Serpent Audio SB4001-S SEPIA

Controls: Threshold -20 to +20dB, Ratio 1.5:1 to 10:1, 10 Attack Times, Classic Stepped Release with Classic/Alternate Auto Release, fully variable Attack and Release (expanded vs. standard SB4001), Wet/Dry Blend, 'Grind' harmonic drive mode, True Bypass

I/O: 1 x 1/4" sidechain (key) input with 60/90/120Hz, Boost, Slope filter options; routed through Karno SEPIA host I/O

Notable use: SEPIA-platform (Karno) edition of the SB4001 SSL-style bus compressor, adding fully variable attack/release and digital recall/control over an analog signal path

Notes: FLAG: NOT listed in serpentaudio.com's own product navigation (which shows only 5 items: Splice MKII, Splice MKII 500, SB4001, Chimera, Send N' Blend). Found via Karno's official store (store.karno.com) and confirmed as a currently-sold Serpent Audio-branded product at Vintage King, Sweetwater, KMR Audio. This is a co-branded variant built for Karno's 'SEPIA' modular platform (digitally-controlled analog infrastructure), distinct hardware/form-factor from the standalone 500-series SB4001. Included as in-scope current hardware but flagged for lower confidence on manufacturer attribution/support since it is not on Serpent Audio's own site. Price only found in GBP (£1,272 on Karno UK store) — per rule, non-USD price omitted rather than converted; price_usd left blank. country_of_manufacture left blank (not stated for this specific SEPIA edition, unlike the core Serpent Audio line which states 'Made in USA/Philadelphia').