DarkTube

DarkTube — Tube-Tech Style Passive Program EQ

A schematic-accurate emulation of the legendary Tube-Tech PE-1C — the Danish-built, modern-classic descendant of the Pultec EQP-1A. The smoothest, most musical program equalizer ever built, with the signature “boost + cut on the same band” trick that gives you that impossibly silky tilt characteristic of high-end mastering. Built around a 12AX7 triode tube stage with authentic harmonic content.

Authentic Tube-Tech topology:

• 12AX7 triode tube stage with very low bias offset (0.08, cleaner than typical Pultec emulations)
• Well-regulated PSU modeling — stable bias depth (0.10) for the Tube-Tech “polished” character
• Less HF pre-emphasis than the Pultec — the Tube-Tech’s signature cleaner top end
• Large coupling caps modeled (DC blocking corner ~1.5 Hz)
• Up to 8× oversampling (Kaiser FIR)

Low Frequency Section:

• Low Boost (0–10 dB) — independent boost amount
• Low Atten (0–10 dB) — independent attenuation amount
• Low Freq selectable: 20 / 30 / 60 / 100 / 150 / 300 Hz
• The classic Pultec/Tube-Tech trick: boost AND cut at the same frequency for a silky, characteristic shelf shape

High Frequency Section:

• High Boost (0–10 dB) — independent boost amount
• High Atten (0–10 dB) — independent attenuation amount
• High Boost Freq: 3K / 4K / 5K / 8K / 10K / 12K / 16K / 20K / 24K
• High Atten Freq: 5K / 10K / 20K
• Bandwidth (0–10, Sharp ↔ Broad) — Q control for the high boost band

Global controls:

• Tube Drive (0–1) — push the 12AX7 stage for added harmonic character
• Output (-12 to +12 dB) post-EQ trim
• Oversampling (1× / 2× / 4× / 8×)
• Bypass