Предусилители — VTL TL5.5 Series II

The TL5.5 Series II is a single-chassis tube preamplifier from VTL Amplifiers of Chino, California, sold in the Signature line. The original TL-5.5 appeared in 1997, and the Series II update carries over technology from VTL's TL-7.5 Reference and TL-6.5 Signature preamplifiers while keeping the all-tube circuit and the option of a phono stage that can be retrofitted.

Key specs that matter

Two 12AU7 and four 12AT7 tubes equip the line stage. Two input pairs accept either XLR or RCA connections, and six further pairs are RCA only, one of them serving as the tape input. Main outputs come as a single XLR pair alongside a single RCA pair, plus a fixed-level buffered RCA record out. In normal mode gain is 11 dB single-ended and 17 dB balanced, and a low setting cuts this to 6 dB and 11 dB. Input impedance is 35 kohm, and output impedance is 150 ohm, rising to a maximum of 400 ohm at 10 Hz. Response runs from 1 Hz to 200 kHz within +0 and -1 dB. At under 1 percent distortion the output reaches 30 V, or 1.75 V into a 600 ohm load. Channel separation exceeds 100 dB at 1 kHz and 80 dB at 20 kHz. Consumption is 60 W for the line stage and 130 W with the phono board fitted. The case is 44.45 cm wide, 43.18 cm deep and 12.06 cm high, and the unit weighs 13.6 kg unpacked.

Engineering and use context

VTL describes a simple circuit topology with low negative feedback, a high current output stage of low impedance and a microprocessor-based control system, together with fully balanced operation and precision-regulated, shielded power supplies. A rigid shielded chassis carries a precision-milled faceplate, and a bi-directional RS-232 port lets external control systems operate the unit. The remote handles power, source selection, volume, muting, fade, channel balance and phase reversal. The optional phono stage offers a moving magnet mode with 40 dB of gain into 47 kohm, and a moving coil mode with 54, 60 or 66 dB and loads of 100, 220, 470 or 1000 ohm or 47 kohm. The input labelled Ph/Aux 2 becomes the RIAA phono input when that board is installed, takes an external phono stage, or works as an ordinary line input when no phono stage is present.

Pairing

Rear 12 V trigger outputs can switch power amplifiers with trigger inputs in step with the preamplifier, and the XLR main output suits amplifiers with balanced inputs.

Alternatives

VTL also builds the TL6.5 Series II Signature, another preamplifier from the same Signature family.