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Kazrog launch Avalon VT-747SP plug-in

Officially licensed by Avalon Designs

Kazrog Avalon VT-747SP Class-A tube valve opto compressor passive EQ analogue emulation plug-in

Kazrog’s plug-in line-up offers emulations of a number of rare and sought-after analogue processors. Their latest offering, Avalon VT-747SP Native, takes the same approach, and this time has been developed in a collaboration with — and is officially licensed by — Avalon Designs themselves. The plug-in models the hardware processor of the same name, a unit which combines a Class-A optical compressor with a six-band equaliser.

Initially designed as a “synthesizer smoothing device”, the original hardware unit has proved to be a popular choice for bus processing duties amongst mixing and mastering engineers thanks to its smooth-sounding EQ and flexible compressor section. The plug-in aims to faithfully recreate those features, whilst also offering a wider choice of compression timing options than was possible with the hardware design.

The compressor section is kitted out with all of the expected controls: an Input level knob is joined by Threshold, Attack, Release and Ratio parameters, the last of which offers a range of choices between 1 and 20:1, and a Make-up Gain dial offers up to 10dB of gain at the section’s output. There are also LF and HF EQ controls which can be placed in the section’s side-chain signal to influence the behaviour of the compression. The first offers a range of 60Hz to 1kHz, whilst the second can be set anywhere between 600Hz and 10kHz, and both offer ±15dB of gain adjustment.

A six-band graphic EQ section follows, promising to deliver the smooth character for which the hardware unit’s passive design is renowned. There are three peak filters which sit between a low shelf and a pair of high shelves, all of which simply offer gain adjustment; their frequency and Q parameters are all fixed, with Avalon saying they were carefully chosen to provide a useful amount of tonal control whilst maintaining a natural harmonic balance and the lowest possible phase variation. Helpfully, the EQ section can be placed either before or after the compressor.

Finally, some tonal variation is offered by a switchable TSP (Tube Signal Path) mode. When active, the plug-in’s compressor section signal path employs three modelled dual-triode valves, offering an alternative sound to the default mode, which models discrete Class-A transistor amplifiers.


Avalon VT-747SP is supported on PCs running Windows 8.1 or higher, and Macs running macOS 10.13 and above. VST2, VST3, AU and AAX plug-in versions are available.

Pricing & Availability

Avalon VT-747SP is available now, and is currently (17 August 2023) being offered at an introducotry price of $79£63, reduced from its full cost of $129£103 (prices include VAT).

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