preamp and power amp !


Death55
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Death55
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02/08/2004 11:04 pm
Ok.. whats the difference between a preamp tube and a power amp tube ?
By virtue of their electrical properties, tubes generate a special waveform when they're saturated, which is why tube engineering has tremendous tonal advantages over solid state or DSP solutions, particularly for crunch and lead sounds. Tubes enter the saturation zone gradually or softly, which lends tube-driven tone its trademark yet totally unique character.
# 1
Lordathestrings
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Lordathestrings
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02/09/2004 2:22 am
About $20.

Seriously, a preamp tube is usually quite small compared to a power tube, and there are often two or more circuits in it.

Power tubes are usually bigger in order to handle the higher voltage and current. This makes them more expensive.
Lordathestrings
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# 2
Axl_Rose
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Axl_Rose
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02/09/2004 3:29 am
Good you remind me the difference between preamp and power amp...
# 3
Lordathestrings
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Lordathestrings
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02/09/2004 6:12 am
I think I covered that on this old thread.
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# 4
Axl_Rose
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Axl_Rose
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02/09/2004 2:14 pm
Ok.. so on my marshall with each channel having Bass, Mid, Treb, Gain, Volume... and then there being on overall volume knob.. what part is pre and wot is power?

Also... what are the implications of the channel volume being at 10 and overall volume at one.. compared with channel volume at 0ne and overall at 10?

Im after a slash tone and need as much distortion as possible, so what settings would you recomend?
# 5
Lordathestrings
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Lordathestrings
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02/09/2004 5:17 pm
The power stage of the amp is the very last section. It's only function is to boost the signal from the preamp to drive the speaker(s). All of the tone shaping is done in the preamp, which is where the gain and EQ is applied to the signal from the guitar.

Channel Volume @ 10; Master Volume @ 1:

The preamp is getting all of the guitar signal. Some of the preamp tubes will be overdriven, producing compression and distortion. The power amp will receive a small, distorted signal from the preamp. There will be no power amp distortion. The sound level from the speakers will be quite low due to the Master setting.


Channel Volume @ 1: Master Volume @10:

The preamp will receive only a small amount of the guitar signal. Unless a lot of gain is applied, this signal will be passed along to the power amp as a 'clean' signal. The high setting of the Master Volume will allow all of the preamp signal to reach the power amp, but because it is fairly small, it will probably not be enough to cause the power amp to distort. The result is likely to be a clean sound from the speakers.


Neither of these situatons is likely to produce power amp distortion. That will only happen if more signal from the preamp is fed to the power amp.

In the first example, raising the Master Volume setting will introduce more of the distorted preamp signal to the power amp. Since this signal is already distorted, the sound from the speakers will be very distorted. Think Metal.

In the second example, raising the Channel Volume will pass more of the guitar signal to the preamp, which will then have more to give to the power amp. Assuming that the preamp does not introduce distortion of it's own, a large clean signal will reach the power amp. If this is strong enough to saturate the power tubes, the result will be a sweet, touch-sensitive distortion. Classic Rock & Blues.

As Lee The V used to say, "Your mileage may vary".
:)
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# 6
Axl_Rose
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Axl_Rose
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02/10/2004 1:12 am
What so hidden somewhere with the combination of those two volume knobs is a sweet tone I probably havent heard yet? Howd i find it!
# 7
Lordathestrings
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Lordathestrings
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02/10/2004 1:49 am
Well, now Chief - that's how th' Great Unwashed can tell an expert from a farkin novice! D'ye ken, gadge? :)

* * * * * * *

To put it more politely, This is something you're going to have to spend a lot of time experimenting with. But seeing people's jaws hit the floor is worth every minute of that effort! :D

[Edited by Lordathestrings on 02-09-2004 at 11:13 PM]
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# 8

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