Goldmund TELOS 250 User manual

USER MANUAL
USER MANUALUSER 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.
NTRODUCT ON
NTRODUCT ONNTRODUCT ON
NTRODUCT ON
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 Contents
Table of ContentsTable of Contents
Table of Contents
1
11
1 PREL M NAR ES
PREL M NAR ESPREL M NAR ES
PREL M NAR ES 5
55
5
1.1UNPACK NG 5
2
22
2 AMPL F ER LOCAT ON & COOL NG
AMPL F ER LOCAT ON & COOL NGAMPL F ER LOCAT ON & COOL NG
AMPL F ER LOCAT ON & COOL NG 6
66
6
3
33
3 L NE VOLTAGE ADJUSTMENTS
L NE VOLTAGE ADJUSTMENTSL NE VOLTAGE ADJUSTMENTS
L NE VOLTAGE ADJUSTMENTS 7
77
7
4
44
4 CONNECT ONS
CONNECT ONSCONNECT ONS
CONNECT ONS 8
88
8
5
55
5 AMPL F ER CONTROLS
AMPL F ER CONTROLSAMPL F ER CONTROLS
AMPL F ER CONTROLS 9
99
9
5.1 AUTO-POWER OPERAT ON 9
5.2 MANUAL OPERAT ON 10
5.3 OTHER D SPLAY 11
6
6 6
6 SOUND QUAL TY OPT M ZAT ON
SOUND QUAL TY OPT M ZAT ONSOUND QUAL TY OPT M ZAT ON
SOUND QUAL TY OPT M ZAT ON 11
1111
11
6.1 WARM-UP SON C EFFECT 11
6.2 THE GOLDMUND “MECHAN CAL GROUND NG” 12
6.3 SPEAKER POLAR TY 12
6.4 MA N L NE PHASE NVERS ON 13
7
7 7
7 SAFETY FEAT U R E S
SAFETY FEAT U R E SSAFETY FEAT U R E S
SAFETY FEAT U R E S 13
1313
13
7.1PROTECT ON AGA NST DC 13
7.2 PROTECT ON AGA NST HF OSC LLAT ONS 14
7.3 OVERHEAT NG PROTECT ON 14
8
88
8 MA NTENANCE
MA NTENANCEMA NTENANCE
MA NTENANCE 15
1515
15
9
99
9 TECHN CAL DATA
TECHN CAL DATATECHN CAL DATA
TECHN CAL DATA 16
1616
16

