Denon dl103 low volume from sa3000

No you will not!

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.

To add to what Lewm said, less attenuation usually leads to better sound quality, all things being equal.

Shakey

The biggest problem is leaving the volume control at 75% and forgetting that, then switching over to your cd player. You can kiss your tweeters goodbye. Don't ask me how I know that.

Also, don't assume your significant other will check the volume control either. Again, don't ask me how I know that.

I am still a bit confused.
How much gain in a step up device should I be looking for? All my sut's are between 20 and 30 db of gain. Not sure what the gains are on my sa 3000 preamp, but the 2 gain values are added together (sut and mm gain)give the total? I don't have the spec sheet for my Counterpoint SA-3000 anymore. Would I be better off just buying a stand alone phono stage with about 60 db of gain and run it into the aux input on the preamp?
Thanks

I also noticed there is a space to put a resistor in the mc section. The cartridge load says it should be 100 ohms. Should I put a 100 ohm resistor in this spot?