#1
What exactly are they used for?

And how do you use them?

i was looking at my head.......... (Ampeg B2RE basically) and on the back there is....... "PreAmp Out" and "Power Amp In"

and ive seen "power amps" and "pre amps" on MF and what not, and ive heard people talk about them and stuff, but ive never really understood them.


so, could somebody please tell me what they are, and how they are used?

thanks.
#2
The preamp is the part of an amp where the EQing is done, the poweramp is where the signal is amplified and sent to the speakers.
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#3
so... why/How would you use a "power amp" with a head that is already supplying power to the cab?

if my head is pushing 450W at 4ohms, would a "power amp" make it push more?
#4
You would use the preamp out to connect another power amp. This would send the signal from the preamp to the separate power amp allowing you to run more cabinets so you could have your head pushing 450w at 4 ohm through one stack, then have the other power amp receiving the signal from your preamp and pushing another stack.
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#5
maybe this is not usefull but
a head is made out of a preamp and a poweramp
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#6
ok.

so the preamp out, would use my amp like a preamp, and send its signal to a power amp which would be powering another stack.

got that.


now........ what would the "power amp in" do?
#7
Quote by PedRoFTWkiddies
ok.

so the preamp out, would use my amp like a preamp, and send its signal to a power amp which would be powering another stack.

got that.


now........ what would the "power amp in" do?


Probably just take input from an external power amp and route it to the speakers, basically just using your setup as a cab
#8
I'd guess that will disable the internal power amp so you run the preamp signal into an external poweramp to power a stack. This would be used if you wanted more power than your head was providing but wanted to keep the exact sound of your head.
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#9
This sounds like an effects loop. Actually I'm almost positive it is. My rumble says the exact same thing. You send a signal from the preamp out to the effects and then a signal back to the power amp. This is for effects that work better after a preamp.
#10
^yeah, it is

The power amp in is a direct line to the power amp in your head, bypassing the preamp, and the preamp out is coming from your preamp...the same signal that it normally sent to the power amp.

I think the best way to understand this is to look at the names:


Power amp, meaning power amplifier, meaning it amplifies the power of whatever signsl is given to it.

Pre amp, pre meaning before, amp meaning amplifier. Before the amplifier.
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Last edited by Mutant Corn at Jul 15, 2008,
#11
I've been wondering about this for a while, I have an EBS Microbass II, which is a preamp, could I just buy a poweramp (like one in a pa) and run it through some bass cabs and get a good sound?
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#12
Preamps bascially give you the tone,
while power amps bascially just drive the speakers. so yh it should get a good sound, altho the poweramp has to be pretty good otherwise it will change the tone of hte preamp.
#13
Quote by fortysix&2
I've been wondering about this for a while, I have an EBS Microbass II, which is a preamp, could I just buy a poweramp (like one in a pa) and run it through some bass cabs and get a good sound?


Yes. The preamp gives the sound, the power amp just lifts the signal to a poitn where the speakers can use it. Lots of people get bass preamps and then choose cheap watts with a PA amplifier.
#14
so.........

lets say i bought a power amp. and instead of running my head straight to my 8x10,
i ran a line from the "preamp out" on my B2RE to the power amp, and then ran the power amp into my 8x10.......... that would give me the Tone of the B2RE, but the power of the power amp?

correct?


and jazzrockfeel, its not an effects loop, i have 2 seperate jacks for an effects loop, these are totally different.
#15
Quote by PedRoFTWkiddies
so.........

lets say i bought a power amp. and instead of running my head straight to my 8x10,
i ran a line from the "preamp out" on my B2RE to the power amp, and then ran the power amp into my 8x10.......... that would give me the Tone of the B2RE, but the power of the power amp?

correct?


and jazzrockfeel, its not an effects loop, i have 2 seperate jacks for an effects loop, these are totally different.


like the other dude said, the preamp out and power amp in sounds like an effects loop. u could do that or just use the line out jack so that u can use the effects loop as well.
#16
So how do poweramps affect the sound? If I go and get a cheap 600W pa poweramp will it sound good just because my preamp does?
Quote by Deliriumbassist

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Skills. Get them.
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Quote by Dempsey68
i can only keep it up for about 30 seconds before my fingers cramp up =[

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Sorry, but because you listen to Tool doesn't mean you're intelligent.
#19
I still think that the "power amp in" bit cuts out the internal power amp and lets you use the head as a preamp with an external power amp.
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#20
I think the power amp in means: the signal inserted here goes in to the power amp; so if you want to use an external preamp instead of the terrible one on the B2RE, you can send that signal to be used by the power amp.

TS, you can use it as a second effects loop, it's just always after the preamp, while the intended effects loop is switchable between pre and post preamp.

This way you can have an effects loop, followed by an external preamp, followed by the B2RE's internal poweramp-if you wish to do something like that.

Now I could be wrong in this single case, but every single amp I've ever tried with a "power amp in" plug works this way. A signal inserted there goes straight to the power amp. Don't plug another power amp into that jack.