"Contour" control

[greiswig]

Hi, all,

Larry and a couple of others had chimed in on the TR contour control. It kind of piqued my curiosity, since I don't find a lot of use for the presence control and I tend to leave it at a fairly low setting.

I looked at some Vox schematics, since that was what Larry described as being the gist of the contour circuit. I put together the relevant section of a D'Lite schematic with what I understand to be a contour control. I'm putting it up here to get critique/input from people who actually know what they're doing. I'll revise the diagram as needed and keep it current here if that would be helpful.

My idea would be to replace the presence control on the front panel with this. The presence could either be an internal trimmer or permanently dimed.

[novosibir]

Yes, the schem concerning the Contour is correct and is, what I've said.
In the Two Rock the 'usual Presence' is permanently dimed internal, the 390 ohms bypassed with the 1µF cap.

Larry

[keithrick]

Not trying to hijack the thread but instead of the Hi-Cut, do you think a resonance control similiar to TUT's or Soldano's would work in the Dumble style circuit? Something to tame the bass. I have that on my list of things to try.

[Funkalicousgroove]

How does Komet do it? don't those have both the presence control and the high cut?

[Funkalicousgroove]

Not trying to hijack the thread but instead of the Hi-Cut, do you think a resonance control similiar to TUT's or Soldano's would work in the Dumble style circuit? Something to tame the bass. I have that on my list of things to try.

I think that would work just fine, with the Bluesmaster PI it should plug right in, with the regular PI you'd have to scale it-

[tubedogsmith]

How does Komet do it? don't those have both the presence control and the high cut?

Yes. The cut control all the way attenuated and the presence cranked is a weird compressed tone. It seems odd 2rock would have liked the sound of this setup. The cut control is a very primative type of tone control.

[greiswig]

How does Komet do it? don't those have both the presence control and the high cut?

Yes. The cut control all the way attenuated and the presence cranked is a weird compressed tone. It seems odd 2rock would have liked the sound of this setup. The cut control is a very primative type of tone control.

I don't know; I've never used one. I guess you could say that vacuum tubes are a pretty primitive form of amplification, though.

I just was curious about it because I just don't find much use for the presence control as-is. When I read something like this (from the Two Rock site):
"At the twelve o'clock position, the amp's frequency response is flat. Rotating the knob counter-clockwise, will decrease the highs and increase the lows, and vice-versa for clockwise movement. This is ideal for switching between single coils and humbuckers without touching other controls or compensating for different speaker cabinets."

..it makes me wonder whether this might be a more useful control for a guy like me. Easy enough to try out on a temporary basis, at least.

[tubedogsmith]

Well, the cut control is a good way to take the edge off a too bright amp. 2 Rock designed the amp to be too bright with the presence all the way up and then put in a cut control to take the edge off, an edge that didn't need to be there in the first place, or so it would seem. Anyway, that was my reason for calling it "primative". It's kinda like we've tried everything so let's think of something we haven't tried and throw it in there, voila, a new design. Hey, not knocking them just scratching my head over this one.

[keithrick]

Tubedog,

That is why I was curious if the presence and resonance might be a more elegant way to go. For example, the cut control on my Rocket is fine but it can get dark really quick!

It would seem that on the Dumble style amp where there is a fizz just at the top of the note you want to get rid of that the cut control would be like using a saw to cut a slice of bread.

[greiswig]

Well, the cut control is a good way to take the edge off a too bright amp. 2 Rock designed the amp to be too bright with the presence all the way up and then put in a cut control to take the edge off, an edge that didn't need to be there in the first place, or so it would seem. Anyway, that was my reason for calling it "primative". It's kinda like we've tried everything so let's think of something we haven't tried and throw it in there, voila, a new design. Hey, not knocking them just scratching my head over this one.

I hear ya. Sorry if I came off too sarcastic.

I could guess one way in which they are different: to me, the presence changes not only the tone, but how "hard" the amp hits when you pick a string. So in that regard it is different from boosting the treble, for example. If the contour control lets you change the tone similarly without changing that response, maybe it is useful. Like I said, it's easy enough to try out, so I think I shall.

[novosibir]

For example, the cut control on my Rocket is fine but it can get dark really quick!

I've also noticed, that a .0047 cap makes an amp unuseful dark with the control on zero, hence I'd recommend a .0022 cap in seies to the pot.

Larry

[Funkalicousgroove]

Has anyone considered a Brown deluxe style tone control on the Overdrive?

[briane]

yeah, I've tried the cut control, aka ac15 - 250kb & .0047.

sounds great on a vox. Not my favorite in a dumble, that may just be me. In general I find the dumble to be a somewhat dark amp, especially when compared with an amp with an ef86 front end. You dont notice the darness so much unless you have a shootout with an ac15 or comparable.

[keithrick]

Funk,

Which schematic is the "Brown" Deluxe? I think the "treble bleed," circuit used in many clones is similiar to what you describe. (.001 w/ 250K-1Meg pot to ground.) On a non-hrm amp would that not pretty close?

Please enlighten me (us) if you are referring to another idea.

FWIW- Larry has piqued my interest in the smaller cap in the Hi-cut function as well as an article in Premier guitar where they allude to using smaller caps in guitars to extend the useful range of the tone pots. When I am tuning my personal amps and guitars I find that I am constantly trying to find the balance between trimming the perfect amount of high end without the tone turning to mud.

As an aside I installed a modified high cut in my Express build to fill a hole in my front panel from my modding excursions. If I can recall correctly it is (180K resistor and a .005 cap) What I found was that engaged it is pretty dramatic which prompted my earlier allusions to the hi-cut being a little overboard in an area I want to be as conservative as possible.

It is alot to wrap you head around because there are a few places in the amp where treble bleed can have a dramatic either positive or negative effect on tone.

[ampexplorer]

I think 6G3 is the brown Deluxe. Tone and volume the reverse of the tweed 5E3. could be cool if you just used it for overdrive. If my 5E3 is similar there is not much headroom