#85 Harley Benton HB-80R teardown & modding

Right, so i had been on the hunt for the cheapest way i could get a 1x12" or 2x12" guitar cab for a while now - mainly because i landed a toasted Celestion Greenback for free some months ago, and a recone kit is arguably affordable. Budget being a prime concern, i was compelled to look locally, and a couple weeks ago finally pulled the trigger on this thing.

#81 MOTU Traveler teardown & upgrade

As a follow-up to the recently posted MOTU Ultralite teardown, i had to grab this as soon as it popped up in my search results, because it had a price i couldn't ignore or refuse, and it had the ideal feature set for recording my band's jams and rehearsals. While the former had most of the features i needed in the 828mk2 i had been using, but in a smaller form factor, this Traveler packs more of the features i need (two extra mic preamps, while retaining the -10dBV/+4dBu line inputs with optional 6dB boost), in an intermediate form factor, as well as having a full 53dB of gain available on the mic preamps, but without weirdo custom potentiometers to wear out. Just about best of all worlds, really, especially for the paltry 85e this cost me. And as the cherry on top, it even has a separate battery input - hello, fully mobile recording sessions...

 

 

#79 Focusrite Saffire 6 USB 2.0 repair

 Ok, this is gonna be a bit of a quickie. Basically, i got this one ridiculously cheap as well, with the intention of repairing it and gifting it to the new singer in my significant other's band, in order to facilitate more productive creative work. Just like the first one i did a teardown on and then modded, this was sold as faulty, but with more... obvious issues, let's call them.

#78 Focusrite Saffire 6 USB 2.0 modding (adding a battery)

And here we are, on the third and final(?) part of the modding journey involving this little fella. As presented in the previous post, i managed to "persuade" the thing to power up fully despite not being attached to a computer, only to a USB-connected 5V source. But now, the time has come to integrate what is virtually a "power-bank", within the enclosure, and thus have the Saffire be entirely "self-sufficient", as it were.

#74 Focusrite Saffire 6 USB 2.0 modding (for stand-alone operation)

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.

#62 Jamo Sub 200 modding

For background / context: https://mehlau.net/audio/multisub_geddes/

I had been off-and-on "hunting" for a twin, for my Jamo Sub 200 that i bought and revived years ago. Partially for SPL reasons, partially for the multi-sub approach mentioned above, and most recently, for actually sitting my couch on top of the subs.

At long last, a couple months back i finally found one locally, and in matching black finish. And with the 5.1 Jamo speakers it came in a set with, to boot! Those might get reused / repurposed later, (i'm thinking, in a manner similar to one of my previous projects).

#55 Focusrite Scarlett 2i2 (1st gen) teardown & modding

I had fiddled with one of these a couple years back, but here's another chance to take a look inside a (1st gen) Focusrite Scarlett 2i2, their second-smallest USB audio interface of the range.

#53 JMicron JM20330-based mSATA to ZIF-ATA adapter power modding

A few years ago, in the quest for more storage space, power saving, weight reduction and eliminating sensitivity to shock, i decided to upgrade my old iPod Video (5.5G) from the stock 80GB hard-drive to a 256GB SSD, with the aid of an mSATA to ZIF-ATA adapter, and some mods to the "aftermarket" Rockbox firmware.

... Except that recently, for whatever reason, it's been kinda flaky, and ended up giving up altogether. To aid with stability, i had also performed some hardware mods on the power supply side of things (as well as on the iPod's mainboard). The rationale behind that, at least in part, was the source of the above-mentioned mods, so i'll need to transplant those to this newer one as well.

#51 Solar A2.7 & Fishman Fluence Keith Merrow & 5-way install

Local guitarist buddy time again (owner of the Fortin Grind and the Warwick bass amp featured here previously) - after taking several swings at it, he got fed up and let me have a go at installing a brand new set of Fishman Fluence Keith Merrow pickups into his Solar A2.7 guitar. Complete with some custom switching and whatnot, to take full advantage of the entire feature set the pickups offer.

#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?

#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).

#23 SM Pro Audio TB202 dual tube preamp / channel strip modding & upgrade, part 3

Even before having received the thing, i had already started thinking of daisy-chaining the two channels. In the context of something like a bass preamplifier, for example, one would want a "clean" channel, perhaps with some heavy compression, in order to have a consistent signal (especially in the lower registers), as well as a "dirty" channel, with a high-passed signal having some distortion applied to it.

#22 SM Pro Audio TB202 dual tube preamp / channel strip modding & upgrade, part 2

Once the "adventures" from the previous post were completed, i proceeded to hook up one channel to my audio interface and feed some test-signals into it. This revealed a few things which didn't sit with me all that well.

First of all, the compressor didn't seem to be doing much of anything. No level reduction with the knob turned up to full (even with full input gain and clipping the snot out of the tube), the associated LED stayed green (instead of going red), nothing. A bit of oscilloscope-probing in the signal rectifier area quickly pointed out the issue - there was no real rectification going on. The signal coming out of that stage was still largely sinusoidal, albeit with a small kink at the zero-crossings. Well, that's no good...

Removing the diode in the signal-rectifier for testing didn't reveal anything, it measured as a normal 1N4148 both in and out of circuit. My aforementioned buddy pointed out that the arrangement they had used in this design, a "precision diode" circuit, was somewhat flawed as a concept, as is described in this link over here. I then proceeded to upgrade both channels to the "precision rectifier"circuit (see link above).

