Goldmund TELOS 250 User manual

USER MANUAL
GOLDMUND TELOS 250
Universal Power Amplifier

Thank you for purchasing the GOLDMUND TELOS 250.
You have acquired the best Universal Power Amplifier ever made for professional and
domestic uses.
Please take some time to read this manual. It will provide you with useful information to
make your pleasure of listening to the TELOS 250 even higher.
INTRODU TION
GOLDMUND TELOS 250 – 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.

GOLDMUND TELOS 250 - Universal Power Amplifier - 3
Table of ontents
1 UNPA KING 5
2 AMPLIFIER LO ATION & OOLING 6
3 LINE VOLTAGE ADJUSTMENTS 7
4 ONNE TIONS 8
5 AMPLIFIER ONTROLS 9
6 SAFETY FEAT U R E S 12
7 TE HNI AL DATA 14
8 MAINTENAN E 16

GOLDMUND TELOS 250 - Universal Power Amplifier - 4
W A R
W A R W A R
W A R N I
N I N I
N I N
N N
N G !
G ! G !
G !
No connection or manipulation must be done
before reading these instructions. Damage to
the amplifier may result if the following
instructions are not consciously understood
and applied.
These extremely high quality amplifiers
possess new technical features which are a
necessity for accurate sound reproduction in
the best audio systems.
Only careful installation and use can provide
the satisfaction you are expecting.
The installation instructions must be carried
out in full and the mentioned precautions
taken to get the expected result and to avoid
impairing the amplifier’s performance.

GOLDMUND TELOS 250 - Universal Power Amplifier - 5
1 UNPA KING
You will find in the GOLDMUND TELOS 250 box:
- The amplifier
- The power cord
- This manual
Please keep the packaging in case you need to transport the amplifier at a later date.
ATTENTION
IF YOU NEED TO RETURN THE TELOS 250 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 TELOS
250 IN TRANSIT.
USE OF ALTERNATIVE PACKAGING IS LIKELY TO RESULT IN DAMAGE,
INVALIDATING WARRANTY COVER.

GOLDMUND TELOS 250 - Universal Power Amplifier - 6
2 AMPLIFIER LO ATION & OOLING
The GOLDMUND TELOS 250 amplifier, as all high quality amplifiers, generates a large
amount of heat when driven at high levels and must be vented properly. It is mandatory to
allow a proper cooling of the heat sinks. Do not put temperature sensitive equipment on top
of the amplifier.
Due to its weight, and to maximize the effect of the built-in "Mechanical Grounding"
construction, the TELOS 250 can be located on the floor or on other very strong supports if
they offer rigid transmission to the floor.
The TELOS 250 is built on four rubber feet to ensure proper the amplifier support. This
avoids all detrimental vibrations inside the amplifier, following the famous GOLDMUND
"Mechanical Grounding" principle.
If you use more than one TELOS 250 at any location, you may decide to stack them. You
may stack up to 3 amps provided extra care is taken to ensure proper air circulation vents
the side heat-sinks.

GOLDMUND TELOS 250 - Universal Power Amplifier - 7
3 LINE VOLTAGE ADJUSTMENTS
A voltage selection is provided inside the amplifier.
If your line voltage is not adapted to the voltage indicated on the serial plate of the
amplifier, please consult your local GOLDMUND dealer for internal adjustment.
ATTENTION
On the 220V position, the GOLDMUND TELOS 250 amplifier will function properly for main
line voltage between 190V and 245V. On the 110V position, the main line must deliver
between 95 and 125V. If your main line is usually out of these tolerances, please consult
your GOLDMUND dealer.
Please check the value of the main line fuse. This fuse is located on the back panel of the
amplifier, above the two power cord receptacles.
Use a 8A delayed fuse.

