Wunder Audio PAFour Plus

Wunder Audio PAFOUR Plus

The PAFOUR Plus is a 19" four-channel microphone preamplifier — four channels of the identical PEQ2 preamp circuit in a single 1U rack unit. It is the most channel-dense way to build a Wunder Audio preamp section in a rack environment: the same discrete Class-A topology, the same NICO transformers wound on core material dating from 1970, and the same extended output stage before the output transformer — all repeated four times across one rack slot. The physical size of the transformers in the PAFOUR Plus is unprecedented for a four-channel rack mic pre.

Four Channels of PEQ2 — No Transformer Compromises

The defining engineering decision of the PAFOUR Plus is the use of exactly the same Mu-Metal NICO transformers as the PEQ2 — on all four channels. The transformer core material dates from 1970 and contributes the characteristic fat vintage sound with minimal phase shift inherent to the PEQ2 line. The low winding ratio of 1:1.4 allows the preamp to handle very high input levels without requiring a pad in the signal path. The line and instrument input circuit is identical to the PEQ2R's line input stage — 60 dB of gain on the line input, enabling direct bass guitar or instrument recording into the Wunder without an external DI box. The new beefy output stage added directly before the output transformer increases maximum gain and headroom over the original PAFOUR. Gain switches carry more than three times the gold contact area per position compared to the previous generation. The gain knob includes an additional counterclockwise position reaching -24 dB. Per channel: discrete active HPF, output fader, LED metering with separate signal and clip indicators, and light-pipe pushbuttons. Knobs are milled from aluminum, anodized red, with white plastic dowel markers that will not wear off.

PSU Scalability and System Expansion

The PAFOUR Plus draws power from an external Wunder Audio PSU: the Blue Box PSU handles two units (8 channels), the Black Box PSU covers up to four PAFOUR units (16 channels) or up to eight PAFOUR Plus units daisy-chained (32 channels). This makes the PAFOUR Plus the most efficient way to build a large Wunder Audio preamp section in a rack: eight PAFOUR Plus units from a single Black Box PSU deliver 32 channels of PEQ2-equivalent preamp character at the minimum possible rack space. The 5' DC Main Cable and 1' daisy-chain cables per additional unit are required and sold separately.

KEY FEATURES

• 4-channel mic preamp 19" 1U — identical PEQ2 preamp circuit on every channel
• NICO Mu-Metal (Ni/Fe/Co) transformers with 1970 core material — same spec as PEQ2, 1:1.4 winding ratio
• New beefy output stage before output transformer — greater headroom than original PAFOUR
• Line/instrument input: 60 dB gain, Active or Classic Input mode (DI without external DI box)
• Gain switches: over 3x gold contact area per position vs. previous generation
• Gain knob: additional -24 dB position
• Discrete active high-pass filter per channel
• Output fader per channel
• Light-pipe pushbuttons per channel
• LED metering: green (signal) / red (clip) per channel
• Knobs: milled aluminum, anodized red, non-wearing white plastic dowel markers
• Tack-welded thick-gauge enclosure — improved RF protection vs. previous generation
• 1% Metal Film resistors throughout PCB
• Power: Blue Box PSU (up to 2 units) or Black Box PSU (up to 4 PAFOUR units / up to 8 PAFOUR Plus = 32 channels)

TECHNICAL SPECIFICATIONS

• Type: 4-channel mic preamp, 19" 1U rack format
• Channels: 4
• Circuit: identical to PEQ2 preamp section (discrete Class-A, 1970s topology)
• Transformers: NICO Mu-Metal (Ni/Fe/Co), 1:1.4 winding ratio, 1970 core material
• Line input gain: 60 dB
• Instrument input: 1/4" jack, Active / Classic mode
• High-pass filter: discrete active (per channel)
• Output fader: yes (per channel)
• Gain range: to -24 dB (additional CCW position)
• Switches: light-pipe pushbuttons, Grayhill
• Metering: LED green (signal) / red (clip) per channel
• Resistors: 1% Metal Film throughout
• Enclosure: thick-gauge tack-welded metal
• Power: external PSU — Blue Box (up to 2 units) or Black Box (up to 4 PAFOUR / up to 8 PAFOUR Plus = 32 channels)
• Required accessories: 5' DC Main Cable, 1' daisy-chain cable per additional unit (sold separately)