Anthony DeMaria Labs ADL 670
Stereo tube variable-mu limiter (Fairchild 670 recreation)
Compressor / LimiterPrice not published
Specifications
- Type
- Compressor / Limiter
- Description
- Stereo tube variable-mu limiter (Fairchild 670 recreation)
- Topology
- all-tube/valve, Fairchild-style, variable-mu, transformer-balanced; 16 vacuum tubes and 8 custom transformers, no ICs/chips
- Signal path
- Analog
- Channels
- 2
- Channel format
- stereo (dual-mono capable)
- Form factor
- 6U rack chassis + separate remote power-supply unit
- Rack units
- 6
- Frequency response
- 50 Hz – 20 kHz ±1 dB
- Impedance (Ω)
- 600
- Back design
- Two rear PCBs (low/high voltage) plus one hinged bottom PCB; front and side ventilation with two 24V fans (run at 20V for quiet operation); front and side carry handles; detachable AC cable; 18-gauge 600V 5-pin, 5-ft umbilical cable to remote power supply
- Introduced
- 2001
- Country of manufacture
- USA
Details
Controls: Adjustable attack (0.2–0.8ms across selectable positions); output level +4/+8 VU; general limiting/threshold controls per original Fairchild 670 layout (not itemized in detail on ADL's features page)
I/O: Balanced XLR in/out, 600-ohm; separate remote power supply connected via umbilical cable
Notable use: Described by ADL as 'the mother of all compressors,' used by award-winning engineers/producers per marketing copy (no specific named users on this page)
Notes: Explicitly a recreation of the classic Fairchild 670 stereo variable-mu limiter ('all parts designed based on the original Fairchild 670; capacitors/resistors match original values'). Tube complement: 2x12AX7A, 2x12BH7A(12AU7A), 4x6973, 8x6386 (16 total). Technical-specs page literally states '4 input channels' — this is treated here as referring to the Fairchild-style internal program/channel-selector concept rather than 4 discrete audio I/O paths, since ADL and all secondary sources describe the 670 as a stereo (2-channel) limiter; FLAGGED as an interpretive judgment call. Weight 45 lb. Third-party dealer/retail listings (not ADL's own site) have historically cited prices in roughly the $18,500–$20,000 range, but since this is not manufacturer-published MSRP and varies by source/date, price_usd is left blank per golden rule.