Frequency response (*w/o additional RIAA curve*) for all 4 preamps. After reviewing the graph from the THD+N v. amplitude (along with the average output of the cartridges which will be used in future stages of this project), a comparison could be made by choosing an input voltage that was within the optimal input range of all the preamps. I therefore chose .5 mVrms. The output level references were chosen as relative measures for each device to produce approximately .5 Vrms from the input.

Below is the frequency response for all four preamps:

• Blue = Pass Labs XONO
• Red = Manley Steelhead
• Yellow = Bryston BP26
• Green = GSP Audio Jazz Club w/ Elevator (various boost and r/c settings)