PROLogue SEVEN

ProLogue Seven Monoblock Amplifiers

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. The monoblocks 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 monoblocks 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, EL37, and any of their equivalents.
• Proprietary Custom low hum, wide bandwidth dual output transformers allow the monoblocks to drive most any speaker with ease. Read the white paper here.
• 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 parameters: Though PrimaLuna amplifiers are powerful, tubes run well below their maximum ratings.

Reviews at AudioReview.com