Doepfer A-199 Spring Reverb

With so many cool new modules being released, it's easy to overlook some of the classics. Similar to my A-156 quantizer epiphany, I've only just discovered the Doepfer A-199 Spring Reverb. Primitive though the effect may be, it's breathed new life into my system.



Here's a demo of how it sounds and some ideas for patching the feedback path:

Doepfer A-199 Spring Reverb Demo by navs

I'd tried the A-199 before, but wasn't taken by it: I guess I was looking for reverb, when I should have been listening to the effect for what it was. While on a recent hiking holiday, I came across an old, rusted gate. Because of its age and construction, opening and closing it generated wonderful, resonant/ reverberated sounds. I 'played' this gate for a full five minutes and spent the rest of the walk thinking about how one might recreate its sound. The A-199's time had come.

Today's Patch of the Day features a Cwejman RES-4, the A-199 and Metasonix R54 in the feedback path:



The one criticism that's leveled at the A-199 is its tendency to hum, but, keeping the module far enough away from the PSU and the springs outside the case, I haven't noticed this to be too bad. I'm also happy with the sound of the stock Belton tank, but if you want to change it, consult this spring reverb wiki compiled by Tim Stinchcombe for a suitable replacement.

The A-199 is a lot of fun. It can add simple ambience to sounds or be patched as a special effect. This module was the missing element in my system, adding space, colour and character - spring reverbs and modular synths seem to be made for each other.

A-143-1 Modification

Adding voltage control and a combined trigger output to Doepfer's Complex Envelope Generator. An update to these posts (1, 2).



The A-143-1 is king of the shonky rhythm. There's something about the swing generated by its four chained envelopes and comparators that is hard to replicate with a VC-LFO and sequencer. This modification provides two features I wanted when using the A-143-1 as a wonky clock: a combined pulse stream to control other modules and an automated means of influencing the rhythm.

For the latter, I chose to add simultaneous voltage control to the threshold of all four comparators. For me, this is the parameter that makes the A-143-1 tick. It means a single CV can be used to stretch and shrink the rhythm without affecting its inherent groove. Think 'Funk Soul Brother'. Just as importantly, the modification can be accommodated on the original panel.

The Comparator outputs are chopped down to 1ms pulses, so they can easily be mixed without the need for a 'proper' logic circuit. They are also hot enough to ping filters. Add a Sample & Hold to grab values from the A-143-1's bipolar mix out and the results can sound like this:

a-143-1_mod.mp3



The star of this mod is the H11F1 Photo FET Optocoupler. It may not have the cachet of a VTL5C3, but this vactrol alternative might make a better choice for some synth mods. It's smaller, cheaper and, most importantly, has a fast, linear response.

The circuitry used in this mod is simple. The difficulty arises out of the need to quadruple the parts. You can download my build-notes here (the usual DIY disclaimers apply!) to see how I went about it. See this thread for more A-143-1 modification ideas.

To close, today's Patch of the Day offers a musical example of this modification:



The patch uses just two envelopes, sometimes chained, sometimes running as LFOs. The new combined trigger was multed to ping a Cwejman RES-4 and trigger a S&H and CTG-VC envelope. The A-143-1's mixout was sampled by the S&H and sent to the RES-4's FCV and CTG-VC's Attack CV-in. The RES-4's audio output was sent to a VCA-4MX and multed to an A-199 Spring Reverb. The 100% wet signal was sent to a second VCA/ mixer channel and opened by the CTG-VC's envelope. Altering the threshold changes the timing and also the CV that is sampled from the mix output.

Feedback Looper

A DIY expander for the Doepfer A-112 Sampler/ Delay/ Wavetable Osc.



Since re-buying the A-112 earlier this Summer, it's become a frequent feature in my music. The one thing I wished it had was a built-in feedback function for delay duties. This can be patched, but ties up a mixer, usually a four-channel, 8HP one. This passive 4HP mixer is dedicated to that task. It also incorporates a mod to bypass the A-112's filter and AC-coupling circuit which allows one to record and process CVs.

