Admittedly, i went against the first commandment of teardowns (ie. "Don't turn it on; take it apaaaah't!.."), but only because it was the first troubleshooting step, and it used the same drivers as my Scarlett 18i6 "daily driver".
Somewhat different in/out arrangement compared to the older Saffire Pro 24, but it is also a slightly more "upmarket" unit. In addition to the four mic inputs on the front (2x mic/line/instrument and 2x mic/line), all with software-switchable attenuator pads, there's another four line-level inputs on the back, and only a single pair of line outputs. The digitals are one optical ADAT input and an S/PDIF in & out, MIDI in & out, plus the USB connection to the computer.
The back panel comes off after undoing all the jack nuts, the four screws from the MIDI connectors, one from the S/PDIFs and the two in the corners, revealing... Not a whole lot, just yet.
The front panel needs to be unhooked from the top edge of the casing with a long sturdy flat-blade screwdriver, after which all of the guts can comfortably slide out of the beefy one-piece aluminium casing.
Like i said - beefy. Looks like an extruded profile, about 4mm (a bit over 1/8") thick, with the exposed end-edges CNC'd nice and smooth.
And here we have the guts. Reasonably tightly-packed, but not overly so.
In fact, let's get those cables going to the top board, out of the way, so we can get a clearer overall view.
You'll have to excuse me if i don't bother removing the top board, but there's literally nothing underneith it worth seeing - the two phantom-power switches, the combo-XLRs, the headphone jacks, and the main volume potentiometer.
Starting off with the power supply section. A pair of National Semiconductor (now TI) LM2672 are in charge of the 3.3V rail (top), and the +6.9V rail (bottom), respectively.
Nearer to the front of the unit, an interestingly-packaged National semiconductor (now TI) LM2670 acts as an inverting buck, to create the -6.9V rail. The package, as it turns out, is "VSON" - [something] Small Outline No-leads.
A tucked-away ST L7805 regulates the +6.9V rail into the 5V that powers the analog side of the CODECs, and possibly some of the other logic chips around the inputs.
A tiny little Texas Instruments LM3488 is responsible for the phantom-power rail, driving a chunky International Rectifier (now Infineon) IRFR024N N-channel MOSFET in a boost-converter configuration.
You'll note some of the inductors in interesting (45-degree) positions - my guess is, the designers did that in order to minimize magnetic coupling between the various power-inductors.
Near this, we have another little buck-converter, namely an OnSemi NCP1529, providing the +1V core voltage for the main processor.
The electrolytics are a bit of a grab-bag, spread among a few CapXon GF in the power section, and Jamicon plus smaller CapXon's on the audio side.
Running the whole show is an Xmos XS1–L16A–128 (1000MIPS version). Veeeery funky dual-row QFN package...
Right next door are a Winbond 25X40C 4Mbit (512Kbyte) SPI Flash memory chip containing the firmware, and an SMSC (now Microchip) USB3343 interface chip.
Not far off, a Cirrus Logic CS2300 is in charge of clock generation and syncing.
A quartet of Cirrus Logic CS4272's handles all the conversions from analog-to-digital and vice-versa.
Moving on to the analog side of things - JRC NJM4565's make up the bulk of the opamps used in this unit. On the right side of the picture are the ones responsible for the four line inputs on the rear of the unit. In the middle we have the pair of JRC NJM2122's as the adjustable preamplifiers for inputs 1 and 2.
A lone TI TL072C is the first stage of the high-impedance instrument inputs. The pair of NXP (now Nexperia) HEF4052's i would reckon handle the selection between mic / line / instrument inputs for the first two channels. The HEF4053's on the other hand, i would suspect switch the attenuator pads in and out, since there are several more of them near the other inputs as well.
Preamps for channels 3-4, pretty much same deal as above.
And last but by no means least, a pair of SIP-packaged (for extra power dissipation capability) JRC NJM4556's drive the two headphone outputs.
And that about covers it. No repair needed this time, but i've got enough of a headache with the Presonus Audiobox 1818VSL from the previous post. Presonus support have been anything but helpful...
Hey, thanks for the teardown. I couldn't figure out how to get the front panel loose after the back panel came off. Now I think I can give it another go. Not that there's anything wrong with my unit. I just like tearing things apart and putting them back together.
ReplyDeleteI'm glad there are people who find my curiosity-driven efforts, useful! I recall, back in the day, not being able to find almost any information on the insides of audio interfaces and such. But since i got into hunting down revivable ones, i figured it couldn't be a bad idea to also document things, at least for my own "posterity", if not even to inform others.
DeleteRegarding the front panel, i can't recall 10000% for sure, but i'd guess the construction is similar to some of the smaller Scarlett units. You'll want to remove that top daughterboard, so you can then have easier access to the one-screw-per-XLR that fastens the front panel on. And, "of course", also removing the nut & washer from the master volume pot.
Yes thanks for putting this up, great job on identifying everything too, I will be following you !!!!
ReplyDeleteMuch appreciated, and glad this helped!
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