owner's manual contents | 01 12/01 02 04 06 07 08 15 20 21 24 25 26 28 30 controls welcome introduction construction amplifier module set up operation remote control TAGtronic Communications Bus running in and warming up care and maintenance appendix technical data 250MR 9339X 02 | controls controls | 03 TAGtronic communications bus balanced input socket line level input socket BUS IN OUT LINE INPUT Double insulated: When servicing, use only identical replacement parts. CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN RISK OF ELECTRIC SHOCK DO NOT OPEN BALANCED INPUT class 2 wiring minimum rated load impedance 8 per channel 2 1 3 220-240V ~ 50-60Hz 21 Fuse; T5A L250V 3 + ­ ground ­ + LOUDSPEAKER OUTPUT ­ made in United Kingdom by serial number ­ monobloc 250MR s power/ standby LED remote control active LED remote control window ac supply socket and fuse carrier loudspeaker terminals Specification shown may var y for different countries 04 | welcome welcome | 05 welcome to Dr. Udo Zucker Chief Executive Officer TAG McLaren Audio TAG McLaren Audio exists with one aim in mind: to produce the very best audio and audio-visual equipment. Like many people, I often have my best ideas when relaxing to a piece of music or watching a movie. For years, knowing the technical capabilities of TAG McLaren, I have nurtured the ambition to push music and movie reproduction to the absolute limit without compromising ease of use; that's why we formed TAG McLaren Audio. At the core of our development team are highly experienced engineers whose heritage of award-winning hi-fi and worldbeating electronic control systems is envied by many and equalled by few. Pushing technological boundaries; TAG McLaren's F1 electronics There are many immediate spin-offs into audio from our expertise in automotive electronics, mechanical engineering and the material science of Formula One motor racing: multi-layer printed circuits, fast digital signal processing, electronic noise suppression, radio frequency technology and software expertise to name but a few, all prerequisites of an outstanding audio product. TAG McLaren's aim is sonic perfection combined with aesthetic delight and solid build quality ­ a rare combination in hi-fi but one which TAG McLaren Audio is already delivering. Dr Udo Zucker 06 | introduction construction | 07 Thank you for purchasing the TAG McLaren 250MR A monobloc, also known as single channel amplifier, is the ultimate power amplifier configuration, eliminating channel crosstalk and, if placed close to a loudspeaker, the influence of the loudspeaker cable! The 250MR houses a self-contained, hi-performance 250 W amplifier module, described in detail on the following pages, and a control board, spaced apart for minimal interaction. control electronics The 250MR's control electronics is powered by an additional, tiny transformer and a local power supply, allowing the 250MR to be put into standby without incurring a high energy bill. The remote control circuitry acts on commands received from either the user via the IR remote control or the AV32R via the TAGtronic Communication Bus. The protection control circuitry monitors the performance of the amplifier in order to power it down should a fault occur. main transformer amplifier module TAGtronic Bus The 250MR achieves typically 255 W per channel into 8 ohms and 400 W into 4 ohms. Its IHF tone burst performance is also impressive: typically 300 W into 8 ohms, 550 W into 4 ohms and 1000 (!) W into 2 ohms. The monobloc 250MR is a refinement of the highly regarded three channel amplifier 250x3R, using a single 250 W amplifier module and its associated control electronics in an attractive case. This has many benefits: · The 250MR can be placed close to the loudspeaker, resulting in extremely short loudspeaker cables, which in turn minimises their influence. The result is improved loudspeaker control. · Each 250MR connects individually to the mains supply, reducing the influence of the mains cable and hence potential channel crosstalk. · Adjacent amplifier modules, located in the same enclosure will interact with each other through magnetic coupling, which can be minimised but never completely eliminated. This is extremely small in the 250x3R, but non existent in the 250MR! tiny standby transformer control electronics 08 | amplifier module The module has a high-efficiency aluminium heatsink for excellent heat dissipation, allowing it to drive even the most critical loudspeakers safely and dependably. This results in uncompromised sound quality with perfect channel separation. Each 250MR delivers typically 255 Watts into 8 ohms, 400 Watts into 4 ohms and will drive 1000 Watts into 2 ohms for short durations. As a result of the 250MR`s monobloc construction, this performance is wholly independent of the number of system channels being driven and thus even during the loudest passages of your favourite movie the soundstage remains stable, controlled and detailed. There are many design features which have been derived from our excellent 100x5R and our F1-600MR amplifiers to make this amplifier very special. We have listed a few on the following pages. an optimised mix of global and local negative feed back The 250MR gives excellent linearity and low distortion without relying on high global negative feedback, which can present difficulties when handling rapidly changing signals. The amplifier implements at each amplifying stage a controlled amount of local feedback, which not only linearises but also defines the gain and other vital parameters closely. cascode compensation The 250MR uses an advanced stabilisation concept called Cascode Compensation. This might be the first time that this sophisticated and elegant system has been used in an audio amplifier. Its advantages are excellent stability, inherently good supply-rail rejection and a reduction in DC drift. This gives outstanding stability with performance drifts being virtually eliminated. output transistors The output devices are bipolar junction transistors chosen for maximum linearity. The advanced MT-200 package is used which gives a greater area for heat transfer than amplifier module the traditional TO3, enhancing the amplifier's reliability for many years to come. | 09 deep under the skin The 250MR power amplifier includes a selfcontained power module, as shown above. The module is a complete amplifier, with its own power transformer, bridge