Fostex 3050 Owners Manual

Modei3050
DIGITAL DELAY UNIT
Owners Manual
TABLE OF CONTENTS
SECTION
SECTION
SECTION
SECTION
SECTION
SECTION
© N >= © N —
SAFETY INSTRUCTIONS
WARNING
“READ BEFORE OPERATING”
1.
Read Instructions—All the safety and operating instruc-
tions should be read before the appliance is operated.
Retain Instructions—The safety and operating instruc-
tions should be retained for future reference.
Heed Warnings—All warnings on the appliance and in
the operating instructions should be adhered to.
Follow Instructions—All operating and use instructions
should be followed.
Water and Moisture—The appliance should not be used
near water—for example, near a bathtub, washbow,
kitchen sink, taundry tub, in a wet basement, or near a
swimming pool, etc.
Ventilation —The appliance should be situated so that its
location or position does not interfere with its proper ven-
tilation. For example, the appliance should not be situated
on a bed, sofa, rug, or similar surface that may block the
ventilation openings; or, placed in a built-in installation,
such as a bookcase or cabinet that may impede the flow
of air through the ventilation openings.
Heat— The appliance should be situated away from heat
sources such as radiators, heat registers, stoves, or other
appliances (including amplifiers) that produce heat.
Power Sources—The appliance should be connected to
a power supply only of the type described in the operating
instructions or as marked on the appliance.
Power-Cord Protection —Power-supply cords should be
routed so that they are not likely to be walked on or
pinched by items placed upon or against them, paying
particular attention to cords at plugs, convenience recep-
tacles, and the point where they exit from the appliance.
INTRODUCTION
FRONT PANEL CONTROLS
REAR PANEL JACKS
OPERATION
SPECIFICATIONS
BLOCK DIAGRAM
10.
11.
12.
13.
14.
Cleaning—The appliance should be cleaned only as
recommended by the manufacturer,
Nonuse Periods—The power cord of the appliance
should be unplugged from the outlet when left unused for
a long period of time.
Object and Liquid Entry —Care should be taken so that
objects do not fall and liquids are not spilled into the
enclosure through openings.
Damage Requiring Service—The appliance should be
serviced by qualified service personnel when:
A. The power-supply cord or the plug has been damaged;
or
B. Objects have fallen, or liquid has been spilled into the
appliance; or
C. The appliance has been exposed to rain; or
D. The appliance ‘does not appear to operate normally or
exhibits a marked change in performance; or
E. The appliance has been dropped, or the enclosure
damaged.
Servicing—The user should not attempt to service the
appliance beyond that described in the operating in-
structions. All other servicing should be referred to
qualified service personnel.
WARNING: To avoid possible electric shock hazard,
do not expose this appliance to rain or moisture.
There are no user serviceable parts inside.
Refer servicing to qualified service personnel.
PAGE
10
1
Figure 1. Model 3050 front panel features.
Figure 2. Model 3050 rear panel features.
SECTION 1 INTRODUCTION
The Fostex Model 3050 Digital Delay Unit is an Audio Delay Line
capable of wide application as a flanger, chorus effecter, echo effecter,
etc. It features a constant frequency range and good S/N by the noise
reduction circuit, throughout the entire delay time setting.
Numerous effects can be created by this unit alone as it contains
a feedback circuit and a modulating oscillator,
It also has an input for external control of delay time, making it
possible to externally set delay time by a DC voltage or modulate delay
time with the LFO and envelope generator of a music synthesizer.
SECTION 2 FRONT PANEL CONTROLS
[1] INPUT LEVEL
The control for matching the input signal level to that required by
the digital delay circuit.
[2] INPUT LEVEL INDICATOR
Indicates condition of signal level set by above [1].
The LIMIT LED indicates functioning of the limiter circuit when
there is an excessively high input signal.
[3] DELAY TIME: RANGE
Delay time range is set up by this ten position switch.
[4] DELAY TIME: MULTI
The delay time value set by above control [3] can be continuously
varied from 1/2 through 2 times.
[5] MODULATION LIMIT INDICATOR
This indicator will light up when delay time drops or exceeds the
1/2 through 2 times range due to the overall effect of [4] and [6]
setting and the external control voltage. When lit, delay time will
not change any further.
[6] MODULATION - DEPTH
Modulation is the sweeping of delay time with the value set by (3]
and [4] as the center. The depth of this modulation is controlled
by this knob.
