The OMA RIAA Phono Stage is ultra transparent, utilizing a proprietary circuit without input or output transformers, with 55-60db of gain (depends on tubes used). Suitable for moving magnet, moving iron and moving coil cartridges with an outboard step up transformer (SUT) such as from Consolidated Audio, Berlin.
Like virtually all OMA amplifiers, it is hand built on two chassis using one inch thick solid Pennsylvania black walnut, with hand made dovetailed joints and finished with hand rubbed oil and wax.
The OMA RIAA eq is extraordinarily accurate, and is DC coupled to the driver stage. The power supply is housed in a separate chassis to isolate the signal chain. The circuit is dual wide band, high gain and low z output. It will easily drive almost any amplifier directly, including all OMA power amplifiers. A selector switch allows the user to choose between four inputs.
Tube compliment for the OMA RIAA is one 85A2 neon tube, 6080 and EF186, two 5963 and two E280F. These are superior tubes in the proper circuit and allow the user a wide choice of tube brands for experimentation if desired.