The predecessor and backbone of the new MD 108T, the MD 108, is one of the most successful standalone FM tuners we have ever introduced. It has been a staple of the Magnum Dynalab collection for over 10 years and the first of our tuners to employ the distinctive and incredibly precise MAGIC EYE tube for tuning, and also the first of our products to utilize a separate audio stage within the unit.
In 2005, the Magnum Dynalab design team took this discrete audio stage to the next level. Our proprietary TRACC technology (Triode Reference Audio Control Center) was introduced first with the launch of the MD 109, and this innovative design has resulted in our most impressive audio output ever. With our most inspiring audio section now available to the market, we felt it appropriate to apply this new technology to some of our classic Analogue FM tuners. Introducing the MD 108T.
In addition to the inclusion of the TRACC audio section (also found in the MD 109), we have employed the latest in micro-technology from Archetronics Ltd. to design a software control center that results in a very low noise floor. Further, the ability to isolate the digital control information from the audio information ensures that the control center does not interfere with the integrity of the original signal. We have also utilized an ultra-stable power supply, a new RF design with greater sensitivity, closer tolerances for the critical components, and a thicker printed circuit board with gold plated solder pads. Finally, a true differentially balanced circuit utilizes the full influence of the Triode tube design and insures that the balanced signals are perfectly matched – thus realizing the full benefit when used in a balanced system.
Not to be outdone by the many notable design features, our audio tubes themselves are different. Designed and manufactured specifically for Magnum Dynalab, our 6922 Reference CryoValve tubes
have been through an exclusive process before landing in the 108T. Each tube passes through a series of operations, including a 100 hour cryogenic treatment process at -320oF. This reduces microphonic effects, lowers the dynamic noise floor and increases the “apparent gain” to greatly relax and improve the dynamic and low level resolving power. Further, the pins have been individually cleaned back to base metal and polished for much improved contact quality and sonics.
Advanced RF Features
Dual MATRIX EYE Tube Tuning
Three Ultra-Sensitive Bandwidth Settings
Low Noise Dual gate MOSFETS
Custom “Potted” Torroidal Transformer
Six Stage Tuning Front End
Custom Ultra-Linear Power Supply
Two Analogue Antenna Inputs
Hand Matched Resonators
Auto Blend RF quieting circuit
The six stage front end is a slight improvement on the existing MD 108, and with three ultra-sensitive bandwidth settings and enhanced selectivity, you are ensured the best possible signal from any of the four antenna inputs (two analog, two digital), each selected from the front panel. A muting circuit eliminates unwanted inter-station noise. To verify performance, the MD 108T employs two accurately calibrated taut band analog meters to indicate multipath and signal strength. In unison with these meters, a unique dual MATRIX EYE tube for centre tuning means there is little guess work in optimizing FM reception.
The Audio Section
The four tube audio section is unique – the direct output from the tubes does not employ any capacitors after the gain stage of the tubes. This design using our TRACC technology (Triode Reference Audio Control Center) creates an environment where the specifications of the unit are unsurpassed. These are:
200 ohm output impedance flat from 0.2 Hz to 200 KHz, eliminates the influence of the interconnects
Signal to noise ratio > than 110 dB, the micro information from the original signal is maintained.
Zero phase shift from 0.2 Hz to 200KHz
Zero distortion variance from 0.2 Hz to 200KHz
This demanding level of pristine signal movement requires a solid foundation. Double sided 0.093 thick printed circuit boards provide the base and minimize potentially damaging vibration. With isolation insured, individual components can perform as planned without unbridled influence from neighboring elements and activity. To maximize conductivity and insure that all micro-information is maintained, ceramic tube sockets and all circuit board contacts are generously gold plated. Special feet have been designed using Vibrapod Isolators to insure that the performance is not comprised from external vibration.
To minimize the stress on the tube and insure long tube life a special turn on circuit is incorporated that has a very slow rise time slope. This brings the tube up to the optimum operating current at a very controlled and safe rate.
The Power Supply
When designing the unique power supply in the MD 108T, designer Zdenko Zivkovic concentrated much of his efforts on the ground plane. By lifting the audio ground from the chassis ground, all sources of impurities that originate with the ground plane are eliminated, once again leaving only the purity of the original signal. What you notice about the MD 108T is how free the sound is of any transients and mysterious high frequency noises. To insure that the audio signal is isolated all inputs and outputs are isolated from the chassis with a special insulator. The MD 108T power supply is free of ripple at 60 Hz, 120Hz and 180 Hz.
The primary design criterion was to develop the cleanest, continuous source of DC power possible.
- Usable Sensitivity-Mono : 0.7 uV 9.0 dBf
- 50 dB quieting-Mono : 2.0 uV 9.9 dBf
- 50 dB quieting-Stereo : 2.3 uV20.0 dBf
- Capture Ratio : 1.5 dB
- Image Rejection : 125.0 dB
- Signal to Noise Ratio : 80.0 dB
- Alternate Channel Attenuation – WIDE : 46.0 dB
- Alternate Channel Attenuation – NARROW : 60.0 dB
- Alternate Channel Attenuation – SUPER NARROW : 80.0 dB
- Adjacent Channel Attenuation – WIDE : 3.0 dB
- Adjacent Channel Attenuation – NARROW : 21.0 dB
- THD – Mono : 0.10%
- THD – Stereo : 0.10%
- Stereo Separation : 50.0 dB
- AM suppression : 70.0 dB
- SCA rejection : 80.0 dB
- I.F. Rejection : 125.0 dB
- 19 Khz and 38 Khz component rejection : 75.0 dB
- Audio frequency response (=/- 1dB) : 15 Hz – 17 Khz
- Balanced Audio Output : 2.2 V
- Line Audio Output : 1.0 V
- Line power (must be specified) : 120, 220, 230, 240 Vac
- Dimensions (inches HWD) : 5 x 19 x 16
- Dimensions (cm HWD) : 12.8 x 48.3 x 40.7
- Weight (lbs/Kg) : 40/17.7
- Power Consumption (Typ./Max) : 50 W / 100