Search This Blog

Saturday, 12 May 2018

#28 Active full-range surround speaker project (BN96-12832 & TPA3118)

Since the "unofficial" theme of this blog seems to be repair, recycling and repurposing (more or less), i finally got around to getting knee-deep into this idea, which i started devising quite a while ago - a pair of "slimline" surround speakers.

 - No, these are not meant (or supposed) to be "hi-fi". More just for a bit of "ambient noise", if you will, for movies with 5.1 soundtracks. That, and possibly alternative monitoring for checking mixes.
 - No, these are not meant to go terribly loud. Due to, let's call them, physical constraints, they'll be placed at the corners of my sofa (right up against the wall, opposite the TV and the "mains"), so no huge SPL's are required.

Monday, 19 February 2018

#27 Samsung 5V 1A ETA0U81EBE USB travel charger

This one's a quickie, but i figured i might as well document it.

A friend passed me this a few weeks ago, not quite sure why. I don't recall it being mentioned as dead, only not-used. Either way, last night i wanted to charge the battery inside my modded M-Audio Fast Track, in preparation for a local gig next week. Upon plugging it into this thing, the power LED flashed up for an instant, then nothing. I figured it might not like the USB data lines being tied together, as they often are, in chargers; it powered on and worked well with another charger. But that prompted me to crack this one open.

Wednesday, 7 February 2018

#26 Cheap & easy DIY LED light panels

Recycling's all the rage nowadays, right? Right..? Well, either way, freebie raw materials for projects are always welcome, that's something i'm pretty sure we can all agree on. Now, i'm not admitting to be a hoarder, far from it, but i kinda-sorta couldn't bring myself to throw away the dead (read: cracked) laptop LCDs that i had replaced for various clients at work. And what with "finally" expanding this blog onto YouTube, i figured i'd need some extra lighting for the workbench. Catching my drift yet?

Tuesday, 14 November 2017

#25 Behringer ADA8000 "Ultragain Digital" revival

I got my hands on one of these a few months ago, as faulty (as in, totally dead) for about 50$ shipped. Having done some preemptive googling before going for it, i was expecting the transformer to be toasted. Sure enough, that's exactly what the problem was - one half of the center-tapped primary measured in the hundreds of kohm, so pretty much open-circuit (as opposed to the 50-odd ohms the remaining good half measured).

Initially i was planning on finding / getting a "drop-in replacement" toroidal transformer, ie. similarly sized physically and power-wise, but with less insanely-high secondary voltages. The stock one, according to some "inspection notes" i found online, seems to have had roughly 2x20VAC windings for the analog +/-15V (meaning the voltage regulators had to "burn off" uselessly much power / voltage), 12VAC for the 5V regulators, and a whopping 58VAC winding for the phantom power regulator. That's about a 50% overkill across the board. One can only wonder just what possessed them to spec the transformer quite like that, especially since it must've been a custom order - you'll rarely find retail units with more than two (identical) secondary windings, and when you do, expect to pay a pretty penny for'em.

Sunday, 5 November 2017

#24 SM Pro Audio TB202 dual tube preamp / channel strip modding & upgrade, part 4

On the note of front panel switches, you might've noticed two extra ones, in the previous post (the part 3). One other idea had crossed my mind, already long before this second stage of modding. It took me a little while, but i managed to get my head around how to implement this. The idea was to be able to swap the order of the two processors in the signal path.

From the factory, as described in the "part one" post, the processing order is input - gain - tube - compressor - EQ - output. But in some cases, it can be desirable to have the EQ come before the compression stage. That way, one can attenuate certain frequency ranges that one would not want the compressor to react to (or conversely, boost ranges for the compressor to react to).