#21 SM Pro Audio TB202 dual tube preamp / channel strip modding & upgrade

<Further developments can be found in parts two, three and four>

I'll admit, this was a bit of a lucky catch, in that it was mistakenly listed in the wrong eBay category, but one i "stalk" for good deals on certain faulty bits of audio gear. It was up for auction, there didn't seem to be much demand for it, and i ended up winning it for a mere 21 euros. About as much as the shipping for it ended up costing, oddly enough.

But still, even for some 40-odd bucks, not a bad little unit. Two channels, a (bare-bones-ish) compressor on each (1.5-10:1 ratio, 1ms/5ms attack, 500ms/1500ms release, at least according to the specs in the manual), as well as 3-band EQ (80Hz shelving / 1.8kHz bell / 8kHz shelving), and there's a tube / valve involved in the circuitry as well. If nothing else, i figured it would do nicely as a bass DI (or even an overdriven preamp, once some internal re-wiring is figured out and done).

#19 Takstar / Gear4Music WPM-200 Wireless Monitor System part 3: transmitter mods

And at long last(?), we've reached the point where we take a look at the transmitter end of this wireless monitoring system. Not a whole lot to see on the outside, really: power switch, power LED, channel select rotary switch (1 to 6) on the front, and the DC input barrel socket and the 1/4" stereo input jack socket on the back.

#18 Takstar / Gear4Music WPM-200 Wireless Monitor System part 2: receiver mods

Ok, turns out i lied in the previous post, as this part 2 won't be about the transmitter - so sue me...

Either way, into the meat of it: upon some listening tests with music, it turned out the expanders were misbehaving just awfully. They made the volume jump up and down virtually all the time, in a very disconcerting manner - basically briefly increasing the volume (noticeably) upon every louder bass note (and only for the duration), and dropping back down in between.

I took apart one of the receivers, and lifted the schematic of the expander chip and the associated passives around it. Pretty much exactly what's in the datasheet of the TA31101, with the exception of having omitted the coupling capacitor going to the "Comp In" (pin 11), thereby turning the compressor side of the chip into another 1:2-ratio expander, just like the other half.

#17 Takstar / Gear4Music WPM-200 Wireless Monitor System part 1: receiver teardown / li-po upgrade

This "part one" will be dealing only with the WPM-200 receivers and the lithium-upgrade pertaining to them. The transmitters and subsequent mods will be dealt with at a later date.

Fine, i'll admit, i miiiiiiiight be ever so slightly guilty of the whole "if all you have is a hammer, everything around you looks like a nail" thing, what with these nifty little one-cell charger & protection boards, but hey - at least it kinda validates(?) my "stockpiling" of laptop and phone batteries along the years. Now, i finally have the excuse to put some of them to good use and all that...

During my UK eBay browsing sessions a month or two (or seven?) back, i happened to come across a few listings of faulty wireless monitor sets (transmitter & bodypack-receiver) from this British music gear retailer. A bit of googling later, revealed to be straight rebadges of Takstar WPM-200 sets - nope, they hadn't even bothered changing the model number. The one thing they might've customized, though, are the radio frequency ranges / channels (since there are different regulations on different continents, and so on).

#16 Cheap chinese BM700 / BM800 microphone modding / upgrade, part 2 (CK12 & K47 capsules)

<Continuation from part 1>

After quite a while, i "finally" got around to modding the other three BM800 mics i had. Just for the hell of it, i decided to make a matched triplet (to use as, say, three overheads on a big drum set).

I went with more of my modded-Schoeps boards, and matched components between them, as closely as i could (within reason, at least). Resistors were no big deal, and neither were the capacitors; one of those cheapo chinese ATMega328-based "component testers" helped with matching the JFETs and PNP transistors. No, i didn't necessarily care about the absolute values, just that they're the same (or as close as reasonably possible).

#15 Alesis io|26 repair & modding

So, i got my hands on one of these Alesis io|26 interfaces for pretty cheap (50 bucks delivered). "Of course", i bought it as faulty (can you see a pattern yet?), with the already "classic" issue of dead Firewire chip (the ubiquitous Texas Instruments TSB41AB2).

I went for it mainly for two reasons. First, because i knew it was based on the TC Applied Technologies Dice II chip, and as such, should have flexible enough mixing / routing options; second, due to the ADAT inputs available. The sort of "added bonus", one might say, were the gain adjustments for the 8 analog (mic/line) inputs.

#13 Fisher RS-1022 rehabilitation and bling-ification

So i had this old Fisher RS-1022 Studio Standard stereo receiver brought in, with one of the fuses in-line with the speaker outputs blown. Fair enough, that was easy enough to replace, they made it quite easy, with the fuseholders being mounted right on the rear panel. The clamps were nowhere near as elastic (or firm) as they might've once been, but with a pair of needle-nose pliers and a bit of creativity, that was no biggie.

Second issue, five of the six lamps that illuminate the tuning scale and the radio signal level were dead. In four of the dead ones, the fillament was attached only at one end, and in the fifth, it was attached at neither end. Interesting little lamps, 6.3v AC, 250mA, in a similar casing as 6x32mm glass fuses. Good luck finding replacement ones (which may very well just end up dying again anyway); these will get replaced with a few white LEDs recovered from a laptop display's backlight.