[7] MODULATION - SPEED
The modulation frequency is set by this knob.
[8] FEEDBACK
Controls the amount of delayed signal feedback when it is returned
again to the delay circuit.
[9] CUTPUT MIX: DRY
[10]
[11]
[12]
[13]
Controls output level of the unprocessed signal.
OUTPUT MiX: DELAY
The output of this Unit is a mixture of the DRY (original) signal
and the DELAY signal. Level of each signal is independently control-
led by [9] and {10].
DELAY PHASE SWITCH
For inverting phase of the delayed signal to be applied to the
feedback and output mixing circuits.
Power ON indicator
Power switch
SECTION 3 REAR PANEL JACKS
[14]
[15]
[16]
[17]
[18]
INPUT JACK
Pin jack for the input signal.
FOLDBACK JACK
Wired in parallel with the above [14] jack, this jack allows access
to the branched input signal.
QUTPUT
An output signal mixed by [9] and [10] is obtained here.
AUX OUT
Wired in parallel with above [16], the same signal is obtained here.
CONT IN
Delay time can be controlled from 1/2 through 2 times by an external
voltage applied here.
SECTION 4 OPERATION
Please read this section while referring to the block diagram.
Numers [1], [2], ... correspond with those in explanation of the front
panel controls.
4.1
Input connections and level adjusting
Apply an audio signal to the rear panel INPUT jack. As the FOLDBACK
jack is wired in parallel with the INPUT jack, the audio input can be
branched to other equipment from this FOLDBACK jack.
If the INPUT control knob is set at maximum, it will match the
standard level of -20dBV (0.1V). As this INPUT control is located at the
entrance of the input circuit, a higher input level can be controlled to
prevent saturation of the input stage.
When input is over loaded
The Unit contains a limiter circuit to prevent harmful clipping in
the A/D converter when the input is overloaded. When this limiter goes
into operation, the red LIMIT indicator [2] is lighted. After lighting
of this LED, there is 10 dB headroom before clipping occurs in the input
stage. When clipping occurs, distortion will suddenly increase.
For operation under best condition, constant care must be taken in
establishing the input level. Good 5/N can be obtained when the level is
set as high as possible without letting the LIMIT LED light up too fre-
quently.
Level changes of an actual music signal is normally very great. Due
to the characteristic of the compressor circuit used for noise reduction,
there is instantaneous limiting at the rising point of sound where the
LIMIT LED is lit but this has only slight effect on actual listening
conditions.
Setting of delay time
Delay time (mS), as set by the DELAY TIME - RANGE knob [3], will be
the direct reading of the knob pointer when the DELAY TIME - MULTI knob
[4] is set at X1. The multiplication factor for knob [3] can be varied
continuously from 1/2 through 2 times of the knob [3] setting as the
center value.
By combined effect of knobs {3] and [4], minimum delay is 0.13mS and
maximum delay 273mS.
4.4 Modulation
4.5
As the DEPTH knob [6] is advanced, delay time is swept up and down
with the delay time set by the aforementioned knobs [3] and [4] as the
center value. Frequency of the LFO for the sweep is adjusted by SPEED
knob [7]. Maximum depth of modulation is 4 times (1/2 through 2 times
against delay time set by RANGE knob ([3]). Knob [4] must be set at Xi
for maximum depth.
External delay time control
Delay time can be controlled by a voltage applied to the CONT IN
jack [18] on the rear panel. When this external voltage is zero, delay
time is directly as established by knobs [3], [4] and [6] but delay time
is multiplied by 1.15 for each one volt increase of the external voltage.
On the other hand, multiplication will be 1/1.15 = 0.87 times for each
one volt decrease. Multiplication will be 2 times for a 5 volt increase
and 4 times for a 10 volt increase.
Notes on range of continuously variable delay time
As shown in the block diagram, the DC voltage set by the delay time
MULTI knob, the LFO signal controlled by the modulation DEPTH knob and
the external control voltage are simply summed and applied to the anti-
log VCO (Voltage Controlled Oscillator) to control it. The VCO output
establishes the fundamental timing of the control logic circuit. The delay
time is inversely proportional to the VCO frequency. The delay time control
limit from 1/2 through 2 times is derived from the sum of the above three
voltages. In other words, the frequency (delay time) will not go below or
above this range even though a voltage exceeding this range is applied to
the VCO.
Figure 3.
