hissing sibilants

Btw, it is sort of obvious, but did you also check that your cartridge is properly aligned otherwise? You only mentioned the VTA, but even more important is the overhang, azimuth, proper offset angle, etc. I'd start there to exclude an improper set-up as the cause.

I think you need to adjust the VTA by ear. It is very difficult to get the optimal VTA alignment by just looking with the naked eye. Select a record with plenty of silibant sounds and adjust until it sounds right. If you have the same recording on CD that will give you a benchmark, so you are not trying to adjust something that was recorded too hot.

agree about the phono stage....it is the most forgotten art of vinyl, that you have to find the best match for your cartridge (either loading it properly or the best match step up transformer....)

IMBW but I believe that the spec you are quoting is refering to the ECP1's gain if the internal or "self" impedence of the MC is 10 ohms. They do not actually state what the input impedence of the ECP1 is when using the MC setting. Delos recommends loading anywhere from 98 to 806 ohms so I can see how people are getting good results when loading the cartridge anywhere from 100 to 500 ohms. The ECP1 in MC mode must be directly coupled (no coupling cap between the cartridge and the first transistor) to the cartridge as the HI-FI choice excerpt on the Electro website states that some MC are effected by the DC voltage that it runs through the cartridge coils. Maybe Delos could answer how the DC would effect there cartridge... BTW when a dealer says 10 ohms would "kill" the cartridge he just meant that the voltage drops by half when the input impedence of your phone pre is the same as the internal or "self" impedence of your MC.

Jjrenman,
The gain value surely cannot be dictated by the internal impedance of the cartridge. From what I understand it is dictated by the cartridge's output voltage. You want to use the lowest value that provides sufficient gain for the signal. Tools such as the KAB calculator are useful to approximate what that value is. My own personal experience with both MM and MC cartridges and several different phono, line and power amplifiers confirms that it is critical to use correct gain to match the output voltage of the cartridge for the cartridge to perform its best. Too little gain and the signal will be too low to provide enough volume, while too much gain (at the phono level) will result in a sound that is shrill and strident, and it becomes all but impossible to adjust the volume to get the sound right.

My concern about using this particular phono preamp with a Delos seems to be confirmed by this review that's reprinted on the preamp's page:

"The only test result that might be significant is the very high (in context) current it passes through a cartridge's windings, up to 0,2mA. It certainly won't do any damage, but with some cartridges might affect the sound. That apart, this is an extremely fine piece of kit and is strongly Recommended."

I thought the current went from the cartridge to the phono stage where it gets amplified, rather than the other way around, which the above-quoted text would suggest. It's possible that it was incorrectly translated into English, and it simply means that the preamp uses a very high voltage to amplify the signal, which might not be ideal for medium or high output MC cartridges such as the Delos.