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Double Bass Can a pre/DI's input impedance be too high?

M

Murphbass

Jun 12, 2005
151
58
Sacramento, CA
#1
I'm running a Fishman Full Circle pickup on a '59 Kay upright. I've plugged it into various DIs, audio interfaces and amps with pretty spectacular results. Engineers always comment on how good that setup sounds.

I purchased a d-tar Equinox for live use, as I wanted a pre with a high enough input impedance and flexible EQ.

I'm currently in a recording session where the engineer provided a Daking Mic Pre One preamp. It's modeled after a Trident A-Range pre, and sounds amazing. When I did some research, I read that the input impedance is >100kohm. I'm assuming it's nowhere near the 4.7megaohm input impedance of the Equinox. When I asked to hear what the Equinox sounded like, they said that the Daking sounded great, why change anything? I was curious, though, and the Dtar was much bassier and lacked the clarity of Daking. It was hugely eclipsed.

I realize that the Daking is a higher end piece. My understanding was that piezo pickups want to see a much higher input impedance than the Daking offered. I thought that the higher the value, the better.

What's going on?

Other searches (gearslutz, for one) suggested using a Countryman DI because of it's high input impedance for a DI. I'm thinking about getting one for live use- XLR to house and 1/4" split into my dTar and amp. With that setup, I could EQ my amp feed without affecting the house signal. Will this work? Will the 1/4" feed into my amp affect the impedance of the PA send?

And, lastly, is it all about finding the right input impedance to match the pickup? Should I find something with variable impedance? I believe Radial and ART offer such products. Any suggestions for a nicer pre with that feature? I love the features on my Equinox, but it's letting me down a little bit.

Thanks for your help!
 
#3
Murphbass said:
I was curious, though, and the Dtar was much bassier and lacked the clarity of Daking. It was hugely eclipsed.
Click to expand...

A higher input impedance might make the Dtar have more bass response, which could also have affected the apparent clarity. In addition, the additional low end could be causing distortion somewhere downstream in the recording system.

These are only guesses.
 
#5
The studio is only a few months old and doesn't have iso booths yet. It's still pretty nice- (2) Studer A80s running 16 tracks each @ 15ips. The live room is gorgeous sounding for drums. The project is very much rock oriented. Even though the instruments are acoustic, the tones we're getting with pickups work better than mics would. I'm not a purist- whatever means achieves the end is okay by me.
 
#6
As I understand it (and I don't understand it at all) the input impedance is only one part of the whole design of an amp or preamp. There are other factors as well and the sum of these factors create the result.
For example Markbass amps sound bassy as hell with their 500kOhm input, while GK sounds brighter with it's 1MOhm.
AND, Full Circle or Realist do not require that high input impedance. They are fine with nearly anything.
 

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