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For instance, with the external voltage at 0 V and the modulation
DEPTH [6] set at a certain point, the actual delay time will be as in
above schematic in relation to position of the delay time MULTI [4]. The
modulation LIMIT LED [5] will be lit to warn that multiplication has
reached the limit of 1/2 or 2 times.
As shown by the extreme right curve, a short duration ON of the LED
does not pose any problem in practical use.
The relation between external voltage and delay time is shown below
(when modulation DEPTH [6] is at O).
Figure 4.
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4.7
4.8
4.9
Feedback
The amount of delay circuit sound signal output to be returned to
the delay circuit input, is controlled by this FEEDBACK knob [8].
The actual delay circuit input signals are the sum of the external
input and the feedback signal. Therefore, there is a point of excess
input to the delay circuit as the FEEDBACK knob is rotated CW. This condi-
tion is also shown by the level indicator {2] as it indicates the condition
after this summing. If the input level is in excess, lower it by the INPUT
knob {11}.
The signal level will increase at each round of the feedback loop as
gain will be larger than 1 if the FEEDBACK knob is set at maximum (10).
The gain, however, will drop temporarily when it reaches the limiting
area.
Output connections and level adjustment
Exactly the same signals are obtained at OUTPUT jack [16] and AUX
OUT jack [17].
The output signal is a mixture of the signal from the point imme-
diately after the input control pot (DRY) and the delay circuit output
signal (DELAY).
Output levels of the DRY and DELAY signals are respectively control-
led by knobs [9] and [10]. The nominal output will be -10dBV (0.3V) when
either one of knobs [9] or [10] is set at zero and the other at maximum.
With the output level set as above and the INPUT pot [1] set at 10 ав
below maximum (approx. scale 7}, the input vs output levels of this Unit
will be 1:1.
If the DELAY - PHASE button is depressed, phase of the delay circuit
output signal applied to the output mixing circuit and feedback circuit
will be inverted.
Examples of application
In the following explanations, it is presumed that the INPUT control
pot [1] and OUTPUT MIX - DELAY pot [10] are set at the best point for the
equipments connected to the Unit. It must be noted, however, that the
input may be overloaded if FEEDBACK [8] is raised, and the output go too
high if the OUTPUT MIX - DRY [9] is raised.
Except when using the Unit as a flanger or adding vibrato to the
sound, whether you raise [9] or not is your choice.
a) Echo
Set the front panel controls as follows:
[3] DELAT TIME - RANGE
[4] DELAY TIME - MULTI
[6] MODULATION -— DEPTH
{8] FEEDBACK
[11] DELAY - PHASE
Higher than 34mS
Variable
“o
Variable
NORMAL
Only one echo is obtained with FEEDBACK [8] at "0" but advancing the
pot results in multiple echoes.
b) Chorus/doubling
Set the front panel controls as follows:
[3] DELAY TIME - RANGE
[4] DELAY TIME - MULTI
[6] MODULATION - DEPTH
[7] MODULATION - SPEED
[8] FEEDBACK
[11] DELAY - PHASE
8.5 v 34mS
Variable
variable
variable
son
NORMAL
Pitch of the sound is changed when delay time is continuously varied.
Using this effect, if a song with a slight change in pitch is heard together
with the original song, one singer could have the effect of two performers.
Also, when this effect is applied to sounds from an instrument, it could
add depth, particularly to a continuous note. The shift in pitch is increased
if any one of the three factors - delay time, DEPTH, or SPEED - is increased.
In addition, if delay is set to the larger value within the above setting,
not only shift in pitch but shift in time can also be heard.
c) Fianger
Set the front panel controls as follows:
[3] DELAY TIME - RANGE
[4] DELAY TIME - MULTI
[6] MODULATION - DEPTH
[7] MODULATION - SPEED
[8] FEEDBACK
Less than 4.3 mS
Xl
9 v 10
Variable
Variable
[9] OUTPUT MIX - DRY Same setting as OUTPUT MIX - DELAY
[11] PHASE NORMAL or INVERT
If a delayed signal is mixed with the original sound in 1:1 ratio,
numerous dips will occur in the frequency response. The effect of shift-
ing these dips over the frequency response by sweeping the delay time is
called flanging.
If a shorter delay time within the above setting is selected, it
will successively affect only the higher frequencies.
In order to obtain maximum sweep, MULTI {4] is set at Xl. The sweep
cycle can readily be confirmed if DEPTH control [6] is set such that the
MODULATION - LIMIT LED [5] is instantaneously lit at each end of the sweep.
