@dotneck335: After actually reading the project article, it was found to have a buffer for lower value resistors hence less noise (which I require), so if split, another buffer would need to be added--no way. Two boards it is. 4-Band is enough for guitar, I think. Essentially, it's to divide the Mid-range for more control.
I modded a Baxendall with a dual-gang so that when the Treble was turned up along with some Mids, the upper range of the Mids were boosted more, and sloped almost linearly down towards the Bass end using Db scale. I also wanted a Treble Booster so I built one but the noise was too loud and unwieldy, however it was a real quick build. With the extra bands of the P84 board, there should be a way to switch on/off a Treble band. Better there than before the preamp--too noisy.
Thanks to Osvaldo de Banfield for identifying the filter type. I Binged to see what they were all about and shortly wound up at the ESP site !!
I modded a Baxendall with a dual-gang so that when the Treble was turned up along with some Mids, the upper range of the Mids were boosted more, and sloped almost linearly down towards the Bass end using Db scale. I also wanted a Treble Booster so I built one but the noise was too loud and unwieldy, however it was a real quick build. With the extra bands of the P84 board, there should be a way to switch on/off a Treble band. Better there than before the preamp--too noisy.
Thanks to Osvaldo de Banfield for identifying the filter type. I Binged to see what they were all about and shortly wound up at the ESP site !!
The ESP Project 84 mitigates that shortcoming substantially. According to the ESP article, it's only at the ends of the potentiometer range where it becomes a problem. Also read ESP Project 150
I custom made almost impossible to find "S" curve pots: starting as Log and ending as anti Log in the same track, go figure.
Needed for my own Bass amplifier equalizers, and active gain controls in PA mixers.
Only problem is I had to order 1000 tracks and only used some 200, tops.
So later compromised and just used Linear ones, not as good but "acceptable".
Needed for my own Bass amplifier equalizers, and active gain controls in PA mixers.
Only problem is I had to order 1000 tracks and only used some 200, tops.
So later compromised and just used Linear ones, not as good but "acceptable".
@JMFahey: That is done to correct a shortcoming in the circuit, or to make it behave according to preference, but sometimes the only reasonable way to go. The farthest I ever went is to buy another of the same series of pot and trade wafers (the values of the switching style pot were limited), or utilize the second element of a dual gang somewhere else in the circuit.
In principle as long as end to end track resistance is the proper value, "any" taper will allow any expected setting; problem is Ergonomy, or "Human interface", some settings will change A LOT in a small area, others sweep half a turn and "do nothing", so different curves make the control easier to use, and "more intuitive".
But again, "all work" so often linear is used simply because of availability.
Yes, switching wafers is a somewhat desperate move, but often the only one left.
Specially in servicing, when a defective pot is housed in a weird OEM factory special order case, or special legs, or switches, or ´push-pull action, etc.
But again, "all work" so often linear is used simply because of availability.
Yes, switching wafers is a somewhat desperate move, but often the only one left.
Specially in servicing, when a defective pot is housed in a weird OEM factory special order case, or special legs, or switches, or ´push-pull action, etc.
Rod Elliot said that none of his projects will work for 4-Band parametric. The ranges are too narrow to use only 4 bands. So it's either adding a fourth band to the Baxendall, or using something similar to the Boss Metalzone EQ. The Metalzone EQ is elaborate but works good. The concentric pots are confusing, difficult to adjust, and the labeling adds to the confusion. I think 4 traditional front panel pots are the way to go either way: Bass, Low-Mid, Upper-Mid, Treble.
Hello, Understanding the specific behavior of the "Range Node" component and the phasing of the dual potentiometer connections in the 4-Band ParaEQ circuit would require a detailed analysis of the circuit's schematic and signal flow. It's recommended to consult the circuit's documentation or seek guidance from experts familiar with that particular circuit design.
I wound up using 4 of these in series. Phase shift from the caps and the inherent distortion of the design seem to have no adverse affect on my subjective sound using a guitar. In one of Rod Elliot's articles, he shows what happens to the signal when going through these kind of circuits. In determining the Q and Freq settings, I ran a 16 tone test signal with the spectrum analyzer of my scope. The dials were twisted until I verfied the Freq ranges and the desired overlap (Q) into each of the others. The Freq and Q pot wires were disconnected to read the resistance values, because those pots will not be used in the design; the Boost/Cut will be adjustable so the amp will just have Bass, Lower-Mid, Upper-Mid, and Treble controls like the traditional tone stack except for the split Mid. In the schematic, the Freq pot parallel numbering is correct. Boosting Upper-Mid and Treble produces considerable noise so a noise gate is required for those who hate noise, which is everyone I think.
There are fully adjustable 4-band rack units one could buy but are kind of large to stuff into a reasonably sized cabinet and are rather expensive. Then there's the pot problem of either being stuck with moving the Boost/Cut pot to the front panel and getting it to match the other pots' shaft sizes and styles so the knobs are all the same. No one knows what kind they are since none of the details are published. For two examples, there is the 1 channel Midas 512 500 Series and the 4 channel Rolls RPQ 160b which would require cutting up the PCB.
Is all this worth it? I believe that's a matter of opinion. I personally prefer to keep the amount of controls to a bare minimum, so 4 bands is as far as I would go with expanding the tone stack, and a series of sliders seem to be visually out of place on the front panel of a guitar amp. Also keep in mind if you have two of these, one for two channels, and a noise gate for two channels, the power requirements for the opamps becomes quite high.
There are fully adjustable 4-band rack units one could buy but are kind of large to stuff into a reasonably sized cabinet and are rather expensive. Then there's the pot problem of either being stuck with moving the Boost/Cut pot to the front panel and getting it to match the other pots' shaft sizes and styles so the knobs are all the same. No one knows what kind they are since none of the details are published. For two examples, there is the 1 channel Midas 512 500 Series and the 4 channel Rolls RPQ 160b which would require cutting up the PCB.
Is all this worth it? I believe that's a matter of opinion. I personally prefer to keep the amount of controls to a bare minimum, so 4 bands is as far as I would go with expanding the tone stack, and a series of sliders seem to be visually out of place on the front panel of a guitar amp. Also keep in mind if you have two of these, one for two channels, and a noise gate for two channels, the power requirements for the opamps becomes quite high.