GOLDMUND TELOS 250 - Universal Power Amplifier - 8
4 ONNE TIONS
Connect the power cord to the back of the amplifier and plug it into the nearest wall plug.
Use only a 3 lugs grounded plug, for safety reasons. To get the best sound from the
amplifier, avoid any multiple plug or extension cord.
If used with an analog signal, connect the interconnect between the preamp and each
power amp and position the Analog/Digital input switch to analog.
When used with a digital input signal, connect the digital input cable to the digital input and
switch the input switch to digital. Since a digital Spdif cable carries 2 channels you may link
the digital output to the next amplifier to transfer the second channel.
Connect the speaker cable to one of the red and black terminals in the back of the
amplifier, or, if you use a Goldmund High Definition speaker cable, you can connect directly
from the speaker cable to one of the coaxial plugs on the back panel of the amplifier,
bypassing the amplifier adapter module of the speaker cable.
The 2 separate outputs (both 5 way post and coaxial) are connected internally in parallel.
They are provided to facilitate the connection in bi-wiring systems.
You may notice that the ground of the input plug and the black speaker terminal are the
same polarity. The amplifier is non-inverting in phase.

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5 AMPLIFIER ONTROLS
As soon as the amplifier is connected to AC line and the amplifier has not detected an error
previously, the yellow light on the amp front panel is ON.
The TELOS 250 may be powered on either manually (Manual Operation) or automatically
when receiving a signal (Auto-Power Operation). This is selected internally by the small
white 10-position circular selector located on the top circuit of the amplifier, close to the big
capacitors.
There is 1 position for Manual operation and 9 for Auto-Power operation. Positions 1
through 8 enable various delays to be set. This supports powering-up a quantity of
amplifiers without a big surge on the AC line.
Position 0: Manual Operation
Position 1: Power after 200ms
Position 2: Power after 400ms
Position 3: Power after 600ms
Position 4: Power after 800ms
Position 5: Power after 1s
Position 6: Power after 1.2s
Position 7: Power after 1.4s
Position 8: Power after 1.6s
Position 9: Power after 1.8s

GOLDMUND TELOS 250 - Universal Power Amplifier - 10
5 AMPLIFIER ONTROLS ( td.)
MANUAL OPERATION
On the front plate of the GOLDMUND TELOS 250 amplifier you will find only one POWER
key.
When first connected to mains power the green led will flash (equal time on and off) for
around fifteen seconds whilst the amplifier goes through the POWER UP sequence.
At the end of this sequence, the amplifier enters STANDBY mode. The green led flashes
slowly (four sequences off then one on).
Once in STANDBY mode, a short key press (<1 second) switches the amplifier ON. The
green led is permanently illuminated in this mode.
If the digital input is used, the yellow led may flicker, showing there is no lock and the amp
remains muted until a lock is found. With an analog input, the amp is immediately
operational and the orange led illuminated
The amp may be returned to STANDBY mode with a short key press. A long key press (>2
seconds) takes the amplifier in POWER OFF mode.
If an error is detected the red Led will be illuminated. Once the cause of the error has been
removed, the amplifier can be returned to STANDBY mode with a long key press.
These security features are provided to reduce the risk of accidental POWER ON or
POWER OFF and to protect the amplifier in ERROR mode.
Key Press Sequence Summary

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5 AMPLIFIER ONTROLS ( td.)
AUTO-POWER OPERATION
In AUTO-POWER mode, the amplifier is turned on automatically when receiving an audio
signal.
This mode is useful when several amplifiers are used together in a multi-amp system or
when the power amplifiers are not easily accessible.
OTHER DISPLAY
If an abnormal situation is found by the TELOS 250, one of the front panel red lights may
turn ON, and the power of the amplifier is instantaneously set OFF.
The left red Led indicates an over temperature situation.
The display indicates if the problem is an over-temperature situation, an HF oscillation or
DC signal has been detected or an overload (for example when output is short-circuited).
Before re-starting the amplifier, detect what caused the problem and remove the cause
first.
The amplifier will remain OFF with a red led on until the user intervenes.
To unlock the amplifier from the error mode, press the power key for >2 seconds, or restart
the power sequence.

