active basses - make pedals play nice with them

[Wounded Paw]

Some designs work well with them, others don't.  I know the signal is slightly hotter and the impedance is different but what is the quickest, best or easiest way to make pedal circuits work equally well with active and passive basses?

[Meanderthal]

 A buffer.

You could also use a 1:1 transformer for circuits that like to be first in line.

[kvb]

one of the bazz fuss schemes at ROG shows a TMO18 transformer being used as an inductor to simulate a guitar pickup.

[Wounded Paw]

a buffer was my first thought and much cheaper/smaller than a transformer.
A lot of designs have a pre section which is basically a buffer/amp before the main fuzz or whatever section.  Can you assume that an input section like:

input -> resistor -> cap with resistor to ground -> base of npn transistor .... etc.

will be enough or do you need to put a dedicated buffer in front of the circuit?

[Gus]

Not knowing what active bass and what the active circuit is makes it harder to help.

Two Simple things to try

One a series resistor say a 10k as a first try, after the bass and before the effect.  This should help with FF types

Or a resistive divider after the bass to add series resistance and reduce the level Try a 10K and a 10K to start take the output off the 10ks node.

[puretube]

pot

[R.G.]

... which means that active basses already are buffered, and have a big output signal. Some effects are so wedded to the idea of a guitar signal of about 100mV through 4K and a 2H inductor that they don't react well.

So lower the signal level with a resistive divider, which will probably be, or include a pot. It doesn't need re-buffered.

[Wounded Paw]

so I think if I have a circuit with a 22k resistor in series with the input before input cap/highpass filter, before the pre-amp stage of the pedal I should be fine.

[lowstar]

i once built a pedal that had a combination of the "one half of a 1:1 transformer" idea (i forgot where it comes from) together with a pot wired as a variable resistor in front of the circuit, and it worked ok.
but let´s face it: if you want perfect bass behaviour with fuzz-face like circuits, you have to use a passive bass.
there´s many active electronics circuits nowadays that have an on/off option, and if not, most of them can be modded to have that option (i once did it to an AmDlx Jazz V that i owned).
if your pickups are already active, you´re out of luck. get another bass that has passive pu´s. 
who owns only one bass anyway ?
btw, the passive is not only an option for fx usage - you´ll be surprised how good (and different) it can sound !
a sandberg california PM5 in passive mode through an aguilar db750 with the switch in passive mode as well really kicks major booty and satisfies all your vintage mojo needs (if you don´t have sufficient mula to buy that early 60ies precision bass, that is  ) !

cheers,
lowstar

EDIT: the idea is from jack orman of course, the article on his website is called "guitar pickup simulation" and uses a 42TM019 transformer.

[Meanderthal]

Here's an idea- turn down the volume on your bass until it behaves, then measure the resistance across the pot. Find a resistor that matches, stick it across your output. Kinda like a governor on a rental truck.

Edit: or more like setting the bias on a fuzz.

[Wounded Paw]

I'm gonna test out the idea of having a trim pot on the input instead of the fixed resistor my Attack Goat currently has.  I'm borrowing an active bass this weekend and gonna do some testing.