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wooly mammoth w/ actives
- Thread starter ARCtrooper225
- Start date
moogboy
Inactive
But they aparently go for about $200, so I don't want to waste that kind of money only for it to not work (I'm also planning to use it with either a DOD fx 25, chunk 00 funk, or moog murf) maybe putting one of those before it in the chain could help?
I thought the issue was usually the impedance, so if one had the impedance "buffered" (I'm probly using the term in the chemistry student sense there, hence any confusion) at a level the mammoth likes then a preamp beforehand wouldn't be an issue?
And to the above post, I think you'de still be better off trying it out first, using a pedal before it is still going to be active electronics, so one will probly only work if it has the right output impedance level.
bongomania
Commercial User
Right, there's the rub. In electronics, a buffer is specifically an active powered device that converts a signal from low z to high z. Anything else could be a "convertor" or an "impedance changer" or some other generic term, but not a "buffer".
The flip side of that is that it is entirely possible to make or buy a device that converts your signal from high z to low z, but don't make the mistake of asking for a buffer!
bongo's got it, but his highs and lows are backwards... i think 
adding some impedance in series like the volume control is one idea, but i wonder if a passive tone control before the fuzz would be better.
adding some impedance in series like the volume control is one idea, but i wonder if a passive tone control before the fuzz would be better.
bongomania
Commercial User
Aaggh, you may be right. I just went on a Google quest to find out for sure, but the results are sketchy. Here are some definitions I've dug up:
But notice that none of these definitions compare the z out of the incoming signal with the z out of the buffer. And a low z out is not the same as having a low z in on the next device in line. OK, here's one that puts it in simple terms, but I wish it was a little more "definitive":
Hmm... Sounds like I was wrong, but I'm still not sure. Any EE's here care to weigh in with a solid ruling?
I'm thinking of getting an Ibanez ATK305, which as far as I know has an passive pickup but an active preamp. I'm thinking of a Little Big Muff, will it be fine or what?
bongomania
Commercial User
The whole "passive pickup"/"active pickup"/"preamp" thing has a lot of people confounded. A preamp is an active device. "Active pickups" are just pickups that have a preamp installed inside the pickup housing, instead of an external board with knobs.
So impedance-wise, active pickups are the same as a combination of passive pickups and a preamp.
So impedance-wise, active pickups are the same as a combination of passive pickups and a preamp.
Alright alright, stand back you kids... <hoiks up trousers>
A buffer is a unity gain amplifier with high input impedance and low output impedance.
For the most part they are used to "buffer" a high (output) impedance device, like a pickup, so that the downstream electronics has less of a detrimental effect on the pickups performance. In this sense they can be considered to be converting a high impedance to a low impedance.
Regarding active/passive pickups.
It's true that all magnetic pickups are passive at heart. Some people around here try to make the distinction between a pickup with an integrated preamp, and one where the preamp is installed in the bass body cavity, but from an engineers point of view there is no difference. Any pickup with a preamp should be considered active, because while there are passive elements to the circuit, you would never normally have direct access to them. Besides, the only real difference is the physical location of the preamp electronics.
Regarding the Mammoth:
The line Zack takes is that he doesn't recommend its use with active instruments. That doesn't mean it won't work, or that you won't like how it sounds, it just means he doesn't like it, and therefore doesn't recommend it.
Without testing it for myself, I cannot say definitively, but it's my guess that there's more than just impedance to blame here. Yes, forcing an active instrument to appear as a high impedance source might work, but while it benefits the mammoth, it's likely to have the opposite affect on the rest of the signal chain.
Even so, an impedance matching device such as the Dragster still does not allow interaction between the Mammoth and the pickups, so the forced-high-impedance trick might only partially work. The active electronics is still in the picture, and it's still doing it's job which is to isolate the passive pickups from external influences. Other tricks such as using low volume settings or a half-cocked volume pedal have been reported to have worked, but it's still no substitute for passive pups.
A buffer is a unity gain amplifier with high input impedance and low output impedance.
For the most part they are used to "buffer" a high (output) impedance device, like a pickup, so that the downstream electronics has less of a detrimental effect on the pickups performance. In this sense they can be considered to be converting a high impedance to a low impedance.
Regarding active/passive pickups.
