Double Bass Preamp for mixing pickup with piezo

[Mark Gollihur]

Mark, that's interesting, something I didn't know about the Schaller...

I actually discovered it because occasionally someone would complain that the pickup had a buzzing vibration when it's not being used. It turned out that the buzzing was coming from that "extra" terminal on the TRS jack -- since nothing was soldered to it, it could be a little loose in the jack, and if there was no plug in the jack, it could vibrate with the bass. So the solution is either to wrap a piece of electrical tape around the jack to mute it, or more permanently, to pull out that contact from the jack (assuming you don't need it.) One of those "accidental discoveries."

 

[Michal Herman]

I am considering Schatten Design Mini Pre 2 (Invalid Link Removed
But I am little worried about impedance - I have little knowledge in that matter.
For this preamp input impedance is "Up to 10 Meg ohm", which is great for piezo, but will it work with magnetic pickup, f.e. Schaller? Such a big impedance wont be issue for magnetic pickup?

 

[DoubleMIDI]

I am considering Schatten Design Mini Pre 2 (Invalid Link Removed
But I am little worried about impedance - I have little knowledge in that matter.
For this preamp input impedance is "Up to 10 Meg ohm", which is great for piezo, but will it work with magnetic pickup, f.e. Schaller? Such a big impedance wont be issue for magnetic pickup?

Not really.

Input impedance means how much the output of the device in front (here the pickup) is loaded. A high impedance means a low load. A low impedance may distort and/or reduce the amplitude of the input signal if the pickup can not deliver more than a very small current, like with many unbuffered piezo pickups.

The only bad thing with high impedance inputs is that they are more sensitive to electric noise and cable microphonics (knocking on the cable might be heard in the signal). Might happen with 10 MegOhms, but depends on the cable. For that reason it is wise to keep the first cable from pickup to high impedance input short.

 

[Michal Herman]

@DoubleMIDI Thank you for explanation, now it makes sense

For that reason it is wise to keep the first cable from pickup to high impedance input short.

Do you think 1.5m (or 3m) cable from DB to pedalboard is OK or rather should I mount preamp on tailpiece and connect with really short cable?
Having preamp in pedalboard is more comfortable, but if sound will be better with shorter cable, than I can arrange that option.

 

[DoubleMIDI]

The Schatten two-channel preamp could be easily mounted to the tailpiece and The Gollihurs have mounting hints for that. It's probably also easier to reach the controls there. The only reason not to mount it there is that the additional mass on the tailpiece may degrade the acoustic sound a bit. But check that for yourself and decide what is more important to you.

You can use a 1 to 2 m cable, but don't step on it and use a rather stiff (hard core) one. I would prefer a short cable, but this depends on the effects of the tailpiece mounted preamp.

For the magnetic pickup you can put a resistor (330 KOhms for example, like in the Polytone) from hot to shield at the amp end to lower the input impedance, then these effects go away. Since the Schatten has one stereo TRS for both channels together, you need a splitting cable anyway. If you make one yourself, you can solder in the resistor too, but use the resistor-free hot input for the piezo or you make it worse, not better. (Mark the mono ends!)

 

[dukeorock]

DTAR Solstice works pretty good, IMO. I recently got a Grace Designs FELIX, which looks promising but is pretty expensive. Would the Radial PZ Pre also be a contender for you?

 

[jmlee]

I am considering Schatten Design Mini Pre 2 (Invalid Link Removed
But I am little worried about impedance - I have little knowledge in that matter.
For this preamp input impedance is "Up to 10 Meg ohm", which is great for piezo, but will it work with magnetic pickup, f.e. Schaller? Such a big impedance wont be issue for magnetic pickup?

I've got one of those and it works fine with my Full Circle piezo and my Biesele electromagnetic pickup. I checked with Schatten up front.