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previous: Frits Jensen Hello from CopenhagenMy bro... -- 11/29/2000 7:49 AM

Re: Pre-amp for spanish guitar

11/29/2000 10:45 AM
GFR	Re: Pre-amp for spanish guitar The sound at the sound opening has too much resonance at bass frequencies, so it will sound "boomy". You need to cut a lot of bass, altough it can be as simple as using a smaller coupling cap from the electret to the base of the transistor. Also, you'll problably have problems with feedback and with the mic picking up ambient noise and other instruments. Here's what I do with one of my classicals: I stuff a foam ring inside the sound opening, and fix the electret on the foam ring pointed to the inside of the guitar. The foam ring has several purposes, the most obvious being hold the mic in place. There's also a light pressure against the guitar top that dampens it a little (good to avoid resonances and feedback). And it isolates the inside of the guitar from the outside world, help with killing feedback and unwanted noises. Then I send the electret to a single BC549 stage that also cuts some bass. It's not as good as a piezo in rejecting noise and feedback, but on the other hand it sounds like a guitar, while the piezo doesn't It's very easy and quick to install (and uninstall) and there's no harm or mods to the guitar. Funny, I've got the idea from a German device called "DeByll" - only they use a stereo Seinheiser mic instead of a cheap electret and it has a preamp with ballanced outputs.

11/29/2000 10:45 AM

GFR

Re: Pre-amp for spanish guitar

The sound at the sound opening has too much resonance at bass frequencies, so it will sound "boomy". You need to cut a lot of bass, altough it can be as simple as using a smaller coupling cap from the electret to the base of the transistor.

Also, you'll problably have problems with feedback and with the mic picking up ambient noise and other instruments.

Here's what I do with one of my classicals: I stuff a foam ring inside the sound opening, and fix the electret on the foam ring pointed to the inside of the guitar. The foam ring has several purposes, the most obvious being hold the mic in place. There's also a light pressure against the guitar top that dampens it a little (good to avoid resonances and feedback). And it isolates the inside of the guitar from the outside world, help with killing feedback and unwanted noises.

Then I send the electret to a single BC549 stage that also cuts some bass.

It's not as good as a piezo in rejecting noise and feedback, but on the other hand it sounds like a guitar, while the piezo doesn't

It's very easy and quick to install (and uninstall) and there's no harm or mods to the guitar.

Funny, I've got the idea from a German device called "DeByll" - only they use a stereo Seinheiser mic instead of a cheap electret and it has a preamp with ballanced outputs.