Line / Mic switch?

[frespe]

Hello there,

As you may notice for what I'm about to ask and my previous posts, I'm new to this big DIY'ing passion

In this occasion I came across a question:

I'm setting things up for building an Aquaboy DX. The thing is I plan to use a dynamic microphone with it aswell as my guitar.

Should I consider building a preamp and attach it to the aquaboy's PCB with a "line/mic switch" which decides wheter to pass the signal through the preamp or go directly to the aquaboy's PCB?

Hope I was clear enough!

Thank you guys in advance

Francisco.-

[HamSandwich]

I think you will get best results building a small mic preamp into the pedal, then you can just bypass it when you want guitar. The INA217 makes a SUPER simple mic preamp and takes your balanced input to unbalanced (what you need). You'll have to mess with the gain to make it similar to a guitar input. If you don't want to fuss with power requirements, there are a number of simple opamp based mic preamps.

[frespe]

I think you will get best results building a small mic preamp into the pedal, then you can just bypass it when you want guitar. The INA217 makes a SUPER simple mic preamp and takes your balanced input to unbalanced (what you need). You'll have to mess with the gain to make it similar to a guitar input. If you don't want to fuss with power requirements, there are a number of simple opamp based mic preamps.

Will the INA217 work for a phantom powered mic as well as for a sm58?

[frespe]

It concerns me the fact that building a preamp into the pedal might "burn it"?

[HamSandwich]

Where is the quoted "burn it" coming from?

If you want to do phantom powered, you are going to have to provide the phantom supply prior to the effect. If this is what you want, it would almost (definitely) be easier (and more versatile) to build a mic preamp with the phantom power, then feed that to the delay. You cannot go mic -> delay -> preamp/phantom power as that will either not let power get to your mic or "burn it".

The INA217 data sheet circuit does allow for phantom power if that was what you're asking?

[frespe]

Where is the quoted "burn it" coming from?

If you want to do phantom powered, you are going to have to provide the phantom supply prior to the effect. If this is what you want, it would almost (definitely) be easier (and more versatile) to build a mic preamp with the phantom power, then feed that to the delay. You cannot go mic -> delay -> preamp/phantom power as that will either not let power get to your mic or "burn it".

The INA217 data sheet circuit does allow for phantom power if that was what you're asking?

What I meant by "burning it" was that I don't know what would happen to the AquaboyDX if I send a phantom powered signal to it: mic -> preamp/phantom -> delay

[HamSandwich]

Those 47u (IIRC) are DC blocking caps, so phantom power goes to your mic and not to the input of the INA217 (or anything else). Check out the datasheet for the INA217. The input voltage is something like +/-3 or 4V. If phantom power was getting to it, I wouldn't be happy. Same with almost any type of music equipment. Line level is typically 1V. Nothing would be happy with 47V! That's why you apply phantom power before the preamp and not after. I'm sure there a better way to say it, ah well.

[frespe]

Those 47u (IIRC) are DC blocking caps, so phantom power goes to your mic and not to the input of the INA217 (or anything else). Check out the datasheet for the INA217. The input voltage is something like +/-3 or 4V. If phantom power was getting to it, I wouldn't be happy. Same with almost any type of music equipment. Line level is typically 1V. Nothing would be happy with 47V! That's why you apply phantom power before the preamp and not after. I'm sure there a better way to say it, ah well.

Thank you very much for your explanation!!

You made it pretty clear to me

Cheers!