EHX - Polyphonic Octave Generator (POG)  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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Post by Aen »

I get a 404 :(

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Post by OrionManMatt »

Aen wrote:I get a 404 :(
For which link?

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Post by jazzmaster »

thank you for sharing this!

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Post by OrionManMatt »

vanessa wrote:
OrionManMatt wrote: In my limited opinion, the "tricky thing" is what the (Micro) POG seems to do so well. Is the Boss unit you're referring to their Super Octave (OC-3) or something different?
Harmonizers have been around for years, just not in a small stomp friendly package. Their prices have always been prohibitive. I think pretty much all the manufacturers have had one to offer at one time.
Eventide was the king for years. Roland came up with one of the finest tracking units in the late 90's (GP-100). They were calling it an "intelligent harmonizer". I think Robert Fripp and The Edge still use it for that effect to this day.
I'm pretty certain that this technology is the same that is used in their PS-5 stomp unit (http://www.bossus.com/datasheets/PS5FaxBack.pdf). It would seem that you could get more millage out of that unit than a POG. If you don't mind rack units the GP-100 has an endless amount of effects in it. Some are pretty good (harmonizer being the best, Leslie, tremolo, phase shifting, delay, reverb, some of the guitar amps are pretty convincing). It used to retail at around $1200. Now an ebay darling at around $200-300. A lot more bang for the buck compared to a POG.
You might want to check into the Boss GT (5) series. I think it has the same harmonizer in it, I'm not sure.
Thanks for the comments, Vanessa. I played the OC-3, GT5, and Micro POG this weekend at a Guitar Center in town and I'm pretty set on purchasing the Micro POG (unless someone wants to offer a cheaper alternative). I should be able to pull one for $180. The only thing that I want to use it for is "organ" tones to supply a chordal sustain for longer passages when we don't have a keyboard player. I can record and loop them for whatever.

I'd love to hear what others think. "All" I'm looking for is a B3 in a box. I'm such a newbie to all of this and it's been a huge learning session to be on this forum.

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Post by trad3mark »

is there a micro pog topic/schematic?

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Post by Scruffie »

There isn't cause there not far off eachother, but it's still digital, therefore uncloneable so with uncloneable products the threads usually get dropped.

If you reallyyy want I can probably open mine to have a peak, but I don't think it'd get anyone anywhere.

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Post by trad3mark »

i'm gonna have to buy this one, right?

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Post by Scruffie »

If you want it... yea, you ain't gunna make it... if your looking for that Jack White Bass (from your previous interest in him) tone may I suggest some other options though such as the Octave Multiplexer (which can be cloned & is cheaper if bought) & the BOSS OC-2 (cheaper, more sub octave options and I think can be cloned aswell)

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Post by soulsonic »

POG is a DSP unit. The schematic is pretty much just a drawing of a DSP chip with some I/O and control circuitry. You're not going to get too far without having the software for the DSP.
Here, you can get this one with a broken slider for relatively cheap:
https://cgi.ebay.com/Electro-Harmonix-P ... 1|294%3A50
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Post by trad3mark »

is the boss oc3 superoctave a DSP too or is it buildable?

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Post by Scruffie »

I dunno about the OC-3 But here is a simplified version of the OC-2 With just one octave down
http://www.aronnelson.com/gallery/main. ... d.gif.html
& Full version
http://www.freeinfosociety.com/electron ... php?id=135

I'd imagine the OC-3 Being newer though most likely is DSP...

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Post by Brian M »

vanessa wrote: Harmonizers have been around for years, just not in a small stomp friendly package. Their prices have always been prohibitive. I think pretty much all the manufacturers have had one to offer at one time.
Eventide was the king for years. Roland came up with one of the finest tracking units in the late 90's (GP-100). They were calling it an "intelligent harmonizer". I think Robert Fripp and The Edge still use it for that effect to this day.
I can't speak for the eventide stuff, but all the roland products that I know of which are capable of tracking multiple notes require a special pickup for your guitar. The GP-100 could produce multiple notes in harmony... but it could only track a single note as an input. If you played a complex chord the tracking would just go crazy.
I'm pretty certain that this technology is the same that is used in their PS-5 stomp unit (http://www.bossus.com/datasheets/PS5FaxBack.pdf). It would seem that you could get more millage out of that unit than a POG.
I believe that the ps5 claims to track chords. it does only a slightly better job than a whammy pedal though. play anything more complex than a major chord and it seems a bit jittery.
If you don't mind rack units the GP-100 has an endless amount of effects in it. Some are pretty good (harmonizer being the best, Leslie, tremolo, phase shifting, delay, reverb, some of the guitar amps are pretty convincing). It used to retail at around $1200. Now an ebay darling at around $200-300. A lot more bang for the buck compared to a POG.
as i said earlier, i dont recall the gp-100 being able to do this... not with chords anyway.
You might want to check into the Boss GT (5) series. I think it has the same harmonizer in it, I'm not sure.
similar but not the same... and still has the same problems. The gt5 has the same harmonizer as the gx700. I still have one of those. it will only track one note at a time... not chords. maybe a power chord... kind of, but not really.

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Post by DougH »

The PS5 will track chords in "pitch shifter" mode (i.e. octaves & fixed intervals). It will not track chords when "harmonizing". If your guitar is in tune (kind of stupid that you have to mention that but you would be surprised...) the tracking on it is near flawless as far as I can tell.

