Double Bass Pre-Amp and Graphic EQ

[gypsydjango]

Does anyone use a pre-amp and a Boss GEB-7 EQ plugged into each other? Any benefits using both?

I currently use the Boss GEB-7 which boosts the signal very well. Would the pre-amp add to the system? The pre-amp I have is the Ehrlund pre-amp. Any other pre-amps better?

If one uses a mic is there a graphic EQ that accepts an XLR connector and not the 1/4” jack?

 

[Wasnex]

AFAIK the Ehrlund is a good sound preamp but a bit fragile. It's pretty much pure gain and does not have any tone controls. If you amp is not flexible enough to dial in the sound you want or deal with acoustic problems, the GEB-7 may be helpful.

The GEB-7 input impedance is listed as 1meg. This is about the minimum for piezos. Nominal input is listed as -20dBu. A preamp will have more gain and possibly a higher input impedance. AFAIK the Ehrlund has a higher impedance (4.7meg) that is optimized for the EAP.

It can be useful to use both a preamp and a utility EQ with upright. But putting too many devices in your signal path can also degrade your sound. So try them out and make your own decision.

IMHO a 7-band graphic is not a great choice for a utility EQ, but it may still be helpful for dialing in your basic tone. The frequency bands have fixed center frequencies, and the bandwidth of each filter is fairly wide. A parametric EQ or graphic with more bands tends to work better as a utility EQ. A 31-band graphic works really well as a utility EQ, but I don't think you will find one in pedal format.

Empress used to make a semi-parametric (model = ParaEQ) that I think would work well. This pedal has been discontinued and used ones are currently selling for premium prices. If you want to try a ParaEQ, I suggest getting the V7, which has white script. Earlier versions had black script.

If you want to use a low impedance mic with an XLR output in a high-Z, 1/4" input, you need a line matching transformer if the mic is dynamic. If the mic is a condenser that requires external phantom power, you also need an inline phantom power supply.

The line matching transformer converts from balance XLR to unbalance 1/4", and also converts the impedance from low to high.

An external phantom power supply provides operating voltage for a condenser mics active electronics. For true condensers, phantom power is also required to provide a charge to the mic element.


-20dBu is instrument level. Mic level is even lower, so the GEB-7 may not work well without a preamp to boost the signal a bit.

 

[Ric Vice]

• I had the Boss GEB/7 and used it with the Roland Cube 60 (orange) amp. If memory serves, introducing that pedal into the circuit path will boost the signal a considerable amount, depending on how much you boost each of the seven frequency bands. Introducing a preamp will add some additional noise. You might want to look at an all in one preamp EQ box

 

[Wfrance3]

Boss GEB-7 EQ

I had one a while back to help coax the mwaa out of a fretless. Did a great job. Mine was modified - Modest Mike's did it, bought it new from their website... It was a really great EQ, but the sliders were super easy to bump out of place, so I changed it out for a Source Audio programmable eq. But I digress...
In my opinion, you don't really need tons of duplication when it comes to eq-ing.
I eventually settled in on an MXR M81, and NO EQ Pedal.
At that time my signal chain was

tuner - Thumpinator - Compressor - M81 and out.

I added one of the spark clean boosts for a while but kinda figured out that between the makeup gain on my compressor and the M81, it really wasn't needed.

Any benefits using both?

I spent a few dollars getting the education that a piece of gear is something that solves a problem. Once I got to that point, ease of setup, simplicity of signal chain, just overall efficiency made my life a lot simpler. The enemy of good is always "better".