Another possibility, which would be consistent with the fact that there is no problem when the preamp is used with the Marantz amp, is the scenario described by Atmasphere in his two posts dated 8-3-12 in this thread.
Basically, the very high input impedance of the DNA-1 may be bringing out a design issue in the preamp. The Marantz presumably has a much lower input impedance, perhaps 47K or less, which does not bring out the issue. The very extended low frequency bandwidth of the DNA-1 (specified as 0.5 Hz) is presumably also a factor that contributes to bringing out the issue, as explained in Ralph's (Atmasphere's) posts.
If that is what is occurring, and I suspect that it is, a readily practicable solution would be to insert a pair of 10 db Rothwell attenuators at the inputs of the DNA-1. That would result in the preamp seeing a load impedance of something like 33K.
Doing that would cause you to operate your volume control at settings that are 10 db higher than those you would otherwise be using. But given the relatively high gain and sensitivity of the DNA-1, as noted in the Stereophile measurements that Unsound referred to, I doubt that would be a problem. It might even be beneficial.
Best regards,
-- Al
Basically, the very high input impedance of the DNA-1 may be bringing out a design issue in the preamp. The Marantz presumably has a much lower input impedance, perhaps 47K or less, which does not bring out the issue. The very extended low frequency bandwidth of the DNA-1 (specified as 0.5 Hz) is presumably also a factor that contributes to bringing out the issue, as explained in Ralph's (Atmasphere's) posts.
If that is what is occurring, and I suspect that it is, a readily practicable solution would be to insert a pair of 10 db Rothwell attenuators at the inputs of the DNA-1. That would result in the preamp seeing a load impedance of something like 33K.
Doing that would cause you to operate your volume control at settings that are 10 db higher than those you would otherwise be using. But given the relatively high gain and sensitivity of the DNA-1, as noted in the Stereophile measurements that Unsound referred to, I doubt that would be a problem. It might even be beneficial.
Best regards,
-- Al