It's true that all magnetic pickups are passive at heart. Some people around here try to make the distinction between a pickup with an integrated preamp, and one where the preamp is installed in the bass body cavity, but from an engineers point of view there is no difference. Any pickup with a preamp should be considered active, because while there are passive elements to the circuit, you would never normally have direct access to them. Besides, the only real difference is the physical location of the preamp electronics.
Regarding the Mammoth:
The line Zack takes is that he doesn't recommend its use with active instruments. That doesn't mean it won't work, or that you won't like how it sounds, it just means he doesn't like it, and therefore doesn't recommend it.
Without testing it for myself, I cannot say definitively, but it's my guess that there's more than just impedance to blame here. Yes, forcing an active instrument to appear as a high impedance source might work, but while it benefits the mammoth, it's likely to have the opposite affect on the rest of the signal chain.
Even so, an impedance matching device such as the Dragster still does not allow interaction between the Mammoth and the pickups, so the forced-high-impedance trick might only partially work. The active electronics is still in the picture, and it's still doing it's job which is to isolate the passive pickups from external influences. Other tricks such as using low volume settings or a half-cocked volume pedal have been reported to have worked, but it's still no substitute for passive pups.
i AM an EE
signals don't have impedance, inputs and outputs do. typically for good voltage matching you want low output impedances and high input impedances. this tranfers a louder, brighter signal to the next stage. the rule of thumb is the input impedance of a stage should be at least 10x the output impedance of the stage connected to it.
going against this philosophy, most fuzzes have a very low input impedance which lowers the volume of the signal, particularly the highs making the fuzz sounds smoother. the problem with active basses is that their output impedance is so low this doesn't happen.
i'm also not sure that passive pickups with an active preamp is really the same as active pickups. my understanding was that active pickups have very few windings, giving them a tiny yet very high fidelity signal (since the impedance is lower due to fewer windings). the low amplitude of the signal makes them very susceptible to noise, and the windings alone are incapable of driving almost any length of wire, which requires having the amp in the pickup itself. by contrast the passive pickups in an active bass have more winding changing the sound from the get-go.
bongomania
Commercial User
I'll absolutely concede the point about buffers and impedance, thanks for the clarification; but I've never heard what you are describing about active pickups. Link?
Here's mine:
[Invalid or Expired Link Removed]
"ACTIVE PICKUPS: pickups and electronics that use electricity to enhance the direct sound coming out of the pickups."
http://www.sweetwater.com/forums/showthread.php?t=14925
"By definition the difference is that active pickups are powered. There is a power source (usually inside the instrument in the form of a battery) that powers a small preamp for conditioning the signal before it leaves the guitar or bass. Really the term should be "active electronics" because the pickups themselves aren't much different from any other pickups."
Here's mine:
[Invalid or Expired Link Removed]
"ACTIVE PICKUPS: pickups and electronics that use electricity to enhance the direct sound coming out of the pickups."
http://www.sweetwater.com/forums/showthread.php?t=14925
"By definition the difference is that active pickups are powered. There is a power source (usually inside the instrument in the form of a battery) that powers a small preamp for conditioning the signal before it leaves the guitar or bass. Really the term should be "active electronics" because the pickups themselves aren't much different from any other pickups."
"Active" pickups typically have a lower number of coil windings, giving a low output, low impedance, and very clean and clear, uncoloured sound. The low output is boosted by an on-board active preamp which maintains the low impedance. Low impedance pickups (on their own, or with a preamp) can drive long cables without noticeable treble loss.
Invalid Link Removed
basically passive pickups use a crapstack of windings to get their juice, but the mode windings change the tone. active pickups uses less windings giving a broader spectrum, but rely on the internal preamp for juice.
Invalid Link Removed
basically passive pickups use a crapstack of windings to get their juice, but the mode windings change the tone. active pickups uses less windings giving a broader spectrum, but rely on the internal preamp for juice.
bongomania
Commercial User
OK... But is the z out typically any different between the average "active pickups" and the average on-board preamp?
not sure, probably not but i was pointing out its wrong to say passive pickups + active preamp is the same as active pickups... the tone will be different.
bongomania
Commercial User
Fair enough, but what I said was "So impedance-wise, active pickups are the same as a combination of passive pickups and a preamp."
I know, we're both just picking nits here, but accuracy is important!
I know, we're both just picking nits here, but accuracy is important! i agree completely. i didn't even see that post! i was addressing niftydogs comment "Besides, the only real difference is the physical location of the preamp electronics."