GOLDMUND TELOS 250+ - Universal Power Amplifier - 4
W A R N N G !
W A R N N G !W A R N N G !
W A R N N 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.
MPORTANT
MPORTANTMPORTANT
MPORTANT
PLEASE DO NOT CONNECT ANY CABLES OR
MOVE ANY PARTS BEFORE READING THE
FOLLOWING INSTRUCTIONS.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 5
1
11
1 PREL M NAR ES
PREL M NAR ESPREL M NAR ES
PREL M NAR ES
Please read the following instructions very carefully. This high-precision unit will provide the
best signal possible to your speaker thanks to its unique technology.
For exacting technicians, musicians, and all high-fidelity music purists who demand the
very best in musical reproduction, we strongly recommend the use of top quality analog
pre-amplifier or acoustic processor such as the Mimesis 20H or Mimesis 32.5 with analog
or digital input.
The connection between the analog and digital sources and the acoustic processor as well
as between the pre-amplifier and the power amplifiers are critical. Ultra low reflection
interconnect cables are absolutely mandatory in analog and precise impedance SPDIF
cables in digital to keep the time integrity that the acoustic processor is designed to
provide. In all typical cases Goldmund recommends using the special Goldmund Lineal
interconnect and digital cables.
1.1 UNPACK NG
You will find in the GOLDMUND TELOS 250+ box:
- The amplifier
- The power cord
- This manual
Unpack the above-mentioned parts carefully, keep all packaging for future use.
WARN NG
WARN NGWARN NG
WARN NG
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
22
2 AMPL F ER LOCAT ON & COOL NG
AMPL F ER LOCAT ON & COOL NGAMPL F ER LOCAT ON & COOL NG
AMPL F ER LOCAT ON & COOL NG
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+ is better located on the floor. Other very strong supports
can be used if they offer rigid transmission to the floor.
The TELOS 250+ is built on four very hard conical feet to ensure proper vibration
transmission to the amplifier support. This evacuates 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. Be
careful that the conical feet of the top amp are inserted properly on the top of the steel bars
of the amplifier located below. You may stack up to 3 amps provided extra care is taken to
ensure proper air circulation vents the rear heat-sinks.
Depending on the flatness of the surface where the amplifier will be located, you will adjust
the four round flat feet of the amplifier to allow full contact of the points with the support.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 7
3
33
3 L NE VOLTAGE ADJUSTMENTS
L NE VOLTAGE ADJUSTMENTSL NE VOLTAGE ADJUSTMENTS
L NE VOLTAGE ADJUSTMENTS
A voltage selector 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.
ATTENT ON
ATTENT ONATTENT ON
ATTENT ON
On the 220V position, the GOLDMUND TELOS 250+ amplifier will function properly for
main line voltage between 211V and 257V. On the 110V position, the main line must
deliver between 105 and 129V. 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 an 8A delayed fuse.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 8
4
44
4 CONNECT ONS
CONNECT ONSCONNECT ONS
CONNECT ONS
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.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 9
5
55
5 AMPL F ER CONTROLS
AMPL F ER CONTROLSAMPL F ER CONTROLS
AMPL F ER CONTROLS
5.1 AUTO-POWER OPERAT 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 one position for Manual Operation and 9 for Auto-Power Operation with various
delays to power a number 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
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.
When the amplifier is in AUTO-POWER mode and is operative, it may be muted by
pressing the front key, as in the normal mode.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 10
5
5 5
5 A
AA
AMPL F ER CONTROLS (Ctd.)
MPL F ER CONTROLS (Ctd.)MPL F ER CONTROLS (Ctd.)
MPL F ER CONTROLS (Ctd.)
5.2 MANUAL OPERAT ON
On the front panel 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 in STANDBY mode. The green led flashes
slowly.
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 is lit, showing the amplifier is locked. If the digital
input is not used, the amp remains muted until a lock is found. With an analog input, the
amp is immediately operational and the yellow led is always illuminated.
The amp may be returned to STANDBY mode with a short key press.
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.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 11
5
5 5
5 AMPL F ER CONTROLS (Ctd.)
AMPL F ER CONTROLS (Ctd.)AMPL F ER CONTROLS (Ctd.)
AMPL F ER CONTROLS (Ctd.)
5.3 OTHER D SPLAY
If an abnormal situation is found by the TELOS 250+, the front panel red light will turn ON,
and the power of the amplifier is instantaneously set OFF.
The red led indicates that the problem could be 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 more than 2 seconds,
or restart the power sequence.
6
66
6 SOUND QUAL TY OPT M ZAT ON
SOUND QUAL TY OPT M ZAT ONSOUND QUAL TY OPT M ZAT ON
SOUND QUAL TY OPT M ZAT ON
6.1 WARM-UP SON C EFFECT
When the amplifier has not been used recently it will take 10 to 15 minutes for the amplifier
to reached optimum operating temperature, as the circuits have to warm up to around +55
degrees Celsius.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 12
6
6 6
6 SOUND QUAL TY OPT M ZAT ON (Ctd.)
SOUND QUAL TY OPT M ZAT ON (Ctd.)SOUND QUAL TY OPT M ZAT ON (Ctd.)
SOUND QUAL TY OPT M ZAT ON (Ctd.)
6.2 THE GOLDMUND “MECHAN CAL GROUND NG”
In the GOLDMUND TELOS 250+ amplifier, GOLDMUND has, as in other of its Ultimate
Line components, fully implemented an optimized vibration evacuation path. This is called
by GOLDMUND: "Mechanical Grounding". The perfect adjustment of this evacuation
provides the Telos 250+ with an extraordinary dynamic capability and transparency,
especially on low efficiency speakers.
To get all the benefits of this design, the TELOS 250+ must be located on a very rigid
support, or better directly on the floor, to be directly coupled with the building’s rigid
construction. Try various locations until you find the most rigid one. Avoid any decoupling
material, carpet especially, even between the furniture and the floor. Use the four pin-point
feet to couple the amplifier to the supporting furniture or to the floor.
With a very top system, the sonic improvement when the proper grounding is found is
obvious and worth the effort.
6.3 SPEAKER POLAR TY
Even if you have a phase inverter on your preamplifier and have carefully selected the
proper line phase (see next paragraph below), there is a possibility to further increase the
sonic quality of your speakers by reverting the polarity of the speaker cable amplifier
termination. Line phase and speaker polarity interfere with each other however. We
therefore advise careful experimentation with all the combinations in order to arrive at the
best solution for your installation.
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…

