Eico HF 89 Owners Manual

Page 2

moon HF 89 STEREO DUAL POWER AMPLIFIER

general description

GENERAL

The very finest techniques known to the mdio art are
applied in the HF-89 stereo high fidelityduai power am-
plifierto insurethe utmost in wdio quality underthe most
demanding circumstances. The HF-89 can be used with the
superb EICO HF85stereophonic preamplifier or with any
good self-powered stereo preamp.

Each power amplifier of the HF-89is conservatively rated
at 50 watts and employs the thoroughly proven cathode-
coupled phase inverter-driven circuit, preceded by a
direct-coupled voltage anplifi er. Ultra linear connected,
fixed-biased, push-pull EL34's are used in the output
stage and provision is madefor both bias md dc balance
adiustments. The very low impedance characteristic of
silicon diode rectifiers gives the common power supply
for the two amplifiers very good regulation. As a result,
sigsal conditions in one amplifier have negligible effect
on the operating conditions of the other amplifier -- a
very worthwhile feature in a high quality design. To
insure long life for the silicon diode rectifiers, electro-
lytics, and tubes, asurgistorisincludedto limit the start-
ing surge currents.

SPECIFICATIONS

Outfit Power: 100me (two 50watt amplifiers) contin-
uous, 200 watts peak

IM Distortion (60 s 7000 CPS at 4:1): 0. 596m lOOwatts
Harmonic Distortion: Less than 0. 25% from 30 to l5, 000

cps «:13 less than lg from20 to 20, 000 cps within idbof
lOO watts

Frflency Resense: 1:0. 5db 5 cps - l00l Rise Time: 2.51sec

Sgare-Wave Rename: Essentiallyundistorted to 20, 000
cps

Inverse Feedback: leb

' Stability Magin: 13 db
Damping Factor: above i2, 20 cps to 20kc

The intrinsic quality of the driving circuit, the output
tubes, and the output transformers in the HF-89 is unsur-
passed. lM distortion at normal listening levels drops to
below 0. 1%, andeven at 100,000 cps atotai of 60 watts
undistortedoutput is availableto insure unimpaired trm-
sient (square wave) response even at very high power
levels. The low end is extremely solid and full, as an
undistorted total power output of 78 watts at 15 cps md
28 watts at 10 cps would imply. Furthermore, the high
circuit and component quality results in less feedback
required to achieve these very low distortion figures, so
that the HF-89 amplifiers have a very healthy stability
margin to insure perfect results in any application.

The methods of stereo recording are such that, at moments,
practically all the sound is in one channel or the other.
For this reason, the best stereo installations require an
amplifier in each channel as powerful as that used in the
best monophonic installations. 50 watt amplifiers have
been found very worthwhi Ie in the best monophonic instal-
lations and adsal 50watt amplifier will befound equally
worthwhile in the best stereo installations.

Channel Sgparation: 60db
Sensitivity: 0.55V for full output

Hum: Better than 90db below full output

Controls: Level Ch. i, Level Ch. 2, "ServiceSelector"
switch, bN-OFF switch

SEaker Connections: 4, 8, and I6 ohms

Tubes: l-ECC83/12AX7, 2-6SN7GTB, 4-EL34, 25ilicon
diode rectifiers (power), 1 selenium rectifier (bias); sur-
gistor protected for long life

Power Source: 117V, 60 cps

Power Consum tion: 25me atno signal, 270 watts ot
lOO watts out

Size: l5'.x II" x 6

Shipping Weight: 37 1/2 lbs.

COPVRIGHY© '760 ELECTRONIC INSVIUMENT COMPANY, Inc.