I’m very excited to start writing about this delay processor. A piece, I believe, that deserves some more words, as I couldn’t find too much written on it. The reason for not being popular, not to be found on its low digital resolution or for being very noisy, but for the reason that it has never been produced in series. The Powertran DDL came out in 1982 as a DIY project, published on the popular electronics magazine Electronics & Music Maker, so just a small number of units were built. The project was developed by the electronic designer Tim Orr, famous for the EMS synthesizers. The idea was giving access to the new digital technology, before extremely expensive and present only in big studios, to a wider public.

http://www.muzines.co.uk/articles/digital-delay-effects-unit/3714

I’ve been lucky enough, to having fun with three different units of the Powertran Delay in the past, all a bit different from each other. Being the DDL a DIY project, all these processors had some modifications like the optional CV/Gate or additional knobs/switches.
The first unit I had was borrowed, a friend kindly left his Powertran in the studio and it remained in my hands for several years. Being his music more focused on acoustic instruments, he wasn’t using it anymore. Those were times when a dirty digital sound wasn’t appreciated too much and just a few bit-reduction plugins like the Digidesign Lo-Fi, existed. My friend’s Powertran had voltage control too, samples could be played from the keyboard, through a MIDI/CV interface and its dirty 8-bit sound reminded me a bit, the Emulator Paul Hardcastle had used in “19”, a song I’ve been loving so much. The Powertran delay became the crazy spice for almost anything experimental I’ve been doing, until before moving the studio to an other country, when I wanted to give it back. My actual Digital Delay was bought on eBay in a lucky bid, as very few units were still around, a few years ago. Unfortunately, my second unit, bought in the UK in 1999, had died after a few years of use and I couldn’t stay without a DDL!

The Powertran Digital Delay Line front panel is pretty simple and there’s nothing surprising, apart the time selector switches same as the MXR, we have already seen in a previous post.

The Time Delay buttons always select multiples of the original tempo. If the delay is in sync with the track tempo, pushing different switches, gives a today very fashionable Beat Repeater effect, where, for example, a loop is faster or slower, but always remaining in sync with the song. Some machines like the Powertran, had a freeze button so that the sample could be repeated without decaying, same as a sampler.

Specifications:

“Digital encoding for studio quality results. Time delays from 0.625ms to 1.6 seconds. Produces all popular time delay effects: Phasing, Flanging, ADT and chorus, Echo (including “freeze” for infinite repeats), Time domain vibrato, etc.”

The Powertran Delay has a delay time of 0.625ms to 0.64 at 10KHz Bandwidth, while it has 1.6ms up to 1.6 seconds at 4KHz, these times can be halved through the delay knob.
The modulation LFO has a range from 0.025Hz, up to 17Hz and a triangular shaped waveform.

The input signal, once amplified, is passed through two switchable HPF at 4KHz and 10KHz, working as anti-aliasing filters. The ADC analog to digital converter is an 8-bit one. The dynamic range of the Digital Delay is 72dB. The RAM memory is 16K bytes.

Included are some examples of the crazy effects obtainable with this processor:

Interesting links:

Free impulse responses from Floaudio: https://floaudio.bandcamp.com/album/flo-audio-x-powertran-digital-delay-line

https://bugbrand.co.uk/Powertran_Digital_Delay_Line.htm

http://www.loopers-delight.com/tools/powertran/powertran_review1.html

http://www.milton.arachsys.com/nj71/index.php?menu=2&submenu=6