Coil Audio CA-70 Modular Microphone / Line single channel Tube Preamplifier
The CA-70 preamplifier module pays homage to the classic American two-stage circuit invented by Western Electric in 1913 and manufactured by multiple companys from the 1930's through the 1950's – most notably RCA, Gates, and Langevin. This old octal tube circuit has a huge thick tone and is what many consider to be the quintessential “ old tube preamp ” sound.
The CA-70 preamp module uses Coil Audio's CT-110 or CT-110HN (by default) input and CT-41 output transformers, high quality capacitors, resistors, and NOS octal tubes. It's powered by Coil Audio PS6 Rack Tray and Power Supply.
PS6 Power Supply and Rack Tray sold separately
The Controls
The INPUT pad section contains a phase reverse switch, and a 6 position pad network. The first four positions are various 150/250 ohm mic pads; -6db, -12db, and -19db. The final two (LN 1 & LN 2) positions allow line-level signal to run through the amplifier providing tone-shaping capabilities while mixing from your DAW, Tape Machine, or other Line Level Devices – including other Preamps.
The NF control varies the amount of negative feedback present in the circuit. Counter-clockwise brightens and moves the sound forward while raising harmonics and sensitivity. Clockwise increases negative feedback, producing a darker tone with a smooth, dampened harmonic structure.
The HIGH switch transitions from the natural openness of the tubes to a gentle filtering of upper frequencies.
The LOW switch reacts with the NF, boosting or cutting low frequency while moving the low end from front to back in the sound stage.
The OUTPUT control is placed between the 1st stage 6J7 and 2nd stage 6C5 tubes and sets the final level Output level.
Specifications
• Two-stage 6J7/6C5 vacuum tube circuit
• Negative Feedback tone adjustment with HIGH/LOW filters
• 42db-54db of available gain
• Flexible input pad section for mic or line level operation
• 150 Ohm Mic, 20k Line input, 600 Ohm output
• Interchangeable/Optional hot swappable input CT-110 (optional) or CT-110HN (by default) and CT-41 Output transformers
• NOS tubes, signal caps & resistors, PEC 2W carbon pots
• Up to Six CA Series Amplifiers mount into our PS6 Rack
• Hand built and tested in the USA
Data sheet
- Condition
- New
- Type
- Tube Preamplifier
- Application
- Tracking & Mixing
- Channels
- Mono
- Circuit
- Tube
- Inout transformer(s)
- CT-110, or CT-110HN at your choice
- Output transformer(s)
- CT-41
- Format
- 19"
- Chassis
- 1 U
- Quantity
- 1
- Direct I/O
- Through PS6 Rack