ukulele

Welcome! Here's all the sheet music.

My record collection

A list of record stores I've visited

Introducing the Amp Omitter!

I've created a portable pre-amp for my steel guitars. It's called the Amp Omitter: it omits the need to have an amplifier. It's a guitar pedal that amplifies the signal from a guitar up to levels that can go straight to an audio interface or mixer. It runs on batteries or it can use a power supply.



For a long time I have been unhappy with the methods to interface my Rickenbacher B8 to my computer. I like the sound of the instrument when played through an amplifier and I want to record it and mix it with our band's tracks. I don't want to use a microphone to record, I want to go directly in to the computer. The solution is to put the pre-amp section of an amplifier in between the guitar and the computer.

Our group doesn't use stage amplifiers, we all plug in to the board and let the sound crew mix us. I want the capability to plug my steel guitar into any channel on any mixer I encounter as we perform at various venues.

These needs drove the design of a portable preamp. The idea came from a convergence of conversations I had at Aloha International Steel Guitar Club conference in July, 2024. I decided to make a box that can amplify my level, adjust the tone, and can travel anywhere. Here's a thank you to ideas from Ivo Garza (transistor circuit simulations of guitar amplifiers), Doyle Grisham (reference to the Walker Stereo Steel preamp) and Bobby Ingano (plug straight in to the board). Other credits go to Portable Guitar Preamp at Instructables.com and JTEX Indicator: 9V Low Battery Indicator & Power-On Flasher

I made four units with variations with or without batteries and with or without tone controls: a prototype to learn how to design a build these things, a finished product that works on batteries or power supply, a smaller product that requires a power supply, and the smallest product having only volume control and no tone control.

My favorite is the battery powered version. The gain of the unit is quite high; I use two batteries to get 18 volts of DC power, leading to undistorted gain of about 34 dB for my Rickenbacher B8. Yet because of using battery power the unit is quiet as a mouse. Using the battery-powered Amp Omitter with all neighboring power supplies turned off gives a delightfully clean tone to my steel guitar. My signal path for recording is steel guitar->Amp Omitter->DI box->Mackie Pro FX4v2->Focusrite Scarlett 4i4->iMac. I could skip the DI box and Mackie mixer and go straight to the Focusrite Scarlett interface.

Since this is an amplifier, it will amplify any noise. To prevent noise getting into the box from the surroundings, I use shielding within and around the electronics. However, noise can come in on the power line from DC power supples, and can come in at the input jack. The power supplies on typical pedal boards broadcast voltage variation through the power line (conducted emissions) and through the air (radiated emissions). The conducted emissions are called power supply ripple because the direct current is not without some alternating current. Much of this voltage variation can be attenuated in the filter circuit, but what doesn't goes straight to the transistors and ends up in the amplified output.

The radiated emissions can't be filtered out without losing some tone. These emissions appear on the audio input to Amp Omitter. They get the full 34dB of gain just like the guitar signal does. Power supply radiated emissions are strong at the power plug. Once the plug is inserted into the case of the AmpOmitter, the radiated emissions are free to contaminate the neighboring input jack. Maybe an improved version of the Amp Omitter will be able to isolate the audio circuit from the power supply plug's radiated emissions.

The versions of Amp Omitter without batteries are smaller and can fit more easily on a pedal board. Since this means they will be in the noisy environment of DC power supplies, they'll send a buzz to the output. My solution is the HumDebugger by Electro-Harmonix. I already had that unit on my pedal board because my Canopus steel guitar has noisy single-coil pickups. AmpOmitter will amplify that buzz as it shapes the tone, then HumDebugger takes out the noise caused by DC power supplies.

I went to the trouble of adding a battery level detection circuit to the battery powered units. The green light will be on when the batteries are in their useful life range, then a red light will indicate that the batteries are losing power but might still be useful and eventually both lights will fade out as the batteries die. When the battery level is low, the output will be low.

Unit Battery option Tone Controls Volume control Feature
1 Two 9 volt batteries Yes Yes Prototype unit for learning
2 Two 9 volt batteries Yes Yes Quiet operation, battery level detection, using power supply will save battery
3 No Yes Yes Smaller since there are no batteries
4 No No Yes Smallest size by using a fixed tone

An index for all the licks

The bag of licks has more than 1300 items, including licks, vamps and outlines in five different musical keys. Here's a table that indexes all of the individual licks. The table is grouped by chord progression and musical key. For some, a small image of the lick is linked to a larger image with a recording of the lick. Use these licks if you want a reference or if you want to practice outside the context of a song.

String clusters added to Bag of Licks


String clusters are added to the practice songs in Bag of Licks. The display shows the potential string clusters for each chord in a song.

String clusters were taught by Alan Akaka in a symposium in Cupertino, California, in 2022. This was the workshop at the Oddfellows Hall on the Sunday after the Hawaiian Steel Guitar Association conference in San Mateo, CA.

String clusters are chords played three strings at a time. The chords are played rhythmically in a pattern of the player's choosing. The rhythm of the string clusters is inspired by the rhythm of the melody.

Because of the tuning of the strings, a three-string cluster can be viewed as three notes from one of many different chords. The role the cluster plays in the harmony is related to what the rest of the band is playing. The same three strings can sound harmonious over a C, an Am, a D7, or an F. They can add a 6 note, a sus4, or a 9 note, which theoretically might not "belong" in a chord, but they bring flavor.

The string clusters make a great method for paʻani instrumental breaks in a song. Memorize the various clusters that work over a chord, then play them as if they were the melody. Alan Akaka taught them using the song Noho Paipai, here's a demonstration of me playing over Na Moku Eha.



My plan is to first memorize the string clusters in the key of C and play them over songs have only three or four chords. Over time I'll move into other keys and other chords.

Page 1 of 3