Piezo and magnetic combination?

Oakbear · #1 11-19-2010, 05:38 PM

I'm considering a self build, and whilst my general woodworking skills are pretty good, i know little about electrics.

The concept is a singlecut fretless 6, and i want plenty of mwah and acoustic tones, but a bit of flexibility is always nice.

I'd like an under-saddle piezo, but also a single humbucker, switiching between either or both, with the possibility of blending.
I know i'll need some kind of buffer for the piezo. How would it work if both were wired to a preamp?

Any suggestions or wiring diagrams?

Thanks in advance!

MrLenny1 · #2 11-19-2010, 08:29 PM

I had a bass built last year. It's a chambered solid top. The builder recommended an Aero humbucker and Ghost Graphtech piezo bridge. One volume, one pan & one tone.
I wanted a simple set up but flexible. Piezo alone is phat and deep. Blended sounds
acoustic still and the mag pick up sounds like a P bass to me.
I have GHS black tape wounds on it. I got the bug after hearing several Rob Allens but wanted more flexibility.

m.oreilly · #3 11-19-2010, 09:38 PM

i use the fishman buffer with the graphtech saddles, the mags going through an ACG/East on board pre w/sweep filters. very nice for fretless, as the filters really dial in the sweet spot of the mags, and you can mix in the piezo woodiness. magnificent mwaaaaah

4Mal · #4 11-19-2010, 11:21 PM

My barker has a Graphtech installed along with an old Sadowsky P Bass pickup. The Graphtech pre blends the mag & piezo pickups. I'm setup as Vol & Vol. Love it ...
Samples are in the basses forum, Barker thread.

Oakbear · #5 12-01-2010, 11:28 AM

Thanks guys that's very helpful!

Much love for the Graphtecs it seems!

Mr Lenny - So you just have pots coming directly off the Graphtec?

m.oreilly - Do you need a buffer going into the ACG then? I thought that might buffer it? Or is it so the mag and piezo are at matched levels?

4Mal - So the Graphtec bridge has a inbuilt buffer and blend? You have the vol pots wired before or after the bridge preamp/buffer?

Any more opinions and options appreciated

**line6man** · #6 12-01-2010, 11:43 AM

Quote:

Originally Posted by Oakbear

I know i'll need some kind of buffer for the piezo. How would it work if both were wired to a preamp

The purpose of the piezo buffer is to lower the piezo pickup's output impedance. You want a medium-ish impedance, because if it's too low, the resistance at the output is going to load down the magnetic pickups.

As long as you have similar output impedances from the piezo buffer and magnetic pickups, you can run them into the same preamp.

m.oreilly · #7 12-01-2010, 11:43 AM

the buffer has input connections for the mag/pre out, so the acg pre goes to the buffer, along with the piezo saddle's signals, and is stereo split if using a trs cable, or mono mixed with a standard mono cable, the buffer having a volume knob just for the piezos, so the acg pre controls the mags tone and master volume, with the buffer volume controlling the piezo volume.

Skelf · #8 12-01-2010, 11:44 AM

I run the graphtech piezo into an attenuator then into the preamp no buffer. It is then possible to balance the levels using the trim pots on the preamp. Special offers on the preamp at the moment and I can supply the attenuator if needed.

m.oreilly · #9 12-01-2010, 11:47 AM

awesome alan

thanks for that.

Skelf · #10 12-01-2010, 11:53 AM

The output from the graphtech piezo is huge which is the reason for the attenuator without it there is no way to get the levels between the mag and piezo anywhere near close. The input impedance on the preamp is high enough to allow direct connection without a buffer. I use the 02 version in my piezo only fretless basses.

jasonbraatz · #11 12-01-2010, 11:59 AM

I have a Nordstrand Dual Coil, Aguilar OBP3, Bart piezo buffer and a Hipshot bridge with Graphtech saddles in my Stambaugh fretless. Works quite well.

Oakbear · #12 12-01-2010, 12:39 PM

Thanks for the swift and informative replies folks!

It's given me a much better idea of what i need.

Skelf - I've seen Your offer and it's tempting indeed! The car's in for repair atm though, so depending on the bill for that....

Skelf · #13 12-01-2010, 12:51 PM

It will be running until at least Christmas,best of luck with the car.

bassbenj · #14 12-02-2010, 01:41 AM

Quote:

Originally Posted by Oakbear

I'm considering a self build, and whilst my general woodworking skills are pretty good, i know little about electrics.

The concept is a singlecut fretless 6, and i want plenty of mwah and acoustic tones, but a bit of flexibility is always nice.

I'd like an under-saddle piezo, but also a single humbucker, switiching between either or both, with the possibility of blending.
I know i'll need some kind of buffer for the piezo. How would it work if both were wired to a preamp?

Any suggestions or wiring diagrams?

Thanks in advance!

What you want to do is pretty simple. I have done this with guitars but not a bass (yet). And by the way a fretless 6 with piezo and magnetic IS what you want!

The electronics of choice for me is the Fishman "power chip". I don't know where the name comes from as I'm not sure where the "chip" is in this, but basically it's this smallish circuit board that comes with a volume pot. MF sells them. It has ALL the features you want plus more. The volume on the "powerchip" is for the piezo. it has a 10 meg input so does a bang-up buffer job on bass (many are only 1 meg and will tend to cut some lows if used on bass). It also has the ability to mix in a magnetic pickup. It has provision for a switch to go one, the other or both pickups. and (get this) it even has a stereo feature where when you plug in a stereo cable it feeds one pickup to one channel and the other to the other channel which is a TRULY COOL effect if you are set up for it.

In short the "power chip" has everything you need already built in waiting for you to wire to it. Runs on typical 9 volt battery. You wire the magnetic pickup like most passive basses (volume + tone pots) the output of that goes to the Fishman. This give you a volume on the magnetic, a volume on the piezo and a tone on the magnetic. A tone on the piezo is trickier and I'm not quite sure what that takes. You add the selector switch and install the jack and battery holder and you are good to go.

This setup is for a single under the saddle pickup. For multiple ones it's more complicated and I guess you'd follow the bridge maker's recommendations.

Good Luck.

jibreel · #15 12-02-2010, 09:07 AM

If you want to experiment and not spend a lot of money, you could try this: http://cgi.ebay.com/3-Band-Bass-Prea...item563fedfec4.

I have one right next to me. I am returning it [ these guys have a great return policy ], because my particular under saddle bridge does is not hot enough so I could not get a sufficient mag/volume match even with the adjustments. However, I did have it fully installed and the sound/tone quality is very good, especially for the price.

You would want to make sure your piezo pickup system is hot enough.

And no, I am NOT associated with these guys etc. I have also tried most of the high end preamps Bart/Delano/Aguilar/Audere etc. so I can compare the sound.