Members Numb Sensitive Posted February 2, 2009 Members Share Posted February 2, 2009 Wrong. Link to comment Share on other sites More sharing options...
Members TheEsupremacy Posted February 2, 2009 Members Share Posted February 2, 2009 When properly implimented into the tone they are win. But some just make the amp sounds fizzy/buzzy/overly bright/crappy. Link to comment Share on other sites More sharing options...
Members Numb Sensitive Posted February 2, 2009 Author Members Share Posted February 2, 2009 When properly implimented into the tone they are win. But some just make the amp sounds fizzy/buzzy/overly bright/crappy. If the presence makes it buzzy you can just turn it to zero...?? usually that buzz/fizz fades once the volume is turned up to band levels anyways. It's nice to have it though, cause it really helps. Link to comment Share on other sites More sharing options...
Members Dropsix Posted February 2, 2009 Members Share Posted February 2, 2009 It depends on speakers aswell in my experience. Trimap with V30s with presence controlling highs = Trimap with GBs with presence controlling highs = I think it's moar wrong to not have individual presence controls tbh. Link to comment Share on other sites More sharing options...
Members TheEsupremacy Posted February 2, 2009 Members Share Posted February 2, 2009 If the presence makes it buzzy you can just turn it to zero...?? usually that buzz/fizz fades once the volume is turned up to band levels anyways.It's nice to have it though, cause it really helps. I'll agree. I have high frequencey hearing loss from years of Marshall stacks in my face so when I play, I always end up cranking the treble. Having a presense control helps me compensate. (No, I do NOT eq like that in public). Link to comment Share on other sites More sharing options...
Members Dropsix Posted February 2, 2009 Members Share Posted February 2, 2009 I'll agree. I have high frequencey hearing loss from years of Marshall stacks in my face so when I play, I always end up cranking the treble. Having a presense control helps me compensate. (No, I do NOT eq like that in public). lol I should hope not:cop: btw, I hereby dub you incapable of having teh toanes Link to comment Share on other sites More sharing options...
Members newholland Posted February 2, 2009 Members Share Posted February 2, 2009 i think you guys might be mistaking what presence actually does most of the time-- it's a negative feedback loop that feeds the output signal back to the input signal to cancel distortion.. turning it to zero fully engages it so that it has maximum effect-- turning it fully to 10 turns off the NFB.. i prefer the looser, more open feel of practically NO negative feedback because it 'rings' more the way i play.. it's not really a 'treble knob'-- although it has a similar effect... but i like to think of it as a 'global feel' knob--- and i'd rather turn the treble down than overdamp the amp with too LITTLE on the presence knob! Link to comment Share on other sites More sharing options...
Members Chrisjd Posted February 2, 2009 Members Share Posted February 2, 2009 i think you guys might be mistaking what presence actually does most of the time-- it's a negative feedback loop that feeds the output signal back to the input signal to cancel distortion.. turning it to zero fully engages it so that it has maximum effect-- turning it fully to 10 turns off the NFB.. i prefer the looser, more open feel of practically NO negative feedback because it 'rings' more the way i play..it's not really a 'treble knob'-- although it has a similar effect... but i like to think of it as a 'global feel' knob--- and i'd rather turn the treble down than overdamp the amp with too LITTLE on the presence knob! I don't really get it, but that's interesting. Link to comment Share on other sites More sharing options...
Members TheEsupremacy Posted February 2, 2009 Members Share Posted February 2, 2009 i think you guys might be mistaking what presence actually does most of the time-- it's a negative feedback loop that feeds the output signal back to the input signal to cancel distortion.. turning it to zero fully engages it so that it has maximum effect-- turning it fully to 10 turns off the NFB.. i prefer the looser, more open feel of practically NO negative feedback because it 'rings' more the way i play.. it's not really a 'treble knob'-- although it has a similar effect... but i like to think of it as a 'global feel' knob--- and i'd rather turn the treble down than overdamp the amp with too LITTLE on the presence knob! I cannot wrap my brain around this, but I'll give you credit for sounding very smart. Link to comment Share on other sites More sharing options...
Members JBecker Posted February 2, 2009 Members Share Posted February 2, 2009 Besides the fact that presence is not a treble knob, I have no problem playing amps that have a presence control and an amp that doesn't. Like newholland says, I adjust it for feel anyway. Link to comment Share on other sites More sharing options...
Members Johnny Z Posted February 2, 2009 Members Share Posted February 2, 2009 Lots of old Fender amps had them but later they changed to a Bright Switch, which I liked better. It's all in how you adjust the amp and guitars controls. Traded my Blues jr for a Pro jr. which only has 1 volume and 1 tone control and I think sounds better than the Blyes Jr. ever did. Link to comment Share on other sites More sharing options...
