The first stage in the Eros is an EF86 for both channels, and this is where tube rush will be really critical. Once the signal has been amplified by the EF86, it is again amplified by the 6922. In the Seduction/Reduction, half of each 6922 is the first gain stage, and the noisy half of that particular tube may just happen to be the first gain stage in the circuit.
We have found that noises like that will subside with 100 or so hours of use.