A complete set of measurements was made on the Manley Reference 240 in both the triode and tetrode modes using the balanced inputs. Selected measurements were also made using the unbalanced inputs.
The Manley Reference 240 was warmed up for one hour at 60W into 8 ohms, one-third of its rated maximum power in the tetrode mode. Although the top plate became very hot, this was not enough to be an operational concern. However, it was hot enough that the amplifier should be kept out of reach of small fingers. (The same might be said of the sharp edges on the…