Tony p Posted April 3, 2016 Share Posted April 3, 2016 Hi , I played a festival last night, turned up, plugged my active bass into the active input of the supplied bass amp and it sounded like a bag of spanners, sound guy comes over and says plug it into the passive input, did that and it sounded like a bass again Can someone more enlightened than me explain what the effect of active into passive is? Ps we only had 20 mins in between bands so I didn't have time to play about with settings etc as I had my semi accoustic guitar to sort aswell..... Cheers. Quote Link to comment Share on other sites More sharing options...
RhysP Posted April 3, 2016 Share Posted April 3, 2016 Generally speaking an active bass into a passive input will just give you more gain. Depends on the amp & the output of the active circuit as to how much. There's an older thread that goes into it in a bit more detail here: http://basschat.co.uk/topic/178776-does-active-and-passive-inputs-really-matter-in-a-bass-amp/ Quote Link to comment Share on other sites More sharing options...
colgraff Posted April 3, 2016 Share Posted April 3, 2016 A long time ago, I had an amp which sounded flat when I plugged into the active input, it sounded great in the passive input because i could get a meatier/slightly overdriven sound from it. Quote Link to comment Share on other sites More sharing options...
TimR Posted April 3, 2016 Share Posted April 3, 2016 Active only refers to the tone controls. The output of an active bass should be no different to that of a passive. Quote Link to comment Share on other sites More sharing options...
Dood Posted April 3, 2016 Share Posted April 3, 2016 [quote name='TimR' timestamp='1459692648' post='3018655'] Active only refers to the tone controls. The output of an active bass should be no different to that of a passive. [/quote] Should but never is Quote Link to comment Share on other sites More sharing options...
Dood Posted April 3, 2016 Share Posted April 3, 2016 To be honest TonyP, those labels these days are meaningless. In reality, the input labelled 'active' should actually just be called 'padded'. What this actually means is that the signal from your instrument is [i]more[/i] attenuated in the first part of the signal path after the 'active' socket on the amplifier verses the 'passive' input. If you happened to have an instrument with a very high output (and this can be a passive instrument by the way, it doesn't have to have active circuitry for example) then the higher output signal could distort the input section of the amplifier (be it valves or transistors in fact). Well, you may ask, why don't I just turn down the gain control, sure that will solve that problem? - Yes in many amplifiers it can, but there are plenty on the market that feature some sort of gain stage that appears before the gain control in the signal path, so it'd actually be possible to get it to distort even with the gain control all the way down at 1. The Ampeg SVT's are a good example of this sort of schematic. By having an 'input pad' you reduce the possibility of unwanted distortion at the input before the signal travels through the rest of the amp circuitry. In terms of which you should use - your ears will help you there - which one sounds the best? If you have a bass, either active or passive that has a lower output (you may or may not realise this) then the 'passive' output may suit it better - similarly for an instrument with a very high output (such as mine where I have three pickups wired in series) then I'd want to use the 'active' or 'padded' input to stop the amplifier from distorting at the input. So, to sum up - manufacturers should rename those input sockets, or just offer one socket and a button marked 'pad' 'or attenuate'!! Quote Link to comment Share on other sites More sharing options...
TimR Posted April 3, 2016 Share Posted April 3, 2016 (edited) They used to be high and low impedance, referring to different types of microphones. Low would be expecting an input with about 150ohms and hi would expect about 15kohms. Active basses have buffered inputs and present a low impedance to the amp and while it doesn't really matter whether you plug them into the high or the low, it can have an effect on the high frequencies. Edited April 4, 2016 by TimR Quote Link to comment Share on other sites More sharing options...
Tony p Posted April 3, 2016 Author Share Posted April 3, 2016 Thanks for all of your replies, most festivals we play seem to supply a bass amp on stage, to save turn around time. so it's good to know the difference in the inputs and that I won't fry anything anyway Quote Link to comment Share on other sites More sharing options...
