Фонокорректоры — VTL TP-6.5 Series II Signature Phono

The TP-6.5 Series II Signature is a phono preamplifier from the American valve company VTL and a major update of the earlier TP-6.5 Signature. The revision borrows circuit refinements first developed for the TL-7.5 Series III Reference line preamplifier, and it enlarges the power storage feeding the active moving coil stage. Every unit is handmade in the USA, while the transformer step-up is priced as an add-on.

Key specs that matter

Connections comprise two RCA input pairs, each with its own load settings, plus an XLR output pair alongside an RCA output pair. Maximum gain from the balanced outputs is 68 dB for moving coil and 40 dB for moving magnet cartridges, and gain can be changed in five steps of 6 dB. Output impedance is 150 ohm. Frequency response extends from 1 Hz to 100 kHz within +0 and -1 dB. Mains consumption is 80 W, and the unit weighs 22.7 kg.

Engineering and use context

VTL combines JFETs with valves in this circuit for quiet operation. The valve complement consists of two 12AU7 in the moving coil stage, two 12AX7 and two 12AT7 in the moving magnet stage and a further pair of 12AT7. RIAA equalisation is passive and uses an accurate 4-corner network. Power comes from separate dual-mono supplies for the two channels with several low-noise cascaded regulators, and shielding throughout the chassis rejects electromagnetic and radio interference. Shunt regulators provide better ripple rejection and lower the background noise. The active moving coil stage draws on a large low-impedance reservoir built with gel capacitor technology, again to reduce noise. Gain, choice of MC or MM, cartridge loading, a mono mode and phase reversal can all be operated from the front panel or with the remote control. As an option, a transformer step-up can be installed, adding a second moving coil stage whose low-noise transformer gain serves cartridges of very low output, which also lets owners connect several arms and cartridges at once.

Pairing

The balanced outputs make best use of the full gain and suit a balanced-input line stage like the VTL TL-7.5 Series III Reference whose circuit ideas fed into this design. Its two independently loaded inputs allow two tonearms, or a moving coil and a moving magnet cartridge, to stay connected.

Alternatives

The VTL TP-2.5i is another phono preamplifier in the VTL catalogue, built with a hybrid MC stage, an all-valve MM stage and selectable 56 or 62 dB MC gain.