Yamaha MX-70 Owner's manual

Yamaha MX-70 Owner's manual
 OWNER’'S MANUAL MODE D’EMPLO! BEDIENUNGSANLEITUNG + BRUKSANVISNING ~~ MANUALE DELL’UTEN
E Front Panel illustration... 3
E Connection Diagram ............e...eeeerencciioiconceeoce. 32
Francals...........................e.... EEE 8
E ¡Nustration du panneau avant............. eee... 3
E Schéma des connexions................. ee. eer 32
16
B Abbildung der Vorderseite......................... SE 3
B AnschluBschema........................ pnireo nene enne ceo ene. 32
E INustrationen pá framsidan .................e.2...e.esm..... 3
E Kopplingsdiagrammet ...............eeneesrenecrconconenec 32
E //ustrazione del pannello anteriore.................... 3
B Diagramma di collegamento................ ferrari EEE ‚| 82
Thank you for purchasing the YAMAHA MX-70 stereo
power amplifier.
To obtain the finest performance from your new power amplifier, please
read this manual carefully, keeping it handy for future reference.
After you know which PRECAUTIONS to take, the section CON-
NECTIONS will show you how to hook up the MX-70 to your control
amplifier and speakers. Operation of this power amplifier 1s explained
under FRONT PANEL CONTROLS AND THEIR FUNCTIONS.
If you have any trouble, the final section on TROUBLESHOOTING
tells you what to do before contacting your YAMAHA dealer.
FEATURES eee eee aire ere ea ea 1
21-107 Ugo] <A 2
FRONT PANEL CONTROLS AND THEIR FUNCTIONS 4
CONNECTIONS .............eieie eee eee. eee, 5
TROUBLESHOOTING ooo eee eee eee eee, 7
SPECIFICATIONS ooo eee eee eee eee eee eee eee eee eee sree eases Y
IMPORTANT:
Please record the serial number of your unit
in the space below.
Model: MX-70
Serial No.:
El Hyperbolic Conversion Amplification Circuit
Advanced Power Supply (APS) Circuitry
Three-Pair Speaker Support
LCD (Liquid Crystal Display) Power Level Meters
i Overload Protection Circuitry
Hyperbolic Conversion Amplification Circuit
This new kind of circuitry, developed by Yamaha, eliminates the only
serious drawback of previous Class A operation amplifiers. These
had to switch to non-linear class AB operation above a certain load
current, causing a slight deterioration in the otherwise excellent
sound quality. The new Hyperbolic Conversion Amplification Circuit
does away with this problem, allowing your Yamaha MX-70 to deliver
superior performance constantly, without switching or cut-off, over
its entire power range.
Advanced Power Supply Circuitry (APS)
An amplifier is only as good as its power supply — this simple truth
has prompted Yamaha to develop the APS circuitry incorporated in
your new MX-70. The problem with conventional power sources was
their tendency to produce pronounced voltage ripples during medium
to large amplitude music signals, particularly under low impedance
loads, together with voltage fluctuations in the power transistors.
APS solves this problem by providing an active power source that
ensures stable voltage in the final transistor stage under all operating
conditions, thus greatly improving power supply to the amplifier.
Keep this manual in a safe place for future
reference.
— LOCATIC
Avoid placing your MX-70 in direct sunlight
or close to a source of heat. Also avoid lo-
cations in which the device is likely to be
subjected to excessive dust, cold or mois-
ture.
The openings on the cabinet ensure the
ventilation of the amplifier. If these openings
are obstructed, the temperature inside the
cabinet will rise rapidly and eventually
damage the circuits. Therefore, avoid plac-
ing objects against these openings and do
not install your amplifier in a place such that
the flow of air through the ventilation
openings could be impeded.
El Power cord
When removing the power plug from the wall
outlet, always pull directly on the plug. Never
yank the cord as this may result in damage
to the cord and possibly a short-circuit.
If you do not intend {o use this unit for an
extended period of time, it is advisable to
unplug the power cord.
B Switches and knobs
Avoid applying excessive force to the
switches and knobs.
@ Relocation
Before moving your amplifier, be sure to
unplug the power cord and remove all other
connecting cables.
B Troubleshooting Chart
Consult the Troubleshooting Chart for advice
on the common operation errors before
concluding that your amplifier is faulty.