The source signal is mixed with the output of the A-112 via resistors. Feedback is controlled via a pot. A mult of the return signal is used as the main output. You can download the schematic and extra pictures here. Experiment with the values of the resistors to get the best results for your set up. I'm sure an active circuit would have been better, but to paraphrase Nicolas Collins: if it works and doesn't smoke, don't sweat it!

As with Bitsy, I used a PCB blank, this time from MFB. Thanks to Schneidersladen for the spare Cliff jacks and Cwejman-style knobs. They're D-shaft, but that's nothing a quick blast with a drill can't solve.

Today's Patch of the Day is a jam with two feedback paths: the output of the A-112 was first sent to the A-199 spring reverb before being returned to the mixer. The oscillator was the A-143-9 QLFO, itself receiving a little feedback to bend its sine into a triangle.



DIY can be fun and frustrating but it's worth the effort, especially if you end up with a module that meets your own needs. As ever, the usual disclaimer: modding your A-112 will void your warranty, carry out at your own risk!

Simple-Mod Tuesday

Two easy Doepfer modifications: a port-hole for the A-199 Spring Reverb and another cap change for the A-162 Dual Trigger Delay.



Like many A-199 users, I keep my tank outside my case. It's less noisy and means I can play the springs. Until today, this meant an ugly, useless 1HP gap next to the module to allow the cinch cable out of the box.

Once drilled and threaded, the hardest part was feeding the cinch back under the second cable tie before soldering. I gave up, snipped the plastic tie and used one of those twisty things everyone has lying around the kitchen.

It's such a simple, useful mod - maybe Doepfer could be persuaded to offer it as an option?



While the soldering iron was out, I took the opportunity to change the timing cap of the delay section of my A-162. I'd already fixed the length parameter to make the module suitable for pinging filters and was unhappy with the delay too. The stock 10uF cap provides delay times of up to 10 seconds - far too long for my uses. I still had a previously-soldered 1uF from my length experiments, so in it went. Here's how it sounds:


(original left, delay right)

The 1uF gives a maximum of around one second delay time. This is more appropriate for echo-type delays. Depending on the frequency of the incoming trigger, higher settings can still be used to generate clock divisions, audible as 'missed/ skipped' notes in the above recording.

It's another simple mod that enhances the use of this module. To be honest, I don't know why the A-162 comes fitted with such large caps as most musical uses lie within the first 10% of the pot's throw.

So, just to re-cap, I swapped out both 10uF capacitors in the top section: a 1uF for the delay and a 0.01uF/ 10nF for the length. I left the lower section un-modded for now, but it's just a matter of time …

Basic Electricity - Concert Today!

A reminder about tonight's gig with Derek Holzer, Vanessa Ramos-Velasquez and JenaMu6. The venue is the Kino on Kastanienallee 77, 10435 Berlin Prenzlauer Berg. Doors at 21:00, music at 22:00 sharp.



I won't be playing, but had some fun with this patch last night:



Inspired by the sound of Japan's Gentlemen Take Polaroids, it features a Plan B M15 VCO FM'd by Doepfer's A-143-9 QLFO. The gated sound was fed to an A-199 spring reverb with the feedback routed through Cwejman's FSH-1 frequency shifter. I added a touch of Logic's Ensemble, but 90% of the effect is the shifting reverb. Lovely.

Look forward to seeing you tonight at BE#6!

Release: Basic Electricity #1 Live EP

For those who couldn't make it to the recent Basic Electricity event at the Auxxx in Berlin, here are the recordings of my set.





Making their debut at this gig were the Doepfer A-199 Spring Reverb, A-112 Sampler/ Wavetable Osc. & Cwejman FSH-1 Frequency Shifter. They were supported by the usual suspects: RES-4, MMF-1, Toppobrillo Triple Wave Folder & Sport Modulator, Harvestman Hertz Donut, Makenoise Wogglebug and, of course, the EHX Stereo Memory Man w/ Hazarai.