Goldmund SR150 User manual

USER MANUAL
GOLDMUND SR150 2-CHANNEL
Universal Power Amplifier

INTRODUCTION
The GOLDMUND SR150 2-CHANNEL UNIVERSAL POWER AMPLIFIER
User manual - SR150 2-CHANNEL UNIVERSAL POWER AMPLIFIER
Goldmund was founded in 1978 and has ever since been dedicated to the accurate reproduction of sound
and image.
At Goldmund, we strive to lead in the creation, development and manufacture of the industry’s most
advanced technologies, including audio and video systems, home - networking and music distribution.
The guiding principle at Goldmund is to produce a precise sound with the least possible loss of quality
through the different stages. Goldmund will never adopt a technology before it is sufficiently developed to
satisfy the high quality standards we set. This is why Goldmund has often rejected mainstream technologies
and developed its own.
Congratulations.
Thank you for purchasing the Goldmund SR150 2-CHANNEL Universal Power Amplifier.
You have acquired the best multi-usage Power Amplifier ever made for professional and domestic uses.
Please take some time to read this manual.

No connection or manipulation must be
done before reading those instructions.
Damage to the amplifier may result if the
following instructions are not consciously
understood and applied.
WARNING
!
SR150 2-CHANNEL Universal Power Amplifier
User manual - SR150 2-CHANNEL UNIVERSAL POWER AMPLIFIER

1UNPACKING p 4
2CHOICE OF AMPLIFIER LOCATION AND COOLING p 4
3LINE VOLTAGE ADJUSTMENT p 5
4CONNECTIONS p 5
5AMPLIFIER CONTROLS p 6
6SOUND QUALITY OPTIMIZATION p 7
Warm-up sonic effect.
Speaker polarity.
Mains line phase inversion.
7SAFETY AND PRECAUTIONS p 8
Protection against DC.
Protection against short-circuits.
8MAINTENANCE p 9
9TECHNICAL DATA p9-10
Power
Frequency response
Analog input sensitivity
Group delay
Distortion
Speed
Noise
D/A Converter
Operating temperature
Power supply
Size and weight
Warranty
CONTENTS
User manual - SR150 2-CHANNEL UNIVERSAL POWER AMPLIFIER

UNPACKING
You will find in the GOLDMUND SR150 box:
❑The amplifier
❑The power cord
❑This manual and the warranty card
❑Accessories and spare fuses
Please keep the packaging in case you need to transport the amplifier at a later date
or if you have to send it for maintenance.
WARNING
IF YOU NEED TO RETURN THE SR150 TO THE FACTORY OR TO YOUR LOCAL
REPRESENTATIVE FOR A WARRANTY REPAIR, PLEASE NOTE THAT IT MUST BE
REPACKED IN THE ORIGINAL PACKAGING.
THIS PACKAGING HAS BEEN DESIGNED SPECIFICALLY TO PROTECT YOUR
SR150 IN TRANSIT. USE OF ALTERNATIVE PACKAGING IS LIKELY TO RESULT IN
DAMAGE, INVALIDATING WARRANTY COVER.
CHOICE OF AMPLIFIER LOCATION AND COOLING
The GOLDMUND SR150 amplifier, as all the high quality amplifiers may generate a large
amount of heat if driven at high power.
It is mandatory to allow a proper cooling of the heat sink. Avoid any location which is not
properly ventilated and avoid putting other equipment on top of the amplifier.
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LINE VOLTAGE ADJUSTMENT
An AC line voltage selection is possible inside the chassis. Please ask your dealer for
assistance if the line voltage provided is not appropriate.
ATTENTION
On the 220V position, the GOLDMUND SR150 amplifier will function properly for AC voltages
between 200V and 245V.
On the 110V position, the AC line must deliver between 95V and 125V. If your AC line is
usually out of these tolerances, please consult your GOLDMUND dealer.
Please check the value of the mains line fuse. This fuse is located in the power cord
receptacle. The lid can be removed with a small screwdriver when the cord is removed.
Use a 5A slow-blow fuse for 220V and a 8A slow-blow fuse for 110V.
CONNECTIONS
Check if volume control is down to zero on the preamplifier.
If you are using analog inputs, connect the interconnects between the preamp/processor
and each of the power amps inputs.
If you are using a Goldmund Universal Preamplifier, connect a lineal digital cable between
one of the preamp outputs and the amplifier digital input. Then change the amp switch back
to digital input.
Connect the speaker cables to the red and black terminals accessible at the back of the
amplifiers.
You may notice that the ground of the input and the black speaker terminal are of the same
polarity. The amplifier is non-inverting in phase.
Then, connect the power cords to the back of the amplifier and plug it in the nearest wall
plug. Use a 3 lugs grounded plug, for safety reasons. Toget the best sound of the amplifier,
avoid any multiple plug or extension cord.
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AMPLIFIER CONTROLS
On the front plate of the GOLDMUND SR150 amplifier you will find only one switch:
The POWER key, used to power the amp on and one power Led.
When turned ON the 2 channels are immediately connected and the front panel POWER Led
lights up. If you use the digital input, the lock of the digital input will indicate this by changing
the Led from green to yellow.
The amp may be powered off by turning off the POWER switch at any time. The Led will fade
very slowly,indicating discharge of the filter capacitors. The speakers will be disconnected
after a few seconds.
It is absolutely normal that a slight sound is heard from the speakers when the amplifiers
are turned ON or OFF. The SR150 is self-protected and the sound heard is corresponding to
the charging and discharging of the capacitors.
On the back panel, there is a 5 Switch set which allows adjusting the D/A Phase and
Gain for the digital input.
Each Switch has 2 positions : ON (high) and OFF (low)
Phase adjustment:
Switch 1 (rightmost) ON: 180 OFF: 0
Left Gain - 6dB: Switch 2: ON Switch 3: ON
0dB: Switch 2: OFF Switch 3: ON
+6dB: Switch 2: ON Switch 3: OFF
+12dB: Switch 2: OFF Switch 3: OFF
Right Gain - 6dB: Switch 4: ON Switch 5: ON
0dB: Switch 4: OFF Switch 5: ON
+6dB: Switch 4: ON Switch 5: OFF
+12dB: Switch 4: OFF Switch 5: OFF
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6SOUND QUALITY OPTIMIZATION
❑Warm-up sonic effect
If the power amplifier has not been powered on for a few days, the optimum sound quality
is reached after 15minutes. This delay has been optimized to be minimal and the sonic
quality when just powered on is much higher than other quality power amplifiers.
❑Speaker polarity
Even if you have an absolute phase inverter on your preamplifier (Mimesis 22M), and even
if you have carefully selected the proper line phase (see in next paragraph), there is a
possibility to again increase the sonic quality of your speakers by reverting the polarity of
each speaker cable at amp termination. But since the line phase and the speaker polarity
interfere to each other, you have to experiment carefully with all the combinations before
picking the right one.
If your preamplifier has an absolute phase inverter,this will interfere too. If it has not, don't
forget the result will depend on the source, as most records and CDs have been recorded
without care for the absolute phase. Be patient…
❑Mains line phase inversion
The sonic quality of your GOLDMUNDSR150can be greatly improved if the mains AC line is
properly connected. Try to invert the AC plugs of both your amplifiers, using special adapters.
Werecommend that you try this carefully. You must do it in combination with the speaker
polarity and/or with absolute phase switching to be sure of the best result.

