I actually found the noise floor to be lower using the built in phono-amp as well. The CI-Audio was quiet enough though and the difference wasn't huge. I often wondered if this was due to the added cabling necessary to run an external phono-amp.
I've used that calculator on KAB before too - it's great to have resources like that available. You're right - when playing around with buying MC's I've always found the low-output ones to calculate out better with the A300 than the high-output MC's. i.e. better to use a .25mv and the MC stage than a 2.5mv and the MM stage.
I would agree that you'd have to spend more than $500 to better the A300's built-in sound to a degree that it would be worth the expense. The one exception would be if you required more control over loading and gain.
Thanks for the compliment on the system - it's been a long running project finding equipment I really feel satisfied with and I'm on a fairly tight budget. I'm finally at a point though where I've stopped thinking about upgrading anything other than playing around with different cartridges - which is half the fun of vinyl!
I've used that calculator on KAB before too - it's great to have resources like that available. You're right - when playing around with buying MC's I've always found the low-output ones to calculate out better with the A300 than the high-output MC's. i.e. better to use a .25mv and the MC stage than a 2.5mv and the MM stage.
I would agree that you'd have to spend more than $500 to better the A300's built-in sound to a degree that it would be worth the expense. The one exception would be if you required more control over loading and gain.
Thanks for the compliment on the system - it's been a long running project finding equipment I really feel satisfied with and I'm on a fairly tight budget. I'm finally at a point though where I've stopped thinking about upgrading anything other than playing around with different cartridges - which is half the fun of vinyl!