A couple weeks back, an acquaintance contacted me about his Axe-FX II suddenly not powering up anymore. I saw this as an opportunity to at the very least take a peek under the hood of one of these things (still selling for four-figure amounts), so why not?
I had neglected to snap photos of the outside of the thing (because other priorities), so you'll have to settle for some "stock" shots. Not that there's anything overly interesting to see anyway.
Perhaps a bit anachronistically, only *after* getting my hands on the previously-torn-down 2i4 gen2, i also came into the possession of a 2i4 gen1, that was no longer being detected completely / correctly by the computer. But hey, better late than never, right? I also grabbed a working one (because the price was near-irresistible), to have a known-good source for the firmware, in case that was the issue.
First of all, the main issue with using this stand-alone (without a computer) is that the Xmos controller only enables the analog power supplies (the two MIC2505's and the LM3488) once it's done whatever handshaking it needs to, with the computer. But since i'd only need / want it to act as a rudimentary preamp / mixer / headphone amplifier, i kinda-sorta need the analog supplies working.
Initially, i was thinking of getting and modding a Scarlett 2i4 to use as an updated and more flexible in-ear headphone amp, to replace my aging modded M-Audio Fast Track (incidentally, the subject of the very first article on this blog). I even ended up with two 1st gen ones as well as two 2nd gen ones. But recently, i came across yet another deal i couldn't pass up - a Saffire 6 USB for a nearly ridiculous 36e, shipped(!). Virtually the same structure as the 2i4's, but i can definitely get more money (back) from reselling those, and keeping the Saffire. That, and i had come across instructions for a mod to the Saffire 6, to enable stand-alone operation.
Yet another eBay score - caught this one with a blown power supply. Blown, as in, skidmark inside the casing, circuit board scorched, tracks vaporized. But maybe i'll make that into another article on its own, someday. In the mean time, let's take a peek under the hood of one of these arguable "classics".
The practical side of this one was performed and documented a couple months back, but since i've had this back-log to work through, the text is only getting written now. But good things come to those who wait, right? Or so i've heard...
Regardless, i couldn't not grab this deal when i saw it. A shure 55SH "Elvis mic", with allegedly low(ered) output, for 75eu shipped (considering it retails around 160-ish). Now, granted, i HAD peeked around the interwebs beforehand, and it seemed that, at least in some cases, the on/off switch could be a suspect. But on the other hand, even IF the capsule itself turned out to be a dud, i could still MacGyver another capsule in there, one way or another (possibly from a Grundig GDSM-202, but shhhhh!...). Aesthetically it was in good shape, so why not?
This summer's "already" been quite fruitful, gear-scoring-wise anyway. This find cost me a colossal 86eu, with allegedly none of the outputs working. This, in the context of it retailing for a somewhat eye-watering 500eu(!!!) or thereabouts, brand new. On the bright(?) side, it came with the original packaging, manuals still in their plastic bags, as well as a USB and a Firewire cable to boot, both also still factory-packed. So why not?
For a little while now, i've been thinking of "upgrading" from my old-but-modded M-Audio Fast Track to use as an in-ear monitor amplifier, and the Scarlett 2i4 caught my eye. The mono/stereo direct-monitor selection, as well as the hardware-switchable pads on the inputs made up just the right feature set, in addition to it being usable as a mobile recording interface. As it happens, just the other week, mere days after having saved an eBay search for 2i4's, an email notification revealed a 2nd gen allegedly-faulty unit being up for sale from Italy. I quickly asked the seller about shipping costs, and ended up sealing the deal for an even 50e.
Over on the Badcaps.net forums, a thread was started all the way back in 2010, about power supply issues in these arguably "classic" low-cost active studio monitors. It even ended up being stickied just this winter, so it's been quite active and useful. It served as motivation for myself, to take up hunting for faulty ones - not sure if i had gone through three pairs, but at least two pairs i revived and sold off to a couple friends, some 7-8 years ago, and to this day i've yet to hear back about any further issues, so i take that as a good sign. In the mean time, i still contributed with thoughts and advice there, which helped lead to several successes.
Recently, a fellow forum member there got fed up with his failed attempts to revive his pair of monitors, and got himself a pair of new ones. In that context, we struck a deal for the Alesis'es, and a few weeks later, here they are.
And now, getting back to the issue affecting this unit... As pointed out in the ad, the LT3439 apparently used to have a piddly little heatsink glued on top of it, but it got detached. Now, there's a chicken-and-egg type mystery here - did the heatsink glue fail because the chip overheated in the first place? Or did the chip get fried because the heatsink fell off? Regardless, investigation showed that one of the two switching transistors inside the chip seems to be stuck in a conducting state, despite the transistor itself not being shorted, though. But since it handles all the power for the analog circuitry, it's no shocker (no pun intended) that only the digital ins & outs work.
