#1
I am looking to buy an amp, and after looking at some of the specs, I saw this phase inverter mentioned alot. What is it? thanks so much in advance.
#3
Quote by stykerwolf
It inverts the phase of a signal and feeds it to the other half of the poweramplifier and produces a more efficient output (it increases the wattage so to say)

It's in 99.9% of all amps with more then one output tube/thing


I thought it was more specific to A/B class amps?

I could, of course, be wrong though.
Last edited by Mathamology at Jun 10, 2010,
#4
A phase inverter is essentially the opposite of a rectifier. The phase inverter is generally the preamp tube that is the most close to your output tubes in most amps. In master volume amps we have pre and post phase inverter master volume controls. Marshall amps generally used a 12AX7 valve in the phase inverter. In real life we rarely get to the point of pushing our output tubes to their limits. Our front end is going into distortion. Our phase inverter is breaking down too. The ratio of this front end distortion to phase inverter drive and breakdown is determined by amplifier design topology.

The bottom line here is simple. The phase inverter is one of the most important tubes in your amp and the hardest worked tube in the preamp section of your amp. It is how this tube breaks down that provides your output stage distortion tone, character, and amp feel.
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
#7
not all amps have them, class a/b amps will most often have them.
it does ampy things.
Prs se Holcomb is the answer
#8
Class A amps are 'more pure', 'higher fidelity', 'audiophile'... mathematically yes, but can you hear it? Maybe.

Class AB amps are more efficient but retain less signal integrity (how much less depends on the amp itself). But Class A amps rarely get to more than 20W because the valves would simply cook.

Also, 'wattage' isn't a word. It's power.
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
#9
Wattage is a perfectly usable term. If you want to talk about incorrect terminology, refer to where you called the PI the opposite of a rectifier.
#10
watt·age   [wot-ij] Show IPA
–noun
1.
power, as measured in watts.
2.
the amount of power required to operate an electrical appliance or device.
Prs se Holcomb is the answer
#11
Nobody has really answered him. I'll give it a go.

With a push/pull amplifier one half of the pair(s) of power tubes amplifies the positive half of the cycle and the other half amplifies the negative half. The phase inverter receives the signal from the pre-amp and splits it up to be fed into those two halves of the power amp.

That's as simple as I can get it while still describing it's function. Doesn't explain how it does it but I think it's close enough for what it is.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#12
In a class AB amplifier, the power section consists of 2 or more power tubes. Typically, it will have 2 or 4 tubes for guitar applications. In any case it will be an even number.

Let's take an amp with 2 power tubes for example. Your guitar signal is an AC voltage, a sine wave. This sine wave has a positive side and a negative side. In our example class AB amp with 2 power tubes, 1 of those tubes will handle the positive side of the signal and the other tube will handle the negative side of the signal. Going further, when 1 tube is actively handling say, the positive side of the guitar signal, the other tube is effectively "turned off" (I use the term to keep things simple). Then when it comes time for the second tube to handle the negative side of the guitar signal, the 1st tube is turned off.

In a very simplistic sense, this is what is happening. In order for this to be possible, there must be a phase inverter in the amplifier.

A phase inverter can be thought of as a tube stage with a single input and two outputs. The guitar signal is fed into the input. The signal leaves the tube via both outputs, however each output is 180 degrees out of phase with the other. So one output is considered "non-inverting" and the other is considered "inverting" because it has inverted, or flipped upside down the guitar's AC sine wave signal.

Output 1 is fed to 1 power tube and output 2 is fed to the other. This ensures that each output tube handles only 1 side of the AC waveform and is "turned off" during the swing of the other side.

A phase inverter is found in every class AB amplifier. It is NOT the opposite of a rectifier. If it were the opposite of a rectifier, then it would convert DC voltage to AC. This is what a power inverter does. A power inverter is not the same thing as a phase inverter.
#14
Quote by Cathbard
Nobody has really answered him. I'll give it a go.

With a push/pull amplifier one half of the pair(s) of power tubes amplifies the positive half of the cycle and the other half amplifies the negative half. The phase inverter receives the signal from the pre-amp and splits it up to be fed into those two halves of the power amp.

That's as simple as I can get it while still describing it's function. Doesn't explain how it does it but I think it's close enough for what it is.


+1

it's push-pull more than class a versus a/b, as far as i'm aware, anyway. You can have a class a push-pull amp and that amp would have a phase inverter, as far as i'm aware.
I'm an idiot and I accidentally clicked the "Remove all subscriptions" button. If it seems like I'm ignoring you, I'm not, I'm just no longer subscribed to the thread. If you quote me or do the @user thing at me, hopefully it'll notify me through my notifications and I'll get back to you.
Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

Quote by K33nbl4d3
Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

Quote by T00DEEPBLUE
Et tu, br00tz?
#15
Quote by Roc8995
Wattage is a perfectly usable term. If you want to talk about incorrect terminology, refer to where you called the PI the opposite of a rectifier.

Snap!
Everyone is entitled to an opinion.

Feel free to express yours so I can make an informed judgement about how stupid you are.