LayDownThaFunk Posted April 3, 2016 Share Posted April 3, 2016 Clipping the amp much more regularly is the result. Thus, damaged equipment. Anyone who disagrees hasn't used a Spector before. Quote Link to comment Share on other sites More sharing options...
seashell Posted April 3, 2016 Share Posted April 3, 2016 Interesting. I played an open mic once where the previously bass player was accused of blowing up the amp. Sound guy said it was cos he had plugged his active bass into the passive socket. They had to put mine through the PA. I've always been really careful to make sure I use the correct socket or setting since then. Maybe it's not as drastic as I thought? Quote Link to comment Share on other sites More sharing options...
dave_bass5 Posted April 3, 2016 Share Posted April 3, 2016 [quote name='Tony p' timestamp='1459677826' post='3018503'] Hi , I played a festival last night, turned up, plugged my active bass into the active input of the supplied bass amp and it sounded like a bag of spanners, sound guy comes over and says plug it into the passive input, did that and it sounded like a bass again Can someone more enlightened than me explain what the effect of active into passive is? Ps we only had 20 mins in between bands so I didn't have time to play about with settings etc as I had my semi accoustic guitar to sort aswell..... Cheers. [/quote] I'm not sure what a bag of spanners sounds like when referred to bass, but to me it sounds like the input might have been buggered. As others have said, it's normally a pad, so should give you a lower volume. As the passive input seemed ok I'd say your bass wasn't putting out a hot signal. Can't think of any other reason. Quote Link to comment Share on other sites More sharing options...
mcnach Posted April 3, 2016 Share Posted April 3, 2016 (edited) Some basses are hotter than the norm, so the so-called 'active' input (which is nothing but an attenuated input) provides a way to not run the preamp to hot and distort (which can sound ugly, but I'm not quite sure it can damage anything with the kind of signals an electric bass produces). It's better when we just have an input and a input gain knob... but hey, we use what we have to. Active basses are not necessarily hotter than passive basses. Most I have tried tend to be just around the same as most passive basses I've tried. My two Stingrays are no hotter than any of my passive Jazz or Precision basses, for instance. The L2000, passively, was hotter than nearly every active bass I've used. The loudest output bass I've owned is this passive Precision with neodymium magnet pickups... Thinking in terms of active/passive is pretty irrelevant in this context. I always use the Passive input if there's a choice, as on many amps the active input doesn't sound very good. But I pay attention to the signal I am using and I know which of my basses is hotter than usual so in the absence of an input gain control... you can often turn down the volume on the bass if it's an active bass. If it's passive that will change the sound... so it depends. The issue is not just with amplifiers. If you use pedals you encounter issues too... some basses produce a signal that's too hot for certain pedals to function nicely. But the vast majority of pedals work well with the vast majority of basses too. I haven't heard of pedals being damaged because a bass was too hot, however. Edited April 3, 2016 by mcnach Quote Link to comment Share on other sites More sharing options...
peted Posted April 4, 2016 Share Posted April 4, 2016 If you're clipping and distorting the input stage of the amp switch to the 'active' input. This doesn't relate to whether your guitar is passive of active, though if active and you do a lot of boosted tone shaping in your guitar you're more likely to need the active input of the amp. Quote Link to comment Share on other sites More sharing options...
EssentialTension Posted April 4, 2016 Share Posted April 4, 2016 Effects pedals or pre-amp pedals can also make a difference to which amp input is preferable. Quote Link to comment Share on other sites More sharing options...
dave_bass5 Posted April 4, 2016 Share Posted April 4, 2016 [quote name='peted' timestamp='1459756577' post='3019144'] If you're clipping and distorting the input stage of the amp switch to the 'active' input. This doesn't relate to whether your guitar is passive of active, though if active and you do a lot of boosted tone shaping in your guitar you're more likely to need the active input of the amp. [/quote] [font=arial,helvetica,sans-serif]We dont know if it was clipping or just not a good tone, but if it was clipping im at a loss to figure out how the passive input was fine but the active (assuming its a pad) wasnt.[/font] Quote Link to comment Share on other sites More sharing options...
