Goldmund SR2.3 User manual

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GOLDMUND SR2.3
2 CHANNEL POWER AMPLIFIER

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GOLDMUND SR2.3
2 CHANNEL AMPLIFIER
USER MANUAL
ATTENTION :
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.

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1 - UNPACKING
You will find in the GOLDMUND SR2 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.
2 - CHOICE OF AMPLIFIER LOCATION AND COOLING
The GOLDMUND SR2.3 amplifier, as all the high quality amplifiers may generate a large amount of
heat if driven into 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.
3 - 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 SR2.3 amplifier will function properly for AC
voltages in 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.

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4 - CONNECTIONS
Check if volume control is down to zero on the preamplifier or the 5 channel processor.
First, connect the interconnects between the preamp/processor and each of the power amps inputs.
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. To get the best sound of the amplifier, avoid any multiple plug
or extension cord.
The switch marked inputs link is connecting the 2 inputs together if the amp is to be used with a
monaural source or for bi-amping.
5 – AMPLIFIER CONTROLS
On the front plate of the GOLDMUND SR2.3 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.
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 SR2.3 is self-protected and the sound heard is corresponding to the charging and
discharging of the capacitors.

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6 - SOUND 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 15 minutes. 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 (as on the Goldmund SR2.3,
Mimesis 27+ or 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 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 of the source, most of the record and CD being recorded without care for the
absolute phase. Be patient…
- Mains line phase inversion.
The sonic quality of your GOLDMUND SR2.3 can be greatly improved if the mains AC line is properly
connected. Try to invert the AC plugs of both your amplifiers, using special adapters.
We recommend that you proceed carefully to try this. 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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7 - SAFETY AND PRECAUTIONS
Attention :
The GOLDMUND SR2 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 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 SR2.3 is a DC-coupled amplifier. Without protection and if the associated
preamplifier is badly designed or defective (often true for tube preamps and some 5 channel
processors), the speakers could easily be damaged by the amplified DC.
The SR2.3 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 is self-limiting its output so the current doesn’t
become too high.
However, such accident should be limited in time to avoid excessive heat-up to occur. 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.
8 - MAINTENANCE
The GOLDMUND SR2.3 amplifier usually requires no maintenance. For the audio purists who want to
keep their amp sounding as new, we only recommend that after a year or two, you have a technician
or an official GOLDMUND representative readjust the DC offset. This very simple operation takes only
two minutes and will give you the safety of long years of unmatched sound quality.
To clean your SR2.3 use only a soft cloth slightly damp. Always turn the power off before cleaning
your amplifier.

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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 for all channel driven
FREQUENCY RESPONSE
These figures are valid for the circuit alone, at any level between 0 and nominal power.
- +/- 0.1 dB, 10 Hz - 1 MHz.
- +/- 1 dB, 6 Hz - 1.2 MHz.
- +/- 3 dB, 3 Hz - 1.4 MHz.
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.
DISTORTION
Figures valid for all levels from 0 to 20 V / 8 Ohms.
- Dynamic : TID < 0.01 % (- 80 dB).
- Static : THD < 0.01 % (- 80 dB).
SPEED
- Slew rate : > 240 V/us
- Rise time : < 260 ns.
NOISE
- Weighted ASA A : > 100 dB.
OPERATING TEMPERATURE
- Room temperature : -30 to +40 degrees Celsius ( -22 to +104 degrees Fahrenheit).
- Internal temperature : +45 to +65 degrees Celsius ( +113 to +149 degrees Fahrenheit).
POWER SUPPLY
- Nominal line voltage : 117 or 234 V.
- Input voltage range : +/- 15 %.
- Maximum power consumption : 450 W.
SIZE AND WEIGHT
- 44 cm W x 33 cm D x 9 cm H. - Weight : 13 kg net.
WARRANTY
- 3 years parts and labor.