Rod Elliot P37?

[roger-k]

I have try to simulate ESP's P37.
http://sound.westhost.com/project37.htm

What I find out was: The preamp is inverted.
Should I do a inverted stage on the input or the output
so the preamp does not invert the signal?
Or it doesn't matterif if it's inverted?
(The main amp is not inverted)

 

[SpittinLLama]

Doesn't matter if inverted. Only matters if channels are inverter relative to each other. As long as all are inverted or not or any combination as long as all channels are the same phase by the output.

-SL

 

[Tube_Dude]

I have try to simulate ESP's P37.
http://sound.westhost.com/project37.htm

What I find out was: The preamp is inverted.

Hi Roger

The project of preamp ESP P37 is no inverting ...

 

[roger-k]

hi.

Are you one hundred percent sure?

I think Q1 inverts the signal because Q1 has about +15V on emitter and the collector controls the base on Q3, which is the ouput transistor.

 

[Tim__x]

He's one hundred percent sure. Look at the orientation of Q3, it's common emitter, not emitter follower.

If your simulation actually shows it as inverting, you've made a mistake in drafting the schematic. Or it doesn't actually show that, and you're just looking at the wrong data.

 

[roger-k]

I don't know why it's inverted.......

Any suggestion?

 

[Nordic]

Hi, what software is that?

 

[Leolabs]

Hi, what software is that?

Multisim.

 

[roger-k]

The software is Electronics Workbench
http://www.electronicsworkbench.com/

 

[Nordic]

thanks, downloading....

 

[roger-k]

I have found an other pic of P37 on ESP.
I think this is very strange because I have beeb drawing the schematic, in the simulator, for many times now.
But is still inverted.......???

 

[Tube_Dude]

I have found an other pic of P37 on ESP.
I think this is very strange because I have beeb drawing the schematic, in the simulator, for many times now.
But is still inverted......

I think that our simulator is better in fiction , than in simulation...

 

[roger-k]

Maybe..... that....
But the simulator can not be as wrong as 180 degrees in phase lead.

 

[MikeW]

Q1 and Q3 invert the signal. It should come out the same polarity as the input.
http://www.passdiy.com/pdf/mos.pdf

Repalce the Gate, Drain, Source with the Base, Emitter, Collecter for the bipolar.

 

[Agent327]

Invert channel button on scope?

 

[keantoken]

Would the phase shift if one of the transistors had a different Hfe as in more than the other one when it is supposed to have less? I don't think this happens in diffamp's though. You might want to check the Ic of each of the output transistors and see if one isn't functioning or something like that...

I am still a noober... Does Q2 act as a constant current source? Or does the ground connection act as input while the diodes produce a constant bias?

 

[Tube_Dude]

I am still a noober... Does Q2 act as a constant current source?

Yes, Q2 is a CCS...

 

[jerluwoo]

I think also that it is noninverted. The input transistor is working as common emitter feeding the lower transistor which is working as common emitter also (2 inversions making it in phase with input). The output taken from the collector of the lower trans with the upper trans working as the sink and not providing signal. There may be some inversion because of 90 deg. shift through input capacitor and another 90 deg from output cap. It may show up if taking input signal before the input cap and after the output cap.

Laugh at me if I'm wrong and I'll laugh with you

 

[sam9]

doesn't matterif if it's inverted?

It seems to me that if the signal is inverted (regardless of why) when it reaches the speaker binding posts the simplest remedy is to reverse the connection..

this assumes you consixder there is anything that requires remedy.

 

[jony]

My old simulation (Orcad Pspice) is showing such a result
This amp is notinve..
Is looks like Electronics Workbench is wrong but why