Dynaco SE 10 Owners Manual

Page 1

SERIAL NUMBER

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S E-1D EGUALIZER

INSTRUCTIONS FOR
ASSEMBLY
OPERATION

POST omce BOX as
NUIIBCD INC. sons 0 3' "95" "E aucxwoon. N. J. 08012. U.S.A.

Page 2

CAUTION: For continued protection, replace power fuse with the same type and rating as indicated.

WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.

TYPICAL EQUALIZER RESPONSE CHARACTERISTICS

SPECIFICATIONS

Slide Control: at zero, 2 volts rms output,
into 10k ohm load paralleled with 1000 pt.

Equalizer range:-

Maximum Output:

Total Harmonic Distortion:
Intermodulation Distortion:
Frequenq Response:

Gain:

Hunt and Nuke:

Input Impedance:

Output Impedance:
Inputs:

Outputs:

:12 dB at octave intervals from 30 Hz to 15 kHz
8 volts

0.04% (typically less than 0.01 /40

0.02% (typically less than 005%)

:1 dB, 10 Hz to 35 kHz

-12 dB to +6 dB

85 dB below 2 volts output (10 Hz to 80 kHz)
50k ohm

600 ohms

Tape Monitor, Line 1, Line 2

Tape Out (same as Line 1 input), Line 1, line 2

SINGLE SLIDE CONTROL
BOOST CURVES
(invert diagram for cut curves)

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Page 11

SE-IO FUNCTIONAL BLOCK DIAGRAM

I'APE OUT
rm
thE I IN macros
studios
TAPE IN
,_ ____________
[I
I
thE 1,
our 2 6""
NE 2 IN 0- mm! 0-0 sun:
ssucnou comm

+ Isv. rsoumror (val 125v.
momma

am
-Isv. nouuros (15) (01.02. on. 04)

won: mum mssmfl. (on. 04. as. no)

lINE I
OUT PU'IS

llNE 2

IOOSI'fCU'I RESPONSE SUD! m5

30 60 I70 240

ACTIVEJPASSWE
ill!!! IESONAIOCS
(IQ, ICJ)

00 0 I010 3840 7680 5.360

PASSIVE FILM EMAIOIS

CIRCUIT DESCRIPTION

The components in the SE-IO are of the highest quality. and
all parts are operated conservatively with close tolerances to as-
sure proper operation for many years. All the semiconductors
have been thoroughly researched and selected for minimum noise
and distortion with sustained use. The printed circuit board.
which contains all the audio circuitry and the power supply
components (except for the power transformer). has been pre-
tested to ensure that every unit will meet the laboratory proto-
type-like specifications.

AUDIO CIRCUITRY

Audio signals are first applied to a voltage follower containing
a PNP~NPN direct coupled transistor pair. Q1 and Q2. This
stage has a high input impedance and a fixed low impedance
output. It generates a fixed source impedance for the subsequent
equalizer circuitry, regardless of the source impedance of the
input signals. This stage has unity gain.

Signals from the input follower drive a high performanCe op-
erational amplifier. ICI. which is the entire gain element. It
provides equalizer output signals.

The boost/cut response slide controls connect the. individual
filter resonators to either the inverting (summing point), or the
non-inverting inputs of the output amplifier, lCl. Boost action
occurs when the wiper of a slide control is moved toward the
amplifier's summing point: cut action takes place when the wiper
of a slide control is shifted toward the nominverting point. Boost
action occurs when the gain of the output amplifier is increased
in a frequency selective manner, because the resonator imped-
ance. through slide control movement. approaches the summing
point of the output amplifier. Frequency selective attenuation
of the signal at the input of the output amplifier causes cut ac~
flow The amount of boost or cut in a given octave is determined
by the position of the associated slide control.

Both active and passive filter resonator components are used.
All of the filter capacitors for resonant action are close tolerance,
polyester dielectric types. Both real and simulated inductors
are employed. Capped pot core inductors are used {or the octave
bands from 480 Hz through 15.360 Hz. Simulated active induc-
tors have been selected for the. 30 Hz through the 240 Hz bands.
The simulated inductor circuits employ two operational ampli-
fiers for each inductance.

POWER SUPPlY

A full wave bridge supply generates a nominal 2% volts DC
unregulated output with 120 (alternately 240) volts AC lino
input. Further filtering and regulation are achieved by a pair of
integrated circuit regulators. 104 and 1C5. For AC lino inputs
between I00 and I30 (alternately 200 land 260) volts, the outputs
will he +l5 voltsl-ls volts. :1 volt. The IC regulators are
thermally and short circuit protected. Under high temperature
or shorted output conditions. they will turn of! and then return
to normal operation once the problem has been corrected.

A fully regulated supply is used so that AC lino variations will
have no effect on audio performance. This is particularly im-
portant if a very powerful amplifier is used, where its current
demands can exceed the wall outlet capability.

In addition, potentially annoying turn-on and turn-off noises
are attenuated at the output by the low on" resistance of the
PET. Q3. During normal (on) operation of the SE-lO. 03 is
biased oil". 03s gate signal is fed from 04. The time constants
and divider networks for Q4 are selected so that. at turn-on and
supply turn-oft. Q3 will be in its normal "on" state.

