Plate driven tone stack

[Sonofmickel]

"Plate driven tone stack as compared to the traditional Marshall style cathode follower makes the tone controls very active." The Reinhar** amplifiers are using this type of tone stack as apposed to a cathode follower design. Are there plus minus for this design or is the 36 TMB RP just fine? I would just like to know a few opinions as I am about to pull the trigger on the Ceriatone 36w TMB RP.

Thanks and what a great site!

[zaphod_phil]

"Plate driven tone stack as compared to the traditional Marshall style cathode follower makes the tone controls very active."

I've used both kinds, and I don't see much basis in reality behind that statement. I hope I don't offend anyone by saying, that sounds like marketing BS to me.

[Mooreamps]

Maybe "active" was not the right word he was looking for. I've seen a couple prints with the tone components inserted into their own feedback loops inside the gain stage that would make the control a little more "active". I've not tried any of these myself. But, I am going to try a cathode driven stack mostly because I took the Banaxdell circuit and split it in half and it was my understanding that type of circuit works better cathode driven.

-g

[rjgtr]

I have used both and while they do respond a little differently I find the values of the parts makes a far bigger difference in how the controls react than whether a stack is cathode or annode driven. The biggest difference is the slope resistor followed by the caps.

I do find that to my ears the cathode driven stack has a nicer curve in the lower mids, generally. The plate driven stack is a little brighter, given the same components.

At the end of the day I don't sweat it too much. Using Duncan Amp's wonderful Tone Stack Calculator you can get one close to the other with the right parts.

[zaphod_phil]

. The plate driven stack is a little brighter, given the same components.

Are you 100% sure about that? From when I was last experimenting with tone stacks, IIRC the higher frequency output increased when a typical Marshall TMB stack was cathode-driven. Duncan's TSC shows the same.

[rjgtr]

. The plate driven stack is a little brighter, given the same components.

Are you 100% sure about that? From when I was last experimenting with tone stacks, IIRC the higher frequency output increased when a typical Marshall TMB stack was cathode-driven. Duncan's TSC shows the same.

I'm not 100% sure of anything!

But there's something more full sounding to my ears in a cathode driven tone stack to my ears. Hmm...

I was curious, so I fired up Duncan and set the Fender stack to the same component values as the Marshall, except for the inital load (and yes I know it is really the Fender Tweed stack, but Duncan calls it Marshall). And darn if you aren't right - the bass ratio is greater in the Fender style stack.

But I also noticed a few things. First the bass peak is somewhere around 50hz and is just slightly less DB than the Marshall stack. The Mids and Highs are 6-8db lower on the Fender.

Maybe I'm not hearing so much more high end as a fuller sound due to the Cathode (Marshall) stack driving the tone stack better. The Fender stack is probably not pushing the next stage as hard. With the bass on the Cathode stack centered at 100hz it's actually more in the guitar range and the higher midrange, the highs are more balanced.

Funny how our perceptions are different!