3 Channel Recto Presence Mod....

[3124+]

I think I understand what you meant, now. I think they're comparing the same modes, not modern vs vintage. That's apples to oranges as you pointed out.

Even comparing same modes is apples to oranges because... ch2 modern keeps the negative feedback loop connected and the presence control functions in the traditional way as part of the power amp. But ch3 modern disconnects the negative feedback loop in the power amp and the presence control moves to the treble pot wiper.

 

[afu]

http://wp.me/p4h97k-c8

My article about the Presence pot circuit. Some notes in regards to the modification are included.

 

[afu]

https://wordpress.com/post/warpedmusician.wordpress.com/4738

I finally got around to plotting the Vintage presence control's filtering. In the pictures, as the frequency drops away it is able to pass the phase inverter more easily. R2 is variable and represents each 30 degrees on the control.

I haven't done the Modern version yet and I'm beat. I'll get back to this very soon.

 

[EooN]

A quick question here (please bear with me - I don't want to dig through all the posts ) -

the basic channel 3 presence mod is the same one that the manual describes?
Fluff got his pot. straight from the Mesa guys?

Thanks!

 

[afu]

A quick question here (please bear with me - I don't want to dig through all the posts ) -

the basic channel 3 presence mod is the same one that the manual describes?
Fluff got his pot. straight from the Mesa guys?

Thanks!

Yes.