I have both the PS5 and the HOG. There is a small subset of functions each has that overlap, but for the most part they are very different and are used for different purposes. Comparing a "harmonizer" to a POG/HOG is like comparing an apple to a peach. Yes, they are both round and are juicy when you bite into them. That's where the comparison ends.

If you want to do intelligent modal harmonizing, get a harmonizer, not a HOG or POG. HOGs (and POGs?) do octaves and fixed interval major-thirds and fifths only. If you want the unique features of a HOG/POG (organ sounds, synth functions) don't get a PS-5. Etc...
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Post by nothingman »

Do someone know where to find the foot controler schematic of the HOG (for the memories and the expression pedal)?

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Post by theehman »

nothingman wrote:Do someone know where to find the foot controler schematic of the HOG (for the memories and the expression pedal)?
You would need not only the schematic but also the source code for the micro-controller.
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Post by jefcon1 »

Brian M wrote:
vanessa wrote: Harmonizers have been around for years, just not in a small stomp friendly package. Their prices have always been prohibitive. I think pretty much all the manufacturers have had one to offer at one time.
Eventide was the king for years. Roland came up with one of the finest tracking units in the late 90's (GP-100). They were calling it an "intelligent harmonizer". I think Robert Fripp and The Edge still use it for that effect to this day.
I can't speak for the eventide stuff, but all the Roland products that I know of which are capable of tracking multiple notes require a special pickup for your guitar. The GP-100 could produce multiple notes in harmony... but it could only track a single note as an input. If you played a complex chord the tracking would just go crazy.
If you don't mind rack units the GP-100 has an endless amount of effects in it. Some are pretty good (harmonizer being the best, Leslie, tremolo, phase shifting, delay, reverb, some of the guitar amps are pretty convincing). It used to retail at around $1200. Now an ebay darling at around $200-300. A lot more bang for the buck compared to a POG.
as i said earlier, i dont recall the gp-100 being able to do this... not with chords anyway.
I realize this thread is pretty old, but in the interest of having correct info out there -

the Roland GP-100 was, and is still, capable of tracking chords from a standard guitar pickup. The Harmonist, 4 Voice Harmonist effects have a Modes: 1-5, Mono, Harmony, Inv 1, and Inv 2. Modes 1-5 are capable of tracking chords. The rest of the modes are for harmonizing from single note input.

From the OM, "1-5: This is a conventional Pitch Shifter, and chords can be input. As the mode number increases the response will slow down, but the sound will have a less modulated feel."

Modes 1 and 2 track quickly but they seem to "seek" a lot on sustained notes. Mode 3 is a happy medium of quicker tracking with solid hold. I mostly use Mode 4 to get organ like effects that fade in after the beat. If you are using the 4 Voice Harmonist you can set 4 voices to there own pitches from -2 octaves to +2 octaves, with fine tune (detune) for each of the 4 voices. Very similar to a POG or POG2 without the filters. In addition you get individual predelay (0-740ms), pan L-R and Level for each voice.

One of the problems that the GP-100 suffered from was pathetic factory presets. I don't believe that the Modes 1-5 were even represented in the presets at all, possibly the "Twelve String" preset, but it was so drenched in syrupy digital chorus and over EQ'd that it was painful. I can't say that the GP-100 is a credible replacement for any of the POGs. The tracking is not on that level. But if you're like me and you've already got a GP-100 resting in your rack, and you've developed a new interest in having synth or organ type layers to your sound, the GP-100 can deliver.

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Post by Mbas974 »

Hello, can anyone explain to me would know what is the Octave Detuned the EH POG?

I found instructions here:

http://www.ehx.com/products/pog/instructions

In the specific:

Detuned +1 OCTAVE Slider - Controls the output volume of the +1 OCTAVE signal detuned. This signal is a modulated, detuned version of the +1 Octave signal. The frequency of the signal is detuned +1 OCATVE modulated at a fixed rate above and below the frequency of the original +1 Octave signal. The volume of the detuned +1 OCTAVE signal will INCREASE as this slider is pushed upward. Mixing the +1 OCTAVE detuned signal along with the dry signal will yield a 12-string guitar sound from one 6-string guitar.

... in other words, the signal (+1 octave) is modulated at fixed time OK?
what is unclear to me is when it says "modulated at a fixed rate above and below the frequency of the original +1 Octave signal"
The modulation/delay is only post the signal... "above and below" is refferred to what ?

Many thanks in advance.

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Post by Zokk »

It seems to be intented to create a chorus effect when added to a clean signal, so I imagine this works like that: you're playing A 440HZ on your guitar, on its side the +1 oct modulated waveform will oscillate around this frequency above and below few Hertz (don't know how much is the modulation depth but this could be +/- 3Hz or less).
This will result in a pitch modulated signal which goes from 337Hz to 443Hz (depending on the modulation depth setup).

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Post by Mbas974 »

Dirk / Krome_magnon,
can you re-post the schematics or a link to them for the ones mentioned in page 2 ....please ?


I'm interested in octave generator.
octavemultiplexer.pdf
pog.pdf
...sound good :-)

Many thanks in advance.

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Post by guycapuano »

Oh I thought we were gonna disect this............ :lol:

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