Designer for DSP circuit...

Yeah, no kidding...

To the OP, you can almost certainly give out more details without a NDA in place, not that I'm opposed to signing one but a few more details would help narrow down if it's something I or another would be interested in pursuing further without wasting our time... And 'professional' help will not come cheap and might very well hit you real hard with sticker shock...

Can you give some more details in regards to application? Anything that would narrow down the application and implementation would be helpful... A->D and back is easy in many applications and extremely more complicated in others...

 

Designing the circuit isn't all that hard, I believe Analog Devices has some over the counter developer boards that are pretty much a complete real time DSP that can do this right off the shelf once you write the firmware and effects... You can develop on there and simply port the circuit to your own design... Creating the effects is going to be the time consuming part, there are so many ways to emulate it and all the fine tuning to get that 'perfect' sound could rack up hours upon hours...

At this time it's way too involved for me to tackle, and honestly you might want to locate someone local so that you can sit down and have multiple face to face meetings where you run through tweaking the effects in a studio environment...

If you plan to take this from design from idea to finalized 'prototype' level meaning something that isn't just an over the counter project box, but a box and finalized circuit of your own design you can expect to burn through a big portion of that $100K... And more if you pursue certifications and the sorts that are needed to openly market the product in most places beyond the 'hobbyist' level of sales... UL, CE and FCC compliance can easily cost $10s of thousands if you don't do it in house, and have to pay a third party to do all the testing...