Wednesday, 26 October 2011

Sport Modulator Explained

A lot of people are confused by the Toppobrillo Sport Modulator. They needn't be. As you can see from the easy-to-follow diagram below, using the SM is child's play.

When patched correctly, the Sport Modulator should sound like this.

If your Sport Modulator sounds like this ...

... you have done something wrong. Please consult the diagram and start again.

Sunday, 23 October 2011

Even More Hazarai!

Modifying the Electro Harmonix Stereo Memory Man w/ Hazarai delay pedal for external tap clock. A follow-up to this post.

Two years on from blogging Rechner7's project, I've finally modded my SMMH, a delay which features heavily in my recordings and live sets. I'd never found the original tap tempo function a hindrance to getting interesting echo, but was inspired to give the mod another look after seeing Mr Biggs' video of his project. I'm glad I did, as the additional inputs have yielded a few surprises.

Here's how it sounds: smmh_mod1.mp3

I kept my mod simple, adding one external clock jack, a three-position switch (on + HP filter, off, on without filter) and a softer response tap button. The internal changes consist of Ken Stone's Gate to Trigger and Doepfer's Gate to S-Trigger circuits. Here's my perf-board layout. As r7 originally warned, the most difficult part of the operation was removing the PCB from the enclosure. After a few frustrating attempts, I gave up, masked the PCB with paper and drilled my holes with the board in place.

So, was it worth it? Yes, but not for the reasons I originally assumed. While tempo-syncing is nice, I actually prefer the sound of echos which are not perfectly in time. The new momentary switch was a last minute decision and I'm glad I added it. It's less clunky than the original foot-switch and makes tapping easier. That doesn't mean the clock input is redundant - it comes into its own when fed with random gates, for example from a tail-chasing Wogglebug.

As you can hear, this is where the real fun starts: smmh_mod2.mp3

Thanks to Rechner7 and Mr Biggs for answering my questions and for their encouragement. It's a simple project that helps integrate the SMMH with the modular, so highly recommended. As ever, the usual disclaimer applies: modding you pedal will void your warranty and is carried out at your own risk!

Friday, 14 October 2011

Bitsy - Stepped CV Generator/ Recorder

A DIY Ring Counter based on Ken Stone's Gated Comparator circuit.

My inspiration for this module was Grant Richter's Wiard Noise Ring - a random CV generator with a form of memory. While I liked its ability to capture an eight note sequence, I found it hard to control and wanted some method to reliably input my own data.

I first thought an analogue shift register - a chain of sample + holds - might provide the solution. Thanks to a prod in the right direction from Matthias of Fonitronik, I discovered Scott Stites' Klee sequencer and later Rob Hordijk's Rungler and Ken Stone's digital shift register circuits.

Using a CMOS chip like the 4015 or 4021 won't allow you to sample your own CV stream, but the end result is the same. A series of zeros and ones is converted into a stepped CV via a DAC, in this case an R/2R network. Feeding the last stage of the shift register back to the input allows you to hold a sequence. Here's how it sounds:

I built Bitsy as a companion to the Wogglebug, which provides the clock and data, via its burst output. Like the Klee, it can also be programmed via a sequencer or manual gates. To simplify the design, I left out the input comparators of Ken Stone's circuit. A switch is used to manually hold a sequence. The last stage is also available, allowing VC over new/ old data selection via a sequential switch like the Doepfer A-151. An LED reflects the voltage level.

I used the DIY Layout Creator to plan my perfboard and a 6HP Makenoise blank as faceplate. This was the first time I'd made a parallel board, which meant using wire connections for the jacks etc. However, the benefit of this was I didn't have to be totally accurate when drilling holes.

Thanks to Matthias for the hint and to the designers of the original circuits which inspired this project!

Sunday, 9 October 2011

Patch Tips#18 - ADSR 'Free-Run'

Using a gate delay and comparator to trigger 'full length' ADSR runs, achieve looping ADSRs and delayed looping of AD envelopes. As suggested in this thread.

Unlike AD envelopes, ADSRs generally need a gate signal to fully complete their cycle. The gate determines the duration of the sustain phase of the envelope's run. So, what to do if your sequencer only generates triggers?

With a gate delay like the A-162, set the delay to zero and the length to taste. If using Maths' channel 1, the rise sets the delay time and the fall the length of the gate, available at the EOR. This provides the gate that the sustain requires. This mimics the response of AD envelopes like the VCS, which complete regardless of gate duration.

If you then mult that gate to a comparator with a suitable threshold, you'll get a second gate when the first expires. I used the Sport Modulator with the multed gate fed to the bottom input and 5V as a threshold reference sent to the top input. The middle output provides the comparator function. Mix the two gates and feed them to the input of the gate delay and you've got a looping ADSR.

The A-162 is great for these sorts of tricks and can also be used with AD envelopes which have an End Out (VCS, Maths, A-143-1) to achieve the Envelator's delayed looping.

Tuesday, 4 October 2011

Tom Bugs Live in Berlin

If you're in Berlin this Friday, be sure to catch Mr Bugbrand, Tom Bugs, at the Auxxx in Prenzlauer Berg:

Kastanienallee 77 (Lichtblick Kino) 10435 Berlin
Friday 7th Oct. Doors @ 21:00, Show @ 22:00

"Legendary analogue electronic instrument inventor Tom Bugs comes over from Bristol with his personal BugBrand Modular setup for a discussion and performance." More info at the Auxxx blog.