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ATTENTION
The GOLDMUND SR150 is an extremely high speed amplifier.
Any bad ground connection can generate high frequency oscillation which is
dangerous for tweeters.
It is also generally dangerous to run analog input cable and speaker cables in parallel for a
long distance. If these cables are not of high quality or badly shielded, an “Antenna-Effect”
can generate dangerous high-frequency oscillations.
❑Protection against DC
The GOLDMUND SR150 is a DC-coupled amplifier. Without protection and if it is associated
with a badly designed or defective analog preamplifier (often true for tube preamps and
some 5 channel processors), the speakers could easily be damaged by the amplified DC.
The SR150 protects itself from such an accident by a feedback DC control that limits the DC
amplified by the circuit.
This protection circuit is totally transparent and has no sonic effect.
❑Protection against short-circuits
If one output is short-circuited by accident the amplifier self-limits its output so the current
doesn’t become too high.
However, such accidents should be limited over time to avoid excessive heat build-up
occurring. In extreme cases, such mishandling could destroy the amplifier,which is not
covered by the warranty.
There is no risk to leave the speaker terminals unconnected when the amps are on.
SAFETY AND PRECAUTIONS

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8MAINTENANCE
The GOLDMUND SR150 amplifier usually requires no maintenance.
To clean your SR150 use a very soft, clean, damp cloth to avoid scratching the surface.
Dampen with water or a mild detergent solution. Avoid abrasive or harsh cleansers (eg.
products containing sodium carbonate). Always turn the power off before cleaning your
amplifier.
TECHNICAL DATA
POWER
• Nominal power before clipping: 2x200 W RMS (2 - 8 Ohms). 150 W RMS (1 - 16 Ohms).
•Maximum power : > 400 W RMS (3 Ohms).
• Maximum voltage : 55 V peak. - Maximum current : > 15 A peak.
These values are for both driven channels.
FREQUENCY RESPONSE
These figures are valid for the circuit alone, at any level between 0 and nominal power.
• +/- 0.1 dB, 10Hz - 1 MHz.
• +/- 1 dB, 6 Hz - 1.2 MHz.
• +/- 3 dB, 3 Hz - 1.4 MHz.
ANALOGUE INPUT SENSITIVITY
•Nominal level : 0.75 V.
• Input impedance : 50 kOhms.
GROUP DELAY
Propagation delay < 100 ns stable with frequency from DC to 200 kHz.
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