MAR-CHAMP

[TIMBO]

Hey guys, This https://www.aggh.net/discussion/index.php?topic=51724.msg581099#msg581099
Got gutted last week, due to the lack of interest on my part.
It's now marshall 2144 preamp, champ power amp kinda.



All fired up well, haven't had a chance to chank it

[sluckey]

Neat and tidy as usual!   

[Latole]

Very nice job.

[tubenit]

Man, you are always coming up with such cool stuff!   Thanks for sharing, Tubenit

[TIMBO]

Thanks guys.
I have a spare hole in the control panel...
Is there a way to add a presence control in an SE amp?

[passaloutre]

Yes, negative feedback can go to the cathode of that final triode stage.

I’m curious how you like the footswitchable boost on the first stage?

[sluckey]

Is there a way to add a presence control in an SE amp?

Here's one way. Just play with the resistor values and I bet you will come up with something useful. I suggest to first add the NFB loop and get the phase sorted. Then convert to the presence circuit.

[shooter]

Is there a way to add a presence control in an SE amp?

for the alternative SE amp view;


plug into a Marshall full stack
move the guitar closer to the speakers, your presence will be soon known 

[TIMBO]

 

[TIMBO]

Hi guys,
My stunt guitarist has had a bash and has given it a low rating.
The LOW input was given a 5/10 sounded good but when cranked didn't quite hit the mark with a smooth overdrive.
So the HI gain input was 1/10 with the sound "fracturing" at low volume and when the boost is engaged it would only sound OK at a very low volume.
Comparing the two circuits and voltages https://www.aggh.net/discussion/index.php?topic=54528.msg610886#msg610886
So my starting point was to drop nodes C and D to get a similar voltage to the preamp valves with an increase to the dropping resistor between nodes B and C to 20k
Even with this increase voltages and still a touch high.
I'll have a play with this with a thought to use an AT7 or AY7 in V1