Eico HF-61 (1959)
This is the preamp that taught a generation how to build high fidelity.
Overview
The Eico HF-61 High Fidelity Master Control was built in 1959 by EICO (Electronic Instrument Company) of New York City. It is a mono tube preamplifier, and it arrived when hi-fi was still a hobby, not a commodity. It wasn't aimed at the luxury market or the audiophile elite. It was for the do-it-yourselfer who wanted real tube sound without emptying their wallet. That was EICO's whole deal: educational electronics you could assemble yourself, or buy fully wired if you preferred to skip the soldering iron.
Founded in 1945, EICO started as a test equipment manufacturer and quickly became a leader in kit-based electronics. By the late 1950s, they were producing a full range of high-fidelity gear - receivers, amplifiers, tuners and speakers. The HF-61 was a dedicated mono preamp, designed to be the control center of a custom-built audio system. It didn't try to match the refinement of high-end commercial units. It offered solid performance at a low cost, and you got the satisfaction of building it. Kit or factory-wired, it was made for enthusiasts who valued function, flexibility, and working with vacuum tubes.
Specifications
| Manufacturer | EICO (Electronic Instrument Company) |
| Model | HF-61 |
| Year Introduced | 1959 |
| Type | Mono Tube Preamplifier |
| Tubes | 1 x 12AX7, 2 x 12AU7, 1 x 6X4 |
| Phono EQ Settings | RIAA, Flat, American 78, European 78 |
| Inputs | 2 separate phone inputs |
| Power Source | A.C. Powered |
| Power Connection | Non-self-powered, 8-pin input for power from Eico HF-60 amp |
| Maximum Output Level | Can just about deliver +20dBu into 10K load |
| Output Load Limitation | Does not want to drive true 600-ohm "Pro" inputs |
| Gain (modified for mic preamp) | Total gain around 80dB, trimmable down to 40dB |
Key Features
Feedback Tone Control – The Heart of the HF-61
The circuit's feedback tone control is widely regarded as "probably the best part of the EICO," according to experienced builders. Unlike simpler passive designs, this active feedback system shapes the frequency response with a smoother, more musical character. It isn't clinical. It's responsive and useful for tailoring records to your room or taste.
Loudness Control with a Flat Sweet Spot
It has a Loudness control, which is no surprise for a 1950s preamp. The neat bit is that when you turn it all the way up, the frequency response goes flat. So you can use it to boost bass and treble at low volumes, then dial it back to neutral for full-range listening. Owners report the control is variable via a front-panel knob, not a switch, which allows fine adjustments.
Cathode Follower Output Stage
The output stage uses a cathode follower configuration, which lowers the output impedance and improves drive capability. It still struggles with low-impedance loads. Owners note it really doesn't want to drive true 600-ohm pro inputs. Into 10K or higher it performs reliably, delivering up to +20dBu of output. Don't expect it to feed a modern recording console without buffering.
Flexible Phono Stage with Multiple EQ Curves
The phono stage includes switchable equalization: RIAA, Flat, American 78, and European 78. That kind of versatility was rare at the price point and made it a favorite among record collectors with mixed libraries. LPs, 78s or raw acetates, the HF-61 could handle them with no external EQ. Some sources note the unit has eleven different phono settings, though the exact configuration beyond the four main EQ curves isn't detailed.
Power Integration with the HF-60
Unlike many standalone preamps, the HF-61 is non-self-powered. It relies on an 8-pin input to draw power from the Eico HF-60 amplifier. This suggests it was intended to be part of a matched system rather than a universal component. That limits standalone use, but it simplifies the build for kit users and ensures stable power delivery when paired with its companion amp.
Historical Context
EICO, established in New York City in 1945, began as a test equipment manufacturer and became a cornerstone of the DIY electronics movement. From the early 1950s to the mid-1960s, the company produced a wide range of hi-fi products, all available in kit form or fully assembled. The HF-61 was part of this push, designed for budget-conscious enthusiasts who wanted performance without premium prices. The company operated from Brooklyn, later moved to Queens, and eventually returned to Brooklyn. EICO left the audio market in the late 1970s and was liquidated in 1999.
Collectibility & Value
The HF-61 isn't a blue-chip collector's item like some Marantz or McIntosh gear, but it holds steady appeal among tube DIYers and restoration buffs. A used Eico HF-61 from the 1950s in "gold brown" finish was listed for $200 on March 22, 2026, described as either a "gold mine of parts" or a potential restoration project. Listings often sell "As-Is, with no warranty," reflecting the age and uncertainty of untested tube gear.
Restoration is a real possibility, thanks to the availability of support. A full filter capacitor repair and rebuild kit was listed for $95 on August 18, 2022, complete with parts and instructions. While prices for other Eico gear like the HF-81 have reportedly "shot up on eBay," the HF-61 remains relatively grounded. One user on Audio Asylum notes that mono preamps like the HF-61 may be "under the radar" and not go for "big bucks."
Market Value
┌──────────────────────────────────────────────────────────────────────────┐ │ EICO HF-61 Nov 2026 │ ├──────────────────────────────────────────────────────────────────────────┤ │ High $257 Latest $115 │ │ Median $185 Trend — │ │ Low $103 Volume ~1/mo │ ├──────────────────────────────────────────────────────────────────────────┤ │ $300 ┤ │ │ │ │ │ │. . │ │ $214 ┤ │ │ │ │ │ │ │ │ │ │ │ $100 ┤ . .│ │ ├─────────────────────────────────────────────────────────────────│ │ vol │█ █ █ █│ │ └─────────────────────────────────────────────────────────────────│ │ 2026-03 2026-05 2026-07│ └──────────────────────────────────────────────────────────────────────────┘
eBay completed sales. Excludes accessories, parts, and non-working units. Hover points for details.
eBay Listings
Recently sold on eBay: $103–$257 (median $185, based on 4 completed sales, past 12 months)
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