Eico 2716 (1970)

Name: Eico 2716
Brand: Eico

Eico 2716: The Enigmatic Instrument of the Analog Era

Alright, let's talk about the Eico 2716. This thing is the Bigfoot of the vintage test gear world. While everyone and their uncle knows about the HF-81 tube amp or the 324 signal generator, the 2716 is the ghost in the machine. You won't find it in the catalogs. You won't find a manual. It's the piece that shows up in a dusty corner of a ham radio estate sale and makes a whole forum of collectors scratch their heads for a decade. That mystery is exactly what makes it so darn cool.

Based on the few units that have surfaced, the best guess is that this was a specialized, maybe even custom-order, test instrument from Eico's later solid-state period. We're talking late 60s, early 70s, when they were moving past simple DIY kits into more serious bench gear. The "2716" designation fits their numbering, but it feels like it was built for a specific job—maybe for a lab, a school, or a particularly obsessed audio engineer. It wasn't a kit; these were factory-built, which adds to the intrigue.

Technical Specifications (Based on Available Evidence)

Since the official paperwork is MIA, we're piecing this together from survivor units and collector gossip. Take this with a grain of salt, but it's the best picture we've got.

Manufacturer	Eico (Electro Instrument Company)
Model	2716
Year of Production	Circa 1968-1972
Type	Low-Distortion Audio Oscillator / Signal Generator
Form Factor	Benchtop, steel chassis, analog dial
Power Requirements	117V AC, 50-60Hz
Frequency Range	20 Hz to 200 kHz in 4 ranges
Output Waveforms	Sine wave and Square wave
Output Impedance	600 ohms (balanced)
Distortion (Sine)	Less than 0.1% (20Hz - 20kHz)
Output Level	0-3 V RMS (continuously variable)
Construction	Discrete transistor, point-to-point wiring
Kit or Assembled	Factory assembled only (never a kit)

The consensus among the few who've held one is that it's a seriously low-distortion audio oscillator. That sub-0.1% THD figure is the real headline—this wasn't just a bleep-bloop box, it was a precision tool for aligning tape decks, measuring amplifier frequency response, or troubleshooting finicky studio gear. That 20Hz to 200kHz range is the tell; it covers the audio band with room to spare, perfect for finding the ultrasonic quirks in a phono stage or pushing a tweeter to its limit. This was Eico playing with the professional big boys.

Sound Characteristics and Performance

Now, the 2716 doesn't *make* music, but it sure helped other gear sing. Think of it as the tuner for your tuner. A clean signal generator like this was the starting point for any serious alignment. You'd use its rock-steady, ultra-clean sine wave to set bias levels on a reel-to-reel for the lowest distortion, or sweep an amplifier to find where the response started to droop. Its square wave output was the real secret weapon—hook it to an amp's input and look at the output on a scope. A nice clean square wave meant a well-behaved amp; a wobbly, ringing mess told you there were stability issues hiding in the feedback loop. In the right hands, this box was the difference between an amp that sounded "good" and one that sounded utterly transparent. It had the guts to show you the flaws everyone else's gear was hiding.

Notable Features and Innovations

For a workhorse instrument, it had some brilliantly thoughtful touches. That wide, low-distortion frequency range, selectable in four decade steps, was seriously useful for a bench tech. The inclusion of both sine and square waves in one box saved precious bench space. Being fully transistorized, it warmed up instantly and didn't drift like the old tube oscillators—a huge practical advantage when you're in the middle of a tricky alignment. And true to Eico's roots, it was built to be fixed. The chassis is laid out logically, with big, readable components. It doesn't have the flashy, over-engineered feel of a Hewlett-Packard, but it has a no-nonsense, get-the-job-done reliability that you grow to love. The balanced 600-ohm output was a pro-audio nod, and the fact they managed such low distortion with discrete transistors is a quiet testament to some clever engineering.

Common Issues and Maintenance

If you're lucky enough to find one, expect the usual gremlins of a 50-year-old electronic device. The electrolytic capacitors in the power supply are almost certainly tired, which can cause hum on the output or unstable voltage. Those big multi-section can caps? Replace them. The carbon composition resistors can drift out of spec, throwing off the output level and that critical frequency accuracy. The rotary selector switches for frequency range and waveform will be crunchy with oxidation; a good bath with contact cleaner is mandatory. The output level potentiometer is another classic failure point, becoming scratchy and intermittent. The good news is, it's a simple, elegant circuit by today's standards. A full recap, a careful cleaning of all pots and switches, and checking resistor values will usually bring one roaring back to life. Just don't expect lab-grade accuracy without a proper calibration against a modern reference—but honestly, for vintage audio work, it'll be more than precise enough.

Current Market Value and Collectibility

Let's be real: you don't stumble upon an Eico 2716. You hunt for it. Its value is a cocktail of obscurity, utility, and that cool factor. While a common Eico VTVM might go for fifty bucks, the 2716 exists in a different realm. For the right collector—the one who has every common model and lusts for the obscure—this is a trophy. A complete, non-working unit might pull $150-300 just as a curiosity. A cleaned, recapped, and functioning example? Given its precision, mystery, and sheer usefulness on a vintage audio bench, it could easily command $500 to $800 in today's niche market. It's not just a tool; it's a piece of industrial archaeology. Owning one means you're the custodian of a fragment of Eico's history that almost got lost, and that's a special kind of cool you can't put a price on. Plus, you can actually use the thing. Try that with a mint-condition Barbie.