I’ve been retreating back into musician mode and have been eyeballing boost pedals and some unconventional thinking has me wondering if the H2 would be a suitable candidate for a “cleanish” boost pedal for an electric guitar.
For the unfamiliar, a boost pedal doesn’t necessarily have to alter the tone of the instrument as much as it is used to add gain which is often used to overdrive the input/gain stage of an amplifier. Boost pedal types range from very clean and undistorted to fairly gritty, essentially overdriving the signal in and of themselves.
Looking at what’s largely considered the first boost pedal, the Electro-Harmonix Linear Power Booster 1 (LPB-1), it’s a common emitter amplifier with a voltage gain of 25 (+28dB) using a 2N5088 NPN BJT. The H2 V2 kit has a gain of +9dB. I’m thinking I can maybe use the kit as-is but daisy chaining the left and right channels into series mono operation for a total gain of +18dB. It might not be enough gain or grit for your garden variety boost pedal but I’m wondering if it’s a good starting point to add some gain with increased harmonic content to an electric instrument. Perhaps I could alter some values for 14dB of gain per channel, like the original H2 schematic?
Edit: maybe this should be in the instruments forum?
For the unfamiliar, a boost pedal doesn’t necessarily have to alter the tone of the instrument as much as it is used to add gain which is often used to overdrive the input/gain stage of an amplifier. Boost pedal types range from very clean and undistorted to fairly gritty, essentially overdriving the signal in and of themselves.
Looking at what’s largely considered the first boost pedal, the Electro-Harmonix Linear Power Booster 1 (LPB-1), it’s a common emitter amplifier with a voltage gain of 25 (+28dB) using a 2N5088 NPN BJT. The H2 V2 kit has a gain of +9dB. I’m thinking I can maybe use the kit as-is but daisy chaining the left and right channels into series mono operation for a total gain of +18dB. It might not be enough gain or grit for your garden variety boost pedal but I’m wondering if it’s a good starting point to add some gain with increased harmonic content to an electric instrument. Perhaps I could alter some values for 14dB of gain per channel, like the original H2 schematic?
Edit: maybe this should be in the instruments forum?
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Here you go:
H2 V1
H2 V2 (currently in the DIYAudio Store):
I’m aware that V2 was made for 12VDC wall warts and the input gain for both schematics is set by the R1/R2 ratio. Most effects pedals use 9VDC or have an onboard charge pump to boost the 9VDC.
H2 V1
H2 V2 (currently in the DIYAudio Store):
I’m aware that V2 was made for 12VDC wall warts and the input gain for both schematics is set by the R1/R2 ratio. Most effects pedals use 9VDC or have an onboard charge pump to boost the 9VDC.
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considering that signal level for gitah is much lower than line level, feel free to increase drain resistor value, thus increasing gain
be it one stage or cascaded 2
don't obsess too much with measurements for said resistor (working points etc.) you can do that solely by ear
you can even make drain resistor variable - put one fixed resistor and, say, 1K trimpot or pot, connected as variable resistor (use CCW pin and wiper, CW pin left out)
be it one stage or cascaded 2
don't obsess too much with measurements for said resistor (working points etc.) you can do that solely by ear
you can even make drain resistor variable - put one fixed resistor and, say, 1K trimpot or pot, connected as variable resistor (use CCW pin and wiper, CW pin left out)
Check out the Echoplex preamp pedal schematic. It is one of the most popular guitar boost effects. Very similar to the H2. You can buy or build, your choice.
I have a couple versions that I use with bass guitar. They vary from clean boost to somewhat dirty, and make a great preamp to feed into a bass or lead guitar amplifier. Most versions will run from 9V to 18V pedal power supply.
I have a couple versions that I use with bass guitar. They vary from clean boost to somewhat dirty, and make a great preamp to feed into a bass or lead guitar amplifier. Most versions will run from 9V to 18V pedal power supply.
The echoplex preamp looks good but I’m not sure +6dB is enough gain. Which isn’t to say I might not build one anyway….
Would the h2 be canceled since we are entering the second one reverse polarity?
I was thinking doing the same thing as Brinkman but for a bass, to bring out some h2
just try it
engage your pleasure senses with entire setup in action, not too much brain before that
with boost you'll easily get bunch of overtones and harmonics, who cares about dominant and phase?
meaning - first devise what is that you actually like, then make analysis
engage your pleasure senses with entire setup in action, not too much brain before that
with boost you'll easily get bunch of overtones and harmonics, who cares about dominant and phase?
meaning - first devise what is that you actually like, then make analysis
I always have a compressor as part of my processing chain. Most models have input and/or output gain. I adjust the compressor to get my instrument signal into a range where the Echoplex preamp can dial in the final clean/dirty boost to hit the tube input stage of my bass amp right in its sweet spot.
Passive guitar pick-ups would not be too happy with the lowish input impedance of that circuit, especially if volume pot is not at full setting.
A fellow I played with years ago had such a boost built right into his guitar. Really gave him an edge when he flipped that switch. I assume it was able to OD the first tube stage of his amp - as well as the rest further on. The 1st tube stage I assume are ordinarily setup in the hopes of passing a clean signal from most any stock guitar pickup.