Double Bass Piezo pickup and preamp

[Turnaround]

I'm sure this is not news to the seasoned DB players, but I thought it worthwhile to post my experience on the recent addition of a preamp to my signal chain.

When I bought my Realist pickup, it was indicated to me that a preamp was not necessary - that the pickup was designed so that it did not need a preamp. While this may be true strictly speaking, I found that it depends on what you intend to plug into. Since my principal instrument is electric bass, I just plugged straight into my existing bass amp. It's a high quality amp with speakers to match.

I found I had to adjust the EQ on the amp a lot to get a sound that reflected what I heard from the unamplified instrument. And even with a lot of EQ'ing I couldn't get it right. After a little research I found that there is an impedence mismatch between the pickup and the input stage of the amplifier and that there are preamps that take the ultra high impedence of a piezo pickup and provide output that is much more in line with that on the input stage of a typical bass amp. So I purchased just such a preamp.

Bingo. Even without tweaking the preamp settings and with flat settings on my bass amp, the bass now sounds like my bass.

So, consider my experience if you think you might need a preamp. It may not be a cure for all situations, but it is certainly worth a try if you are having trouble with EQ.

 

[altruego]

Agreed! Some amps do have high impedance inputs and a preamp isn't required. For example the Acoustic Image amps sounds great without a preamp. I have a Fishman Platinum Pro preamp that I use when I don't have my Acoustic Image with me.

 

[Peck_Time]

Even if your amp has a preamp designed for DB, it can be interesting to plug in an outboard preamp and hear how the sound changes. Plugging my Fishman pro preamp into my AI head made my fullcircle sound better to my ears.

 

[klem.gote]

Even if your amp has a preamp designed for DB, it can be interesting to plug in an outboard preamp and hear how the sound changes. Plugging my Fishman pro preamp into my AI head made my fullcircle sound better to my ears.

Did you go straight in or into and effects input? And how did you EQ the preamp and head?

 

[Peck_Time]

I went from the fullcircle --> Fishman preamp --> effects return on the AI amp. This bypasses the preamp and uses the AI as a power amp only. I try not to eq.

 

[klem.gote]

I went from the fullcircle --> Fishman preamp --> effects return on the AI amp. This bypasses the preamp and uses the AI as a power amp only. I try not to eq.

So you have an AI combo? That's what I'm doing with my SWR, love my Plat Pro. But I have a Clarus head coming, think I'll try that that pre amp for a while, then maybe the Fishman. Thanks.

 

[drurb]

These threads contain a wealth of information on this topic. The typical piezo likes to "look into" 1 Mohm or more. Many piezos also pass nasty infrasonics. You can do a search on that as well. An economical device that optimizes the use of a pizeo is fdeck's pre-amp/adjustable high-pass filter. The input impedance is 10 Mohm. It is not really a true impedance "mismatch" that causes the problem when impedance are lower but, rather, the effective filtering produced by the combination of the piezo and the load impedance.