Post MV R/C pairs

[greiswig]

Hi,

The stock D'Lite has nothing between the MV and the input of the PI. But I notice a lot of other versions of the Dumble amps have something...often a 100k resistor with a 47pF cap across it in series. What is this for?

[Structo]

Of course the 15 pf is a bright cap for the master.
The only time I have seen the 100k is on the pre out on the loop.

[heisthl]

Hi,

The stock D'Lite has nothing between the MV and the input of the PI. But I notice a lot of other versions of the Dumble amps have something...often a 100k resistor with a 47pF cap across it in series. What is this for?

Thats a high pass R/C filter. Fun to play with changing the R and the C to shape things. A good example of this filter is where HAD uses a 220k/500pf (or 220k/330pf on some schematics) to feed V1B, something that you never see in Fenders, but is essential to the Dumble tone.

[RJ Guitars]

George, have you tried this? I'm always up for a new tweak and was curious if this is something I need to do?

rj

[LooseChange]

Thats a high pass R/C filter. Fun to play with changing the R and the C to shape things. A good example of this filter is where HAD uses a 220k/500pf (or 220k/330pf on some schematics) to feed V1B, something that you never see in Fenders, but is essential to the Dumble tone.

Although very popular in Marshalls (470k/470p)!

[novosibir]

Although very popular in Marshalls (470k/470p)!

That's not the same!

In Marshall's the 470K/470p is part of a (frequency dependent) voltage divider, in Dumble's the 220K/330p is a bypassed swamp resistor, to avoid the enhanced, by the swamp resistor caused high loss due to the tube's Miller capacity.

Larry