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High End HiFi |
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Bel Canto Furutech Ortofon Project
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TOWNSHEND
AUDIO 
  TA702s Pre Amplifier and the TA712 Room Bass Equaliser |
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TA702s Pre Amplifier £2,990.00 free P&P UK. Outside please ask. Please call Dave on 01775 761880 The TA702s Stereo Preamp is a minimalist design, passive or active preamp, designed to interface between any one of six stereo sources, in particular the TA565 CD Universal Player and the TA752 stereo power amplifier, as part of the astonishing Townshend Audio state-of-the-art High Fidelity system. The preamp features a precision motorised analogue volume control remotely operated by an infrared handset. All wiring is by Enhanced Deep Cryogenic Treated enamelled twisted pair copper wire. Meticulous care is taken to ensure that the earthing is only in a star configuration to prevent earth loops which inject hum. Further, the wiring is all contained in PTFE sleeving so as to keep the signal wires clear of any steel case material. When the TA702 preamp is in passive mode, the signal path is minimalist! The signal travels from the input phono connectors to the selector switch, then to the potentiometer then the ultra low distortion unity gain buffer, the mute relays and then directly to the output sockets. This configuration achieves the best sound. However, in some circumstances the gain may be insufficient - for example: if the recording is at a very low level, or it is necessary to have the system playing at high pressure level (for a bit of party fun). To accommodate all situations, 18db of gain may be added simply by switching to Active Mode. In Active Mode, an ultra-low-distortion discrete transistor amplifier of purist audiophile quality is switched into the signal path between the volume control and the output connectors. This adds 18dB of gain when ultimate transparency is forgone in order to enjoy some 'high fidelity public address'! (Please be considerate of neighbours, and mind your hearing.). In truth, when one is listening at very high volumes to Mahler or Frank Zappa, via Led Zeppelin and Faithless, the minimal degradation in sound is barely detectable. The TA702 preamplifier is housed in a very simple spectacular mirror finished stainless steel case suspended on our unique spring/bellows air-damped isolation feet. This vibration isolation system isolates ground-borne vibration from 3.5Hz and up to ensure the most open sound possible. Connectors are heavily gold plated phonos and we virtually insist that, for the best possible sound, all interconnections are by way of our DCT 300 Isolda interconnects. The mains input is by way of a fused IEC connector. The low level DC is provided by the Low Level DC Power Supply. Specifications:
The low level DC is provided by the Low Level DC Power Supply. The Low Level DC Supply - technical details All Townshend Audio electronics employ a common design of low level DC power supply. circuitry modelled on the circuitry used in the acclaimed TA565 CD Universal Player. The incoming AC is transformed from 230V AC (110V optional) by high RF isolation “E-I” overload protected transformers to the low voltage required by the dual Schottkey diode rectifier bridges. This raw DC is then filtered by a three stage resistance/capacitance/inductance network to block seriously attenuate all RF and switching noise from 2Hz up 3Ghz +. The plus and minus DC is then fed to the various amplifier/buffer stages where it is regulated precisely by a discrete component, ultra-low-noise, precision voltage stabiliser circuit. This further rejects RF interference. The power supply filter arrangement is so effective that external power conditioners and state-of-the-art mains leads have, so far, had no discernable effect on the sound; however, their use is not discouraged. The
power arrangements for pedantic 'housekeeping' of other functions
(such as the remote control function, and the indicator LEDs)
is derived from a second, completely independent, transformer/rectifier/filter
circuit. A slow-on/quick-off circuit, integrated with the mute
circuit, ensures that no speaker-damaging transient surges appear
at the output terminals. |
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TA712 Room Bass Equalizer £2,990.00 free P&P UK. Outside please ask. Please call Dave on 01775 761880 The Townshend Audio TA712 Active Pure Analogue Room Correction System (APARCS) corrects for speaker boom and room resonance. Unlike DSP (Digital Signal Processing) room correction, where the sound is universally degraded with “digititus” the sound of the all analogue TA712 is pure throughout the mid and high frequency bands. Extensive research and listening tests have shown that for the best sound, correction is only needed in the upper bass region where nearly all box speakers boom due to the “Upper Bass Resonance” of the cabinet/driver combination. The frequency of this resonance is usually around 50-70Hz. Also, for the typical living room with a 9 to 12 foot high ceiling, the floor to ceiling resonance is also around 60Hz. These two resonances combine resulting in a “one-note-bass” boom which is all too common in most reproducing systems. The TA712 APARCS seamlessly removes this boom by interposing an equal and opposite narrow band “suck-out” or “notch” into the response to cancel out the boom, thus leveling the response. Attempts to correct sound at frequencies above 100Hz invariably results in poor fidelity due to time averaging and time smear effects. It is down to the speaker maker to get the direct sound from the speaker right in the first place as this is the sound that the ear latches onto in the higher registers. The TA712 is a separate component designed for all hi-fi systems employing independent pre and power amps, regardless of manufacturer. The size of a slim preamp, and independently powered, it is simply wired in the tape loop or between pre- and power amp(s) using two pairs of analogue interconnects. To remove the boom, the signal from the pre-amp is passed into the unit, modified and then sent to the power amplifier. The unit contains an adjustable filter or “notch” circuit, an audio oscillator and a microphone measuring section. To perform a measurement and correction, each channel is done in turn. The channel to be corrected is connected to the oscillator and the other channel is muted. The microphone is connected and the oscillator volume and microphone gain are adjusted so that the VU meter is reading about half scale. The frequency of the oscillator is then adjusted, within the range of 30Hz to 80Hz, to find the major resonant frequency. This is child’s play as the VU meter indication invariably goes off-the-scale at resonance -and, anyway, the boom is easily heard by the operator. Once the frequency of resonance has been ascertained, the notch frequency for that channel is simply set to match using the appropriate rotary dial on the front panel. The notch depth is then adjusted so that a smooth response is measured/observed when the oscillator frequency sweeps over the offending area. This straightforward dial-in process is then repeated for the other channel. When complete, both channels' select switches are set to “play” and listening may proceed. The circuitry is of the highest audiophile quality with no integrated circuits in the signal path and the power supply filtration and stabilization is to the highest standards we can devise. The most attractive aluminium and mirror stainless steel cabinet is fully vibration isolated on Townshend Audio’s latest Spring Damper Suspension units which isolate down to a few hertz and never require maintenance. The unit comes with a precision Electret microphone, cable and microphone stand. The circuitry is of the highest audiophile quality with no integrated circuits in the signal path and the power supply filtration and stabilization is to the highest standards we can devise. The most attractive aluminium and mirror stainless steel cabinet is fully vibration isolated on Townshend Audio’s latest Spring Damper Suspension units which isolate down to a few hertz and never require maintenance. The unit comes with a precision Electret microphone, cable and microphone stand. How does it perform? Just brilliantly! |
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