6.2 Amplifier¶

8-channel Class-D marine amplifier with integrated DSP. Each subwoofer runs on its own bridged channel pair @ 4Ω; four remaining channels drive the four cabin speakers.

Specifications¶

All specs from the JL Audio MV800/8i Connection Guide unless otherwise noted.¹

Channel Configuration¶

Each sub gets a dedicated bridged pair at 4Ω — directly matches the JL M6-8IB-S-GmTi-i-4 RMS rating (200W @ 4Ω SVC). No series wiring, no impedance mismatch, independent per-sub gain/EQ/delay via onboard DSP.

Onboard DSP¶

Integrated DSP (AKM AK7738, 24-bit / 48 kHz) supports per-channel:

• Parametric EQ
• Time-alignment delay
• Crossover (HPF/LPF) with selectable slope
• Bass boost
• Signal routing & mixing (e.g. summing left/right sub-RCA to both bridged sub pairs)

Configured via JL Audio TüN software:

• USB (PC/Mac) — laptop with USB A/B cable to the amp's USB port. Fallback method.
• Bluetooth — via the VXi-BTC (JLid Bluetooth Communicator), wired to the amp's JLid-COMM port. Phone/tablet running TüN Mobile or TüN Express. Primary tuning method on this build.

The amp's single JLid-COMM port is occupied by the VXi-BTC; no M-DRC-50 preset selector is installed (see Bluetooth Tuning page → Design Decisions for rationale).

Bridged Speaker Wiring (Sub Pairs)¶

The MV800/8i ships with four 2-channel speaker harnesses (A/B, C/D, E/F, G/H). For each bridged pair, the (+) lead is on the lower-channel harness and the (−) lead is on the adjacent harness — the bridged pair spans two harnesses, not one.¹

The unused leads on the same harnesses (Gray + White/Black on harness A/B; Purple + Green/Black on harness C/D) are not connected when running that pair bridged. Cap or trim them at the harness; do not connect to anything.

Ch 5/6 (front speakers) and Ch 7/8 (rear speakers) run stereo unbridged from harnesses E/F and G/H respectively — standard +/− per channel.

Wiring¶

Sub RCA routing: The MS-RA670 has a single mono sub-out. Route it into one amp input and mirror it to both bridged sub pairs (Ch 1+2 and Ch 3+4) via the onboard DSP signal routing — no Y-splitter required.

Circuit Protection¶

The MV800/8i has an internal 80A fuse (primary amp protection). External protection at the AUX battery protects the supply wire:

• Breaker: Blue Sea 187-100A (100A) thermal circuit breaker
• Protects 4 AWG wiring (rated 95A continuous, 100A acceptable for ~3-4 ft run)
• Mount inline within 7" of AUX battery+ terminal (5th stacked lug)

The 100A external CB is intentionally above the 80A internal fuse — the internal fuse remains the primary trip path under amp fault, while the external CB protects the wire from a short upstream of the amp.

Mounting Location¶

Under rear seat (driver side or center, mounted to floor with clearance for Class-D thermals)

• Power feed ~3-4 ft direct from AUX battery+ (short feed, low loss)
• Ground return ~3-4 ft to AUX battery−. All system grounds (head unit + amp) should land at the same point per the manual to avoid ground loops.¹
• Centroid to all 4 speakers + 2 subs — minimizes speaker wire runs
• RCA + remote bundled together from head unit through trans tunnel (~10-12 ft, high-quality shielded RCA required to avoid alternator whine)
• Mounting plate with at least 1" (2.5 cm) clear air space above the shell (manual requirement for enclosed-compartment mounting); convection-cooled, no fan
• Orient with connections pointing downward where practical (preserves IPX2 rating)
• Keyhole mounting screws — insert screws first, then drop amp onto them and slide
• USB access (front of chassis) needed for TüN DSP tuning — leave service loop

Outstanding Items¶

• DSP configuration: corner frequencies, sub delay, channel gain matching (set during install with TüN software + measurement)

Related Documentation¶

• Audio Systems Overview
• Head Unit
• Speakers
• Subwoofer
• AUX Battery Distribution