Singular Audio introduces Tubedrve Mastering: stereo tube saturator w/ stepped controls for api 500
by Singular Audio
29th August 2023

The tubedrve is a stereo tube saturator module for the API 500 series also known as the ‘lunchbox’ format.
This mastering version is the same as the original tubedrve, but with indented/stepped controls for easier recall and stereo matching. It also has a low gain setting which provides an extra -10dB of gain which comes in handy when using it on the mixbus or when mastering.
The tubedrve utilises 2 pentode tubes per channel, for a total of 4 tubes per module. The first one is an EF86 and the second one a 6AS6. The 6AS6 tubes is overdriven, providing the distortion.
The 6AS6 can be switched from pentode to triode operation. Triode mode provides a smoother type of overdrive with more ‘even harmonics’. Pentode mode gives an aggressive distortion with more ‘odd harmonics’.
The module can be controlled with an input or ‘drive’ level, controlling the audio signal going to the tubes. A bias control sets the operating point for the distortion tube, allowing the user to control the bias current. With high and low settings this introduces asymmetrical waveform clipping, providing a more aggressive sound.
Input gain can be selected with a 3-way switch and finetuned with the input knob. An output level control controls the level coming from the tubes.
A simplified overview of how the tubedrve mastering works can be found in the manual which can be downloaded at www.singularaudio.nl/shop/tubedrvemastering
A white led lights up when the distortion tube is being overdriven.
An anodised black aluminium frontpanel is used, providing a long and lasting finish.
high voltage
Plate voltage for the tubes is 240VDC, due to a DC-DC converter which generates the high voltage from the +- 16V power supply of the API 500 format. This is needed for the best possible overdrive sound. This is unlike other designs which use the +48V supply for the plate voltage, which leads to a ‘starved plate’ sound. The +240VDC plate supply in this design allows for the best possible tube overdrive sound.
NOS (‘New Old Stock’) tubes are used, meaning they are unused tubes manufactured in the 70s or 80s.
pricing
The tubedrve mastering is priced at 709 euros, excl. any applicable sales tax.
All info can be found at https://www.singularaudio.nl/shop/tubedrvemastering/