Marshall 1959 muddy bass

[JPA]

Hello,
I recently modded my Marshall 1959 ('91) and did the same mod for a friend. His amp is from 2010 I think, the second reissue series with the fx loop PCB. Anyway the fx loop was disconnected. So both amps are practically the same regarding component values and circuit design. The mod itself is nothing spectacular, just cascaded front end.
Surprisingly there is a huge difference between those amps.

This is my amp:
https://soundcloud.com/nuclearraccoon/m ... -reissue-1

And the other one:
https://soundcloud.com/nuclearraccoon/m ... -reissue-2

How can I get rid of the farty and muddy bass in my amp? Bias is good, tubes are new. I also tried switching the tubes between the two amps - farty bass still there in my amp. Even with a more JCM 800 like circuit in the preamp section the farty bass is still there although it should be way more bright. The electrolytic capacitors in my amp are still stock but not bloated or anything. Maybe change them?

jp

[Roe]

yes, you might have to change them

[herbvis]

Did you remove the bright cap by chance?

[JPA]

Did you remove the bright cap by chance?

As I said, both preamp and poweramp sections modded exactly the same way.

Is there a possibility that the different OT or PT or choke cause the problem? Well, seems like I have to bite the bullet and change all the electrolytic capacitors...

[JPA]

Problem solved: Somehow the 4k7 resistor across the presence pot was missing (I have the version with the 25k pot).