GOLDMUND TELOS 250+ - Universal Power Amplifier - 13
6
6 6
6 SOUND QUAL TY OPT M ZAT ON (Ctd.)
SOUND QUAL TY OPT M ZAT ON (Ctd.)SOUND QUAL TY OPT M ZAT ON (Ctd.)
SOUND QUAL TY OPT M ZAT ON (Ctd.)
6.4 MA N L NE PHASE NVERS ON
To select the proper phase, you have to select, by trying, one of the two power cord
positions. We recommend that you proceed carefully when trying this. You must do it in
combination with the speaker polarity and/or with absolute phase switching to be sure of
the result.
7
7 7
7 SAFETY FEAT U R E S
SAFETY FEAT U R E SSAFETY FEAT U R E S
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.
7.1 PROTECT ON AGA NST 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, the red led will
be illuminated on the front panel.
When the source of DC offset is suppressed, turn ON the amplifier again.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 14
7
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7 SAFETY FEAT U R E S
SAFETY FEAT U R E SSAFETY FEAT U R E S
SAFETY FEAT U R E S (Ctd.)
(Ctd.) (Ctd.)
(Ctd.)
7.2 PROTECT ON AGA NST HF OSC LLAT ONS
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.
7.3 OVERHEAT NG PROTECT ON
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. The red front panel will be lit indicating 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.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 15
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8 MA NTENANCE
MA NTENANCEMA NTENANCE
MA NTENANCE
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 (eg. products containing sodium carbonate).

GOLDMUND TELOS 250+ - Universal Power Amplifier - 16
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9 TECHN CAL DATA
TECHN CAL DATA TECHN CAL DATA
TECHN CAL DATA
FRONT PANEL CONTROLS
FRONT PANEL CONTROLSFRONT PANEL CONTROLS
FRONT PANEL CONTROLS
• 1 control key (Muting/Standby and 2 sec tempo for ON/OFF).
• Red led for Over-heating, DC offset or HF protection and Overload.
• Green led for Power ON, operating mode (blinking in standby).
• Yellow led for signal connection and digital Lock.
REAR PANEL CONNECTORS AND CONTROLS
REAR PANEL CONNECTORS AND CONTROLSREAR PANEL CONNECTORS AND CONTROLS
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 2 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
POWERPOWER
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
FREQUENCY RESPONSE
FREQUENCY RESPONSEFREQUENCY RESPONSE
FREQUENCY RESPONSE
•+/- 0.1 dB, 0 - 300 kHz, +/- 1 dB, 0 - 1000 kHz. +/- 3 dB, 0 - 3 MHz.
NPUT SENS T V TY
NPUT SENS T V TYNPUT SENS T V TY
NPUT SENS T V TY
• Nominal level: 1.45 V RMS.
• Voltage Gain: 28.2 (29dB).
• Input impedance > 50 kOhms.

GOLDMUND TELOS 250+ - Universal Power Amplifier - 17
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9 TECHN CAL DATA (Ctd.)
TECHN CAL DATA (Ctd.)TECHN CAL DATA (Ctd.)
TECHN CAL DATA (Ctd.)
D STORT ON
D STORT OND STORT ON
D STORT ON
• 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
SPEEDSPEED
SPEED
• Slew rate: > 400 V/us.
• Rise time: < 300 ns.
OPERAT NG TEMPERATURE
OPERAT NG TEMPERATUREOPERAT NG TEMPERATURE
OPERAT NG 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).
S ZE AND WE GHT
S ZE AND WE GHTS ZE AND WE GHT
S ZE AND WE GHT
• 385W x 305D x 225H (mm).
• Weight: 18 kg.
WARRANTY
WARRANTYWARRANTY
WARRANTY
• 3 years parts and labor.
Information and product specifications contained in this manual are subject to change
without prior notice. Updated versions of this manual will be posted on our website at
www.goldmund.com.
Please visit our support page at http://www.goldmund.com/support/register to register your
Goldmund product for warranty.
RevA