What is the "presence" control on amps

[Mr Wolf]

My Laney, like many other amps has a "presence" control on it. What does it do??? I can tell it effects the highs etc and turning it up give a more biting sound, sometimes too harsh if over done etc but what is actually going on inside that box? If anyone could enlighten me on this mysterious control that would be awesome.

Jeff

 

[DeadSkinSlayer3]

Re: What is the "presence" control on amps

It's basically like a super high end control. I imagine it as a 12Khz + knob.

 

[Pierre]

Re: What is the "presence" control on amps

It's basically a filter placed on the negative feedback loop that increases super high frequencies, as DDS3 said.

To me, it feels as if presence increases more the overall brightness than a particular frequency, if you see what I mean. Kinda like having a tone knob on top of your EQ.

 

[Erlend_G]

Re: What is the "presence" control on amps

I've always thought of the presence control as a part of the EQ, that boosts\cuts the high mid\low treble piercing sound.

I might be wrong though

 

[Erlend_G]

Re: What is the "presence" control on amps

It's basically like a super high end control. I imagine it as a 12Khz + knob.

Err... guitar speakers doesn't normally go any higher than 5khz .

And freqs over 10khz is just...well... "air" anyway.

 

[jdm61]

Re: What is the "presence" control on amps

Yes Erlend, but "air" matters:fingersx: Overtones, extreme HF harmonics, etc. My take on this knob is that it is the knob that meakes your ears bleed when playing Fender guitars:laugh2:

 

[Skarekrough]

Re: What is the "presence" control on amps

Err... guitar speakers doesn't normally go any higher than 5khz .

And freqs over 10khz is just...well... "air" anyway.

Yes...and how many bass amps do you feel as much as you hear?

 

[Metalman_666]

Re: What is the "presence" control on amps

The way I see it, the presence control is really helpful for adjusting the overall brightness of your amp to match a room. For example in your bedroom, turning the presence up to 7 might be just fine, but then in a hall it might be too bright and piercing so you turn it down to 4.

I agree with jdm61 about the presence controlling the upper harmonics and overtones; turning it up definitely increases those frequencies, but too much makes the amp really harsh in my experience.

 

[Boogie Bill]

Re: What is the "presence" control on amps

In many amps, a Presence control works by filtering the negative feeback loop (as someone else stated). It can have a tremendous impact on the way the amp "feels", as well as affecting the ultra treble range. (Treble is considered frequencies above 2,000 cycles--Presence is the range from about 4,000 to 10,000 cycles.)

However, in some other amps, the Presence control is merely a second HF tone circuit, like the Treble control, and might not affect the Negative Feedback Loop. High will still be enhanced with higher settings of the knob, but the overall "feel" of the amp probably won't change as much with this type of circuit.

Confused?

I could explain how "Brite" switches don't add brightness, but merely take away Bass....

...but I think I've done enough damage here for one day! LOL!

Good luck!

Bill

 

[Zerberus]

Re: What is the "presence" control on amps

When I think "presence" i think: High mids / JB´s nasal spike...

Presence is what you need to cut through in a band setting, but is definitely seated "below" the treble knob as far as frequency range goes..... more in the 1.2k-3k range than anything else in my experience....

 

[Marcel]

Re: What is the "presence" control on amps

Err... guitar speakers doesn't normally go any higher than 5khz .

And freqs over 10khz is just...well... "air" anyway.

Guitar speaker cut off frequency higher than 5kHz but that doesn't mean they do not go higher ...
The higher frequencies are just quieter!

*edit* pictures are easier than words: http://professional.celestion.com/guitar/products/classic/detail.asp?ID=4

I always thought the Presence act where the speakers cut off on the high end like resonance acts where speakers cut off at the low end?!? So they are more for enhancing the frequency range then general EQing?!

 

[Baltar]

Re: What is the "presence" control on amps

the presence knob is sth wich is different implemented every brand.
at g/k is like a tone knob, but affecting 3 different frequencies at the same
time. the frequencies are selected just by taste of the sound engineers i
guess. this one was acutally i did like on my ex-laney top

 

[Lewguitar]

Re: What is the "presence" control on amps

In many amps, a Presence control works by filtering the negative feeback loop (as someone else stated). It can have a tremendous impact on the way the amp "feels", as well as affecting the ultra treble range. (Treble is considered frequencies above 2,000 cycles--Presence is the range from about 4,000 to 10,000 cycles.)

However, in some other amps, the Presence control is merely a second HF tone circuit, like the Treble control, and might not affect the Negative Feedback Loop. High will still be enhanced with higher settings of the knob, but the overall "feel" of the amp probably won't change as much with this type of circuit.

Confused?

I could explain how "Brite" switches don't add brightness, but merely take away Bass....

...but I think I've done enough damage here for one day! LOL!

Good luck!

Bill

Bright switches allow highs to bypass the volume control and leap around it so regardless of what the volume is set at, your highs are on "10" when the bright switch is engaged.

Bright switches do not take a way bass.

Negative Feedback is a signal taken from the audio signal within the amp, usually at the speaker jack on a Fender, and reintroduced into the audio signal but out of phase. It chokes the signal and reduces distortion and gives you a cleaner tighter tone.

A Prescence control is connected to a capacitor that goes to ground, and, when it's turned up, sends the highs of the out of phase signal that is part of the negative feedback circuit to ground...so those out of phase highs cannot choke the in phase highs and the result is the amp sounds brighter and the highs sound looser.

That's a kind of simple, non technical explanation but it's what happens.


Lew

 

[Mr Wolf]

Re: What is the "presence" control on amps

Wow thanks guys the responses are perfect. I knew it was more than a simple EQ contolling knob. Cheers guys as always most helpful

Jeff

 

[greendy123]

Re: What is the "presence" control on amps

To my ears the presence seems to make my tone tighter also to the other changes.

 

[Simon_F]

Re: What is the "presence" control on amps

Which maker was the first to implement Presence? Fender? Marshall? ....

 

[shredaholic]

Re: What is the "presence" control on amps

I would think Fender before Marshall - since the JTM45 copied the Fender Bassman, which must include it's NFB loop and presence circuit.

On a related note, anyone noticed that the presence control seems ineffective when using a PPIMV? That's because the lower the PPIMV is turned down, the less the NFB loop is working. By reading the above posts, you should be able to thus figure out why a reduced NFB loop would render the presence control less operable.

 

[ES350]

Re: What is the "presence" control on amps

global NFB networks were added to Western Electric circuits starting in the early-mid 50's,borrowed from communications technology. They start showing up in Fenders around 1953-1954 ('C' models). The 5D8 Twin and the 5E6A Bassman were some of the first amps to have a presence control.

 

[egicar]

Re: What is the "presence" control on amps

Bright switches allow highs to bypass the volume control and leap around it so regardless of what the volume is set at, your highs are on "10" when the bright switch is engaged.

Bright switches do not take a way bass.

Negative Feedback is a signal taken from the audio signal within the amp, usually at the speaker jack on a Fender, and reintroduced into the audio signal but out of phase. It chokes the signal and reduces distortion and gives you a cleaner tighter tone.

A Prescence control is connected to a capacitor that goes to ground, and, when it's turned up, sends the highs of the out of phase signal that is part of the negative feedback circuit to ground...so those out of phase highs cannot choke the in phase highs and the result is the amp sounds brighter and the highs sound looser.

That's a kind of simple, non technical explanation but it's what happens.


Lew

Perfect explanation!!!