#1
Here's something I simply don't understand:
• Active guitar pickups have a built in preamp and we know that active pickups have a much lower output impedance than passives.
• The input on a guitar amp is designed having a HIz input.
So what happens when you plug the guitar with active pickups into a guitar HIz input?
Since most of acoustic guitars having active pick ups (magnetic or piezo) have 1/4unbalanced jack is that jack of hi z or low Z ?
1. Can it be connected to HI z guitar amplifier input or is needed a DI or it has a buffer and there is no problem?
2. If it las Low Z it must be connected to a line Input of a mixer ,PA… But if my guitar amp has not line in than the only solution is Hi z using a buffer circuit?
3. Some guitars have both 1/4unbalanced and XLR balanced jacks. Does it mean that it can be connected to my guitar amp HI z input or to Line in of any device. My answer is yes. But how is this explained? Any links if difficult to explain.
4. Connecting the active pick up of my acoustic guitar at Hi z Input of my guitar amp (having no Line in) there I have 2 preamplifiers ant 2 EQs (of the active pick up and of the guitar amp). Comment this something about it
Thanks
Stefanos
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#2
You put it into the guitar input.

So the Hi-Z.
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#3
1. The preamp works as a buffer. There's no need for a DI or anything in between.
2. Not true. You can plug it straight into the guitar input, the amp doesn't care about a low-Z signal. It will handle it just fine.
3. I don't understand the question.
4. I don't understand this question either. I think you're asking if it's ok to have two preamps and two EQs, which it is. There's no problem there.
#4
2. Built in preamps have lower output impedance than Input Impedance (The out of magnetic or piezo pick up is high). I mean that it would be better coneccting it to Line In than Hiz.
3. Some guitars have 1/4 unbalanced an XLR outputs. I ask for a circuit or a link describing how the built in preamp gives both outputs.
4. (built in preamp on guitar + preamp in guitar amplifier): 2 preamps + 2 EQs + other tone shape controls .For sure there is no problem and the gains are added. But which tone shape controls is better to use?

Thanks
#5
No. It goes into the HiZ input.
But what pickup are we actually talking about and what is it in - and what amp? And what are you playing? There may be a better solution.

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#6
I think you're making a critical mistake here, thinking that the preamp in active pickups is in any way similar to the preamp in an amplifier.

To put it simply, it isn't.

Active pickups use a preamp because their coils are so underwound and their magnets are so weak, their natural signal is utterly inaudible even to amplifiers, let alone human hearing. The preamp these pickups use simply bring the signal back up to about the same level as standard pickups. The actual difference in signal level between even a very low output passive pickup and the highest output active pickups is only about 0.8dB, and that's at the biggest extreme. In fact there are plenty of passive pickups that generate much higher output than common active pickups do.

As far as impedance goes, it simply does not matter. Lower impedance is nice if you're running a lot of cable, but otherwise, it just does not matter. These aren't hi-fis and the signal out of your guitar is not hitting the speakers directly. An instrument amp doesn't care what the impedance is and it barely cares about tiny level differences like <1dB.

An active acoustic pickup is another, different pickup. Again, don't confuse these with the preamps in amplifiers or the preamps in active electric guitar pickups.

As for guitars which have XLR out, it really depends on the guitar. XLR is just a connection type, there is no hard rule that any guitar which features such a connection must be used X way or does X thing. XLR can be used for hundreds of different things; you need to inspect the guitars in question and deal with it on a case-by-case basis.
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#7
Quote by MrFlibble
I think you're making a critical mistake here, thinking that the preamp in active pickups is in any way similar to the preamp in an amplifier.

To put it simply, it isn't.

Active pickups use a preamp because their coils are so underwound and their magnets are so weak, their natural signal is utterly inaudible even to amplifiers, let alone human hearing. The preamp these pickups use simply bring the signal back up to about the same level as standard pickups. The actual difference in signal level between even a very low output passive pickup and the highest output active pickups is only about 0.8dB, and that's at the biggest extreme. In fact there are plenty of passive pickups that generate much higher output than common active pickups do.

As far as impedance goes, it simply does not matter. Lower impedance is nice if you're running a lot of cable, but otherwise, it just does not matter. These aren't hi-fis and the signal out of your guitar is not hitting the speakers directly. An instrument amp doesn't care what the impedance is and it barely cares about tiny level differences like <1dB.

An active acoustic pickup is another, different pickup. Again, don't confuse these with the preamps in amplifiers or the preamps in active electric guitar pickups.

As for guitars which have XLR out, it really depends on the guitar. XLR is just a connection type, there is no hard rule that any guitar which features such a connection must be used X way or does X thing. XLR can be used for hundreds of different things; you need to inspect the guitars in question and deal with it on a case-by-case basis.


Correct. The active pickups may be lower impedance, but they are still unbalanced, and the regular low-Z input is expecting that, as well as a line level signal, which is much hotter than guitar level signals.

As far as impedance, the goal is to match it. The Hi-Z input basically has a DI built in, to match impedances, otherwise you may get some odd humming due to impedance mismatch.
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#8
Ok thanks . three more questions
What is the out level of a typical built in preamp? -10 dbV lower than that ?
What is the typical level a Hiz Input expecting ?
Since the out of a such a preamp is of lower impedance and unbalanced can I suppose that guitars having both outs (unbalanced + balanced XLR) have different levels?