“A box without hinges, key, or lid,
Yet golden treasure inside is hid.”
― J.R.R. Tolkien, The Hobbit
The Final Part?
At the end of the last Chapter I told you that I had decided to design an effects pedal-sized version of the vintage echo box that had started out as a rough prototype over three years ago.
Initially I made a few measurements to see if there was any chance that Piet’s original eTap2hw motherboard and my Arduino automation could be squeezed into a typical guitar effect enclosure, such as the Hammond 1590XX. It quickly became apparent that this wasn’t going to be possible so I started a re-design of the whole thing from scratch. At first I simply tried to stick with Piet’s motherboard design and designed a new PCB layout for it. One of the most popular PCB design applications is undoubtedly Eagle but I never really liked it or found it user-friendly and once team member Mick Taylor had pointed me in the direction of DipTrace, I immediately found it intuitive and easy to use.
Following various false starts I was beginning to settle on a two-board design with the audio circuitry on one PCB (basically this was Piet’s original motherboard design) and the ‘brain’ which consisted of the Arduino and the circuitry from Piet’s Universal I/O board on another PCB.
An early design with the Audio (L) and Digital ‘brain’ (R) on separate PCBs
This early design retained Piet’s original preamp including the Fetzer valve input stage but Steve and Mick had been quietly working on a new improved design that used four FETs which would end up as the Stanley-FX Baby Blue pedal, a replacement for the already successful eTap2hw pedal from the same company. (The Baby Blue, effectively a Blue Nebula with the original eight eTap2HW echo effects and without the ‘bells and whistles’ of automation etc., is already available to buy from the Stanley-FX website at £129.99.)
The Stanley-FX Baby Blue
I had also discovered the Arduino Nano which is a much more compact little Arduino which still retained all the memory and processing capability of the Arduino Uno I had used in the original designs.
The team consisting of myself, Steve, Mick and Piet (by the way none of us has, as yet, ever met in the flesh) exchanged ideas and designs via email and Dropbox eventually ending up with a ‘final’ schematic that incorporated the 4-FET preamp, the Arduino Nano ‘brain’, the FV-1 DSP chip, two EEPROM memory chips for the DSP programs and another EEPROM that would store the User patches, allowing up to 128 patches to be stored.
Using Diptrace to capture the schematic from our various efforts I came up with an initial PCB design which Mick, who has vast experience in this area from his own Stanley-FX pedal designs, reworked to improve the layout, give better separation of the digital and analog circuitry and add ground planes that would ensure the Blue Nebula would enjoy excellent low-noise performance.
The design did end up on two PCBs: a Main Board (with most of the circuitry) and a Controls Board which had the pots and navigation switches. In this early design the LCD was a separate module that would be connected to the main board by a short cable. The two PCBs were interconnected with a short ribbon cable.
To ensure the design would all fit correctly in the proposed Hammond die-cast enclosure I used DipTrace to export 3D models of the boards and imported these into a 3D CAD package called DesignSpark.
At this stage, with everyone happy with the progress so far, I ordered a batch of PCBs and eagerly awaited their arrival so I could start putting together the prototype. The boards arrived and I was very pleased with the quality so I got busy assembling the first working prototype.
The prototype Blue Nebula PCBs, Controls Board (top) and Main Board (bottom).
By this stage I had come up with the name Blue Nebula for the new effects pedal and the other guys liked that so that name has stuck but, in honour of the original eTap2HW creator Piet, who is Dutch, I decided to built the prototype in an orange Hammond enclosure 🙂
The prototype Blue Nebula – yes it’s Orange!
This initial prototype was put through extensive testing and enabled us to decide on a number of changes and improvements that would make the pedal better from both the user’s point of view and also simplify the assembly if anyone wanted to build one for themselves. For example we decided to
- Replace the separate LCD module with one mounted directly on the controls board
- Replace the small navigation/editing buttons with a larger Navigation switch
- Have the Controls Board plug directly into the Main board so avoiding the need for special tools for making up a ribbon cable
- Relocate the MIDI circuitry onto the Controls Board (it was originally on the Main Board)
- Move the input and output jack sockets slightly further apart for a better fit in the enclosure
- Move the Up and Down footswitches further apart so wearers of Size 12 boots wouldn’t accidentally stomp on the bypass switch 😉
- Fit a Lexan faceplate to protect the LCD from scratches and ingress of dirt and liquids (fancy a beer anyone?)
Mick quickly re-designed the PCBS and after more 3D modelling we ordered a batch which myself, Mick and Steve then used to build a number of final pre-production units to ensure all our modifications had worked out and we hadn’t introduced any other issues.
Blue Nebula 3D Model
A finished Main Board
The Controls and Main Boards powered up and working.
The hardest part of the assembly is the machining of the enclosure to ensure everything will fit together correctly and we realized that this would be quite tricky for the average builder who would possibly lack either the ability and/or the tools to produce a sufficiently accurate result.
The pre-production Blue Nebula before it received its paint job.
Mick invested in a CNC machine and after some trial and error and making extensive improvements to the machine itself he was happy that he could produce accurately machined Blue Nebula enclosures. Mick (proprietor of Stanley-FX) can also undertake powder coating and silk screen printing and the CNC and finishing processes have resulted in a fabulous result:
The finished Blue Nebula enclosure as received from Stanley-FX
Everything fits together perfectly and the end result is really quite stunning to behold. So, at last, that effects pedal I had imagined way back at the start, is now sitting on my pedal board, looking and sounding great and with features I hadn’t even dreamt of when I set out on this ‘journey’ way back in February over three years ago!
The Blue Nebula will soon be available from Stanley-FX as a fully built, tested and guaranteed unit at a very reasonable price (To be confirmed). If there is sufficient interest it may also be available in kit form with the finished enclosure as shown above. Further details will be published as soon as possible.
I want to finish this story by saying a big ‘Thank You’ to Piet, Steve, Mick, Ecca, Rolf, Johan and all the others who all played some part in this journey with their generous help, designs, ideas, suggestions and encouragement that kept me going. I hope you all agree that the end result has been well worth it 🙂
If you’d like to be kept up to date on the Blue Nebula development including prices and availability, head over to the Stanley-FX website and subscribe.