Heritage Audio / Grandchild 670

The Heritage Audio/Grandchild 670 is a tube compressor from the 500 series.

~A ""Fairchild"" in 500 Series Size~

■Thorough Quality Control

Recreating the impact and emotion of the Herchild Model 670 in a 500 Series module. A stereo Variable Mu tube compressor fits into just two slots.

The Grandchild 670 is packed with four 6BA6 (5749) NOS tubes, three custom-designed transformers (one for each channel and one for sidechain), and carefully selected components and circuitry necessary to capture that elusive sound. It delivers the tone and response you've been looking for in a compact size.

Sharing the Herchild, it features an INPUT GAIN control with a 20 dB adjustment range, an AC threshold, a time constant switch with five selectable attack and release settings, and a DC threshold (a unique curve adjustment combining controls) that provides access to a progressive ratio. Adjusting the DC threshold allows the ratio and knee to work in perfect harmony, providing flexible control from hard limiting to extremely smooth, transparent, and light compression. It also features a 3-position high-pass sidechain filter to mitigate low-frequency influences in the detection circuit, making it suitable for modern productions.

As a stereo unit, the combined gain reduction of both channels determines the amount of gain reduction for both channels, ensuring a stable stereo image. The attractive, vintage-inspired front panel features not only a gain reduction meter but also a highly visible 3-position switch indicating active/bypass/off status, resulting in a clear and beautiful design.

Achieving an intimate, classic sound that musically connects and warmly envelops the mix is ??no easy feat, but the Grandchild 670 achieves it perfectly. Heritage Audio engineers responded with a determination to deliver the rich, refined, and elegant tone of the ""Fairchild."" By employing four 6BA6 (5749) tubes and three transformers, every signal passed through the Grandchild 670 is output with improved sound quality.

Input Impedance

15 kΩ

Output Impedance

50 Ω

Output Level

+29 dBu

Frequency Response

20 Hz ~ 20 kHz ±0.5 dB

Self-Noise

-78 dBu or less

Harmonic Distortion

Less than 0.5% at any level up to +24 dBu output (no compression)

Dimensions

180 mm (W) x 133 mm (H) x 75 mm (L)

Weight

1.12 kg

Current Consumption

Approximately 400 mA total per unit: 200 mA+ per slot (1 rail) (+16V / -16V) * 1 unit