The ProLogue Four starts with the same basic topology as the top-rated ProLogue One integrated amplifier. But further improvements are realized from new driver and phase splitter circuitry. The result is no need for any negative feedback. This means even more natural tonality and better overall musicality.
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 percent 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 EL-34s, you can use 6550, KT88, KT90, 6L6GC, KT66, 7581, EL37, 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 Realcap 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 maxim ratings
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Specifications
Power 35 Watts per channel
Frequency Response 20Hz - 85kHz +/- 0,2dB at rated power; 4Hz - 110kHz -3dB @ 1W
THD with AABB <0,1% @ 1W; <1% @ 10W; max 2% at rated power into resistive load
S/N Ratio 89 dB (unweighted) ref 1W
Input Impedance 100 kOhm
Input Sensitivity 600mV rms input for rated output power
Maximum Gain 28x (29dB)
Power Consumption 115W @ idle; 210W @ rated max. power
Net Weight 37.5 lbs / 17 kg
Shipping Weight 41.9 lbs / 19 kg
Dimensions 15.5" x 11" x 7.5" / 395 mm x 280 mm x 190 mm (L x W x H)
Shipping Dimensions 18.3" x 15" x 12" / 465 mm x 380 mm x 305 mm (L x W x H)
Inputs 1 pair RCA
Outputs 4 & 8 Ohm Speaker Taps
Tube Complement 4 x EL-34
2 x 12AX7
2 x 12AU7