If FEEDBACK [8] is successively raised, dips and peaks upon the
frequency characteristic will be exaggerated.
the QUTPUT MIX - DRY [9] must be set at exactly the same position with
DELAY [10]. However, when FEEDBACK [8] is raised, in some cases better
results can be obtained if the DRY knob [9] is slightly lower than the
setting of DELAY [10].
When the DELAY - PHASE button is set to INVERT, positions of the dips
and peaks upon the frequency characteristic will be inverted. In such
negative flanging, the lower the frequency of the signal, the more larger
is the amount of constant cancelling, and therefore, the effect will be
as if the lower region were cut. This effect is promoted by using shorter
delay times.
d) Vibrato
Set the front panel controls as follows:
[3] DELAY TIME - RANGE 2.1 v 8.5m8
[4] DELAY TIME — MULTI Variable
[6] MODULATION - DEPTH Variable
[7] MODULATION - SPEED Between 12 Vv 4 o'clock
[8] FEEDBACK "О"
[9] OUTPUT MIX - DRY "o"
Vibrato is a timewise variation of the pitch. By using this Delay
Unit, musical instruments which originally cannot apply vibrato can be
made to sound with vibrato. Same as in the case of the previous b) Chorus,
shift in pitch is successively greater with progressive increase of DELAY
10
TIME, MODULATION ~- DEPTH and MODULATION - SPEED.
e) External control of delay time
From among the various effects mentioned above, in examples where
the internal LFO is used (to set DEPTH at other than "0") this can be
replaced by an externally applied voltage. In such a case, DEPTH is set
at "0". Tt must be noted that there is no gain control for this input.
A 10V p-p voltage is required for control over the entire range (1/2
through 2 times). If the LFO such as in a music synthesizer with a volt-
age of +5V is to be used, MULTI must be set at X1. If an envelope genera-
tor with a typical 0 v 10V output is used, MULTI is set at 1/2.
SECTION 5 SPECIFICATIONS
Delay time
Delay time modulation
Frequency response
Range
T.H.D.
Nominal input level
Input impedance
Nominal output level
Output load impedance
0.13 msec v 270 msec
Range select : 0.27 msec % 137 msec,
selectable in 10 steps-
Multiplication : X1/2 vv X2, continuously
adjustable.
Frequency : 0.1 Hz v 30 Hz
width : ] : 4 (max.)
Modulation can be controlied by feeding a
control signal into the CONT IN jack.
20Hz Vv 20KHz, +1dB (dry)
30Hz V 10KHz, +2dB (delay)
80dB
0.5%
-104BV (0.3V)
15K2
-104BV (0.3V)
10K or more
Level indication
Format
Power requirements
Dimensions
Weight
3 point indication : LIMIT/NORM/PRESENT
8 bits with X1/2dB analog compressor and X2dB
expander.
100/120/220/240 V AC, 50/60Hz, 12W
120 V AC, 60Hz, 12W
220 V AC, 50Hz, 12W
240 V AC, SOHz, 12W
430 (W) X 44 (H) X 210 (D) mm
(17" X 1-3/4" X 8-1/4")
3Kg. (6-3/4 lbs.)
SECTIONS BLOCK DIAGRAM
#
#
О” Homer]
A
PRESENT
Ode "2008
INPUT D LFF À H
FOLD BACK
INPUT LEVEL
[_DELALY име; мыс — VOLTAGE ~~
Kg, NZ
MODULATION
SPEED LFO (/) +
“y
MODULATION
CONTROL IN (3)
+54 for x0O.5ux72
COMPRESSOR/ ASD D/A
CONVERTER MEMORY CONVERTER LAF Y EXPANDER
ANTI
CONTROL LOGIC INVERT
| DELAY PHASE
DELAY TIME RANGE
Ch27mS IE.
Fe
SWEEP LIMIT]
INDICATOR "ON" LEVEL AT INPUT JACK WITH I0dB ATTENUATION BY
LIMIT - dB
NORMAL —lôd&
PRESENT -26dB
— 1048
3 | Tre OUTPUT
a
OUTPUT MIX, Aux GUT
DELAY
11
FOSTEX
FOSTEX CORPORATION 512, MIYAZAWACHO, AKISHIMA, TOKYO, JAPAN FOSTEX CORPORATION OF AMERICA 15431 BLACKBURN AVE., NORWALK, CA 90650, U.S A,
OPRINTED IN JAPAN JUN. 1882 8288 (018000