Slope resistor and effects send level?

[VacuumVoodoo]

Here's a typical 2 stage cascade. One has RC constants designed to give a 12db/octave high pass response. The other illustrates a more common1st cathode decoupling with a 0.68uF capacitor.
Not how the 12db/octva filter response retain low mid while at the same time providing more attenuation below 100Hz compared to the 0.68uF response.
Volume pots are 500k at max.

[67Mopar]

I tried a 1uf bypass cap at V1b, but it seemed to mess with the gain, so I put it back to stock.

Question:
Reeltarded mentioned that the boost acts as a band-pass, so is there a way to recreate the same effect using the amp circuitry itself?

A switchable mod would be great, but I refuse to drill any holes into the chassis so I'm looking for a fixed mod. I know I've changed the stock components, but I haven't made any 'hard' mods that cannot be reversed. Like I said, if I were to run it completely stock with say a TS9, it sounds perfect! I guess logic dictates that if it sounds 'perfect' with a boost - just you a boost...

[67Mopar]

One more thing; nice to have you here. Thanks for hanging.

Thanks!

[67Mopar]

Here's a typical 2 stage cascade. One has RC constants designed to give a 12db/octave high pass response. The other illustrates a more common1st cathode decoupling with a 0.68uF capacitor.
Not how the 12db/octva filter response retain low mid while at the same time providing more attenuation below 100Hz compared to the 0.68uF response.
Volume pots are 500k at max.

Here's an accurate schematic:
https://tubeamparchive.com/files/rk100_ ... v1_181.pdf

What do you think?

[VacuumVoodoo]

A switchable mod would be great, but I refuse to drill any holes into the chassis so I'm looking for a fixed mod..

Looking at the schematic: install a 4.7nF capacitor in series with C6 and then a switch with which to short circuit it when you want to defeat this mod. Or just replace C6 with the 4n7 cap and leave out the switch. This will give the low end attenuation below 140hz as in my circuit, but using V1.A & V3.B. You can try bypasing R11 with a 2u2 to 10u for more grit.

[67Mopar]

A switchable mod would be great, but I refuse to drill any holes into the chassis so I'm looking for a fixed mod..

Looking at the schematic: install a 4.7nF capacitor in series with C6 and then a switch with which to short circuit it when you want to defeat this mod. Or just replace C6 with the 4n7 cap and leave out the switch. This will give the low end attenuation below 140hz as in my circuit, but using V1.A & V3.B. You can try bypasing R11 with a 2u2 to 10u for more grit.

Genius! I would never have thought to do this. You would think I would have since I had already lowered C8 from 33nf > 22nf... This is a nice progression... 2.2nf > 4.7nf > 22nf. I have a 12000pf, but not a 4700pf.

[VacuumVoodoo]

You'll need 4700pF, not 47000pF

[67Mopar]

Doh! Typo...

Here's something I was pondering last night... Does the actual size of the filter caps matter? I see that the F&T filter caps are 1/2 as tall as my ARS caps. Does it take longer to 'fill' a tall cap vs a short cap? I know they're both the same value, but would the actual size make a difference in response/feel?

[dorrisant]

Value matters... Not physical size.
It is what you write... Not how big the pencil is.

Wait!

Are we talking about caps?

Tony

[67Mopar]

Okay, I tried the 4700pf but it didn't seem to make much of a difference. I decided to test the PI and output section by running a Soldano SP-77 preamp into the effects return, and sure-enough the excessive low-end was still there! I decided to remove the stock 10k resistor from the send jack and replaced it with an 8.2k resistor... Problem solved!