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Double Bass Input impedance, pre-amps and adjustable bridges

#21
agedhorse said:
Again, I suggest that folks TRY before assuming that they MUST have a preamp or buffer. Often, it's completely unnecessary. Sometimes, the improvement justifies the additional expense and hardware.
Click to expand...

1+

Reading posts I assumed I have to use a preamp for my Underwood. Purchased a Fishman Platinum preamp with 10MOhms.

Once forgotten I had to put my bass into the 480kOhms input of my Warwick rehearshal combo. Ooooops - much richer sound.

Tried that out with my TecAmp combo (1MOhms) - oooops - what a rich sound!

The Fishman made my sound bony, nasal and weak - I rendered it to "well, thats the piz-problem. Cannot be better as I drive with 10MOhms and a praised preamp."

All nonsense - the 10MOhms went to the Bay...

I only trust my ears by now...
 
#22
playbass0410 said:
1+

Reading posts I assumed I have to use a preamp for my Underwood. Purchased a Fishman Platinum preamp with 10MOhms.

Once forgotten I had to put my bass into the 480kOhms input of my Warwick rehearshal combo. Ooooops - much richer sound.

Tried that out with my TecAmp combo (1MOhms) - oooops - what a rich sound!

The Fishman made my sound bony, nasal and weak - I rendered it to "well, thats the piz-problem. Cannot be better as I drive with 10MOhms and a praised preamp."

All nonsense - the 10MOhms went to the Bay...

I only trust my ears by now...
Click to expand...

There are many differences besides input impedance between those pres/amps. The Fishman has a very definite voice - I like it in some situations, not so much in others. I certainly agree that you should trust your ears, but not necessarily the post hoc explanation regarding why they're hearing what they are. It's never just one thing.
 
#23
I'm going to throw my two cents in, in a non-technical manner.

I have tried a couple of different piezos into straight into my GB Shuttle 3.0. The signal is useable. The rest is up to the players ears and whether or not he/she feels it's what they are looking for. I'm not going to expand on that much more. There are simply too many variables that come into play when amplifying an upright bass with a piezo to tell someone..."use this or do this, problem solved"

In the end I still use a preamp when I am using a pickup.

I've never used a realist, but I can tell you that I have very little feedback problems with a bassmax bridge wing pickup.

Good luck.
 
#24
GrowlerBox said:
There are many differences besides input impedance between those pres/amps. The Fishman has a very definite voice - I like it in some situations, not so much in others. I certainly agree that you should trust your ears, but not necessarily the post hoc explanation regarding why they're hearing what they are. It's never just one thing.
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+1. Bravo, Growler.
 
#25
As I understood Fdeck's calculations they are not that far of from what Agedhorse said. A lot of pickup's would probably be alright with 500k. However I do agree with Drurb in that a dedicated pre with a 1 meg input is always helpful for several reasons:
-For one it is the safe bet, because with 1 meg you at least know it is not the impedance that is affecting low end response. With 500k there still is a strong possibility you will encounter a problem and IME there often is.
-It's not just the impedance, but also extra's like a phase shift, hpf and a db friendly voicing and transient response(or the absence of voicing in Fdeck's device) that are a big pro for DB.
-Also a big pro is being able to have the pre at close hand as IME it can be difficult to reach the amp with a DB in your hand. (Am I the only one with this problem? I really like having a pre as a remote for the amp as I'm mostly stuck between a drumkit and a piano and like to have some distance between me and my amp).

To the OP: It might be possible your piezo and your Amp do match up, but the 500k input might also be part of your problem. First make sure the piezo is installed in the right way, because they can be very finicky about that. If you're sure about that part and the problem is still there you should check out how your bass reacts to a higher impedance. Buy, rent or loan a good pre or try another amp.
 
#29
you should probably try a different preamp before you generalize about all 10 Mohm preamps. that fishman does have kind of a thin and not so plesant sound, but a few of the other high impedance pre's i have improve the tone greatly over the fishman when compared on the same pickup, and make an improvement over the amp alone too sometimes. for example, my AI head has a high input impedance, but when i use my favorite preamp in front of it it still sounds better than without, and that has nothing to do with the input impedances. so really its a combination of a few things, but for me, the combination always includes a high input impedance, but not all preamps are created equal.

playbass0410 said:
1+

Reading posts I assumed I have to use a preamp for my Underwood. Purchased a Fishman Platinum preamp with 10MOhms.

Once forgotten I had to put my bass into the 480kOhms input of my Warwick rehearshal combo. Ooooops - much richer sound.

Tried that out with my TecAmp combo (1MOhms) - oooops - what a rich sound!

The Fishman made my sound bony, nasal and weak - I rendered it to "well, thats the piz-problem. Cannot be better as I drive with 10MOhms and a praised preamp."

All nonsense - the 10MOhms went to the Bay...

I only trust my ears by now...
Click to expand...
 
#30
In my experience, with the Realist, don't worry about preamp. It sounds great (if your bass likes it) into anything, like my Markbass amp with it's 500Kohm input.
The old design piezos like Underwood or BP-100 sure benefit from 1Mohm or 10Mohm input impedance (but work great without preamp into my Markbass Mini CMD 121P, due to it's filters, but that's another story)...
 
#31
shwashwa said:
you should probably try a different preamp before you generalize about all 10 Mohm preamps. that fishman does have kind of a thin and not so plesant sound, but a few of the other high impedance pre's i have improve the tone greatly over the fishman when compared on the same pickup, and make an improvement over the amp alone too sometimes. for example, my AI head has a high input impedance, but when i use my favorite preamp in front of it it still sounds better than without, and that has nothing to do with the input impedances. so really its a combination of a few things, but for me, the combination always includes a high input impedance, but not all preamps are created equal.
Click to expand...

Indeed, as Growlerbox posted. :) The problem seems to be with "voicing."
 
#32
Jaromir said:
In my experience, with the Realist, don't worry about preamp. It sounds great (if your bass likes it) into anything, like my Markbass amp with it's 500Kohm input.
The old design piezos like Underwood or BP-100 sure benefit from 1Mohm or 10Mohm input impedance (but work great without preamp into my Markbass Mini CMD 121P, due to it's filters, but that's another story)...
Click to expand...

Jaromir,

As I recall, the CMD 121P is a Little Mark III combined with a 12" driver and a tweeter. I liked the Little Mark II for Electric Bass, so whatever works for you then go with it. I've used the Fishman BP-100, Underwood, and the Realist. Among that group of piezo's, the Fishman really needs the 10 Meg Ohm load to sound even halfway decent.
The Underwood sounded fine into a 1 Meg Ohm Load (Walter Woods has been using that input impedance since 1980). The Realist doesn't seem to mind as much what the input impedance is, but with my gear it sounds better at 1 Meg Ohm's, as long as the volume is reasonable. If you have to push the Realist at high volumes it's timbre changes drastically. In my experience, once you try to drive the Realist, it's game over. The signal coming of the Realist is very hot, compared to the Fishman and The Underwood. The Realists true advantage is that it's arco sound quality is vastly better than either the Fishman or the Underwood.

Ric
 

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