Eico

Brooklyn-built tube kits for the golden age of DIY

History

Key Facts

Legendary Products

Eico HF-81 (Late 1950s)

Eico HF-60 (1960s)

Eico HF-20 (1950s)

Eico ST-70 (1960s)

Sound Signature

Eico's tube amplifiers deliver a sound that is quintessentially mid-century American hi-fi — warm, inviting, and musically engaging. The HF-81's EL84 output tubes produce a sweet, detailed midrange with a gentle top end that makes vocal recordings particularly compelling. At 14 watts per channel, the HF-81 is not about raw power — it is about finesse, and with efficient speakers, those 14 watts deliver a richness and presence that far exceeds their modest rating.

The HF-60 monoblocks offer more authority at 30 watts each, with deeper bass control and greater dynamic headroom while retaining that characteristic Eico warmth. Across the range, these amplifiers share a quality that tube enthusiasts call "bloom" — a subtle harmonic richness that makes instruments sound full and dimensional in a way that transistor amplifiers rarely achieve. They reward simple, well-recorded music and make late-night listening sessions genuinely addictive.

Collecting Eico

The HF-81 is Eico's crown jewel and one of the most beloved vintage integrated amplifiers in the hobby. Factory-assembled units are significantly rarer than kit-built examples (most Eico equipment was sold as kits) and command higher prices, though a carefully assembled kit can sound just as good. The HF-81's distinctive industrial design — with its exposed tubes and stamped metal chassis — has an honest, workbench aesthetic that collectors find deeply appealing.

The HF-60 monoblocks are the power enthusiast's choice and are excellent candidates for careful restoration. The HF-20 offers a more affordable entry point into Eico ownership. When evaluating any vintage Eico, look for units with original transformers intact — these are the most expensive and difficult components to replace. Complete units with original documentation, schematics, and assembly instructions are especially prized, as the manuals themselves are beautifully detailed artifacts of the golden age of DIY electronics.

Competitors & Comparisons

Amplifiers

• 2050 — Eico 2050 FM tuner from 1961, built from a Radio-Electronics construction article. A 14-tube design with 10 IF stages and crystal filter.
• 2536 (1970) — Eico 2536: A rare and enigmatic vintage audio component, possibly a preamplifier or test device from the early 1970s. With the complete spec table.
• 3150 (1967) — The Eico Cortina 3150 was a solid-state integrated amplifier from the late 1960s, representing Eico's most serious attempt at transistorized audio.
• HF-12A (1957) — Eico HF-12A high-fidelity audio amplifier kit, a classic DIY tube amplifier from the golden era of hi-fi. With the complete spec table and when it was made.
• HF-14 (1952) — The Eico HF-14 was a 14-watt tube power amp kit from 1952 that brought high-fidelity sound within reach of DIYers—simple, robust, and musically engaging.
• HF-20 (1955) — A classic vacuum tube stereo amplifier from the 1950s, the Eico HF-20 was a DIY favorite known for its solid performance and accessible design.
• HF-22 (1955) — Eico HF-22 (1955) tube amp with 22W/channel, 6SN7GT drivers, 5Y3GT rectifier, and over 40dB separation — a DIY hi-fi classic
• HF-30 (1954) — Eico HF-30 vacuum tube stereo amplifier kit from the 1950s, a pioneering DIY design for early high-fidelity stereo enthusiasts.
• HF-35 (1957) — A classic vacuum tube stereo amplifier kit from the late 1950s, known for its build quality and warm tube sound. Find the complete spec table here.
• HF-52 (1955) — Eico HF-52 vacuum tube stereo amplifier kit from the 1950s, a landmark DIY design for early hi-fi enthusiasts. Find the complete spec table here.
• HF-60 (1956) — Eico HF-60 vacuum tube stereo amplifier kit from the late 1950s, known for its modular design and audiophile-grade performance for home builders.
• HF-61 (1956) — The Eico HF-61 (1959) mono preamp delivers rich tube sound with switchable phono EQ and classic feedback tone control. Covers current market value.
• HF-85 (1955) — A high-fidelity vacuum tube stereo amplifier kit from the 1950s, designed for audiophiles and hobbyists seeking quality sound and hands-on electronics experience.
• HF-86 (1959) — Eico HF-86: A legendary vacuum tube stereo amplifier kit from the golden era of hi-fi, prized by audiophiles and DIY enthusiasts.'
• HF-89 (1955) — Eico HF-89 vacuum tube stereo amplifier kit from the 1950s, prized by vintage audio enthusiasts and DIY builders. Includes detailed specs.
• HF-92 (1955) — A high-performance push-pull tube amplifier from the golden age of hi-fi, the Eico HF-92 offered audiophiles exceptional fidelity and build quality in kit form.
• ST-70 (1957–mid-1960s) — Eico ST-70 tube stereo amplifier kit (1957). 35W/ch, 7591 outputs, $99.95 kit / $149.95 wired. One of the first hi-fi stereo kit amps.

