But there are still questions that need answering though, the big one being: just what is it that makes the Echorec sound so special and can it be replicated without the expense of the heads and Binson’s specially manufactured magnetic drum? Perhaps, although I am pretty sceptical about this being possible. Here’s what I’ve discovered so far…
The first step was to undertake an investigation of different types of delay-line technologies. The limited frequency response performance of the bucket-brigade device (BBD) integrated circuit (IC) ensured it dropped out of the race straight away. BBD technology is only good up around 3KHz, noisy and the delay time is limited to around 300ms—a ‘Deluxe Binson’ would have to have a delay time in the order of 800 to 1000ms. Moving on to digital delay technology, there are plenty of easy to use cheap and cheerful ICs currently on the market including devices such as the Princeton Technology Corp PT2399 digital echo processor IC and the Spin Semiconductor FV-1 complete reverb solution in a single IC. However, these really are budget devices with on-board ADCs, DACs and support components, if this project was going to be digital then it would need to be done with a little more panache and power, after all, we want to do the Binson legacy justice—this Echorec 3° needs to be done properly if it’s going to be done at all.
The higher end DSP (digital signal processing) chips looked very promising with high sampling rates and massive number-crunching capability – if you were going to use a DSP then this surely had to be the way forward. However, even with all the horsepower of a DSP chip such as the Analog Devices SHARC DSP chip I wasn’t confident about quantifying and describing the audio performance (transfer function) of the Echorec as mathematical equations. Here’s why. After working with vacuum tubes since the 1990s I’ve come to realise there are many subtleties in he way an analogue tube circuit behaves. Just adding a capacitor of a few picofarads here or there or changing the value of a bias resistor by a few hundred ohms will have an obvious and often quite dramatic effect on the tonal character and response of the circuit. There are so many variables affecting the distortions, resonances, frequency response that I couldn’t even begin to quantify ‘tube sound‘ let alone reduce it to a set of equations.