Hi guys, first post here! I have 2 basses one active and the other passive, my problem is that, when i play live and want to change bass i have to change the amp's volume too due to the output voltage difference. Is there anyway to solve this problem? Would an active DI Box for the passive bass solve?
Leave the volume on the passive bass on full and wind back the volume on the active bass to match it. On an active bass you should not lose any tone when you wind back - I seldom play my active bass with the volume on full, I use the amp gain for basic volume.
I use a simple 4 channel passive mixer. I added switches so each bass can be selected. If you select more than one then it is a mixer and you can play both at once. Simple. Works. Passive, no wall warts. Basses always plugged in. Unfortunately this item is discontinued, but there are other similar things out there. You simply set the passive volume control maximum on the mixer for the bass with the weakest output and then bring the level of the hotter bass back to match it.
buy a Mooer Pure Boost pedal, problem solved. Dial it in on the passive bass to boost it to the same output as the active. Badabing Badaboom,problem solved, without lowering the active's output,which would defeat the point of having one. I have one for when I switch between my P and the Jazz. http://www.musiciansfriend.com/amplifiers-effects/mooer-pure-boost-guitar-effects-pedal
That will work OK with an active bass but the input impedance is way too low (47Kohms) for a passive - it will work but it will kill the highs.
Actually they are higher than that and the switches I installed mean that you only get 4 pots in parallel when you have all basses mixed. So it's little different from a passive volume control. Although you are right there is a minor effect there. It's easily compensated by a little less on the tone control. Since pickup impedance is much lower than say the volume pots, the effect is really only noticed as a slight loss of highs as you roll back the volume. If you run with volume up or nearly up as many of us do the effect is not noticeable at all.
I have an AB box with a passive attenuator (volume pot) on one channel. it's a dual gang pot with different resistances for each wafer. (pot mods liked this have been covered on this forum many times). if the louder bass is passive, I can switch to a high z pot. I've used this on 2-bass gigs for over a decade. I have no idea why something like this isn't on the market. I made mine from scratch but with passive a-b stomp boxes so cheap these days on ebay, I'd think you'd mod one instead.