[iomegaman]

Frankly the difference in A/D via a nominal set of monitors might not impress you that much.

I would not classify the step up from Motu to Apogee as a "huge upgrade"...we've A/B'd some of the best and the differences are like comparing fish markets...if everyone has their own boat then it becomes a matter of taste and not freshness.

In my humble opinion...if you feel more confident in a converter upgrade, then your mixes will reflect that.

To thine own self be true.

If it were me...I'd be looking at a different vocal chain...not overly impressed with the Avalon stuff we have...

I think it might be more important to determine what you are trying to accomplish here...if you are trying to tweak subtle things in the vocal track a converter upgrade "might" do some of that....but there are no guarantees it will.

I will suggest you give yourself some more options on the vox chain, keep the 610, maybe look at some mics, or perhaps a compressor to add to the chain...more tools can give you more options, different A/D will not.

The way a vox track sits in the mix is more about the signal chain than the conversion process, if that were not so, then there would be one converter to rule them all and you'd be able to hear it on every album...it is a combination of tools, technique and talent.

I've seen incredible voice tracks done on sub-par converters with the right coaching, once it hit the mix you had no idea what converter was used.

If you are completely happy with your tool box then do what makes you more confident.

GC is the last place I would be getting gear advice from, it is a place that is designed to unload quantities of products by any means necessary...YMMV