Hey there good people,
I'm wanting to build a circuit for live use for vocals, and looking for some suggestions.
The gist of it is basically, I need something with a microphone input (it'll be used with dynamic mic), then feeding an effects return/send which will be hooked up to guitar pedals.
Would like to integrate a wet/dry blend knob in.
Lastly, feeding a mixing board, so line level output.
As of right now, I'm looking at the THAT Corp chips for both a preamp, and line driver output.
I'd assume the mic signal coming in needs to be boosted via preamp to an instrument level, fed to the effects loop, then converted to line level.
Do I need something to make up the gain after the wet/dry blend?
Open to all suggestions. All this running on a 9v supply would be ideal, but beggars can't be choosers, so open to anything.
I'm wanting to build a circuit for live use for vocals, and looking for some suggestions.
The gist of it is basically, I need something with a microphone input (it'll be used with dynamic mic), then feeding an effects return/send which will be hooked up to guitar pedals.
Would like to integrate a wet/dry blend knob in.
Lastly, feeding a mixing board, so line level output.
As of right now, I'm looking at the THAT Corp chips for both a preamp, and line driver output.
I'd assume the mic signal coming in needs to be boosted via preamp to an instrument level, fed to the effects loop, then converted to line level.
Do I need something to make up the gain after the wet/dry blend?
Open to all suggestions. All this running on a 9v supply would be ideal, but beggars can't be choosers, so open to anything.
Yes, you will need some PreAmp to boost the low mic level to guitar level, something in the ballpark of a 100x gain.
This can be done by a 2-stage, dual op-amp.
The third op-amp serves as buffer for the effect output and feeds the "wet" side of your wet-dry pot. Its other end is connected to the mic pre-amp output. The wiper of this pot is buffered by op-amp 4.
This is a rough idea that should work anyway.
I would not focus on boutique-amps - better you look for some low-noise budget types that do a good job at 9V: Low power consumption and high output voltage are the interesting parameters here.
This can be done by a 2-stage, dual op-amp.
The third op-amp serves as buffer for the effect output and feeds the "wet" side of your wet-dry pot. Its other end is connected to the mic pre-amp output. The wiper of this pot is buffered by op-amp 4.
This is a rough idea that should work anyway.
I would not focus on boutique-amps - better you look for some low-noise budget types that do a good job at 9V: Low power consumption and high output voltage are the interesting parameters here.
Not yet finished but you might be interested in my project - Balanced microphone preamplifier with effect loop
Can you achieve what you want with a small, cheap audio mixer?
For example, the Behringer Mix 5 is under $60 USD, and has both headphone and main outputs. I think you can probably feed use one of those two outputs (headphone out, say) as your effects send (you may need a stereo to mono 1/4" to 1/4" cable). Plug the output of your effects chain back into one of the unused line inputs on the mixer. The "level" knob for that line input now controls the amount of "wet" signal.
The big disadvantage is that you don't have foot-operated control of the FX loop. For that, you need that Voco Loco or home-brewed equivalent. But you didn't mention footswitch operation, so perhaps you don't need that feature?
If it works for you, a small cheap mixer might very well end up costing less than a DIY build. Once you add up the cost of those XLR and 1/4" jacks, an enclosure, a power supply, multiple pots and knobs and so on, you may find you've already exceeded the cost of a small mixer. And if your needs change in the future, a little mixer is likely to remain useful to any musician.
If you dislike Behringer on principle, there are other brands of small mixers to choose from.
If you want to go the DIY route, you might search Rod Elliott's website. For example, here is an excellent mic preamp using an easily available 5532 op-amp: Project 122
Depending on the singer and the microphone used, you might need one more op-amp gain stage at the output of Elliott's preamp to bring the signal up to line level for your FX send. I've found some singers need as much as 60 dB of preamp gain.
-Gnobuddy