PrimaLuna USA

ProLogue Seven Monobloc Power Amplifiers - $3149/pair

Want the ultimate? Classic Ultralinear all-tube sound, with all the body and glory that you could ask for. For an additional $550 over the EL-34 equipped Prologue Six, you will get an amplifier that has more power, better bass authority, and a little more air on top, but never edgy.

In addition, the ProLogue Seven comes specially equipped with the following upgrades:

Upgraded Solen capacitors made in France. The result is an even better midband and wonderful clarity.
Fast Recovery Diodes. Resulting in increased definition and detail, especially when the music becomes complex.
KT88 Output Tubes. We use the current production copy of the legendary Genalex KT88. The tube sounds wonderful, with tremendous body and punch, while still giving you the warmth and humanity you'd expect from an all-tube amplifier.

The ProLogue Seven starts with the same basic topology as the award-winning ProLogue Five stereo power amplifier. But the monoblocs reach a new level of performance using a unique dual-feedback topology: Cross-coupled current feedback for superior impulse behavior and gain stability. Next a slight amount of negative feedback is used to achieve exact gain setting, low distortion, and low output impedance. This effectively cancels the negative by-products associated with both feedback circuits. The end result utilizes all the benefits of feed-back, without all the drawbacks.

Finally, the monoblocs integrate a newly-designed, wide-band, low-loss, output transformers, built to handle even the most difficult speaker loads. A two Ohm output tap is added for additional flexibility.

Like all ProLogue amplifiers, it boasts:

Soft-start circuit Extends component and tube life by powering up the amp gently every time you turn it on.
Tube plate fuse Protects the amplifier output stage. Other amps may need a trip to the shop if a tube fails. Not this one. Just plug in a new tube and fuse, and go.
Adaptive AutoBias™ Exclusive to PrimaLuna, this circuit monitors and adjusts bias automatically. Each power tube is monitored to stay in a peak operating range. Improved performance and better sound, with distortion reduced by 40% to 50% over conventional designs. No need for matched tubes. No bias adjustments. Ever. It also allows you to experiment with different power tubes. Plug in virtually any power tube. Adaptive AutoBias will automatically adjust itself! In addition to KT88s, you can use 6550, KT90, EL-34, KT77, 6CA7, 6L6GC, KT66, 7581, or even 6V6GT tubes, and any of their equivalents.
Custom designed output transformers Encapsulated low hum, wide bandwidth for great bass and extended highs. Designed by Marcel Croese and one of the most prestigious transformer designers in the USA .
Premium parts . Fully vented chassis, chassis-mounted ceramic tube sockets, Nichicon and Solen capacitors. WBT style speaker terminals. Gold plated input jacks.
Hand made with the finest point to point wiring, with workmanship equal to or better than any product you can buy at any price , period.
Chassis made of finely finished heavy gauge steel, and five step automotive quality finish. Each coat hand rubbed and polished. Removable tube cage included no charge.
Toroidal power transformer for low hum, and a front end that is dead quiet.
Conservative design runs tubes easy for long life.

Owner's manual

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Specifications
Output: 70 watts x 2
Freq. Response: 20Hz-85kHz +/- .5dB
THD: Less than 1% at full power
S/N Ratio: 101dB
Input Sensitivity: 911mV
Input Impedance: 100k Ohms
Power Consumption (per amp): 210 watts
Dimensions (per amp): 11 " x 7.5 " x 15.5" (WxHxD)
Weight (per amp): 37.5 lbs
Inputs: 1 pair RCA
Outputs: 2, 4 & 8 Ohm speaker taps
Tube Compliment (per amp): 2 - 12AX7, 2 - 12AU7, 4 - KT88