Members newholland Posted February 2, 2009 Members Share Posted February 2, 2009 it's a little abstracted.. but not really-- here's the wiki for it: Electronic amplifiers Main article: negative feedback amplifier The negative feedback amplifier was invented by Harold Stephen Black at Bell Laboratories in 1927. Fundamentally, all electronic devices (e.g. vacuum tubes, bipolar transistors, MOS transistors) exhibit some nonlinear behavior. Negative feedback corrects this by trading unused gain for higher linearity (lower distortion). An amplifier with too large of an open-loop gain, possibly in a specific frequency range, will additionally produce too large of a feedback signal in that same range. This feedback signal, when subtracted from the original input, will act to reduce the original input, also by "too large" an amount. This "too small" input will be amplified again by the "too large" open-loop gain, creating a signal that is "just right". The net result is a flattening of the amplifier's gain over all frequencies (desensitising). Thus, though much more accurate, amplifiers with negative feedback can become unstable if not designed correctly, causing them to oscillate. Harry Nyquist of Bell Laboratories managed to work out a theory regarding how to make it stable. Negative feedback is used in this way in many types of amplification systems to stabilize and improve their operating characteristics (see e.g., operational amplifiers). basically-- the presence OFF is as much squash on the circuit as it can pull, with it all the way on, it's totally let loose of negative feedback (or as little as the circuit will allow). i always find that i like presence higher because it doesn't feel like anythings 'gripping' the amplifier. the presence way down always feels too compressed and buttoned up... Link to comment Share on other sites More sharing options...
Members nakedzen Posted February 2, 2009 Members Share Posted February 2, 2009 I cannot wrap my brain around this, but I'll give you credit for sounding very smart. Negative feedback by wiki: Edit lol, slow. Fundamentally, all electronic devices (e.g. vacuum tubes, bipolar transistors, MOS transistors) exhibit some nonlinear behavior. Negative feedback corrects this by trading unused gain for higher linearity (lower distortion). An amplifier with too large of an open-loop gain, possibly in a specific frequency range, will additionally produce too large of a feedback signal in that same range. This feedback signal, when subtracted from the original input, will act to reduce the original input, also by "too large" an amount. This "too small" input will be amplified again by the "too large" open-loop gain, creating a signal that is "just right". The net result is a flattening of the amplifier's gain over all frequencies (desensitising). Thus, though much more accurate, amplifiers with negative feedback can become unstable if not designed correctly, causing them to oscillate. Presence control, http://www.freepatentsonline.com/7412064.html: Presence controls for vacuum tube guitar amplifiers are well known and have been in use for many decades. Unlike preamplifier tone controls, the traditional presence control operates in the negative feedback loop of the power amplifier and phase splitter circuitry. Typically, the presence control allows player adjustment of a higher frequency range than a typical treble tone control and operates by attenuating to ground a portion of the negative feedback spectrum. Using a variable resistor as the control element, whatever portion of the negative feedback signal is deleted results in a corresponding increase in circuit gain and audible Link to comment Share on other sites More sharing options...
Members draelyc Posted February 2, 2009 Members Share Posted February 2, 2009 All I know is, if my Koch is wrong, I don't wanna be right. Link to comment Share on other sites More sharing options...
Members Chezdon Posted February 2, 2009 Members Share Posted February 2, 2009 Just seems to do the same thing as treble to me. Don't really see the need for both. Maybe I'm a noob. Link to comment Share on other sites More sharing options...
Members JBecker Posted February 2, 2009 Members Share Posted February 2, 2009 basically-- the presence OFF is as much squash on the circuit as it can pull, with it all the way on, it's totally let loose of negative feedback (or as little as the circuit will allow). i always find that i like presence higher because it doesn't feel like anythings 'gripping' the amplifier. the presence way down always feels too compressed and buttoned up... Yup. Link to comment Share on other sites More sharing options...
Members Uncle_Milton Posted February 2, 2009 Members Share Posted February 2, 2009 and i'd rather turn the treble down than overdamp the amp with too LITTLE on the presence knob! this is what I do with almost every amp. I have my treble at between 0 and 3 and use the presence as a global "livening" or "anti-dark" sounding knob. I only take the treble up if I need a little more cut. then again. A presence, like any knob, is only useful if you need it. If it sounds good without it, why put it on there? Link to comment Share on other sites More sharing options...
