I have been experimenting with different heater settings for the AD1 tubes, one of which tests very bad, and the results are somewhat confusing. @adamaley is experiencing this same result.
On the recommended PX25 setting there is a large channel imbalance caused by one of the AD1s not being in very good shape. However, if I switch to the 300B setting the channel imbalance goes away and the pair sounds great. My speakers image “perfectly” so I can tell based on the centering of the vocals. Also, I played a couple mono albums and there was no shift in the soundstage when I hit my pre-amp’s mono button.
Anyone care to explain why the AD1 seems fine on the 300B setting but not the PX25?
On the recommended PX25 setting there is a large channel imbalance caused by one of the AD1s not being in very good shape. However, if I switch to the 300B setting the channel imbalance goes away and the pair sounds great. My speakers image “perfectly” so I can tell based on the centering of the vocals. Also, I played a couple mono albums and there was no shift in the soundstage when I hit my pre-amp’s mono button.
Anyone care to explain why the AD1 seems fine on the 300B setting but not the PX25?