The RE-501/SRE-555 were essentially the exact same machine, but built into two different form factors; the RE-501 keeping the classic tolex-covered wooden box of the Space Echo machines before it, whilst the SRE-555 took the form of a large 19” rackmountable chassis.
Cosmetically they departed from the classic green/silver colour scheme in favour of black/orange – to match Roland’s popular range of digital rackmounted processor units being produced at the time. A more modern LED display replaced the traditional VU meter.
Functionally, the RE-501/SRE-555 contained all of the same features of the RE-301, but the new design reduced noise and also added a fourth playback head to provide the user with even more tonal variety. It was the most advanced (and quiet) Space Echo. From subtle sweetening with a subtle dusting of echo and spring reverb, to full on dubtastic self-oscillating madness, this machine is capable of a wide range of effects. The combination of echo, chorus and spring sound fabulous on guitar, piano, synth etc - there is a warm sense of familiarity as a result of these units' classic status whether you're recording or playing live.
The RE-501/SRE-555 proved to be the last tape-based design that Roland ever created. Consumers showed less and less interest in the antiquated technology of Tape Echo. Digital technology was quickly growing in popularity and Roland were keen to be at the forefront of this new revolution.
The Space Echo name was not dead, but it would soon appear in a remarkably different form.