API Audio, Pro Audio products
1-ch mic pre for the 500 format
API Audio, Pro Audio products
Discrete Mic / Line Pre
API Audio, Pro Audio products
All Discret 500 series mic / line / instrument preamp with variable output
Aurora Audio, Pro Audio products
500-series Mic Pre w/HPF
Avedis Audio Electronics, Pro Audio products
500-series microphone preamplifier
Avedis Audio Electronics, Pro Audio products
500-series microphone preamplifier
Burl Audio, Pro Audio products
Burl Microphone Pre-amp modules for API 500 Series. B1 uses BX2 nickel output transformer.
Burl Audio, Pro Audio products
Burl Microphone Pre-amp modules for API 500 Series. B1D uses BX4 steel output transformer.
Buzz Audio, Pro Audio products
500 series discrete class A mic preamp module, Lundahl output transformer.
Chandler Limited, Pro Audio products
500 Series compatible preamplifier module.