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Double Bass are all direct boxes created equal?

B

bluegrass greg

May 5, 2011
11
0
Madison, Indiana
#1
I was wanting to purchace a cheap 20.00 direct box so I can take my 1/4 inch plug from my k&k pre amp, and plug it into a mic cord, for when there are no other place to plug my bass into while on stage, to feed into the house PA.

Am I going to waist my money, or should I get a better one.

Any recomendations are greatly appreciated.

Thanks, Greg
 
#3
Hi.

The answer to that question is simple.

No, all DI-boxes aren't created equal.

Which one of the three (5 if You count the tube DI's as separate options) possible choices You choose, depends on your goals.

Those three choices are:

Passive transformer coupled.
Active SS coupled. (Most common and cheapest)
Active transformer coupled. (Most expensive)

Both actives can obviously have either tube or SS circuitry.

In the past I've been happy with a cheapo active SS Behringer, but I do admit that I use SVTDI live.

What You pay more for (or should be paying more for) is wider usable frequency range, better distortion characteristics and lower noise floor.

Regards
Sam
 
#6
Sam---"What You pay more for (or should be paying more for) is wider usable frequency range, better distortion characteristics and lower noise floor."
I think this is kinda what I was after?

I believe I was wanting a passive unit so I dont have any batteries to worry about. I hope this is a true statement?

Eric--, I have needed one 2 times lately. There was no 1/4 plug on the pa whip. I ended up using a mic wrapped in a rag, stuck in the tailpiece. I think my pickup sounds better than that setup, too muddy!

I like the k&k so far. Its a clean mount, behind the tailpeice, and the sound does ok also.
 
#7
I have a passive and an active one (both rather cheap).

The passive one loads the output of the preamp much more than the active one and still has a lower output. Of course, you don't need to worry about an amp, but a cheap one basically has not much more than a transformer in it and the quality of the box depends mostly on the quality of the transformer (signal distortion).

My active one (a BSS AR133 clone) has a 1 MOhms input impedance (I checked the circuit, I even can replace it with a higher resistance if I want), could be used with a battery (9V) or with phantom power. So you might hardly use the battery at all. I use a low self-discharge rechargable battery with it (without use it holds 80% of charge after a year) and take a charged spare one with me (for longer trips I would take the charger with me too).

I think if you don't get a real quality passive one, the active ones are better because good transformers are expensive. And the passive DI-boxes can only be used with magnetic pickups or following an impedance buffer/preamp, never directly connected to a (passive) piezo.

For the active one with a 1 MOhms input impedance:
If you want to use it with a piezo and without an buffer/preamp, please note, that the impedances of amp and DI are in parallel, lowering the total impedance for the piezo. So you might want to get a higher impedance than 1 MOhms (i.e. 4.7 MOhms or 10 MOhms) for the DI to avoid a lowering of the effective impedance of both units on the passive piezo. Not a big deal to find the input resistor and exchange it (but you will loose your warranty).
Using the DI behind a preamp is of course the better solution, but if the battery of the preamp runs out and you can use an active high impedance phantom powered DI box you might get to this point.

So, my recommendation is a high input impedance phantom and battery powerable active DI box.
 
#8
Hi.

bluegrass greg said:
Sam---"What You pay more for (or should be paying more for) is wider usable frequency range, better distortion characteristics and lower noise floor."
I think this is kinda what I was after?
Click to expand...

Then it's unfortunately up to You to decide what is good enough for You. The rest of Your signal chain(s) (the relative impedances mostly) will affect those variables greatly.
I'd say that around $100 new is the lowest acceptable quality for a passive and around $50 new for an active. Especially if You intend to do any recording with it.

bluegrass greg said:
I believe I was wanting a passive unit so I dont have any batteries to worry about. I hope this is a true statement?
Click to expand...

Batteries/phantom is only one part of the equation, usually people choose between active and passive DI's for other reasons.

But in a passive, look for anything with either Jensen or Lars Lundahl transformer in it, and you can be sure that unless you go for a hand wound boutique transformer, you won't find anything better.

DoubleMIDI said:
I think if you don't get a real quality passive one, the active ones are better because good transformers are expensive.
Click to expand...

^ I think the same way.

DoubleMIDI said:
And the passive DI-boxes can only be used with magnetic pickups or following an impedance buffer/preamp, never directly connected to a (passive) piezo.
Click to expand...

Not all "active" DI boxes can be used directly with piezo, some just use the juice for the balancing circuit.

And who would use a piezo without a pre-amp of some sort?

Regards
Sam
 
#9
Thanks for all the advice.
I have only been playing upright for a couple of years, and the running through a pa or amp has just been the last few months. I am still trying to get a real understanding of it all.

I believe I might just get a" Fishman Platinum Pre", from what I read so far. They are about $150.
Not sure what the impedence is of that unit.
I assume I could use it with my "bassmax pickup" Instead of my k&k preamp?
 
#10
bluegrass greg said:
Thanks for all the advice.
I have only been playing upright for a couple of years, and the running through a pa or amp has just been the last few months. I am still trying to get a real understanding of it all.

I believe I might just get a" Fishman Platinum Pre", from what I read so far. They are about $150.
Not sure what the impedence is of that unit.
I assume I could use it with my "bassmax pickup" Instead of my k&k preamp?
Click to expand...

Which K&K preamp? It should have a low impedance output which means it is already compatible with the mixing board. If all you need is an XLR connection you could buy an inexpensive 1/4" to XLR adapter. If you are only using your bass and not playing through an amp at the same time this should work fine as long as you are happy with the tone.

There are a number of different ways to go but it depends on whether or not you feel that the K&K preamp has enough tonal range for your instrument and if you need functions like phase reversal, ground lift etc.
 
#13
You might contact K&K and see what they recommend. It looks like the output is 3 kOhm. I think my Mackie mixer mic channel is 2.5 kOhm input impedance. It's not a huge mismatch. You are pretty much in the ballpark.

An inexpensive DI will do fine if you're worried. My suggestion would be to just try the adapter or borrow a DI and see what you think. There are many options but why spend more than you need if a simple solution sounds good.
 
#16
The Radial JDI is my favorite passive box, so much that I purchased a second one when the need for another came up. The Whirlwind IMP is very good, well built, and much less expensive.
 
#17
I have the k&k rockabilly pickup and preamp that I use when playing with my more rock band (drummer and electric guitar). I do prefer the sm57 or 58 in foam in my tailpiece when i play with my olde tyme bluegrass band. I use a countryman DI that was recommended by this forum. I love it! Very clean sound and not too pricey 100$.
 
#18
bluegrass greg said:
I was wanting to purchace a cheap 20.00 direct box so .
/QUOTE]

T-Bird said:
Hi.

The answer to that question is simple.

What You pay more for (or should be paying more for) is wider usable frequency range, better distortion characteristics and lower noise floor.
Click to expand...

:) The Countryman DI is a very good choice too, there must be a 'coupla million of those in use today. Very reliable, 10 meg input, long battery life, operates very well with phantom power, and built like a tank.
Click to expand...
 

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