GOLDMUND - Swiss Made High-End Audio Equipment

The Goldmund Telos 250 is the new mono amplifier of the Goldmund "High-End" line. The Telos 250 replaces the Telos 200. It features a new larger chassis with better Mechanical Grounding, offers a higher power and uses the new capacitors developed from the Telos 5000 to considerably improve its “Driver Control”. It includes a Telos circuit and built in digital input, a built in D/A Alize 5 converter. The good news is that in spite of all the improvements made, the Telos 250 is sold at the same price as the Telos 200, and it is available immediately.

Technical Specifications

• Power
  • Maximum instantaneous power: 200 W RMS on 8 Ohms.
• 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.
• Circuit 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).
• Power Supply
  • Nominal line voltage: 117, 234 V (selectable internally).
  • Input voltage range: +/- 10 %.
  • Maximum power consumption: 1000 W.
  • Power used in standby: 60 W.
  • 4 toroidal transformers
  • 4 separated power supplies rails
• Safety Features
  • AC voltage fuse: min 16 A slow-blow.
• Front Panel Controls
  • 1 Control key (Muting/Standby and 2 sec tempo for Power on/off).
  • Red Led for Over-heating, DC Offset or HF protection and overload.
  • Green Led for Power On, operating mode.
  • Yellow Led for signal connection and digital Lock.
• Rear Panel Connectors And Controls
  • Power cord: universal socket 3 lugs.
  • Main fuse (16A slow-blow).
  • Green-yellow AC earth binding post.
  • Output speaker 2 X 5 way binding post, and Goldmund high-speed Speaker Cable coaxial connector.
  • Input connector 1 x RCA for analogue unbalanced input, XLR for analogue balanced input, 2 x RCA (input/output) for digital input.
  • Switch for analogue / digital input selection.
  • Switch for right/left channel selection from Spdif input.
  • 7-step Input level adjustment acting on all inputs.

• Audiophile tuning, the artisan approach

Back in the 20th century, speakers were usually "designed" by talented audiophiles combining a small part of real technique (usually only for the crossover general shape and the bass loading) with a serious dose of hand tuning for the selection of the drivers and the cutoff/slope/level of each part of the crossover. The best "designers" were usually seen soldering resistors, capacitors or coils during long days (and nights) until their baby was up to their taste in its subjective restitution of a (arbitrarily) selected piece of (nobody knowing how accurately) recorded music.

• Speaker modeling, the scientific approach (sort of)

The "Speaker Modeling" approach changed all that. Already used by the most advanced companies in the 90's, it allowed calculating the ideal crossover and bass load, as well as the enclosure dimensions, via a computer program, without touching a soldering iron. In addition to providing perfection in the frequency response (finally not so critical because its variation is a natural phenomenon), it also allowed to measure the phase response, a domain where a speaker, especially if using a passive or active crossover, seriously damages the propagation delay vs. frequency, something unaccounted for by mother nature. Alas, if any serious fault in the phase/time domain could be well measured during the modeling process, its correction was far from obvious and even the best speaker manufacturers were neglecting it, not being able to do anything to correct it inside their crossover.




This is why Goldmund developed Proteus, the only complete solution to control all the aspects of a speaker and making it ideally linear not only in amplitude but also in phase/time.

• The importance of Time Distortion

Any limited-bandwidth device creates time distortion by modifying the propagation delay of a signal in the device in function of its frequency. This distortion is audible, but subjectively corrected by the brain, which "re-synchronizes" the different frequencies of the signal received by the ear until "recognition" is achieved. So it is easily neglected in subjective listening. Correcting it is only possible in the digital domain, using a sophisticated DSP program that Goldmund developed in 2004, as a world premiere, under the name of "Leonardo". The suppression of the Time Distortion is creating a "relaxing" effect to the brain, favoring its perception of more details and an easier localization of various sources in space. Everything happens as if the brain had been freed of a painful and continuous work, and had become more available for a better analysis of the received message.

• The speaker acoustics, room acoustics potential control

Without the use of any passive crossover, the Goldmund Proteus solution integrally rebuilds the crossover in the digital domain, and locates it in one of its Universal Preamplifiers such as the Mimesis 16 or Mimesis 32. So, in a Proteus configuration, each power amplifier is directly attached to each driver, and not anymore through a passive crossover. Thanks to the direct low-impedance connection, some other characteristics are seriously improved as well, especially what is usually called the "Driver Control". The "Driver Control" describes the capability of a brute force amplifier to neutralize the natural resonances of a driver by "holding it" very tightly, blocking any overshoot (which also improves the driver reliability) or cone vibration not present in the amplifier-provided signal. Experimental results show that increasing the "Driver Control" to an extreme level neutralizes not only the driver vibration but also the induced enclosure coloration and even, to a certain degree, the room modes.

• Conclusion

Interestingly, to reach the nearly perfect results that Proteus can achieve requires an agreement between the manufacturers of the electronics and of the speaker. Audiophiles enjoy buying those two parts of their system separately, and from different manufacturers... So Goldmund will have to deal with different speaker companies of similar caliber to be able to exploit this considerable progress in the speaker design technology. This implies very interesting collaborations with the companies who will want their speakers are transcended to their best potential.

Goldmund held it traditional Open House in Los Angeles this January. The presentation of new products was complemented by demonstrations of the latest Media Room technology, of Proteus two channels, and of the full Metis system with the newly available Goldmund Metis Subwoofer.

The Open House was also the occasion to celebrate many years of collaboration with our distributors. A jazz concert was offered during the event and several distributors were remitted awards for their excellent work in various domains:

• Stellavox Japan: Best Service Award
• High End Research and Jefferson Hifi Video: Best Branding Award

Congratulations to them!

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