Marshall tone stack w/o cathode follower?
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Marshall tone stack w/o cathode follower?
What are the ramifications of using a standard Marshall tone stack without running it after a cathode follower? I'd like to skip the follower and just use a ax7 gain stage prior, but am wondering if that would impact compoenent selection? thanks!
Re: Marshall tone stack w/o cathode follower?
I think that is basically what Splawn does: a 2203 with the CF converted into a 4th gain stage. 80's hair metal tone, if you're into that kind of thing.
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Andy Le Blanc
- Posts: 2582
- Joined: Sat Dec 22, 2007 1:16 am
- Location: central Maine
Re: Marshall tone stack w/o cathode follower?
you can sub a srpp for the follower too.... theres a couple of other
gain stage configurations that utilize two gain stages....
the big differences are how differnt circuits behave when viewed
as an impeadance matching device.......
gain stage configurations that utilize two gain stages....
the big differences are how differnt circuits behave when viewed
as an impeadance matching device.......
lazymaryamps
Re: Marshall tone stack w/o cathode follower?
Take care about the fact that a marshall EQ w/o a CF reacts differently.
You have less mids and highs (or more mid-lows if you prefer). You can see this changing Zsrc to 68k on Duncan simulator. It sound more like an Engl. It should be better to raise the slope and maybe lower the treble cap (33k kills dynamics). Maybe you can try a mosfet CF to make the EQ sounds "right".
You have less mids and highs (or more mid-lows if you prefer). You can see this changing Zsrc to 68k on Duncan simulator. It sound more like an Engl. It should be better to raise the slope and maybe lower the treble cap (33k kills dynamics). Maybe you can try a mosfet CF to make the EQ sounds "right".
Re: Marshall tone stack w/o cathode follower?
EDIT:
Double post. See differencies in attached file.
Double post. See differencies in attached file.
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Re: Marshall tone stack w/o cathode follower?
The 68K isnt correct it is more like 35K~40k off the plate with a 100K plate resistor and a 12AX7 depending on bypass cathode and some other variables.
But it is the same idea as this graph above just not as extreme
Most people feel Plate driven EQ is sweeter. On other advantage is there isnt the cathode to heater max voltage to worry about. Most people exceed the 180 V spec, shortens tube life
If you leave the slope resistor and everything the same the primary difference will be about a 4~6db loss off everything over 100 hz. This might be fine depending on the circuit. Use your ears, Cathode followers have more snap to them.
Dont forget that the source impedance of the EQ section will be higher so if you are feeding a master volume you might need to isolate the Master with a series resistor or it will load down the tone stack, this will also add to the signal loss through this section.
But it is the same idea as this graph above just not as extreme
Most people feel Plate driven EQ is sweeter. On other advantage is there isnt the cathode to heater max voltage to worry about. Most people exceed the 180 V spec, shortens tube life
If you leave the slope resistor and everything the same the primary difference will be about a 4~6db loss off everything over 100 hz. This might be fine depending on the circuit. Use your ears, Cathode followers have more snap to them.
Dont forget that the source impedance of the EQ section will be higher so if you are feeding a master volume you might need to isolate the Master with a series resistor or it will load down the tone stack, this will also add to the signal loss through this section.