John Korchok

The Zhaltar won for Best Thing That Makes Sound on Makers Day at the Hillsdale Public Library!

I started designing this new instrument at the beginning of 2022 and finally have a playable prototype. The name Zhaltar comes from the Slovak name for a psaltery. It’s played by plucking the strings, and it’s fully chromatic, with a range just over 5 octaves (C2 to C#7). The zhaltar is a solid-body instrument and a MIDI controller.

The strings are colored the same as on a piano. The right-hand and left-hand set of strings are each arranged as a whole-tone scale, with the left hand set being a semitone higher than the right. This means that once you learn a melody, you can easily transpose it by moving it up or down a string.

The strings and pickup contacts are made with Aquila Nylgut to give the sound a lute-like mellowness. The MIDI controller functions are still in development. I’ll post some musical samples, as soon as I teach myself how to play the thing!

This is what the iPhonarium has evolved into. This whole rig is be 100% battery-powered, so I can make noise anywhere.

Top to bottom:
Vox DA-5 amp
iPhonarium case with 4-channel mixer, battery pack and MIDI hardware
Keith McMillen K-Board (connects to 4S)
Akai EWI 4000s wind synth (I use it only as a MIDI controller, connects to 5S)
iPhone 4 running JR Hexatone (a classic, but not on the Apple store any longer)
iPhone 4S running Grain Science (love that app)
iPhone 5S running ThumbJam (still on iOS 10, so I can run old 32-bit music apps)
iPhone SE running iVSC3 (fantastic weird noise app)
Akai LPK-25 with foot switch jack mod for sustain (connects to SE)
Ancient Traynor foot switch
Korg iKontrol (connects to iPhone 4)

This the final iteration of this version. Newer iPhone have a larger form factor that will require a rebuild from scratch.

I’ve had my M-Audio NRV-10 Firewire interface for over 4 years. It’s a combination mixer and audio interface, which I find quit handy. Last time I went to plug it in, I heard a loud repeating percussive static coming from the monitors. My first thought was that the AC-DC adaptor was bad. It’s 12VDC 3500mA, not a size you can get at Radio Shack, but I had another with a larger amperage. Plugged it in, similar sound.

After digging around on-line, I discovered this is becoming close to a common problem for NRV-10s. For some period of time, they used bad electrolytic capacitors (see Capacitor Plague). These capacitors die within a few years of manufacture. After M-Audio discovered the problem, they extended the warranty to 3 years, but my machine went down after that. I suspect that in a few years there will be very few functioning NRV-10s from before 2008.

There is a helpful video on Youtube that details how to open the unit to check the internal power supply board. The photo shows what my bad board looks like:

8 out of 9 caps are leaking black goo and/or have bulging tops. Only the one in the upper right corner is still OK.

M-Audio is owned by Avid now. Avid charges for ALL tech support contacts. They want $14.95 for me to tell them I have one of their defective products. As an alternative strategy, I registered on their forum, found the thread for the bad capacitor problem and found the recommended information below:

We are currently out of stock on these capacitors, but in case you or anyone else needs the info, here is the information you’ll need to replace the capacitors on the NRV10 power board:
Remove the 8 capacitors located at C5, C6, C9, C10, C12, C13, C15 and C16 and replace with PANASONIC- EEU-FM1E681 (Capacitor, Electrolytic, 25V, 680uF, Low ESR, 20%, 10x20x5mm)
Remove the capacitor located at C8 and replace with PANASONIC – EEU-FC1J181S (Capacitor, Electrolytic, 63V, 180uF, Low ESR, 20%, 12.5x15x5mm)

I decided to substitute the Panasonics with Nichicon caps. Nichicon has a good reputation. I also increased the voltage rating on the ones I got to give them more robust power handling and longevity. Nichicon UHE2A181MHD (35V) for the 8 caps C5 – C16 and Nichicon UHV1V681MPD (100V) for C8. These cost $1 each at Mouser (mouser.com) instead of $0.67 each for the Panasonics. They are slightly taller, but there is loads of room in the NRV-10 case.