with the texture on it. It also could be doubled up, possibly one sheet 4" x 4" and another 3" x 3" sheet on the inside of that epoxied/superglued together -- just thinking out loud.

Thanks for the input, guys.

I'll keep you posted.

TomZ

[Kevin K.]

Re: Micro-Sized Subwoofer Plate Amp Idea...

Tom, I think you make a good point on the plastic thickness, not sure 1/8" would be thick enough. I have some 3/16" here, and if that's still not thick enough, I could glue two pieces of it together for a total of 3/8". If you decide you want me to cut something, just send me a PM with a sketch up of your desired dimensions. You could sketch it on a piece of paper and take a photo of it, I wont need anything fancy.

I was looking at your concept again and you may need an additional part to help support the amp board. I don't know how strong the volume knob is, but that looks like your only means of support for the board.