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DIY Stompboxes => Building your own stompbox => Topic started by: yeeshkul on June 27, 2022, 04:59:26 AM

Title: EHX - Octave multiplexer - glitches in sustain
Post by: yeeshkul on June 27, 2022, 04:59:26 AM
I purchased the one in a big box, and i can't get a smooth sustain from it. It interrupts the tone with weird glitches, like yodeling.

Is there any help?
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: Jacob Mariner on June 27, 2022, 06:29:08 AM
I have an EHX Octave Multiplexer.

Hard to say exactly what your problem is without more details, but it sounds like it's picking up on other notes, harmonics, or just noise. It's a mono-phonic pedal, so make sure you're only hitting one note at a time; if the previous note is still sustained then it might "yodel" between them (yodelling is exactly what I call it).

Anything you can do to reduce noise-signal ratio pre-pedal might help. If it's part of a chain, where is it? Does your instrument sustain a note by itself or is your sustain achieved with an amp/chain? Does your instrument or playing style create harmonics, and if so do you want them? If you're playing with others might your pick-up be catching your bandmates?

I often find mine jumps around when I hit the note depending on how "clean" the start of the note is (how aggressive my right hand is, and whether I've hammered down with the left hand). Sometimes it opens up some cool character and effects, but usually I just want clean tone out of it.

Let me know how you get on in the comments, as I'm likely to find any tips for the same pedal useful too!
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: yeeshkul on June 27, 2022, 07:13:49 AM
Thank you Jacob.

I played SG/Les Paul through the EHX straight to a VOX AC15 amp. Clean sound.
I noticed the neck pickup is less prone to yodel.
Higher notes are more prone to yodel.
I played single notes but i need to play notes that kind of blend, i can't play "dag dag dag dag" if you understand what i mean.

I would love to have an octave down pedal that doesn't do this. Thank you.
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: Mark Hammer on June 27, 2022, 10:13:16 AM
The gospel of both analog up and analog down octavers is that you need to feed them signals that come as close to 'pure' tones as possible, so that they aren't confused by harmonics and other elements you're not interested in doubling or halving.  Filtering in the pedal itself will work towards that goal, but the first step is to use the neck pickup, roll the guitar tone back, pick above the 7th fret (where there is less harmonic content) and avoid skinny strings that introduce too much unintended vibrato.  In the absence of those precautions, I haven't found an octave divider yet that won't exhibit the issues described.
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: iainpunk on June 27, 2022, 11:34:55 AM
i have an EHX Pitch Fork, its a digital pitch shifter, and does oct. down very well. its also polyphonic and has no trouble tracking full chords. i suggest putting it before any drive/distortion to keep the ''synth/autotune like nature'' at bay.

it can do way more than octaves tho, it has a bunch of pitch shifts which all work equally well.

cheers
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: Mark Hammer on June 27, 2022, 11:53:09 AM
It IS digital, however, and has the equivalent of a fistful of components necessary to be as foolproof built into the DSP software.
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: ElectricDruid on June 27, 2022, 02:06:02 PM
Quote from: Mark Hammer on June 27, 2022, 11:53:09 AM
It IS digital, however, and has the equivalent of a fistful of components necessary to be as foolproof built into the DSP software.

More than a fistful! I reckon bucketsful would be more like it. ;)
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: Mark Hammer on June 27, 2022, 04:09:31 PM
Fistful of surface-mount = bucketful of thru-hole.
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: StephenGiles on June 28, 2022, 03:59:01 PM
As said before, you need the deluxe Octave Multiplexer which pre conditions the input signal to a sine wave with its Adaptive Filter.
Title: Re: EHX - Octave multiplexer - glitches in sustain
Post by: ElectricDruid on June 28, 2022, 06:45:49 PM
Quote from: Mark Hammer on June 27, 2022, 04:09:31 PM
Fistful of surface-mount = bucketful of thru-hole.

Lol, true enough.