In Nominal Low Noise, we are now reducing the bias on the ETMX ESD from full scale (-430 V, used for acquisition) to -218 V. The attached plot shows the spectrum of one of the ESD DAC drive signals (they're all the same) at -218 V bias, in NLN. The rms is 16,600 counts. This is using the new 20-bit DAC: +/- 512k count range. So there is plenty of headroom.