Preamplifier

• HF-61A — Eico HF-61A master-control preamplifier — kit $24.95, wired $37.95, full phono EQ and concentric controls. A period Eico control center.

Preamps

• ST-84 (1957) — Eico ST-84 stereo phono preamplifier kit for home audio enthusiasts. Covers full specifications and production years. Covers full specifications.

Receivers

• ST-3120 (1973) — Eico ST-3120 stereo tuner – a solid-state, high-fidelity FM/AM receiver component from the golden era of DIY and modular audio.

Speakers

• 3200 (1970) — The Eico 3200 (1967) is a solid-state FM stereo tuner with analogue tuning and a 88–108 MHz range. Specs, history, and context for this late-era EICO.
• 3440 (1975) — The Eico 3440 is a 1975 audio color organ that turns music into analog light shows using fluorescent tubes—quirky, nostalgic.
• 3570 (1972) — The Eico Cortina Model 3570 (1967) was a kit-built solid-state FM stereo receiver—rare today, often non-functional, and always a project for the patient restorer.
• HF-32 (1955) — The Eico HF-32 (1958–1963) is a 30-watt mono tube amplifier with EL84 power, RIAA/Columbia phono, and precision tone controls — a high-fidelity workhorse of the late 1950s.
• HF-65A (1958) — The Eico HF-65A (c. 1960s) is a tube preamplifier with 3x 12AX7, self-powered design, and magnetic phono input. Specs, restoration notes, and collectibility.
• HF-81 (1957) — The EICO HF-81 (1959) is a vintage tube integrated amplifier kit known for its warm, detailed sound and DIY heritage. Covers production years.
• HFS-2 (1958) — Eico's HFS-2 was a pioneering high-fidelity speaker system designed for audiophiles and DIY enthusiasts in the late 1950s.
• HFT-92 — Eico HFT-92 AM/FM tube tuner — an HFT-90 FM section with added AM, mono until paired with the MX-99 multiplex adaptor. Kit $59.95, wired $94.95.
• MX-99 (1961–1962, possibly 1963) — Eico MX-99 (1961–62) FM multiplex adaptor — tube decoder that predated the FCC stereo FM standard. Kit $39.95, wired $64.95.

Test Equipment

• 221 — Eico 221 tube tuner-preamplifier (1959-1962), FM 87.5-108 MHz, 2V output, designed to pair with the HF81 amplifier. Little else documented.
• 625 (ca. 1951) — Eico 625 VTVM — line-powered tube voltmeter from the 1950s-60s kit era with mirrored 4 1/2 inch meter, balanced 12AU7 bridge circuit.
• 667 — Eico 667 dynamic mutual conductance tube tester, 1950s-60s kit, 3400 tube types on roll chart, 4.5-inch 200µA meter, 105-125V AC.

Tuners

• 2536-FM — Eico 2536-FM FM stereo receiver, Classic Series kit — $154.95, or in the $445 Classic Speed Kit bundle. Little documented beyond Eico's own ads.
• 96-FM — The Eico 96-FM is a little-documented FM tuner recorded in a 1961 HI-Fi-Stereo-Buyers directory listing with 4 µV sensitivity, 1.1 V audio output.
• HFT-80 (1957) — Eico HFT-80 High-Fidelity Tuner — a classic tube-based FM tuner from the golden era of hi-fi, prized by vintage enthusiasts for its warm reception and vintage charm.
• ST-96 — Eico ST-96 AM-FM stereo tuner: dual independent tuners, eye-tronic indicators, 1.5 µV FM sensitivity, $89.95 kit / $129.95 wired.
• ST-97 (1968) — The Eico ST-97 FM Stereo Tube Tuner, is revered by some as the best-sounding FM tuner ever made, using matrix decoding and sharing circuitry with the MX99.

