Κώστας Φ.
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- Μηνύματα
- 8.978
- Reaction score
- 895
Description: Tubed, remote-controlled line preamplifier with MOSFET output stage.
Tube complement: two 12AU7.
Inputs: 3 pairs balanced (XLR), 3 pairs single-ended (RCA), 2 pairs single-ended tape.
Outputs: 1 pair balanced/XLR, 2 pairs single-ended RCA, 2 pairs single-ended RCA buffered tape.
Voltage gain: 14dB to single-ended RCA outputs, 20dB to XLR outputs.
Input impedance: 50k ohms (20k ohms minimum).
Output impedance: 25 ohms (maximum 195 ohms at 10Hz).
Polarity: non-inverting at all outputs.
Frequency response: 1Hz–200kHz, +0/–1dB (20Hz–100kHz into 600 ohms with 20' of 900pF interconnect).
Maximum output: 30V, 10Hz–200kHz, into 600 ohms at 1% THD.
Channel separation: >100dB at 1kHz, >80dB at 20kHz.
Signal/noise: not given.
Power consumption: 150W.
Shipping weight: 55 lbs (25kg).
Price: $9500.
"The TL-6.5 Signature ($9500) is derived from VTL's cost-no-object flagship preamplifier, the hybrid, two-chassis TL-7.5 Reference ($16,500). In his review in the October 2003 Stereophile (Vol.26 No.10), Paul Bolin praised the TL-7.5. John Atkinson wholeheartedly agreed; his measurements found that the TL-7.5 "demonstrates virtually bombproof measured performance, with no clue—other than its sound quality—that it is a tubed preamplifier."
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Quality under the hood
The quality of the TL-6.5's circuit components, assembly, and circuit board are topnotch. The power supply's capacitors are bypassed with small polypropylene caps. The audio circuits and their related power supplies use precision low-inductance, laser-trimmed metal-film resistors. The same resistors are used in the level control; the level is set by selecting combinations among an array of these resistors.
Moving from front to rear, the internal components include a shift register board, a huge relay PCB, two 12AU7 tubes, four MOSFET modules, four metalized polypropylene capacitors, and the rear-panel input boards. The two channels are kept separate by a prominent vertical shield that runs down the center from front to rear. Two flat, 24-conductor cables run from the shift register board to each channel's relay board.
The TL-6.5 is run as a fully differential circuit that has "sufficient common-mode rejection ratio while using tubes," according to VTL. The TL-6.5 provides gains of 14dB (single-ended) or 20dB (balanced). Its rated input impedance is 45k ohms, its output impedance a low 25 ohms, except at very low frequencies.
Gain in the single-chassis TL-6.5 is provided by one tube per channel, run in a differential circuit with only 2dB of negative feedback. While the original version had 12AX7s dual triodes, the production unit had 12AU7 tubes because the latter's slightly lower gain—20dB rather than 26dB—results in a lower noise floor. The plate of the 12AU7 drives the gate of two high-voltage MOSFETs per channel. These low-impedance, high-current devices allow the TL-6.5 to drive any load, even as low as 600 ohms, to its full rated output of 30V.
The TL-6.5 includes full power-supply regulation for each stage of amplification. Extensive filtering has been applied to the AC mains input to block radio-frequency interference and other types of spurious signals.
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Conclusion
The VTL TL-6.5 Signature performed brilliantly in my system, revealing dynamic contrasts both subtle and bold, holographic soundstaging, and solid, deep, tuneful bass. Its remote quickly controlled the TL-6.5 from any convenient listening position in my living room, and the preamp's front-panel display is readable from 10' away. The TL-6.5's ergonomics are the best I've encountered for a preamplifier.
For all these reasons, I strongly recommend the TL-6.5 Signature. For $9500, it offers battleship reliability, faultless microprocessor control of tube operation, and extraordinary switching control—as well as first-rate sound, a deep, wide soundstage, and driving dynamic contrasts. Add the five-year warranty, and it's an irresistible high-end preamplifier." -- Larry Greenhill
Και απο το κομμάτι των εργαστηριακών μετρήσεων:
"This is overall excellent measured performance, giving no clue to the pair of 12AU7 tubes hiding within the TL-6.5's hefty chassis." -- John Atkinson
Full Review: Stereophile.com