rectifier, energy storage capacitors and amplification stage, requiring only mains supply and control signals to function. Control signals are used to switch the amplifier module on/off and to protect it in case an error condition, such as a short circuit in the loudspeaker, is detected. exceptionally accurate quiescent stability It is universally accepted that accurate setting and stability of quiescent conditions is crucial to optimal Class-B amplifier operation. The bias range over which the best linearity is obtained is narrow, and on either side of it crossover distortion increases markedly. The 250MR has one of the most accurate quiescent controls ever implemented, stabilising against output level, load impedance and mains voltage changes. sophisticated muting The 250MR has a sophisticated muting system, which stops you hearing loud, annoying switching noises and protects both the amplifier and the loudspeakers. Particular care has been taken to make sure that the muting circuitry, when switched off, doesn't affect the sound quality. For this purpose carefully selected relays with minimal crosstalk between coil and contacts have been used. 10 | amplifier module coupled without any capacitors, an arrangement called `straight line' technology. The result is a very precise reproduction of the lowest bass. supersonic high frequency response In order to reproduce high frequencies, the 250MR is constructed using highly rated, high-precision components. The circuit has been painstakingly designed to minimise audio signals picking up interference and intermodulating. Exceptional transparency and purity of sound are the result. amplifier module input balanced XLR and standard RCA input The 250MR provides both a balanced XLR input and a standard RCA input. There is no need to switch between the two inputs, the 250MR will automatically sense the input used. single ended RCA input A single ended connection sends, as the name implies, the signal via a two conductor cable, one for the signal and one for the ground (which is usually connected to the screen on one or both ends). The single ended connection is the most commonly used connection type between preamplifiers/av processors and their power amplifiers. It works extremely well, even over long distances, if the output stages of the av processor/preamplifier are of a `low impedance' configuration, such as those in the TAG McLaren AV32R or DPA32R. However, if several products are connected together it is possible for a current to flow between the ground connections of those units, caused by electro-magnetic | 11 low distortion A theoretically ideal amplifier reproduces sound perfectly over an infinite range of frequencies - starting from well below the audible range and extending far above the capabilities of human hearing. Although sound outside the human hearing range of approximately 20 Hz to 20 kHz cannot be heard, it can significantly distort the quality of music reproduction through an effect which audio engineers call `intermodulation distortion'. This type of distortion moves imperfections that originate outside the hearing range back into the audible frequencies. To minimise this effect, TAG McLaren amplifiers have a frequency response which extends both above and below the range of normal human hearing. straight line technology An amplifier must respond to very low frequencies but block any Direct Current (DC) to prevent intermodulation distortion. This is traditionally achieved using capacitors, which also block some of the low-frequency signals. In the 250MR, a feedback circuit eliminates DC offset voltage and allows the signal path to be direct interference or ground potential differences. This current is indistinguishable from the signal and hence can become, if severe enough, audible as a hum or buzz. The problem is usually referred to as ground loops. balanced line technology XLR input A major advantage of balanced interconnects is the complete suppression of ground-loop problems. Balanced line inputs use 3 conductors, one for the ground and two for the voltage difference between the signal and the ground at the preamplifier/av processor. As a result the balanced input at the amplifier does not respond to the voltage between input and ground, which could be altered by a ground loop, but to the difference between the two conductors carrying the signal. For this system to work well, it is important that the balanced input performs an accurate subtraction of the signals at its input terminals. The measure of how well it does this is called the `common-mode 12 | amplifier module output OFHC loudspeaker connections For excellent sound quality the 250MR uses TAG McLaren's high grade oxygen free high purity copper (OFHC) loudspeaker terminals combined with a new knob made from non-conductive Pocan. Very few companies provide OFHC loudspeaker terminals due to the difficulties of machining solid copper, an unacceptable excuse for TAG McLaren. The knobs for the 250MR have been manufactured from non conductive Pocan without a metal insert as it was found that this gave the best sonic result, identical to that obtained using an OFHC knob(1) (as used on the TAG McLaren 100x5R). amplifier module when only the best is good enough! | 13 rejection ratio'. In the 250MR this is more than 40 dB, or one hundred times, and best of all, this is permanently fixed as it is set by precision resistors rather than by attempting to balance variable semiconductor properties. combining a single ended av processor with the 250MR It is important to realise that a balanced output on the sending unit, the preamplifier or av processor is not required to gain the benefits of a balanced input. A single ended RCA output is just as good, so long as the unbalanced-to-balanced cable is wired correctly. TAG McLaren provides a special version of its F3-10-ANA, manufactured with an RCA connector at its input and a XLR connector at its output. For more details see www.tagmclaren.com or your authorised TAG McLaren retailer. The Appendix shows how an RCA-XLR analog cable should be wired to provide ground loop hum suppression, as described above. Many small details lead to this exceptional amplifier, some key elements are covered below: premium-grade audio components All components have been carefully selected and auditioned before a decision about their use in the 250MR was made. For maximum performance ultrastable Vishay metal ...