Hi, I’m Loïck, new member of the Anasounds team ! I am going to work during the next few months on an upgraded Utopia analog delay. Today, we will look together at the research I am doing on delay pedals. We are going to talk about analog delay, or rather, analog-voiced delay ! I will also introduce different technologies to create the best delay pedal. Of course, we will only go over them for now, and then go further into other articles ! follow our tone quest what is an analog delay ? The delay is a spatial effect which, by duplicating the input signal, will simulate an echo effect. It comes in many forms, from old analog tape delay to highly complex digital racks. And of course effect pedals ! We will see together the main differences between all of these technologies. Then, which one to choose according to the application we intend to achieve. roland space echotc electronic tc2290dod rubberneckthe legendary roland space echo tape delay, and the tc electronic tc2290 rack delay, one of the first digital delay processors, both now discontinued and with a used price above $1000 !on the right, the dod rubberneck, a modern delay pedal with bbd technology and unique extra features for a price of around $200. origins and first analog delays : the tape echo The first analog delay effects came with the first tape machines. Like a recording machine, a writing tape head records the signal on a magnetic tape. Then, one or several read tape heads read the tape with more or less time delay. This delay depends on the distance between each head, which creates the illusion of an echo. One of the first analog tape delay, the Watkins Copicat : hard to fit in the pedalboard ! Since the driving mechanism of the tape echoes is not perfect, the tape could slow down or accelerate slightly. These speed variations caused a very specific modulation effect. You can experience it when you turn the speed knob of your delay pedal ! In addition, the tape could introduce a slight saturation which degraded the repetitions. Before, these properties were considered as defects requiring improvement. But over time, they became the characteristic of a warm analog delay with a unique sound texture. This explains the strong interest in vintage analog delays today ! example of modulation due to speed fluctuations on a turntable. miniaturization of analog delays The analog tape delays are cumbersome and require constant maintenance. So it was necessary to quickly find a new technology that was more robust and, above all, more compact. The solutions are all more or less based on the same operation with a circuit that delays the signal. In a delay pedal, the input signal is splitted. The first signal goes directly to the output without any modification (the dry signal). The second part is delayed by a circuit before also going to the output. This signal will create a first repetition. At last, to obtain more repetitions, a portion of the delayed signal is returned to the input of the delay circuit with the feedback loop. Simplified diagram of the delay process. The advantage of this process is that any kind of sound treatment can be applied to the signal. For example, by adding filtering or clipping stages on the repetitions, you can make them more or less dark or saturated. Modulation can also be added to simulate an analog tape delay. You can also boost the signal of each successive pass through the feedback loop to make it self-oscillating and create infinite répétitions ! the ending of karma police by radiohead, an example of a self-oscillating delay. modern analog delay technologies Delay technologies are frequently classified into several categories : analog, analog-voiced or digital. So we’re going to decipher this together. I will also explain why from my own perspective, except tape delays, the fully analog delay doesn’t exist ! is the bbd a real analog delay, or an analog-voiced delay ? The BBD (Bucket Brigade Device) is the first technology developed to create compact delay pedals. It’s a chip that delays the signal it receives from its input. electro-harmonix deuxe memory manmxr carbon copytwo famous vintage and modern bbd delays : the electro-harmonix deluxe memory man and the mxr carbon copy. analogy with the bucket brigade technique To explain how BBD works, an illustration of firefighters moving water from a place to another is frequently used. To do this, they each take a bucket. The first one will fill his bucket with water, and then pour it into his neighbour’s bucket. In turn, he will do the same with his neighbour while the first one fills his bucket again. So the water will arrive to the last firefighter after a while. It’s the origin of the “Bucket Brigade”. an animation of the bucket brigade’s technique for delaying a signal. The principle of the BBD is therefore similar. It’s basically a series of transistors that will act as switches. Driven by an external clock, they will “pour” the input signal from capacitors to capacitors (buckets) to delay it. why do i consider the bbd as an analog-voiced delay ? Even if it is frequently presented as a fully analog delay, the BBD requires a clock and several filtering stages, at the input in order to obtain a signal that can be exploited by the BBD, then at the output to reconstruct the signal, which is still very close to sampling techniques. Delay line based on a BBD chip : the circuit looks like a series of sample and hold circuits driven by a clock, and requires a lot of external units that will modify the signal dynamics. So we obtain a circuit with constraints similar to a digitization. But of course this is not pure digital with code written in a processor ! In addition, in the same way as the example of the “Bucket Brigade”, where losses can occur with each water transfer, the BBD generates losses of information. These losses add white noise and prevent bright and clean repetitions. But this is what also makes its characteristic sound, which can also remind the saturation of a vintage analog tape delay ! So in my opinion, the BBD is more like an analog-voiced delay than a fully analog delay. It consists of a delay line close to digital treatment, but surrounded by a fully analog circuit. It is this analog circuit that will give the sound texture. Finally, maybe the real analog delay is still the tape delay, and analog-voiced delay is the technology to get as close to it as possible. the pt2399, the simplicity and flexibility of the analog-voiced delay ! A more recent solution is the PT2399, created by Princeton Technology Corp. This so-called digital delay chip has the advantage of directly including an ADC, DAC, RAM and clock. It means that a delay can be generated quite easily without the need of as many conditioning circuits as the BBD. This also makes it a very good solution to make an analog-voiced delay. Delay line with a PT2399 : all the required elements to delay the signal are in the chip ! Like the BBD, the circuit surrounding the chip and the internal filtering are fully analog. So we have an analog-voiced delay, because even if the delay is created digitally, the sound processing is still analog. In addition to that, we have a fully analog dry signal ! But the main advantage of the PT2399 compared to the BBD is that it provides bright and better defined repeats. Its delay circuit is also simpler, allowing greater flexibility in analog processing. That’s what is used in the Utopia ! discover the utopia the dsp, the swiss army knife of delay Finally the latest technology is the DSP. Here, the delay and its sound processing are entirely generated by a processor. So it’s a fully digital solution. This allows the creation of much more complex effects, managed by algorithms programmed into the processor. The only limit is the creativity of the developers, and the memory capacity of some chips like the FV-1 ! But digital processing also means reduced dynamics, and latency on the dry if it is also processed. Some even say that it would lack “coloration” compared to analog delays ! Nevertheless, technology has advanced a lot, and today the digital delays are on a par with other technologies. We can even simulate analog and analog-voiced delay textures with DSPs ! boss dd-3strymon timelinethe boss dd-3, a reference in digital delays, and the strymon timeline, an ultra polyvalent digital delay. our choice for an analog delay pedal In conclusion, each technology has its advantages and disadvantages. They allowed the creation of a variety of delays, from simple echoes to complex pedals and racks, to match every needs ! Going back to Utopia, the idea was to emulate an analog tape delay. So we naturally chose an analog-voiced delay technology rather than DSP. As the PT2399 is still produced and more easily findable than the BBD, it has the advantage of being cheaper. This allows us to be able to propose a correct selling price. On top of that, its conception leaves more place and flexibility to experiment with analog signal treatment than BBDs, which are less versatile and also noisier. But the BBD also has its advantages, due to its specific sound coloration. That is why we are not closed to this technology and we will explore it more closely in the future ! don’t miss the upcoming articles!