[sdiy] OT: Bass Guitar Preamp

[Antti Huovilainen]

On Wed, 20 Dec 2006, Tim Daugard wrote:

> The input impediance is more than sufficient for bass and guitars. This 
> preamp has been used with both active and passive instuments. It has 
> been used with guitars, basses, micropohnes and a balalika with a piezo 
> pickup.

Sufficient perhaps in the sense that yes, you can hear the guitar. However 
it will significantly affect the frequency response of a guitar, 
especially with single coil pickups. Unless you use a pedal as a buffer of 
course.

> The redesign that I'm not happy with, adds a variable impediance 
> matching network to allow the instrument to be loaded heavier. I play 
> bass, I wanted to be able to load the bass down to reduce the high end. 
> This is the circuit that adds noise.

I would think a simple first order lowpass filter should do the job.

> My greatest source of hum is the pickups on my Fender Jazz. I can reduce 
> hum by carefully balancing the feeds from the pickups. As soon as I 
> change the settings to change the tone, the hum is back.

Perhaps it's time to invest in a single coil sized humbucking pickup? This 
would also reduce the highs.

Antti

"No boom today. Boom tomorrow. There's always a boom tomorrow"
  -- Lt. Cmdr. Ivanova