Micro-B

2.1 Subwoofer Plate Amplifier

designed by Thomas Zarbo, Jr.

Construction videos:

Assembly Instructions:

For anyone who’s interested in possibly building this or are just curious about it, there are links in my signature to 5 videos that I made detailing its construction. There is also a clickable link to the PDF instruction/template packet that describes every aspect of construction in great detail.

It takes me about 2.5-3 hours to build one, but I’m a bit more familiar with it since I’ve put a bunch of these together by now.

Pros:

Good power to 4 ohm speakers/subwoofer… it gets loud enough to be almost too loud.
Distorts gracefully, doesn’t really make any nasty noises.
Super-small form factor, it fits in Jeff Bagby’s tiny “Quark” speakers with no problem.
The bass section is loud enough to match up with the mains in most situations, it powers a Paul Carmody “Voxel” subwoofer just fine.
It takes up no desk/table space and can be completely hidden from view.
Doesn’t get warm, even playing at close to full volume with all 4 ohm speakers. (with a 16V 4.5 amp PS)
It’s fairly inexpensive for what you get.
There are SUPER-detailed instructions in the PDF in my signature…

Cons:

It’s susceptible to noise, although those issues have been largely mitigated.
The low-pass crossover is a bit too high for my tastes, I’m guessing it’s in the 120 to 150 Hz range, I wish it was around 70-80 Hz or so.
A few of the components are easy to destroy during assembly, but I warn you about what’s fragile in the videos.
I wish the sub section was just a smidge more powerful, like maybe 20% more. I’m a bass-head though, and this can be mitigated by using 8 ohm speakers with a sub.

Here is a link to the thread outlining the original idea: http://techtalk.parts-express.com/sh…Plate-Amp-Idea. I kind of abandoned it as I got involved in designing and building it, I’m sorry about that. Hopefully this thread makes up for my lack of continuity… and I’m hoping that doing a search for “Micro-B” will finally bring this project up, I couldn’t even find it before now!
I’d love it if you’d post up some pics if you build it… It would be great to get some feedback from others on what you think of it.

Here is an up to date list of the parts needed to build it as of February 2016.

Amplifier, 2.1 mini hi-fi: #320-608 (1)
Binding Post Plate, black anodized: #091-602, or silver anodized: #091-600 (1)
Panel DC power Jack 2.5×5.5mm: #090-5018 (1)
3.5mm Stereo panel mount jack: #090-317 (1) …but I would purchase (2)
SPST Mini Toggle Switch: #060-526 (1) …but I would purchase (2)
Dual Binding Post: #090-475 (2)
10K Audio Taper Potentiometer: #023-610 (1)
Marshall Type Guitar / Amplifier Knob, Gold: #240-2208 or Silver: #240-2206 (2)

These are items that many of us would probably already have, but I’ll list them just for reference:

Super-Bright LED w/resist 10 ct.: #073-118 (1)
Wire, black, 24 Gauge: #101-710 (1)
Wire, red, 24 Gauge: #101-712 (1)
Wire, green, 24 Gauge: #101-715 (1)
Wire, white, 24 Gauge: #101-719 (1)
Wire, blue, 24 Gauge: #101-716 (1)
Wire, yellow, 24 Gauge: #101-714 (1)
Zip Speaker Wire, 18 ga.: #100-050 (2 ft)
Heat Shrink Tubing kit: #080-726 (1)

TomZ