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Double Bass DI box with piezo pickup?

#22
Looks nice, very simple design and robust build. IME I can’t come up, with a scenario where I would run a piezo pickup
directly into the board and out to the house, without using a preamp for EQ. Generally I’ll use the Grace Felix or Headway EDB-2 H.E. as
my buffer preamp and EQ. Just my take of course. The Ehrlund EAP requires a buffer/preamp.
 
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#23
Ludwig said:
If I want to go from my piezo into a PA with phantom power, no amp connection, I use the
TritonAudio BigAmp Piezo (7.5 MOhm input, € 69.- at Thomann). Works well with a short cable to the Piezo on one side and a long microphone cable to the PA on the other side and looks like just one cable, no box in between.
Click to expand...

the manufacturer’s website states it has 1Mohm impedance…
 
#30
Ric Vice said:
The Realist pickups are designed to just be plugged into any amplifier with a 1 Meg Ohm load. Unfortunately, nearly all of the Markbass Amps, including your Little Marcus 250 are set at 500 K Ohms. The best of the affordable DI’s is the Counrtyman 75, but before you purchase a DI, check with the sound person at the venue to see if they have a DI that will work with a Piezo pickup. Many of them will, but do your homework and check out the PDF’s on their DI’s Just my take. You could also definitely use the GEB-7 as your buffer preamp into the Markbass and use the DI on the Little Marcus 250 out to the P.A. :)

P.S. The input impedance of the Boss GEB 7 is 1 Meg Ohm, so that will work as a buffer preamp, but it’s just not a DI with a balanced output.:)
Click to expand...

According to Link Removed, the Realist is rated at 10 MOhm. To my ears it is very passable at 1, but I do find 10 opens up the low end just a bit more. Just my opinion, the difference is definitely subtle.

Rather than investing in a DI, I'd personally get a preamp with a good DI out. Better bang for the buck in my opinion, and gives you more control if you send the signal post-EQ.
 
#31
Passive DI boxes directly after a passive piezo pickup will kill the sound.

Active DI boxes use a JFET or JFET-opamp that can work with a piezo, depending on the input resistor that is responsible for the input impedance. There are some active DI boxes which have an input impedance of 1 MegOhms and maybe even higher.

But one warning: if you connect an amp to the loop through (second TS jack), then the input impedance of the amp and DI-box are acting in parallel which reduces the effective input impedance to the piezo pickup. If both impedances are the same, the resulting impedance is half of the individual impedances (worst case, but always lower than the lowest of both).
So for a DI 10 MegOhms input impedance is good because even a 10 MegOhms impedance at the amp/preamp following will half it to 5 MegOhms.
 
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#32
DoubleMIDI said:
But one warning: if you connect an amp to the loop through (second TS jack), then the input impedance of the amp and DI-box are acting in parallel which reduces the effective input impedance to the piezo pickup.
Click to expand...

This is true in general, but as I mentioned awhile back, the Radial PZDI thru can be switched to buffered to eliminate this problem. Also the thru on the Radial SB-4 is buffered all the time.

Here's a quick link to my post earlier in the thread: DI box with piezo pickup?
 
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#33
Wasnex said:
This is true in general, but as I mentioned awhile back, the Radial PZDI thru can be switched to buffered to eliminate this problem. Also the thru on the Radial SB-4 is buffered all the time.

Here's a quick link to my post earlier in the thread: DI box with piezo pickup?
Click to expand...
Yes, you are right. I forgot that, but can remember.

Anyway, a DI box after a buffer/preamp works even if it is a passive one.

So one should always carry a piezo buffer or preamp with spare batteries (!) and use the DI it of the preamp or connect the separate DI after the buffer/preamp.

It is easier to remember this than remembering a certain type of DI box that has the piezo buffer integrated. Which one can forget after it was bought and always carried with the bass…
 
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