BE Servicing
Do not open the cabinet or attempt to make
repairs by yourself, as this may aggravate
the damage and expose you to an electrical
shock.
E Object and liquid entry
See to it that foreign objects or spilled liquids
do not enter inside the cabinet. Should this
case arise, consult your YAMAHA dealer.
‘Wipe off dust with a dry soft cloth. To remove
dirt or fingermarks, use a soft damp cloth
then dry immediately with a clean cloth. Do
not use alcohol, thinners or other chemical
solvents since they may damage the finish
or remove the panel lettering. |
Do not use any aerosol sprays near this unit
as these products can easily get into the unit
and damage the circuitry.
Special instructions
for the U.K.
THE WIRES IN THE MAINS LEAD ARE
COLOURED IN ACCORDANCE WITH THE
FOLLOWING CODE:
Blue: NEUTRAL
Brown: LIVE
As the colours of the wires in the mains
| lead of this apparatus may not corresponc
with the coloured markings identifying the
terminals in your plug, proceed as follows
The wire which is coloured BLUE must be
connected to the terminal which is markec
with the letter N or coloured BLACK. The
wire which is coloured BROWN must be
connected to the terminal which is markec
with the letter LL or coloured RED.
FRONT PANEL ILLUSTRATION ABBILDUNG DER VORDERSEITE — ILLUSTRAZIONE DEL PANNELLO ANTERIORE
ILLUSTRATION DU PANNEAU AVANT ILLUSTRATIONEN PA FRAMSIDAN _
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— LU
PEAK LEVEL
POWER PROTECTION
‚ Hyperbolic Conversion
Amplification Circuit
The Front Panel illustration is provided on page 3.
0 POWER switch and indicator: Pressing this switch turns power
on, causing the POWER indicator to light. To turn the unit off,
press again
E) SPEAKERS selectors: Allow you to select any of the speaker pairs
connected to the A, B and/or C terminals by pushing the ap-
propriate switch(es) to the ON position.
NOTE:
If speakers are connected to terminals B, but not to terminals C,
be sure to press only the B SPEAKERS selector when listening via
pair B. Pushing in selector C as well will cut off the sound from
pair B since B and C are connected in series. (The same holds true
if speakers are connected to C and selector B is pressed.)
E) PROTECTION indicator: Lights for several seconds after power
is turned on, showing that the internal protection circuitry is
currently activated. This mutes the output signal to the
speakers, preventing the loud noise otherwise heard when
swiiching on the amplifier.
CD METER switch: Switches the power peak meter OFF. (This power
display is not illuminated when the METER switch is pressed
in.)
& Power peak meter: indicates the power outputon a logarithmically
compressed scale from 0.002 to 600 watis (— 50 to + 5dB), in-
dependently for the left and right output channels. Readings
are accurate for the load determined by the LOAD selectors.
($ LOAD selectors: These three switches let you adjust the peak
power display according to the speaker load impedance. Whe
using more than one pair of speakers at the same time, you ce
work out their combined impedance with the following formula
where X and Y are the impedance values of each speaker pai
1) 2 pairs in parallel (A+B ог А+ С)
(XxY)/(X + У) = combined impedance
Example for 2 pairs of 8 ohm speakers:
(8x8)/(8 + 8) = 4 ohms
2) 2 pairs in series (B+ C)
X + Y = combined impedance
3) 3 pairs (A+B+C) )
Same formula as 1), with A=X and (B+C)=
if the combined impedance does not correspond exactly to or
of the three LOAD settings, select the closest one.
© LEFT and RIGHT LEVEL controls: These give you independent
control over the power output levels to the L and R speakers
This allows you to preset speaker balance for optimum stere
imaging. These controls can also serve to protect speakers
with power handling capacity lower than this amplifier's rate
output. |
The connection diagram is provided on page 32.
49 CONTROL AMPLIFIER
2 SPEAKERS A
87 SPEAKERS E
4) SPEAKERS ©
Make sure the left (L) and right (R) channels are connected consist-
ently between components.
NOTE:
Before making or altering any of the connections described below,
be sure to turn off the power of the MX-70.
Making sure that the control amplifier is also turned off, connect the
output jacks of your control amplifiertothe corresponding INPUT jacks
on the rear panel of this unit. Always check that
a) the RCA plugs of the connecting cord are clean,
b) the left and right channels of both units correspond,
- C) connections are secure, and |
)
d) both units are properly grounded.
ep re.
