Grove Hill Audio introduces the LIVERPOOL — a hand-assembled, all-tube feedback compressor.
Tube compressors were first introduced in the early 1930’s, and became widely used in the United States and Europe in the 60’s. An original American Mu tube compressor found its way to England where it was improved with several modifications; these units are still in use today. However, these rare custom configurations have never been commercially available. For years there’s been much curiosity surrounding the modifications made to these renowned compressors. To differentiate the modified units, the original green front panels were painted gray and a new model number was assigned.
In the spirit of the pioneering engineers, we respectfully made subtle circuit and control modifications that further enhance this extraordinary compressor design. With input from industry experts, we refined the design over months of testing to perfect the authentic vintage tone and vibe of these unique compressors.. We then experimented further and exposed additional creative capabilities.
The LIVERPOOL compressor is a distinct and unrivaled product, and NOT a clone of its predecessors. It is a fusion of the American compressor and the British-modified feedback compressor designs, with modern enhancements that were thoughtfully developed in the spirit of the original Mu tube compressor.
The designers of the LIVERPOOL compressor took well over a year to recreate the sonic character of the original units still in use at world famous recording studios. Custom-wound input and output transformers (Made in the USA), critical component choices and circuit layout make the LIVERPOOL compressor a reliable, creative tool for a wide variety of instruments, vocals and program sources. The LIVERPOOL power supply also provides low noise and exceptional stability even at high (30dB) gain reductions.
We are passionate about this remarkable compressor and are excited to offer it at an accessible price to the creative recording arts community. Because of the rare components used in the LIVERPOOL design, we are building the compressor in limited quantities.
Musical Performance Video Courtesy of Ben Karlstrom & Rick Lovrovich
Type: Tube compressor, 2U rack mount design
Frequency Response: +/- 1.5dB, 10 Hz to 40,000Hz
Power Output: +20 dBu
Total Harmonic Distortion: 0.08% at 1 KHz with output at 0dB
Noise Level: 82 dBu below rated output
Source Impedance: Any up to 15,000 Ohms
Load Impedance: 600 Ohms
Attenuation: 30 dB in 5 dB steps – Constant impedance.
Maximum Compression: 30dB
Attack Times (msec): 3*, 19*, 48*, 77*, 109*, 138*.
Recovery Times (*msec): 127*, 447*, 917*, 1.9 sec., 3.4 sec., 6 sec.
Threshold: 0dBm to +16dBm Output
Compression Ratios: 2:1 at 0dBm Threshold, 4:1 at +16dBm Threshold
Tube Complement: 6BC8/6BZ8, 6CG7, 6AL5
Circuit Design: Variable transconductance compression circuit utilizing a medium Mu, semi-remote cutoff twin triode tube.