Skipper,
The circuitry in your phono stage is running at whatever voltage and current levels it can be excited to run at, based on the input it is receiving from the cartridge. The phono stage does not "know" or care where you set your volume control. Another name for volume control is "attenuator". It is simply attenuating the output of the phono stage. So, no, you cannot possibly ever damage your phono stage in this manner. The DL103 has a VERY low voltage output; this is most likely why you need less attenuation of the signal than is typical for other cartridges in your system.
Just one other point: When you use the SUT, I hope you are careful to plug it in to the MM section of the SA3000, not the MC section. Or, if there is only one pair of phono inputs but gain is selectable, simply use the low gain setting with the SUT, and if load resistance is selectable, select 47K with the SUT. You may find that the noise floor is then actually lower with the SUT than straight in via the high gain settings or MC inputs.
The circuitry in your phono stage is running at whatever voltage and current levels it can be excited to run at, based on the input it is receiving from the cartridge. The phono stage does not "know" or care where you set your volume control. Another name for volume control is "attenuator". It is simply attenuating the output of the phono stage. So, no, you cannot possibly ever damage your phono stage in this manner. The DL103 has a VERY low voltage output; this is most likely why you need less attenuation of the signal than is typical for other cartridges in your system.
Just one other point: When you use the SUT, I hope you are careful to plug it in to the MM section of the SA3000, not the MC section. Or, if there is only one pair of phono inputs but gain is selectable, simply use the low gain setting with the SUT, and if load resistance is selectable, select 47K with the SUT. You may find that the noise floor is then actually lower with the SUT than straight in via the high gain settings or MC inputs.