The nominal output impedance of the SE-IO is 600 ohms un-
balanced. It ran he used with long output cables and is rela-
tively non-critical of load impedance. Its specifications are based
on a load impedance of 10.000 ohms or higher. which means that
virtually every solid state preamplifier, control amplifier or rc~
ceiver may connect to it. If a lower impedance load is connected.
there will be some reduction in the maximum output level at low
distortion.

ll

Page 22

IN CASE OF DIFFICULTY

If there is an initial fault with your component system, or
one develops in use. separate units enable relatively easy diag-
nosis of the source of the problem. Before blaming the elec-
tronics check the connections on all components, particularly
carefully on the preamplifier. See that the connections agree
with the instructions supplied for each component. If a Dynaco
PAT-4 preamplifier is employed and the 3132-10 is connected to
it. check to see that the monitor switch is in its tape" position.
If the PAT-5 is used. see that its E.P.L. switch is pushed on.
On the SE-IO. observe that the three button switches at the bot-
tom of the front panel remain out.

If neither channel works with any program source (phono,
tuner and tape), it is unlikely that all sourcu would be faulty.
Electrically disconnect the SE-lO from the rest of the high
fidelity system by restoring the monitor switch on the pream-
plifier to its input position (on the PAT-5. release the E.P.L.
switch). If the system now operates. double check the connec-
tions between the preamplifier and the SE-IO. Also substitute
audio cables. for it is possible that one or a pair is defective
(open or shorted).

A fault in only one channel of the SE-lO suggests interchang-
ing audio cables at both ends of the cables. If the other channel
now operates when the cables are interchanged. a cable is de-
fective. If the fault remains in the same channel. one channel
of the SE-lo is faulty.

Because 90% of the difficulties which are encountered in kit-
huilt units can be attributed to incorrect wiring or to poor solder
connections, it is strongly recommended that you ask someone
else to check your wiring against the Pictorial Diagram, since
frequently the builder will make the same error in checking as
he did when building the unit.

There are certain general precautions to be observed when
servicing any semiconductor equipment.

I. Never make circuit changes of any kind when the SE-lO is
plugged in.

2. Be particularly careful not to short any semiconductor leads
to each other or to the chassis when the SE-10 is turned on.

3. Exercise caution when soldering and unsoldering semicon-
ductor leads to avoid excessive heat.

If circuit difficulties are encountered with the SE40. the aver-
age builder will not likely be able to locate the source of the
problem. DO NOT ATTEMPT TO SERVICE THIS EQUAL-
IZER UNLESS YOU HAVE THE KNOW-HOW AND SUIT-
ABLE TEST EQUIPMENT.

CHECKING SEMICONDUCTORS

An ohmmctcr can sometimes serve as a gross check for tran-
sistor or diode failure. The device must be removed from the
circuit. Diodes should have a high resistance in one direction
(probe polarity) and a low resistance in the other.

Transistor types vary widely in resistance. but a (near) short
circuit indicates probable failure. Readings from base to col-
lector should be similar to those from base to emitter. Both will
have a higher reading with one probe polarity than with the
reverse orientation. NOTE: Some types of solid state meters
do not provide enough probe voltage to forward bias a silicon
junction. Hence, a high resistance reading may he obtained in
both directions.

Such gross checks can only ascertain clearly faulty semicon-
ductors. More sophisticated test equipment. or direct substitu-
tion, is necessary to qualitatively evaluate their performance.

SIGNAL @ POSSIBLE CAUSE
PROBLEM INPUT msr POINT mar POINT (som-cououcrons) '
1. No Output Shorting D1, D2; Cathode +25 v D0 D1, D2. D3. D4
Either Channel Jack (Line Dependent) IC-4 (Shorted)
g 1.5 v Puak-to-peak
Ripple
D3, D4; Cathode -25 v 00 D1. D2, D3, D4
(Line Dependent) IC-5 (Shorted)
2; 1.6 v Peak-to-peak
Ripple
IC-d; Output +15 v, :tl v IC-4
Terminal <4 mv Peak-to-peak +16 v Supply Line
Ripple Shorted
[05: Output --15 v. :1 v IC-5
Terminal <4 mv Peak-to-peak -16 v Supply Line
Ripple Shorted
2. Output Present hut SE-lO z22 dB Below Q3, Q4
Greatly Attenuated Any Output Input Level
3. No Output 1 v Sine Q2; Collector 1 v Q1, Q2
Kala? 101; Pin 3 z 130 mv 10-1
10-1; Pin 6 :2 v
4. Incorrect .25 v Sine 813-10 :2 v IC-2
Equalization Wave @ Output
300r60Hz 30or60Hz
5. Incorrect .25 v Sine 813-10 :2 v IC-3
Equalization Wave @ Output

120 or 240 Hz

120 or 240 Hz

CHART NOTES:

'Chart indicates possible defective semi-conductors, but associated components should also be investigated.
Problem #2 and #3 Only-Control Settings:

Problem, #2, #3. #4 and #S-Control Settings:

Left/Right Gain Controls: +6 dB
Input/Tape Switch: Input Position (out)
EQ. l/EQ. 2 Switch: EQ. 1 Position (out)
Power Switch: On Position (in)

Connect to: Line 1 Input

Boost/Cut Slide Controls: Any Position

EQ. In/Defeat Switch: Defeat Position (in)
Problem #4 and #5 Only-Control Settings:

Boost/Cut Slide Controls: Slide control under test at full boost
All other slide controls at 0
EQ. In/Defeat Switch: Equalize Position (out)