The Sunstone OTA Phaser is a modern adaptation of the classic Electro-Harmonix Small Stone phaser, which was popularized by musicians like Jonny Greenwood, David Gilmour, and Carlos Alomar. The Small Stone was originally released in 1975 as a smaller alternative to the earlier Bad Stone phaser.

One of the key differences between the Small Stone and other popular phasers of the time, such as the MXR Phase 90, was the use of operational transconductance amplifiers (OTAs) instead of matched JFETs. In 1977, EHX made some improvements to the Small Stone circuit, resulting in the highly regarded “Issue J” version.

The Sunstone OTA Phaser is based on the Issue J version of the Small Stone, but with a few changes. It replaces the CA3094 OTA with the LM13700, which is essentially two CA3094s in one package and is still in production. Additionally, the Sunstone adds an output buffer in discrete format to address compatibility issues with the LFO configuration.

To compensate for the volume difference between the two Color switch settings in the original Small Stone, the Sunstone also includes an output volume control. This control is preceded by an added gain stage based on the EHX LPB-1 booster, ensuring there is plenty of signal to work with.

If you enjoy the sound of the Sunstone OTA Phaser and want more features, you may be interested in the Blackout Whetstone, which is based on the Small Stone Issue J circuit. The Whetstone, available from Aion FX as the Redshift Deluxe Phaser, offers a wide range of modifications and additional features.

Summary created by AI from the original source.