Members Casey4s Posted February 2, 2009 Members Share Posted February 2, 2009 There are so called Presence controls on various amps and some of them are not true presence controls, they are whatever tone enhancement the amp maker decided he wanted to call presence. Leo Fender first introduced the guitar amp "Presence Control" in 1954. First you need to understand how the negative feedback loop works on a guitar amp. This was initially a Hi-Fi thing to reduce distortion and stabilize frequency response. It takes a small portion of the amplified signal going to the speaker and sends it back into the amp before the power tube(s). As the amp gets louder, this negative feedback tends to cancel out any distortion, unevenness in frequency response (like Peaks), or noise created by the amplifier. The FENDER "Presence Control" acts on the negative feedback loop by passing progressively more of the hi-frequency portion to ground, leaving lows and mids to control how the feedback loop affects the rest of the circuit. As the amp is pushed, the highs start to break up; normally, the feedback loop would act to control this, but instead, it's as if there is no feedback on the highs. The intensity of this effect changes with volume. The exception to this is the (CBS) Super Twin where the presence control is merely an active tone boost at 3.9KHz. There are probably some more of the newer Fenders that fall into this group as well. Link to comment Share on other sites More sharing options...
Members draelyc Posted February 3, 2009 Members Share Posted February 3, 2009 You know there was a thread a while back in which it seemed everybody was sayin' how presence controls suck & are useless & orta be set to zero, &c. Now, I'd posted some clips before that which some folks had said were too "fizzy," so in the spirit of experimentation, I tried putting my presence knob on zero and got what I thought were decent enough results... But after reading this thread, I tried cranking that bad boy back up & dialing down the treble knob -- sounds like a whole new amp, almost. I'll have to try it at full volume, but my first impression was that the amp had come back to life. Link to comment Share on other sites More sharing options...
Members GuitarHitman Posted February 3, 2009 Members Share Posted February 3, 2009 An amp with a presence control just feels a bit eerie and haunted to me Link to comment Share on other sites More sharing options...
Members chad_sux Posted February 3, 2009 Members Share Posted February 3, 2009 I have been anti-presence for some time. It always seemed to me (in my tube amps at least) that it was just adding fizz and sizzle and harshness no matter what I did. I did some recording's last week with my uber and framus 2x12 cab. I found that no matter what I did, I just couldn't get it to sound in your face. I had the presence on zero. The mids cranked to 3 o'clock the bass at noon and the treble at around 1. I played with the low mids and highs but never could get it to sound right on tape. Then, last saturday, I decided to think outside the box for once (meaning outside the box for me). I was getting set up at band practice, and I just {censored}ing stuck everything at noon. Flipped the amp on...and OMG, what a difference. I had heard about this before with the uber, but the treble and presence really need to work together to tame the fizzyness. Now, I think I have a SOLID foundation for some serious toanz!!!! Link to comment Share on other sites More sharing options...
Members C-4 Posted February 3, 2009 Members Share Posted February 3, 2009 Actually, it depends on the amp's design. Some amps do not need a presence control, while others do. It's only wrong if the amp has no presence control, but actually would have a sonic improvement by having one. there are ways around that, however. Add an EQ to the signal path and just boost the upper frequencies. Amps don't reproduce frequencies above 6K most of the time as the speakers are not normally designed to do it. Link to comment Share on other sites More sharing options...
Members draelyc Posted February 3, 2009 Members Share Posted February 3, 2009 An amp with a presence control just feels a bit eerie and haunted to me Sure you're not thinkin' about the midz... :poke: Link to comment Share on other sites More sharing options...
Members Carcinogen Posted February 3, 2009 Members Share Posted February 3, 2009 this is what I do with almost every amp.I have my treble at between 0 and 3 and use the presence as a global "livening" or "anti-dark" sounding knob. I only take the treble up if I need a little more cut. then again. A presence, like any knob, is only useful if you need it. If it sounds good without it, why put it on there? Yeah, that sounds about right. I typically keep my treble around 4 or 5 and the presence on six or seven. Then again, I put the mids on 8, the bass on 4, and then boost the upper mids on the graphic EQ... I like brightness. Link to comment Share on other sites More sharing options...
Members Nemesys Posted February 3, 2009 Members Share Posted February 3, 2009 i think you guys might be mistaking what presence actually does most of the time-- it's a negative feedback loop that feeds the output signal back to the input signal to cancel distortion.. turning it to zero fully engages it so that it has maximum effect-- turning it fully to 10 turns off the NFB.. i prefer the looser, more open feel of practically NO negative feedback because it 'rings' more the way i play..it's not really a 'treble knob'-- although it has a similar effect... but i like to think of it as a 'global feel' knob--- and i'd rather turn the treble down than overdamp the amp with too LITTLE on the presence knob! You're describing a tweed-style presence control, which doesn't really impact the treble frequencies. The more common type is just a tone control which affects the very high frequencies. It does the same thing to the circuit that a "Bright" switch does, but the amount of brightness is dial-able. Link to comment Share on other sites More sharing options...
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