EICO HF-81 Integrated Tube Amplifier| 4 Restoration | Working Iron AND NEW TUBES

EICO HF-81 Integrated Tube Amplifier – Restoration Candidate – Working Iron

Some units are plug-and-play.
This is not one of them.

This EICO HF-81 is a largely original example and should be viewed as a restoration project. The transformers appear healthy, but the amplifier will require electronic servicing for stable, long-term operation. This is for someone who will selectively change parts for stability but retain the sonic character the HF-81 is famous for.

Operational Status (Please Read Carefully)

• Powered up slowly on a Variac

• Power transformer energizes

• Output transformers pass signal

• Video included demonstrating that both channels produce output

• One channel is weaker and exhibits distortion. The stronger channel distorts at high volume.

• Power switch (integrated into treble knob) does not function properly

• Unit is likely running on original capacitors

Given its age, full recap and restoration is recommended before regular use.

Tube Complement (Installed & Working)

The original Eico factory installed tubes tested weak or shorted and were replaced with.

• Quad Sylvania EL84 / 6BQ5 – New old stock (NOS) and new in box (NIB)

• Working 12AX7

• Working 12AU7

• Working EZ81 rectifier

Tubes are functional, but the distortion issue suggests underlying circuit components (likely caps or resistors) require attention.

Condition Overview

• Classic gold faceplate with vintage wear

• Knobs present

• Original layout intact

• Appears largely unmodified internally (based on current inspection)

This unit is being sold as a restoration candidate, not as a fully restored or turnkey amplifier.

Why This Is Worth Restoring

The HF-81 is widely regarded as one of the most musical EL84 integrated amplifiers ever made. Properly restored examples command strong market value and are known for:

• Lush, dimensional midrange

• Excellent phono stage

• Balanced push-pull EL84 output

• Highly respected transformer set

The transformers are the heart of these units — and this one passes signal.

Recommended Buyer Profile

• Experienced hobbyist

• Tube tech

• DIY restorer

• Collector seeking original platform for rebuild

If you’re looking for a fully restored, daily-use amp, this is not that listing.
If you want a strong foundation with working iron and upside potential, this is an excellent candidate.

Disclosure

• Sold as vintage electronic equipment

• Will require recap and service

• Distortion present in one channel

• Power switch requires repair

• See video for operational demonstration