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6 SAFETY FEAT U R E S
The GOLDMUND TELOS 250 amplifier provides features to protect the amplifier and the
speakers against all mishandling or component failure. However precautions must be taken
to avoid problems with a very high power amplifier.
Protection against DC
The TELOS 250 is a DC-coupled amplifier. If the associated preamplifier is badly designed
or defective (often true for tube preamps), the speakers could be damaged.
In such a case, the DC protection circuit of the TELOS 250 will automatically turn off the
amplifier. This detection circuit is totally immune to any sonic effect.
To indicate that the amplifier has been turned off by the protection circuit, a red led will be
displayed on the front panel.
When the source of DC offset is suppressed, turn ON the amplifier again.
Protection against HF oscillations
In the same way, the speaker must be protected against a large amount of high frequency
oscillations, if present, before and after to avoid any danger for the tweeters, even if these
frequencies remain unnoticed.
The amplifier is by itself extremely stable. However some mishandling must be avoided in
order to avoid any oscillation:
• Never plug an input cable into a power amp when it is turned on.
• Be careful to use only very high quality interconnects. If the ground connection becomes
loose, there is a big danger of oscillation. Warranty is voided if this occurs.
• Never run the input and output (speaker) cables in parallel.
If the TELOS 250 detects excessive oscillation, the amplifier will be turned OFF
automatically. You will have to suppress the source of oscillation and turn it ON again once
the protection is activated.

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6 SAFETY FEATURES ( td.)
Overheating protection
If for any reason (malfunction, too high level, too low load impedance) the temperature of
the amplifier could reach a dangerous level and the TELOS 250 could be damaged.
To avoid this type of damage, if the temperature rises too high, a protection circuit switches
the amplifier OFF automatically. A red front panel light indicates that the amplifier has been
turned OFF by the protection circuit.
If this happens, let the amplifier cool for some time. We strongly recommend investigating
the cause of the temperature gain before operating the amplifier again.

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7 TE HNI AL DATA
SAFETY FEATURES
• AC voltage fuse: min 8 A slow-blow.
FRONT PANEL CONTROLS
• 1 control key (Muting/Standby and 2 sec tempo for ON/OFF).
• Red led display for Over-heating, DC offset or HF protection and Overload.
• Green led display for Power ON, operating mode (blinking in standby).
• Yellow led display for signal connection and digital Lock.
REAR PANEL CONNECTORS AND CONTROLS
• Power cord: universal socket 3 lugs.
• Main fuse (8 A slow-blow).
• Green-yellow AC earth binding post.
• Output speaker 1 x 5 ways post in parallel.
• Output speaker 1 x Coaxial connectors in parallel.
• Analog Input connector RCA.
• Digital Spdif input and output RCA connector.
• Switch between analog or digital input.
• Switch right or left channel selection from the Spdif input.
POWER
• Maximum instantaneous power: 300 W RMS on 8 Ohms.
• Rated power consumption (IEC 60065 at 8 Ω): 170 WRMS.
• Maximum power consumption: 470 WRMS.
• Nominal line voltage: 117, 234 V (selectable internally).
• Input voltage range: +/- 10 %.
• 4 toroidal transformers
• 4 separated power supplies rails

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7 TE HNI AL DATA ( td.)
FREQUENCY RESPONSE
•+/- 0.1 dB, 0 - 300 kHz, +/- 1 dB, 0 - 1000 kHz. +/- 3 dB, 0 - 3 MHz.
INPUT SENSITIVITY
• Nominal level: 1.45 V RMS.
• Voltage Gain: 28.2 (29dB).
• Input impedance > 50 kOhms.
DISTORTION
• Figures valid for all levels from 0 to 40 V / 8 Ohms :
• Dynamic: TID < 0.01 % (- 80 dB) unweighted.
• Static: THD < 0.01 % (- 80 dB) unweighted.
SPEED
• Slew rate: > 400 V/us.
• Rise time: < 300 ns.
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).
SIZE AND WEIGHT
• 385W x 310D x 220H (mm).
• Weight: 18 kg net.
WARRANTY
• 3 years parts and labor.

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8 MAINTENAN E
The GOLDMUND TELOS 250 amplifier usually requires no maintenance.
Always turn the power OFF before cleaning your amplifier. Use a clean, soft, damp cloth to
clean the amplifier surface. Dampen the cloth with water or a mild detergent solution.
Avoid abrasive or harsh cleansers (e.g. products containing sodium carbonate).
RevB