Acoustic Nerdville: A New Toy

The last update of the Acoustic Nerdville setup saw the addition of a Digitech PDS-8000 delay pedal. Looking at the diagram in the last post, you might wonder why I need another delay pedal, in addition to the other two here.

I had been looking to get one of those early-digital vintage devices for quite some time. In fact, I used to own the RDS-2001 from the same family many years ago (and got rid of it when I redesigned my rig in a  way where I removed most single-use effects, like the Digitech, the Electrix FilterFactory and the MAM RS3). And this Nerdville setup is for me the best place to play with it, and to see how it can fit in. If it will remain in the setup, and maybe replace some other devices remains to be seen; architecture-wise, it’s currently driven by Aux1 (together with the DD20 and the G2.1u). But let’s take a look at what this thing can do.

Digitech PDS-8000

A Behavioural Look

Looking at key features, the PDS-8000 is an eight-second mono delay stompbox with additional sampler and trigger modes (more on those later). Different from the sister family (the Digitech RDS), it does not offer modulation capabilities, so no way to do flanger/phaser/chorus-kind effects.

Controls are a switch to set the delay range, knobs for delay time, feedback (here  named “Regeneration”), wet/dry mix and input/output gain. This is complemented by two footswitches, one for bypass, the other for infinite delay (in delay mode) or trigger in trigger/sampler mode. We’ll be talking about the delay mode right now.

Now what makes this thing special? After all, today you can get digital delay pedals in the 20-plus-second range, and with much higher fidelity at that (at maximum delay time, the PDS has a frequency range only extending to 7kHz).

Two things: Firstly, the device offers true varispeed, i.e. turning the delay knob will change the playback speed of the delay contents, and not result in either glitches or moving-head-kinda effects. This is something only a few delay pedals offer (of the current breed, the Pigtronix Echolution comes to mind). Secondly, the feedback chain obviously does not happen in the digital world. This means that unless you hit the “infinte delay” footswitch, the signal degrades at every pass, and bringing the feedback to 100% will actually bring up the feedbacks, resulting in solid-state analogue distortion.

My assumption here is that the digital section of this delay simply consists of a memory with converters on each side, the clock of those being adapted by the delay time knob (which will result in the true varispeed, as well as the loss of bandwidth at longer delay times, as the sampling frequency decreases). If you hit infinite delay, the memory content is simply played back and not changed. Normally, however, the output from the D/A converter is fed back to the input of the A/D (together with the device’s input signal) via the feedback knob – which leads to analogue things happening here.

What makes this unique?

In addition to the varispeed (which, as I mentioned, only a few pedals offer), it’s really the analogue feedback chain. While this could be simulated in current delay pedals easily, this is usually not the case, at least not with that specific sound, and usually not in combination with the varispeed functionality. So the unique sound of an early-digital-age analogue/digital hybrid really is the USP of this.

Using it

I didn’t state it so far, but if you’re an avid delay user, you might already see the biggest drawback here, and that is that setting the delay time exactly in a musical context, be it be precisely adjusting ms vaules or by tapping tempo, is not possible. That means if your playing is rhythmical in nature, you would need to roughly set the delay time with the knob, then record one note/event as a kind of “pulse” and then build your delay content on top of that. Still, with a maximum phrase length of eight seconds, this is not completely easy. Also, it’s noteworthy that while 8 seconds are definitely more than the slapback/quarternote-range delay times of old pedals, and also of those shorter rhythmic ones in the 2s range, it is not enough to record complete theme-oriented statements (Rough order of magnitude: 8 seconds is four 4/4 bars at 120bpm). It’s good, however, for phrase/motif-like statements, and in that way, the trigger mode would allow you to trigger them with the pedal to come in if you so desire. A more texture-oriented approach works much better: for example play some arbitrary notes (or noises) into the delay at medium delay time, have it run a few times at full regeneration (so it’s driven a little with that odd combo of analogue solid-state and early digital converter distortion), and then set it to a tempo where the feel is right regarding tempo or pitch.


This delay is even more of a one-trick-pony than my other ones. And from the way it works, I see it really more as a tool to aid in generating sonic textures than as a rhythmic or phrase-oriented kind of tool.

Maybe I’ll remove it from the setup. Maybe I’ll take something else out. Maybe I’ll use it in another context. But I’m sure that I’ll keep using it somehow – because it’s got character.


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