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Inexpensive impedance matching device

#22
G Aichele said:
Fishman makes preamps specifically designed for piezos. Other mfg. do too. Check preamp over in the DB forums. Most DBs use piezo pickups.
Click to expand...

He already has a preamp for piezo in his bass which most likely is designed for piezos.

He most likely doesn't need another preamp and almost surely he doesn't need an high impedance preamp to treat signal coming from his bass preamp.
 
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#24
There are a couple of common problems that get referred to as “impedance mismatches”, each of which has an off-the-shelf solution. And your problem sounds like neither of them.

If your bass had a piezo pickup and NO preamp built in, you could need an outboard preamp pedal with a higher input impedance. If your amp was a PA amp built to take the balanced, low-impedance signals from microphones, you might need a DI box (essentially just a little transformer) to convert your instrument output into a more usable signal.

But from your description, your instrument has a preamp built in that’s too “hot” for your amp. Not so much an impedance thing as a signal level thing. Many amps and pre-amps have a “pad” circuit to bring down hot signals to a range where they don’t distort. Sometimes it’s labeled an “active/passive” switch, or just “-6dB” (or 10 or 12). I think that’s what you need here. There are pedals out there - Electro Harmonix makes some - that do just this, though it’s an incredibly simple circuit to put in a $40 box.
 
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#25
kumimajava said:
Does the preamp look similar to that on this page:

https://www.tuneguitars.com/wb5-2wn

4c18ca_19ef4250d64d44098c905540ac228b3f.webp


If so, I doubt the issue is an impedance mismatch. Tune has been makign electronics for quite a while, and they have a rather good reputation (at least here in Japan). It would be very unlikely that they'd not matched the pre-amp's input impedance with the saddles. Having said that - the Tune basses often have quite a "hot" output.

I wonder whether simply turning down all the trim-pots at the same time, you've not also maxed-out the "low-cut" adjustment, which would take a lot of the bottom end out of your tone & make the top-end sound quacky. If you didn't get a manual with the bass, I'd suggest checking for the individual effects of each trim-pot one at a time.

Let us know how it goes - I'd be curious to know, in case i ever come across one of these :) Actually - in any case, if you could share a pic of what the electronics look like, if you deide to have another look - that would be helpful :) Not much info out on this on the net!
Click to expand...
That is exactly what mine looks like, except mine is an 18 volt (2 batteries) version.
I bought it used, online, from GC for $700.
I turned all the trimpots down, (they were all in the “maximum” settings),then brought them back up,
bit by bit,while plucking the strings through an amp. The end result is an overall reduction in tring sensitivity (i have them at about 25%),as well as toning down the midrange and treble.
This is with the 3 band eq controls on the front of the bass set flat. I have noticed if i boost the bass,
I can STILL overdrive the amp a bit. Very hot,indeed!
It sounds much better now, but i still wondered about that impedance thing. I bought a TC Electronics Bodyrez pedal,which allegedly dequacks piezo pickups,and it also helps smooth the tone out a bit.
As to the bass itself, it checks so many of my favorite boxes, I’m determined to get it sounding right.
It’s a very comfortable, shallow contoured semihollow body, 6 pounds, with a satin smooth oil finish.
(Except for some reason on the neck, and I’ve used steel wool to cut the glossy finish on that.)
It has a thin J type neck that plays wonderfully. A small part of me wants to install a magnetic pickup,
except I really love the way it looks without any visible pickup.
6C033218-36AA-4E15-A78D-3E2AF29828D8.jpeg
 
#26
Luigir said:
I disagree with what you've been told. As mentioned above you might have impedance mismatch between the piezo and the pre(amp) but not from the preamp to the amp.

The fact that the signal is super hot depends on the preamp too.

Not everybody likes piezos since they sound pretty different from magnetic pickups. It might just not really be your cup of tea.

Take a look at this review of a completely different bass which nonetheless offers a magnetic and a piezo pickup.
You'll clearly hear a huge difference between the two.

Click to expand...

I’ve seen that video....love Lobster...and that pickup combination is a great thing.
I recently found a (discontinued) Spectorcore hb bass that had an emg pickup plus a bridge piezo,
and really liked the ability to blend in just enough of the piezo to make it sound great.
The bass was really nice,too-light,comfortable,great neck.
It was half the price of the Tune I bought,but it was fretted. (Was looking specifically for a fretless,and didn’t want to pull the frets, been down that road before.)
 
#27
Ha
woodyng2 said:
I’ve seen that video....love Lobster...and that pickup combination is a great thing.
I recently found a (discontinued) Spectorcore hb bass that had an emg pickup plus a bridge piezo,
and really liked the ability to blend in just enough of the piezo to make it sound great.
The bass was really nice,too-light,comfortable,great neck.
It was half the price of the Tune I bought,but it was fretted. (Was looking specifically for a fretless,and didn’t want to pull the frets, been down that road before.)
Click to expand...

I've just shared the video in order to shoe the difference between the piezo and magnetic pickup. I personally don't like anything about the NS Radius. Too trebly for my taste.

