I'm sorry but what is it with people constantly buzzing over the sm7b. It's a dynamic mic, mainly used for radio. I've used it. It sounds boring and dull. Definitely not fit for purpose for r&b.
Because when you have a well treated room, and an interface or combination of interface and preamp that is ideal for any microphone, you will soon realize that the 'boring and dull' quality you think you hear, is likely either your room, or an issue with the voices/talent being recorded in your space with the SM7b. In fact that 'must' be what is happening because your statement shows that you have way bigger issues than the mic itself. The SM7b is likely one of the better mics for R&B vocals IMO.
'buzzing'? If you mean engineers/producers with real world time/experience using the microphone that works consistently pretty much always with any singer, then take that as good advice. 'Buzzing' sounds like a bullshit twitter phrase. If you want bullshit information, listen to the numerous idiots who post Youtube videos so they think they look cool. Ugh... The internet is full of incorrect and wrong information.
If you want real advice from people that actually know what they are talking about and care to direct you to learn, listen to people that are not trying to sell you anything. Base your judgements with research and advice from others before spending a bunch of cash. Take the time to learn from your own experience with basic gear.
I am very curious how you could have a budget of $6,000 for a mic and preamp, and you yet think that the SM7b is dull and boring. If you feel that way, then I can only assume that you have not invested time in building or placed acoustic treatments in your room and would not have a basis to decide what a quality preamp would actually do for you in a beneficial way. And ironically, the SM7b is likely one of the best mics to use if your room isn't treated well.
Unless you have the fundamental knowledge of what it takes to make good recordings, then it can't be possible to know what preamp you 'think' you are in need of. If you have this personal opinion of a mic that Grammy award winning producers/engineers have used for years, then it is an issue that you are neglecting to understand. Sorry man. It is obvious you have issues that have made you form an opinion that most professionals will disagree with.
I am guessing someone told you the Avalon 737 was a good purchase huh? I would say from my own personal experience with them is that they are an overpriced piece of gear that you would be wasting money on if you first do not understand what the most important thing is. Do you know what that is? I hope you do.
Sorry for being so blunt. I just don't want you to listen to bullshit ads or Youtube videos and make purchases because of what you hear from people that don't give a shit. It all starts with talent. I ends with talent. The gear used to record it is worthless if the user doesn't know what they are doing or record in a shit environment.
I hope I didn't read into your post too much and make incorrect assumptions. I am here to help people as much as I can. But it seemed to me that you have not yet taken care of the most important things because of your statement about the SM7b. If you still feel that way after reading my reply, then we should talk more...