Designer, manufacturer and popularizer of tube audio and vinyl sound Thomas Mayer (Thomas Mayer) created a single-channel phono corrector for working with old VarEQ records — he described the process in detail in his blog. It is worth taking into account that these discs were recorded with various frequency response corrections — therefore, the Mayer monophonic phono corrector is equipped with an adjustable equalizer.
The device received separate 6-step controls for low frequencies and high frequency decay at about 10 kHz. According to Meyer, such adjustments will allow you to listen to records with the widest set of equalization curves, from early shellac discs at 78 rpm to vinyl monophonic records with a rotation speed of 33 rpm.
The device is similar to the already classic Meyer model, the LCR phono corrector. The phono corrector itself and the power supply received separate cases of almost the same design. The equalizer circuit repeats the LCR topology, only in the monophonic version, and not in stereo. It uses D3a pentodes mounted in anti-vibration mounts.
The first version of the VarEQ mono-phono corrector, built for 78 rpm recordings, appeared in 2017. The cost of a phono corrector in Europe is 10,500 euros.