active / passive switches

[milwbassman]

I have always run my active Laklands into the passive inputs on my amps. I currently have a GBE 1200, and have no problem with the amp overdriving and clipping at all. 1) Should I be concerned and only use the inputs as directed? 2) How many others do the same?

Thanks,
KB

 

[Mushroo]

Don't worry about it unless there is clipping or it sounds bad. The only difference between the inputs is the "active" input has a "pad" (usually about 10db). The active input is usually only needed if the bass has a very "hot" signal.

 

[KJung]

It's a shame that some manufacturers still use the outdated 'active/passive' labels to describe the padded and non-padded inputs. There is no meaningful correlation between output strength of an instrument and whether it has an on-board pre or not (i.e., I've had passive basses that had much higher output than some of my 'active' basses).

You should always use the non-padded or passive input with all instruments unless the preamp clips even with the gain control turned to a low level. This only happens with extremely aggressive playing technique or with a few very not output instruments (like some of the Reverend basses and a few others).

 

[Mushroo]

ps I used to have a SWR Bassic Black combo, and for jazz gigs, I would plug my passive bass into the active input (on purpose) because it seemed to give me a darker sound, sucking out some of the high end. I wonder if it was all in my head or if it really has a mild EQ effect.

 

[bongomania]

Some active/passive inputs are not just pads, sometimes they also have a different input impedance, which affects the way the signal transfers from the bass to the amp. The "mild EQ effect" is caused by a high output impedance (passive bass) connecting to a low input impedance (active input on amp) which causes some highs to be rolled off, and like the tone knob on a passive bass it may even cause some of the low or low-mid frequencies to be boosted just a bit.

Again though it will vary from one amp design to the next- I know Phil Jones amps use the two different impedances in addition to the pad.

 

[KJung]

Some active/passive inputs are not just pads, sometimes they also have a different input impedance, which affects the way the signal transfers from the bass to the amp. The "mild EQ effect" is caused by a high output impedance (passive bass) connecting to a low input impedance (active input on amp) which causes some highs to be rolled off, and like the tone knob on a passive bass it may even cause some of the low or low-mid frequencies to be boosted just a bit.

Again though it will vary from one amp design to the next- I know Phil Jones amps use the two different impedances in addition to the pad.

That's pretty rare IME. That's a cool thing though, but I'm not sure mixing input impedance and input level is such a good idea. I believe the original AI amps had a high and low impedance switch on the input that didn't impact the gain (non-padded). That was a cool idea!

 

[Mushroo]

That's pretty rare IME. That's a cool thing though, but I'm not sure mixing input impedance and input level is such a good idea. I believe the original AI amps had a high and low impedance switch on the input that didn't impact the gain (non-padded). That was a cool idea!

Yes my 1st gen AI amp has this feature and I have never been able to hear the difference! I guess if I played upright it would be very useful?

 

[bongomania]

Mess with a passive bass into a Summit TD-100 sometime. Going from 10K to 2M ohms is a very audible difference.

 

[Mushroo]

Is that basically what the little switch on the Audere preamp does?

 

[KJung]

Mess with a passive bass into a Summit TD-100 sometime. Going from 10K to 2M ohms is a very audible difference.

+1 with passive instruments, especially with that range of input impedances!

The key here is, even under the very rare condition of the active and passive inputs of the typical bass amp being different impedances, the passive input would virtually always be the one to use. You rarely need a padded input (if ever) with active or passive basses, and an input impedance set for a passive bass would be fine for a bass with a preamp!

 

[lexxmexx]

I would like to hijack this thread for awhile.

Given a passive bass that is connected to a multi-effects pedal, which input (active or passive) of the amp should I rightfully connect these into?

I noticed that when I use the passive input, the sound will get really distorted and I get loads of howling feedbacks but it sounds much better if I change to the active input although the sound tends to be softer. I am curious about whether the signals have become too hot for the passive inputs after being processed by the effects pedal?