Tony p Posted April 4, 2016 Author Share Posted April 4, 2016 (edited) [quote name='dave_bass5' timestamp='1459757512' post='3019151'] [font=arial,helvetica,sans-serif]We dont know if it was clipping or just not a good tone, but if it was clipping im at a loss to figure out how the passive input was fine but the active (assuming its a pad) wasnt.[/font] [/quote] Sorry gents, the " bag of spanners" I mentioned was the sound mans description. Basically he was getting a distorted/ muddy sound from the amp. For what it's worth I use a yamaha rbx374 and ive plugged it into various amps without any issues before. No idea what that particular combo was tho I'm afraid. Sounded ok after tho Edited April 4, 2016 by Tony p Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted April 4, 2016 Share Posted April 4, 2016 [quote name='Tony p' timestamp='1459677826' post='3018503'] ...and it sounded like a bag of spanners, [/quote] I've been out with a few girls who looked like your bass sounded. I think you had an unlucky match between guitar and amp. "Not every penny fits the slot". Quote Link to comment Share on other sites More sharing options...
lowhand_mike Posted April 4, 2016 Share Posted April 4, 2016 been putting my active bass into the passive input of my amps for years now, ashdown btw, and tweaked the input gain on the VU meter to suit. A good example is the ashdown rootmaster that i recently bought had just the one input and you control it with the gain knob, the new evo version has the two inputs again, must have been user feedback (not distortion, opinions) i have a Squire Affinity jazz bass that has a montrous output and had to go in the active input of my mag. as others have said let your ears decide Quote Link to comment Share on other sites More sharing options...
TimR Posted April 4, 2016 Share Posted April 4, 2016 [quote name='dave_bass5' timestamp='1459757512' post='3019151'] [font=arial,helvetica,sans-serif]We dont know if it was clipping or just not a good tone, but if it was clipping im at a loss to figure out how the passive input was fine but the active (assuming its a pad) wasnt.[/font] [/quote] It's not a pad, they're expecting different impedances. As I wrote above. Active basses have low output impedance across all frequencies, but passive basses will have differing impedances depending on the pickups and frequencies. Quote Link to comment Share on other sites More sharing options...
dave_bass5 Posted April 4, 2016 Share Posted April 4, 2016 [quote name='TimR' timestamp='1459766196' post='3019266'] It's not a pad, they're expecting different impedances. As I wrote above. Active basses have low output impedance across all frequencies, but passive basses will have differing impedances depending on the pickups and frequencies. [/quote] Yeah, i meant it has the effect of adding a pad. Quote Link to comment Share on other sites More sharing options...
TimR Posted April 4, 2016 Share Posted April 4, 2016 [quote name='dave_bass5' timestamp='1459768066' post='3019303'] Yeah, i meant it has the effect of adding a pad. [/quote] Adding a Pad is more like turning down the gain. If the impedances are wrong it still won't fix the problem. Some interesting reading: http://www.soundonsound.com/sos/may13/articles/using-di-boxes.htm Quote Link to comment Share on other sites More sharing options...
luckydog Posted April 5, 2016 Share Posted April 5, 2016 My 2p worth is that the pad on active inputs can affect compression, and that can be a cause of gross sound difference between active/passive inputs when used with active bass? Assuming the passive input doesn't distort/overdrive of course. Sometimes even when there doesn't seem to be compression in an amp it can be present and input level sensitive, for example as part of modelling, or just as part the circuit. Just my 2p worth - LD Quote Link to comment Share on other sites More sharing options...
tauzero Posted April 5, 2016 Share Posted April 5, 2016 [quote name='LayDownThaFunk' timestamp='1459700658' post='3018724'] Clipping the amp much more regularly is the result. Thus, damaged equipment. Anyone who disagrees hasn't used a Spector before. [/quote] I disagree, but I haven't used a Spector. I do have one active bass which is quite a bit louder than the others but all but that one produce a similar output to the passive basses I've owned. I always use the passive input or switch off the pad, never use the active input or pad. Quote Link to comment Share on other sites More sharing options...
icastle Posted April 5, 2016 Share Posted April 5, 2016 I've always just shoved stuff into the Active or 'Hi' socket regardless of what bass it is. Never had an amp go bang, never had a problem with distortion, and I hate distorted bass, so I'd notice. I think its a conspiracy leftover from yesteryear put there simply to satisfy a bassists need to analyse stuff into oblivion. Quote Link to comment Share on other sites More sharing options...
luckydog Posted April 6, 2016 Share Posted April 6, 2016 Indeed, the conspiracy has been going on for decades. For interest, did you know the 1 and 2 inputs on most Bassman amps from back in the day are different for a passive bass, a matter of different loading ? Input 1 is true high impedance, 2 is a step toward the sort of lower impedance inputs on modern amps devised for active inputs. 2 has somewhat lower impedance than 1, and the inputs can have subtle tonal differences with passive basses ? Both Bass and Normal Channels are like this, BTW. LD Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.