Have you found the bass and treble trimpots on your preamp as suggested? That might help in taming the highs.
 
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#28
ficelles said:
Piezos are inherently bright and clacky and many onboard preamps accentuate that... with many piezo instruments you need to be aggressive with onboard EQ to tame them. I'd forget about impedance and concentrate on EQ and level trim. @kumimajava has posted some good advice.
Click to expand...
Thanks! I’d say I’ve been pretty agressive with this one! ;)
Another thing I’ve found that seems to help is the use of a compressor/limiter.
I normally don’t use one with my regular passive basses. I have an ART Phatboy multifx pedal,and have tried engaging the limiter on it with this bass.
 
#29
jthisdell said:
Sounds like you should learn exactly how your preamp works, what the trims all do, what the output impedance is. Could be all those electronics are for tone shaping and not buffering. My experience with piezos is that the buffering is the important thing and after that you may need to boost low bass and cut high mids a little. A few times I think my NS Designs NXT sounds like crap and then I will remember to set the high z input on my outboard pre and I then am good.
Click to expand...
What is your outboard pre?
 
#30
bholder said:
I've been thinking of getting one of those, but if the piezo doesn't sound good...
Click to expand...
This is not my first piezo instrument,but it is the most sophisticated (i.e. complicated) one I’ve owned.
I normally prefer passive basses, so i tend to flounder a bit with anything else. I really love the Tune bass from every aspect other than the electronics,so I’m hoping to make it work for me.
I just sold a Spector ns2j after a year, because i couldn’t come to grips with the active sound of the emgs.
 
#31
Sid Fang said:
There are a couple of common problems that get referred to as “impedance mismatches”, each of which has an off-the-shelf solution. And your problem sounds like neither of them.

If your bass had a piezo pickup and NO preamp built in, you could need an outboard preamp pedal with a higher input impedance. If your amp was a PA amp built to take the balanced, low-impedance signals from microphones, you might need a DI box (essentially just a little transformer) to convert your instrument output into a more usable signal.

But from your description, your instrument has a preamp built in that’s too “hot” for your amp. Not so much an impedance thing as a signal level thing. Many amps and pre-amps have a “pad” circuit to bring down hot signals to a range where they don’t distort. Sometimes it’s labeled an “active/passive” switch, or just “-6dB” (or 10 or 12). I think that’s what you need here. There are pedals out there - Electro Harmonix makes some - that do just this, though it’s an incredibly simple circuit to put in a $40 box.
Click to expand...
I use Markbass amps. The inputs are designed for use with either passive or active basses, and the input gain is adjustable....maybe i need to try turning that way down? (As i normally play passive basses with a clean sound I have the gain fairly low anyway).
 
#32
woodyng2 said:
I use Markbass amps. The inputs are designed for use with either passive or active basses, and the input gain is adjustable....maybe i need to try turning that way down? (As i normally play passive basses with a clean sound I have the gain fairly low anyway).
Click to expand...
I was wondering what amp you were using that was so sensitive without being adjustable. YES. That’s what the first stage of gain control is for. Absolutely the first thing to do is roll that way back. If you’ve got it set just right for a passive bass, it WILL be too sensitive for an aggressive pre.
 
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#34
@woodyng2 I sent you a PM, but posted some of that convo here for others...

Having a proper impedance match is not only about 'taming the high end' (w/ LPF) but more importantly, 'extending and opening-up' the bottom end. I have a few passive peizos that really came alive after using a 10MΩ input. (once the bottom end is extended the top seems more 'in control' and its more of a gain level adjustment than a need for EQ shaping.

DIs like the PZDI have a switchable 220kΩ/1MΩ/10MΩ impedance which can be used to find your 'sweet-spot' for each instrument or even use it to "dull/thin" the tone like an effect.
 
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#36
woodyng2 said:
Such a simple thing to overlook....but that’s me! :D
Click to expand...
Hope that’s really it. Look at the bright side. If you’d just gotten rid of distortion by rolling back the gain, you might not have got around to discovering all the trim controls on the pre. Be sure to tweak those again for best tone, once you’ve got the level sorted.
 
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#38
Karl Kaminski said:
@woodyng2
Having a proper impedance match is not only about 'taming the high end' (w/ LPF) but more importantly, 'extending and opening-up' the bottom end. I have a few passive peizos that really came alive after using a 10MΩ input.
Click to expand...
I think this idea of a passive piezo may have been the source of the confusion.
My bass has an extensive, nay, ELABORATE, preamp built in.
 
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#39
woodyng2 said:
I guess you didn’t read my original post?
I’ve adjusted all 9 of the interior trimpots on the bass.
It has helped considerably, as they were all in the “maximum” settings.
Click to expand...

I was referring to this quote:

woodyng2 said:
I turned all the trimpots down, (they were all in the “maximum” settings),then brought them back up,
Click to expand...

I understand lowering everything regarding individual saddlle gain but maybe if you find your sound too clanky you might insist on the HighCut one keeping very low the LowCut.
 
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