It's been a while since I've pounced on an impulse buy, being that I'm essentially hovering in a state of critical mass I've pretty much stopped frequenting the places I run across this sort of thing. That said, I needed 100 feet of ethernet cable, so I made the trip to Next Step.

While I was there, I couldn't resist perusing the piles..

I struck out on the ethernet cable, but wound up scoring a heavy 2U modular video rack processor by Datatek. In poking about the internet I find reference to it being a D701 system, but no where on the device is a badge confirming this, and since eBay sellers are not the end all of cold hard fact I'll leave it somewhat open. Someone has marked KEVU 34 on the underside, call signs date to 1991-1997. I think I may have watched afternoon cartoons through this thing.

Anyway, let's have a closer peek at these modules. Left bank contains, top to bottom, left to right: D706 Leading Correction Generator, D709 Trailing Axis Corrector, D702 System Input & Power Supply, D703 Transmitter Delay Corrector. Right bank: D707 Trailing Correction Generator 1, D708 Trailing Correction Generator 2, D704 Receiver Delay Corrector, D705 Video Low Pass Filter.

D706. All the correction generators read similar to a graphic EQ, with a time based delay as opposed to a frequency. Each time base is variable on a +/- scale adjusted by a pot as opposed to steps of a switch. Without looking at this thing on a scope or finding operation manuals I can only speculate what function this serves. I'm guessing video sync alignment.

Gut shot of the D706 reveals a nice early potted integrated circuit. We're peeking into roughly 1974 here near as I can figure it.

D709. The trailing axis corrector strikes me as the module with the most potential. Perhaps it is the generous front panel patching. Perhaps it is the word "AXIS". I don't know, in skimming over the vast array of elements that comprise an NTSC analog signal, it could sink into numerous slots.

D709 guts. Fully discrete topology.

D702. Power section, with gain control! The power switch to the left is clearly missing the lamp cap, though it seems to actuate just fine. The bypass lit plunger was very loose and required a bit of tightening.

Not much more to say here, D702 gut shot. Does appear to be of more recent manufacture, but I neglected to pull date codes from it to compare.

D703.

D703 really doesn't appear to support anything other than set & forget operation.

D707. The trailing correction generators look similar in function to D706. D708 is also similar, but where D707 has +120, +240, +360, +480, +600 & +720, D708 carries on into +840, +960, +1080, +1200, +1320 & +1440/SPL.

Hey, this looks familiar. D708 is similar.

D704. Another set and forget module.

I really like the wandering line of the ground plane to unpopulated fiberglass. I'm also impressed by the flying wire jumper geometry.

Because no post would be complete without some borderline photography, here's the D705. Another set & forget (I think calibrate is the preferred nomenclature) though honestly this is one function I'd rather have hands on with.

33 adjustments does seem a bit much, how's about one big knob?

Here's a shot of the module back plane, relay bank & power supply. Foreground is the I/O. Speaking of big knobs, there's another that may do better on the front of this unit. Since my video processing is starting to populate my rightmost open rack I'll overlook the nuisance factor.

See, I remain fascinated with video synthesis and a device such as this seems a good "block" to have on hand. If it turns out it does nothing interesting I will have a short module frame enclosure for a future build.

Tropical fish capacitors! Tone zombies friend. These look dessicated, and to some extent falling apart. I'll file that into the "look for" list in the event of magic smoke, I really don't want to mess with any potential mojo prior to discovery. Speaking of mojo, I need some more nondescript milky white through hole parts on hand.

Fast forward 20 years and this assembler will be circuit bending Speak & Spells.

Pretty cryptic in terms of a part number. Not that I think I'd have a lot of luck finding a replacement even if I did know what I was looking for.

Clean heat sink & oxidized legs; oxidized heat sink & clean legs. What gives?

The AC mains fuse housing (5A!) was also very loose in the chassis, and the W/F Correction switch on the rear panel is in need of replacement. I'm hoping these are signs of simple nuisance/post decommission storage type failures as opposed to catastrophic BBQ. Remains to be seen, may need to freshen up those relay contacts.

I think my picture to words ratio is tilted toward STFU today.


