crwnedblasphemy
Well-known member
and how does it shape tone? Thanks.. 
Ventura
Well-known member
Splits the signal into opposite streams right at the onset.
There are a lot of articles on the net about the exact function and the tonal impact of the PI tube within the amp's circuit layout and eventual character.
Peace,
Mo
There are a lot of articles on the net about the exact function and the tonal impact of the PI tube within the amp's circuit layout and eventual character.
Peace,
Mo
crwnedblasphemy
Well-known member
Thanks..
M
mrkmas
New member
I believe it splits the signal in half, giving the signal a + and - signal. The 12AX7 family of tubes is really 2 tubes in 1. Alot of times tube layouts will say V1a or V1b for this reason. Think of a 12ax7 as 2 seperate tubes in one packaged tube which we call a 12ax7. one of those "tubes" gets the positive and the other gets a negative. This signal is then fed to the power tubes and allows them to operate in "push-pull".
If you look at the signal on an o-scope you see the signal going above and below the base line. The phase inverter allows the signal to do this. Without it the signal would either be completely below or above the line.
I could be wrong on this, but I believe that is the quick explanation. It has been awhile though.
If you look at the signal on an o-scope you see the signal going above and below the base line. The phase inverter allows the signal to do this. Without it the signal would either be completely below or above the line.
I could be wrong on this, but I believe that is the quick explanation. It has been awhile though.
crwnedblasphemy
Well-known member
Makes sense for the true soundwave.
D
daveg62
New member
T
thickwood
New member
The argument about unbalanced or balanced PI tube.
In push pull amps the balanced triodes feed the signal evenly and the Power tubes ware evenly and function longer without going out of balance.
A unbalanced set of POWER tubes has boomy bass and some hum possibly and other effects have been reported and all were bad !
So pushing one tube side harder gets you uneven ware !
I tested the Sovtek 12ax7Lps in the PI >
A complex chord using the rebel 30 OD channel was barely usable as it was savage overdriven sound.
The same chord and settings with the Sovtek PI cleared up the congestion and allowed the chord harmonics improve dramatically !
It was still overdriven and savage but string harmonics increased there presence !
I read the sovtek long plate was a good PI tube ,i see they were correct on my amp too !
Im awaiting a sovtek 12ax7Lps and a Genalex 12ax7 both balanced for testing in othere amps also !
Running a PI a little out of balanced may sound a little thicker on the bottom end however.
Over time this may sound flubby as the ware increases !
In push pull amps the balanced triodes feed the signal evenly and the Power tubes ware evenly and function longer without going out of balance.
A unbalanced set of POWER tubes has boomy bass and some hum possibly and other effects have been reported and all were bad !
So pushing one tube side harder gets you uneven ware !
I tested the Sovtek 12ax7Lps in the PI >
A complex chord using the rebel 30 OD channel was barely usable as it was savage overdriven sound.
The same chord and settings with the Sovtek PI cleared up the congestion and allowed the chord harmonics improve dramatically !
It was still overdriven and savage but string harmonics increased there presence !
I read the sovtek long plate was a good PI tube ,i see they were correct on my amp too !
Im awaiting a sovtek 12ax7Lps and a Genalex 12ax7 both balanced for testing in othere amps also !
Running a PI a little out of balanced may sound a little thicker on the bottom end however.
Over time this may sound flubby as the ware increases !