Tone cap to counter deluxe reverb bright cap

[Shuggie]

First post here, sorry if in wrong forum. This will make history
It has come to my attention that many players are reluctant to clip/remove bright caps on deluxe reverbs due to safety matters, time constraints, keeping vintage amps original, afraid of either extremes etc.

I like messing around with the tone caps on my guitar yet seldom find the right value to cut bright frequencies whilst keeping and "open" sound.

What if we calculated the value of a GUITAR tone cap to directly compensate for the bright cap frequencies in the AMPLIFIER? This way we could leave the bright cap in (maybe even out ) and use guitar tone pot to work around it.

Or if you had no reason not to remove the bright cap from your amp, you could remove it, and roll up the tone on your guitar to achieve the original sound; all it takes is the roll of a knob to take you between "clipped" and original "unclipped" sound, but better because you have a whole range of in-between sounds.

Or you could leave the bright cap in and roll down your town knob, where at 0 the amp sounds like the bright cap is clipped. (useful because the effect of the bright cap varies at different amp volumes, you could use the guitar tone knob to compensate)

I know a little about tone caps and eq filter types, and that the ohm value and the capacitor value together equate to certain frequencies. But I'm not sure how this match of frequency could be achieved. Could it be as simple as swapping the bright cap in the amp with the tone cap in your guitar kinda thing? Or would you need to use an equation to calculate the frequencies being boosted/attenuated by the bright cap at that value and ohm load, to figure out the tone cap value in the guitar needed to boost/attenuate the same frequencies?

If I am wrong and the effect of bright cap and tone cap are different eq effects, (say the bright cap is a filter at 4kHz, and one in the guitar is a parametric notch, for example), can we please add a resistor or something to the standard guitar tone system to work as a filter too, so that they are compatible?

Because its the 21st century and I hate my tone knob but love my deluxe reverb so damn much.

 

[Telenator]

I had a 77 Deluxe reverb that sounded a bit harsh with single coil pickups, but was magic with humbuckers.

I pulled the amp apart and snipped one leg of the tone cap on the DR's volume pot.
I ran two wires to the back of the amp, cut a small hole in the chassis, and installed a small switch.
I put one wire to each side of the switch so I could engage or disengage the tone cap simple by flicking the switch on the back of the amp.

It worked great!

 

[Shuggie]

Thanks, I suppose I could cut a tiny tiny hole for a switch, but how great would it be to control it from the guitar? Maybe Ill try clipping the bright cap in one channel, and experiment with extremely small tone cap values and until it sounds the same as the other channel with guitar tone knob on 0

Say, does anybody know of the softwares that draw a frequency response curve? Or measure them, like guys who master records use? That would be useful in my quest.

 

[KokoTele]

Wouldn't be simpler to just use your tone knob to control this? What will you do if you plug in to an amp that's not as bright?

Is there a bright cap on a DR that's not connected to the bright switch?

 

[Telenator]

Is there a bright cap on a DR that's not connected to the bright switch?

Yes. It's on the volume pot. Putting the little micro switch on the back of my DR made an incredible difference. Just what it needed.

 

[Shuggie]

yeah there is koko, a bright cap that can't be switched unless modded to do so, and the frequency it effects is not in the range of the amps treble tone control either, its very piercing,
also I've owned several amps, some too bright some not, but even when i tried to use my guitar tone knob, it sounded awful with stock wiring and caps unless all controls were on 10 on my guitar.

 

[Shuggie]

also please specify what tone knob you referring to? amps or guitar's?

 

[waparker4]

Try some very small tone caps like .0022, .0047, .01

Or just clip the bright cap, everybody's doing it ..

 

[KokoTele]

also please specify what tone knob you referring to? amps or guitar's?

The guitar's tone knob. (The amp has a treble and bass control, but not a tone knob

Regardless, the passive tone control on the guitar is already doing what you're trying to do. By turning that tone knob, you're selecting a cut-off frequency, and everything above that frequency is reduced by about half.

I just looked at the schematic for the DRI, and that cap on the volume pot is simply letting some of those ultra-high frequencies bypass the volume pot, but then they're getting reduced at the amp's treble control.

You've already cut half of those ultra high frequencies with your guitar's tone control before they got to the amp. I suppose you could put another high frequency filter before your guitar's output, but you're not going to like the way that loads your signal.

Just clip that cap on the DR's volume pot.

 

[Shuggie]

Try some very small tone caps like .0022, .0047, .01

Or just clip the bright cap, everybody's doing it ..

Yes thanks mate, I will try the .0022 cap in my guitar and just use my ears from there.

And koko, thanks for your advice, I DO want to use my guitars tone knob to fix the brightness, but the value is wrong and it sounds horrid, actually makes my high e string quiter further up the neck! I don't understand why the "standard" tone cap values are so high. Might have been useful before the wah-wah pedal was invented