Other Models

• 3420 — Eico 3420 (1968) — an obscure tube-driven monophonic analog synthesizer sold as a $59.95 kit. Little documented beyond its educational purpose and collector toy label.
• 3570MS — Eico 3570 (1967) solid-state FM stereo receiver — 70W kit-built hi-fi project with 31 transistors. Rare, often non-working, and a true restoration challenge.
• 377 — Eico 377 all-in-one receiver, possibly the world's first transistor example. Little documented; single-source claims of 40W/channel and transistor design.
• 378 — Eico 378 stereo multiplex adapter from the late 1950s-1960s. Matrix demodulator, two tubes, kit or wired. An early FM stereo decoder for mono tuners.
• Classic 2400 — Eico Classic 2400 three-motor 4-track tape recorder — semi-kit $199.95, wired $269.95, 7½/3¾ ips.
• Cortina — Eico Cortina — late-1960s all-silicon solid-state audio line. Advertising claimed budget pricing with high-end sound; documented models include the 3150 amplifier and 3070 receiver kit.
• Cortina 3150 — Eico Cortina 3150 (1968) — Eico's budget solid-state integrated amplifier with dual FET outputs, 25W/ch RMS, walnut cabinet included, $79.95 new.
• HF-10 — Eico HF-10 integrated amplifier — a little-documented model known only by basic specs: 10W per channel, 20Hz-20kHz, 1% THD, 80dB S/N.
• HF-11 — Eico HF-11 mono integrated amplifier (1956), triode-mode EL84 push-pull, 12 watts. Mono companion to HF-10; two units for stereo. Scarce today.
• HF-65 — Eico HF-65 stereo dual preamp (1958–1961): kit $33.95, wired $49.95. High-Fidelity found measured performance matched Eico's published specs.
• HFS-10 — EICO HFS-10 3-way bookshelf speaker kit — bass-reflex, 10-inch woofer, 5-inch midrange, dual 3-inch tweeters, 98 dB efficiency.
• HFS-8 (mid-1960s) — Eico HFS-8 two-way bookshelf speaker, mid-1960s. 8-inch cloth-suspension woofer, 2-inch cone tweeter, 8 ohms, walnut bass-reflex cabinet tuned to 55 Hz. $54 each; part of the $445 Classic Speed Kit.
• HFT 90 — A tube-based FM tuner kit from the late 1950s, designed for high performance at a modest price. With full specifications and production years.
• HM-85 — Eico HM-85, an obscure tape machine from the early 1960s. Only known from a single 1962 Audio-Collection listing; specs and history largely undocumented.
• HM-90 — Eico HM-90: obscure vacuum-tube ham radio RF wattmeter, 0-10/0-100W ranges, 52-ohm line, extends to 220 MHz. Little documented.
• MODEL-250 — EICO Model 250 AC VTVM & amplifier — 12 ranges from 100 µV to 300 V, 60 dB gain, ±3% accuracy, regulated supply. A laboratory-grade bench instrument.
• MODEL-315 — EICO Model 315 signal generator kit — seven bands, 75 kc to 150 mc, 7F7 buffer, regulated against line sag. A 1950s serviceman's build-it-yourself instrument.
• MODEL-3150 — Eico Model 3150 Cortina integrated amp — 40 W/ch continuous, dual-mono boards, 1969. Measured 55 W/ch at 0.3% THD. Kit $149.95, wired $225.
• MODEL-3200 — Eico Model 3200 Cortina FM stereo tuner (1967) — pre-aligned kit, 2.4µV sensitivity, measured better than claimed.
• RP-100W — Eico RP-100W four-track stereo tape deck, sold assembled at $395 in 1961. Scarce, thinly documented, with a persistent amplifier-vs-deck identity conflict in the record.