How clean/flat is the SHO circuit?

[jtn191]

^ well that's exactly what I wanted to find out  

I read online that somebody of moderate fame plays acoustic guitar through the same SD pickup as me and into a SHO. He liked it so I decided to try it.

After that, I wanted to measure the frequency response of the pedal. So I did it with a program called Fuzz Measure, used in pro audio to test room frequency response and consoles, converters, etc.  BTW, I built mine with higher input impedance (a la stock) with edit: 10M resistors

Default Window


As you can see, it's pretty flat--with some tiny fluctuations in the bass range and a mild drop off near 20kHz...most of which aren't even noticeable. So there you have it...any noticeable brightness is a reaction to pickup impedance or amp characteristics

Meanwhile, this is the Neutrino circuit at "clean boost" setting: Gain 0, Tone: half, Vol: half
Not clean at all...giving it a midrangy, lofi kinda feeling


Compared to Sunking's clean boost






Man, I wish there was an "analysis" or "nerds" section

[jkokura]

Did you build a stock SHO or a Madbean version? I think the SHO came with 10M resistors, not the 1M or 2.2M that often get used. You should try it with at least 4.7M or 10M resistors in there for the impedance/voltage division. I'd like to see that.

Jacob

[jtn191]

yeah, it was with 10M, it's just been a while

[lincolnic]

Just wanted to say how much I appreciate your post here. I'm an audio engineer by trade and I totally dig seeing the frequency responses of these pedals. Thanks for this!

[petesz]

this is really cool!
even though i know nothing technical about this stuff i find it interesting..

[madbean]

Nicely done! I always found the SHO to be pretty flat, and the Jack Orman mosfet boost to be flat and cleaner. The Sunking plot is about what I expected...moderate boost in the "presence" range. I'm a little surprised at the large dropoff at 10k, though.

[bigmufffuzzwizz]

This is something I'd like to learn how to do one day. All these are taken before the circuit gets gainy?

[stecykmi]

very interesting, i guess vex isn't lying when he says using the SHO just like your guitar, but more of it.

[jtn191]

This is something I'd like to learn how to do one day. All these are taken before the circuit gets gainy?

yeah, the ODs are set with gain at 0 (or 7 O'clock-sh) and the SHO with gain at 50%. Really, you could just play your guitar through the pedal, mess around, and find a setting where you go "huh, I wonder what frequency response I'm getting here". This measure frequency response, while an oscilloscope measures harmonic distortion

How it works is: I hook up the output of my audio interface (channel 1 or 2) to the input of the pedal. Then I send the output of the pedal back to the input of the interface. Make sure you aren't sending signal out and listening to the input at the same time, or you'll get a feedback loop.

Fuzz Measure sends a sine sweep--sounds like a quick, deep siren--from 1 Hz to 20kHz out of the specified channel. It's played at the same volume level. Then, it's recorded at the input and graphs what is increased or decreased.

The coolest part of this is what you get back is recorded as an impulse, which can then later be convolved with any audio later--meaning: you can have a song and go "I wonder what the vocals would sound like if they had the same EQ as a klon in clean boost? Load up the IR!"

This idea can be used in reverb to "capture" the sound of a room...but it doesn't work with how a sound is compressed or distorted, only reverb and EQ.