Symetrix SX204 Owner's Manual

Owner’s Manual

Symetrix

SX204

Headphone Amplifier

Symetrix Inc.

14926 35th Avenue West

Lynnwood, Washington 98037

Voice: [phone], [phone]

Fax: [phone]

Copyright 1988, 1994 Symetrix Inc.

All rights reserved.

Subject to change without notice.

Batteries not included.

This manual will not play in reverse.

Revision: 2.0, 10/01/94

Part Number: 530104

1

Rev 2.0, 10/01/94

Table of Contents

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1. INTRODUCTION................................................................................................2

2. USING THE SX204..............................................................................................3

2.1 I

MPEDANCE, SENSITIVITY, LOUDNESS ..................................................................3

2.2 M

AXIMUM AMPLIFIER LOAD.................................................................................3

3. REAR PANEL......................................................................................................5

4. FRONT PANEL ...................................................................................................6

5. BLOCK DIAGRAM.............................................................................................7

6. SPECIFICATIONS..............................................................................................8

7. REPAIR INFORMATION..................................................................................9

7.1 R

ETURN AUTHORIZATION .....................................................................................9

7.2 I

N-WARRANTY REPAIRS........................................................................................9

7.3 O

UT-OF-WARRANTY REPAIRS...............................................................................9

8. LIMITED WARRANTY................................................................................10

2

Rev 2.0, 10/01/94

1. Introduction

______________________________________________________________

The Model SX204 Headphone Amplifier is a 1-in 4-out amplifier
designed to drive multiple headphones of any impedance. Symetrix'
proprietary high voltage converter technology gives the SX204 the
ability to drive high impedance headphones with the equivalent
output voltage of a much larger power amplifier, yet provides more
than ample current for low impedance phones. The four stereo
outputs automatically adjust output power to match the load
impedance.

Controls provided are input level, output level for each individual
amplifier, and a stereo/mono switch.

The

STEREO/MONO switch allows the amplifier to be used several

ways. As a "normal" stereo amplifier (with four outputs), the left and
right inputs are used for stereo signals, which feed the left and right
outputs. Switching to mono with a stereo input provides a quick
check of the mono compatibility of a stereo mix.

As a mono amplifier, one signal fed to either input will feed both out­puts. Also in mono mode, when two different mono signals are fed to
the left and right inputs, they will be combined to feed both the left
and right outputs.

The inputs are electronically balanced, but will operate normally in
an unbalanced configuration when 2-conductor 1/4" plugs are
inserted. The outputs are 1/4" stereo connectors.

3

Rev 2.0, 10/01/94

2. Using the SX204

_____________________________________________________

CAUTION: Do not use any AC adapter other than the
Symetrix PS-2. Do not short the outputs. Do not stick
your finger in a light socket.

2.1 Impedance, Sensitivity, Loudness

Loudness is directly related to the impedance and sensitivity of the
headphones. Impedance determines how much power the
headphones will draw, while sensitivity indicates how much of the
electrical signal delivered to the headphones is converted into sound.

Because low impedance headphones draw more power from the am­plifier they will sound louder, at the same control settings, than high
impedance headphones. Also, headphones of higher sensitivity will
sound louder than those of lower sensitivity. Check the
manufacturer's spec sheet for impedance and sensitivity information.

Proprietary high voltage converter technology allows the SX204 to
drive even high impedance head headphones to maximum levels, be­cause the amplifiers are capable of very high output voltage swing.
However, to get a loudness equivalent to that of low impedance head­phones, the controls will have to be set much higher with high
impedance headphones. This is normal.

If low and high impedance headphones are combined on the same
channel, the low impedance headphones will be much louder. As a
result, when a combination of high impedance and low impedance
headphones is used, only those of like impedance should be used on
the same channel. This allows each listener to properly adjust
loudness, without regard to the impedance and sensitivity of the
other headphones.

2.2 Maximum Amplifier Load

The minimum operating impedance, or maximum load, for each
output of the SX204 is 8 ohms. Use as many pairs of headphones as
desired, as long as the total combined impedance (per output) does
not fall below 8 ohms. Table 2.1 shows how many headphones of
various impedances may be used with each output of the SX204.