A Working Electronic Vulcan Lyre

After a great many trials and much tribulation, I can finally report success in building – from scratch -- a working ka’athyra, a Vulcan lyre as debuted on Star Trek (The Original Series) way back in 1966. Initially designed by Wah Chang, the fascinating instrument which appeared there, with its exotic, otherworldly tones, was, however merely a prop with heavily synthesized music laid over the soundtrack in postproduction. Although the instrument has appeared in various series and films over the six decades since, including as recently as the current season of Star Trek: Strange New Worlds, most appearances are of a different, inferior prop, the original having been lost. An account of its history as well as the replicas appears at Purple Sloth Productions by Scott Lukas Williams (“Wah Chang and the Vulcan Lyre,” 20 Aug 2010 LINK). I am in the process of putting together a full account of my own build as an Instructable (https://www.instructables.com/), but that is taking a while and I wanted to share my success with the world in more detail than the roughly monthly videos I have posted to my Youtube channel (#kentghare8010) ever since I managed to get the basic instrument working acoustically back in January of this year. This post is, however, intended to expand on the most recent of those videos, that of 15 July 2023, which demonstrates the internal electronics as they currently stand. That video is embedded here:

Please bear in mind that I began this project a bit more than a year ago with virtually no woodworking experience and even less electronics experience – even basic soldering. To see how ignorant I was about even basic instrument-building techniques, I refer the reader to my previous post on my first misbegotten attempt at a merely acoustic Vulcan lyre. But I am nothing if not persistent (really obsessive-compulsive), and I continued working, learning from my mistakes, until I achieved success, however imperfect.

Here are a couple of labeled pictures, the first showing the external arrangement from the front, the second showing the internal arrangement from the rear underneath the removeable back:

The main components are:

• Pickup: Rod Piezo Acoustic Instrument Pickup – CBGitty
• Pickup Output: Bakyan 2Pcs 50MM Guitar Pickup Piezo Transducer Prewired Amplifier with 6.35MM Output Jack for Acoustic Guitar Ukulele Cigar Box Guitar (375354)
• Tone: "Tone Distiller" - Pre-wired Active Tone Control Knob for Guitar or Amp - Distill your Tone for the best sound! -- CBGitty
• Reverb: EK1725Youngy PT2399 Microphone Reverb Plate Reverberation Board No Preamplifier DC 6V-15V -- Amazon
• Amplifier: 2.5W Artec Amp Circuit Board with Pre-wired Leads -- CBGitty
• Internal Speaker: Cylewet 4Pcs 2inch 8Ohm 5W Full Range Audio Speaker Stereo Woofer Loudspeaker for Arduino (Pack of 4) CYT1121 -- Amazon
• External Speaker (not shown): Same as the Internal Speaker, but mounted inside a housing with a long wire and plug to match the output jack.

A few notes:

• Pickup: Mounted directly under the bridge atop the surface
• Pickup Output: Actually, I only used the pot. I discarded the piezo disc and spliced on a female jack to receive the male plug from the pickup. I similarly replaced the large female jack with a smaller female connector. I’m not entirely sure what the pot does – despite the description calling this an “amplifier,” it does not function on its own as an amplifier. It does, however, vary the strength of the output from the pickup going to the next component as seen in the video.
• Tone Distiller: I wired an on-off switch as well as an LED in the positive battery lead to indicate power on, as well as added connectors for the signal in and signal out wires.
• Reverb: I discovered this through the Instructables project here (https://www.instructables.com/Echo-Reverb-Box/) and intended to make the modification described to add Echo control, I ultimately did not (so far). I simply detached the pot from the circuit board and soldered wires leading to the Type B 25K pot. In addition, I also added an on-off switch as well as an LED in the positive battery lead. I used a couple of connectors to attach the signal in and out wires to the posts provided rather than soldering those. (I have another of these modules which I may undertake modding to add the Echo control as described in the Instructables project; if so, the pot will take up the first of the currently unused pots.)
• Amplifier: I considered adding modding the board-mounted gain pot with one I would have access to, as described at C. B. Gitty’s page for this item, but ultimately decided not to risk ruining the amp. I simply turned the gain up all the way. I think the Pickup Output pot serves as a gain pot for the entire system, but I could be wrong. There was already an LED wired to the circuit board, so it was merely a matter of attaching connectors to the signal in and signal out wires.
• Speakers: I put a splitter leading into the speakers, with one path leading down to an output jack mounted to the spine about where the switches are. The main internal speaker is mounted near a grill in the side of the instrument as well as a small grill in the removeable back.

As can be seen and heard in the video (which only demonstrates the internal speaker, not the external one), higher settings of the Tone Distiller result in increasing feedback, but I can minimize it by backing off on the pickup volume (unfortunately diminishing the amplification as well). It seems like the best overall balance is setting the Pickup Signal and Amplifier both at full, with the Tone Distiller set to 2 and the Reverb cranked to full.

I will keep tinkering with it, however, and see if I can further minimize the feedback issues overall.

Thanks for reading.