treble peak>coupling cap or coupling cap>treble peak??

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sonofmickel
Posts: 162
Joined: Sun Jan 13, 2008 4:56 pm

treble peak>coupling cap or coupling cap>treble peak??

Post by sonofmickel »

On the "sean superdrive601" schematic there is a 470p/560k>100K>.0022 that runs off the Plate on the second gain stage. The "Naked" schem and the dated 083096 have a .002 coupling cap>500k volume(100p treble cap).

My question is what is happening theory wise when the order is reversed(like Marshall)?
Coupling>Peak vs Peak>Coupling?

I am going to try it and draw my own layman's conclusions.
tubeswell
Posts: 2337
Joined: Thu Mar 27, 2008 6:42 am
Location: Wellington. NZ

Re: treble peak>coupling cap or coupling cap>treble pe

Post by tubeswell »

sonofmickel wrote:On the "sean superdrive601" schematic there is a 470p/560k>100K>.0022 that runs off the Plate on the second gain stage. The "Naked" schem and the dated 083096 have a .002 coupling cap>500k volume(100p treble cap).

My question is what is happening theory wise when the order is reversed(like Marshall)?
Coupling>Peak vs Peak>Coupling?

I am going to try it and draw my own layman's conclusions.
Sean Superoverdrive schemtaic

[img:1024:727]http://i176.photobucket.com/albums/w197 ... ive601.jpg[/img]

560k||470pF is a hi-pass filter. In terms of AC load, the 560k is also in series with 100k and then 500kA||1M. So the 560k is part of an AC voltage divider which is attenuating the signal from V1a in that regard. The .0022uF is a coupling cap.

In the other schematic, the .002uF coping cap comes straight off the plate and the 500kA pot is the variable voltage divider which is bypassed by a 100pF bright cap that only works when the pot isn't at full CW rotation.
He who dies with the most tubes... wins
sonofmickel
Posts: 162
Joined: Sun Jan 13, 2008 4:56 pm

Re: treble peak>coupling cap or coupling cap>treble peak??

Post by sonofmickel »

Thanks tubeswell,
But what happens to the signal physically? Does using a coupling cap before a treble peaking circuit offer protection to the user? Does it provide a less-bass to the treble peaker than a treble peaker feeding a coupling cap? What signal actually has less bass being fed to the 500k volume pot? Is it just additive inverse, same either way? Does one pass less signal?
sonofmickel
Posts: 162
Joined: Sun Jan 13, 2008 4:56 pm

Re: treble peak>coupling cap or coupling cap>treble peak??

Post by sonofmickel »

OK, first test was to add in the 470p/470k treble peak after a .002 coupling cap from the second stage plate. = instant hot rod marshall, it lost most of the bottom chewieness and added too much treble to the signal. I might try a 250p/250k? Would the 250p/250k cut a little less lows and add just a little more zing? That will be my next test tomorrow, or maybe tonight.
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