Wheatstone/Audioarts A32 broadcast console, an over all angle. Minimal clutter lending weight to the 100mm sliders, the wood is a nice touch too (though appears somewhat tainted by greasy DJs).
Modules from left to right: 4x MM-20, 12x SL-20, 2x blank, LS-6, blank, SC-20. CR-20 & OM-20.


MM-20 is the microphone preamp, the input transformer has been wiped clean of any identifying marks. Socketed NE5532N are found throughout the desk, I believe the SN74LS00Ns situated beneath the Penny Giles slider support logic switching and illumination of the front panel controls. Input, output and power feed are hidden somewhere in the forest of pins on those ribbon connectors.


I expect the PGM & AUD buttons control those yellow box relays seen above.


The SL-20 is much like the MM-20, minus the transformer and with an additional dual op-amp, which is sensical because this stage is stereo whereas the MM is mono.


Same stripped down features, but in... ((STEREO))


LS-6 is pretty self explanatory (forgive me, I'm going to go ahead and explain it anyway). It performs Line Selection, from 6 choices. From what and to where, however, are still shrouded in mystery. It's also around this point where I stopped being comfortable pulling the modules out, since it is no longer so clear what is what in the final sections.


SC-20; Studio Control, looks to house the talk-back circuitry and routing to the studio.


CR-20; Control Room loses the TB control, as the operator typically does not require supporting electronics to talk to themselves, and adds headphone amplification.


OM-20; your guess as to what the O stands for is as good as mine. This houses master level and VU meter trim and timer control (which will come in handy if I'm ever trying to record and bake at the same time).


The PSU was naturally absent upon purchase, as was a loom with 29 DB-25 connectors (that's 725 connections, in case you were curious and yet slow in the math).


The switches also seem to be a weak point in the design. I love mechanical indicators, but these are less than crisp in their response, the A/B input plungers also need help to actuate between up and down. The only PGM & AUD switches in the on position are the ones next to the holes.


Upper shelf component selection aside, complexity has worked against this desk in the span of 20 years. The Autogram AC-8 which is almost 10 years older, has the potential to be a far more user friendly and upgradeable desk.

I'm not really one to get rid of stuff. A friend spied this in a clutter photo and voiced interest in it, so it's only fair that I go through it and assess the potential and value within.


The Industrial Research Products, Inc. Voicematic DE-4013A-0100; what amounts to a conferencing 10 into 1 microphone mixer that can duck inactive microphones. This unit contains one DE201 master level module, five DE202 dual microphone channel modules, a blank and one DE205 regulated power supply.


The DE201 contains an LM339 voltage comparator (presumably for the Voicematic level ducking circuit), a Harris HA3-4741-5 quad opamp and a variety of metal package transistors.


In addition to various discrete actives and Beyer TR/BV370 215 006 microphone step up transformers, the DE202 contains an MC14528B dual monostable multivibrator (presumably the respondent to a CV level message provided at the master LM339), a TL083 and one half of an HA3-4741-5 per channel. Component quality here looks pretty upper shelf. The only real questions I have is if the mic pres have usable gain and how they sound, the AGC circuit can be bypassed via front panel switch, so ducking artifacts are not a concern and could prove useful in certain circumstances.


Lead dress is often an indicator in regards to over-all attention to detail, which can factor into sound quality. I remain curious as to how this unit sounds, I'll have to cobble together a rough approximation of a studio session to check this thing out.


Looks like the analog circuitry is going to be seeing +/- 12 volts.


The orange/white twisted pairs are microphone feeds to the channel inputs. I believe all the channels are dumped onto a pair of these wires as a low impedance signal amplified by the HA3-4741-5 at the final level stage.

The aspect of this device that had thus far impeded my interest is the ten in, one out architecture, which isn't something I have a lot of use for. However, in speculation I realized I can switch in a bypass routing that will pull a card pair off the main output and route output to a jack on the rear of the case. The five switches can inhabit the face of the blank panel.

Examining the card also revealed a couple wire jumpers in prime positioning for a phase reversal switch, adding to usability of the preamps. Assuming of course this thing sounds good enough to justify the tinkering and 3U of rack space, which remains to be seen.