A/B for Active/Passive

[baalroo]

I wanna put an A/B box before my amp and run A into the active input and B into the passive, that way when I switch from my bass with active circuitry to my bass with passive circuitry I can switch to the proper input with the A/B pedal. Is this a good idea?

[dannybuoy]

Why do you need a pedal for this? Just plug both basses in simultaneously to the respective inputs, and turn down the volume on the one you're not using. Or am I missing something here?

[baalroo]

bass -> fx chain -> A/B box -> amp

[dannybuoy]

Something that I've been pondering lately, that probably warrants another thread, is which input do you use after an FX chain? After it's gone through some buffered effects, should you use a particular input on the amp? As well as cutting the volume, the active input usually has a lower impedance, which will affect the signal. Some of my pedals sound quite different when plugged into the active input compared to passive.

For example, my DHA VT2. If I set the gains and master volume to give an equal signal level when on and off, then move it to the active input, I get a severe volume drop when the effect is on. I'm sure this is due to impedance mismatching (low inpedance of the amp causing voltage drop at the pedal's output stage) and it confuses the hell out of me!

Once you've gone through a chain of fx, the matter of whether the source bass was active or passive may become irrelevant and you can stick to using one input on the amp. Stick an A/B box at the front of the chain for switching instruments and use some other pedal to control the volume between the 2 (if there is any). You can also get pedals like the Bassbone to take 2 basses with an adjustable volume control for each.

[bongomania]

Originally Posted by baalroo

bass -> fx chain -> A/B box -> amp

In that config. a normal A/B box will work, however that assumes you are OK with drastically different signal levels going through the fx chain.

A better approach is to use a 2-into-1 switcher with a level control on one channel, before the fx chain- then feed the fx chain into whichever one input on the amp works best with the output level of the fx chain. That way your levels are consistent throughout.

[baalroo]

Originally Posted by bongomania

In that config. a normal A/B box will work, however that assumes you are OK with drastically different signal levels going through the fx chain.

A better approach is to use a 2-into-1 switcher with a level control on one channel, before the fx chain

Thanks for the info! soooooo, can you point me towards a 2-1 switcher w/level control?

[bongomania]

Depends on your budget- Lehle, WOBO, Radial, and EBS make some spendy ones with fancy features; Loop-Master, Barge and similar garage operations can easily make you a basic one for cheaper; or you could home-brew it fairly simply if you have basic soldering ability.

[baalroo]

actually, thinking about the above... I don't like the idea of having the bass I'm not playing at the back of the stage with a chord running up to my pedalboard at the front of the stage, too much chord clutter. I highly prefer the idea of plugging and unplugging to one input. Any other solutions to the input level dilema? Maybe something to boost the passive input before it enters the fx chain?

[niftydog]

Originally Posted by baalroo

I wanna put an A/B box before my amp and run A into the active input and B into the passive...

Whether this works or not depends a lot on how the two inputs to your amp are wired, and what technique they use to attenuate the active input. Also, some amps have switching jacks that enable extra circuitry - plugging two cables in at the same time might inadvertently enable some unknown condition that may or may not be a problem. I suggest you work this out before you spend too much money on this!

My approach to this is to balance the levels of my active and passive basses at the top of the signal chain - ie; before the fx. I use an EBS MicroBass II to find a middle ground between my basses so that the signal feeding my fx is always at the same level.

Another approach is to have a boost pedal that you only engage when you use your passive bass. This way you only have one cable that you swap between basses.

Originally Posted by dannybuoy

Something that I've been pondering lately, that probably warrants another thread, is which input do you use after an FX chain?

For the most part, active inputs just incorporate some signal attenuation, and they often have a lower relative input impedance. My advice is to always use the passive input, until such time as you start to overload the amps input stage. Then you have two choices, reduce the signal you are inputting, or use the active input to prevent overloading the input stage.

[nad]

My advice may not provide the answer you're looking for, but can save some $$$ for other useful things like a 9th distortion pedal.

I never use active inputs on amps, when changing basses I match volume by using the input gain control. When it comes to different levels through my pedals, I get to know them as best I can, for each bass, and memorize where the volume control needs to be for each (as applicable). Works great for me.

If it ever gets out of hand, I will run a simple boost pedal in front of my chain, like this one:

[bongomania]

Yeah, a boost pedal effectively turns a passive bass into an active one in terms of type and level of signal. So unless you're especially attached to the "passiveness" of your passive bass, a boost pedal (engaged for the passive and disengaged for the active) is an easy solution.

[baalroo]

The boost pedal sounds like the answer for me. Then, gods of fx knowledge, what's my best bet in "bang-for-the-buck" boost pedals?

[ehque]

Originally Posted by baalroo

The boost pedal sounds like the answer for me. Then, gods of fx knowledge, what's my best bet in "bang-for-the-buck" boost pedals?

Originally Posted by nad

That one looks not bad. A lot of companies produce boost pedals. The GLZ or BV pedals from Barge Concepts look great too.

[Hookus]

Boost pedals are pretty cheap, or you could build your own VERY easily. Look at a LPB-1 if you don't want to build one. I like how those sound on bass.

[RodrigoRamos]

Boss LS-2 is a multi-purpose pedal that´s can help you... and you get a nice pedal for another future use..

[s]