Month: August 2018

Wheatstone Console Connectors

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Putting this note out there for anyone who needs it—

The Wheatstone R-60, A-50, and other Wheatstone / AudioArts products use Amphenol MR series (Miniature Rectangular) for audio connections. The usual configuration of this connector is a 12 pin array – 4 rows of 3 pins.

Pinout for the audio inputs on each channel usually go like this: (Audio – = low, + = high… different strokes for different folks)

Ground / Audio - / Audio +
   1         2        3     Input A Left
   4         5        6     Input A Right
   7         8        9     Input B Left
   10        11       12    Input B Right

what the ass

The connector parts are all available from Digi-Key.
Connector Shell

Connector Female Pins

Pin Extractor Tool

The original crimping tool Wheatstone would send along with the console was the Panduit (now Greenlee Communications) PA1645, which Digi-Key doesn’t stock. It’s available elsewhere. What I’ve been using at the office is an Iwiss IWS-1424A which supports five different sizes – size E works on the wire to pin crimp and size D on the strain relief tabs around the insulation.

GOTCHA: You may find an older Audioarts or Wheatie console prior to the mid 90s or so (I’m unsure on this date!) where a different style pin extractor is present – it’ll look like a fat hat pin with a spherical head. If you find this, DO NOT LOSE IT! At some point the Amp MR series connector was subtly redesigned, and the two extractor tools are not exactly identical. The newer MR pin tool is larger in inside diameter. The old tool is LOOOONG out of availability anywhere (I haven’t even been able to track down a part number on what it was!). The new tool will not cleanly release the old pins – you will wind up with one of the retention barbs on the side folded in half when it comes out. It won’t damage the connector shell when it’s ejected, though.

New pins will release in the old tool, but the retention barbs will be smashed way in there and be difficult to “reset” back into a usable position.

Chances are this won’t matter anyway, as you’re probably not removing the pins unless you’re entirely changing the cable that they’re crimped onto. 🙂

PITAtek

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Upon having the strange experience that a new supposedly frequency agile PTek would only work on half the band (seemed almost like an exciter unlock or something when I tried to dial in 107.1?) I decided to look at the exciter card to see if there’s a tunable tank coil or something

I wish I hadn’t now

SCA and composite inputs, J9 and J10 respectively. C66 lowpasses the composite sorta by shunting everything above an unknown frequency to ground. C65 highpasses the SCA, it’s in series. The two combine at fixed yet frequency dependent levels and go down that via near C63 and R33. U7 under the board is a voltage regulator. J1 is the RF out and L1 is the DC feed to the power amplifier just out of frame.

Yeah just go right ahead and stuff the audio inputs right on top of the RF out. No big deal.

Full view of the card. The DDS is at upper left.

Think you can get away from having your audio run across the butt of a voltage regulator by using the XLR jacks? No.

The trace going down the via next to R81 is one of the audio channels, and it runs right under the header connector for power and data to the board.

A word on this PA. This is a new LDMOS transistor from ST Micro. As such, its dissipation is really low, and it basically gets heatsinked by the leads and traces. Here’s the reference design…

What you get is significantly less copper. The big ground planes that’d soak heat away via the source leads are just not there… so a weird block thing was sandwiched under the board and I don’t even want to look at this any more

The stereo generator used to, in earlier designs, be based off a DSP that I’d heard they couldn’t get anymore. This stereo generator is what I could best describe as “deconstructed BA1414 feeding a high speed ADC”. I’m guessing the two PICs are used for timing generation and the 8 bit ADC, U8 / DAC0800LCM is probably used to generate a sine wave from a lookup table or something. conspicuously absent is any sort of audio filter to roll off program content above 15-18 khz, if this is present the generator flips the hell out. It’s a living nightmare on green circuit board. Gaaah.

Side note– the BA1414 I mentioned above is a chip made by Rohm which is used in a lot of really cheap little FM transmitter baubles and produces TERRIBLE output. It performs stereo multiplexing using a couple of poorly filtered square wave oscillators that are mixed with audio.

Go ahead, change the oil. I dare you.

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This hilarious oversight found on an Allmand Maxi-Power 25 generator. The engine is a small turbodiesel utility engine made by Isuzu. The whole thing was assembled in Japan by Hokuetsu Industries….

… who hopefully sell a special bendy straw funnel.

Here’s the oil fill cap. The drain and filter are very easily accessible from the other side. But the filler… Oy!!

Above, the exhaust pipe.

Perhaps you can get in from the other side? …. Nope.

Look at that cute little tangerine sized turbocharger!

It seems to be like they could have added an access hatch above to make it easier, but yeah… Bring your Crazy Straws….

Yeah I wardrive sometimes

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zowie. click for fullsize

This is the map of wireless APs I was first to discover in the wigle.net database. Note that this is not necessarily areas I have travelled in — rather, it represents intersections between where possibly mobile (as in, cell phone or vehicle integrated hotspots) APs and my travels have intersected. As other wigle users log later locations of these APs, the database will update to reflect where they’re actually from.. or where they’re traveling. That’s why I show up as missing the rains down in Africa, for instance.