The MX-70 can drive up to three pairs of speakers (A, B and C) at the
same time. Those connected to terminals A are in parallel with pairs
B and C, which are in series. The following table shows the minimum
load impedances per speaker for all possible connections.
Number of — MX-70 Minimum speaker
speakers terminals load impedance
1 pair AorBorC 4 onms
2 pairs in parallel A+Bor A+C 8 ohms
2 pairs in series | B+ C 2 ohms
3 pairs A+B+C A: 8ohms
B,C: 4 ohms
Be sure to use only speakers within the rated impedance range and
with adequate power handling capacity. Driving speakers with ex-
tremely low impedance (or several low-impedance pairs simul-
taneously) at continuous full power may cause the protection circuit
to activate.
When connecting the speaker cords, observe the “+” and “—"
markings on the backs of the speakers and MX-70. If the “+” and
“—" polarities are reversed, the sound will be unnatural and lack
bass.
Speaker cords should be cutas short as possible. Donotcoil up excess
cord or bundle it with cables from other components.
Strip approximately 10 mm (3/87) insulation from the ends of the
speaker cords and connect them as explained on the next page:
A.Light-gauge Speaker cords
Partly unscrew the plastic wire holders. Insert the stripped ends
of the speaker cords as shown and retighten the holders.
Splay the strands as shown, then screw the wire holders back
RED for (+)
BLACK for (—)
B.Heavy-gauge speaker cords
First, unscrew and remove the plastic wire holders. Insert the
stripped ends of the speaker cords into the holders until they
protrude on the other side.
Before assuming that your amplifier is faulty, check the following list. If you still have any doubts or questions, contact your nearest YAMAHA
dealer.
PROTECTION indicator is lit.
No power even when the POWER switch is ON. | ® The power cord is not plugged in securely. ® Plug in securely.
No sound is heard from the left and/or right @® The speaker cords are not properly connected. 6 Check speaker connections and correct them.
speaker(s). @ Either or both LEVEL controls are set to — codB. @ Adjust the appropriate LEVEL control(s).
® The cords from the control amplifier are not secure. @ Connect them securely.
® The control amp's balance is set to the extreme left ® Adjust the control amp's balance control.
| or right. | |
The sound ceases suddeniy, and the ® The speaker protection circuit has activated. @ Turn power OFF, then ON again to reset the s peaker protection
circuit. Also see CONNECTING SPEAKERS on p. 5.
6 There is a malfunction in the amplifier.
® Consult your YAMAHA dealer.
Unnatural sound lacking bass.
® The speaker polarities are reversed.
@ Connect the speaker wires with the correct + and — polarity.
Minimum RMS Output Power Per Channel
20Hz ~ 20kHz 0.003% THD, 8 ohms 170W
0.007% THD, 6 ohms 195W
0.02% THD, 4 ohms 230W
Dynamic Power Per Channel
{by IHF Dynamic Headroom measuring method)
8 ohms 270W
6 ohms 330W
4 ohms 440W
2 ohms 570W
1 ohms 600W
DIN Standard Output Power Par Channei
1kHz, 1% THD, 4 ohms 250W
Power Band Width
0.03% THD 85W, 8 ohms
Damping Band Width
10Hz ~ 60kHz
1kHz, 8 ohms 90
input Sensitivity/impedance
MAIN IN . 1.32V/60kQ
Frequency Response
(20Hz ~ 20kHz) +0, —0.2dB
Total Harmonic Distortions (20Hz ~ 20kHz)
MAIN IN to Sp Out, 85W/80
0.003%
intermodulation Distortion
Rated Output/8 ohms 0.003%
Signal to Noise Ratio (IHF-A-Network)
MAIN IN (shorted) 124dB.
MAIN IN (5.1 kQ terminated) 120dB
Residual Noise (IHF-A-Network) 21uV
Channel Separation
Input shorted, terminated,
1kHz/10kHz 89dB/72dB
Power Supply
Europe AC220Y, 50Hz
U.K. AC240V, 50Hz
Power Consumption
1,150W
Dimentions (Wx H x D)
435 x 165 x 425mm
(17-1/8" x 6-1/2" x 16-47/64")
Weight
14.5kg
Specifications subject to change without notice.
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