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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Vinnie
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Post by Vinnie »

Hello,

I personally love the "organ like" effect that can be obtained from the POG, perhaps could be interesting to discuss about the possibility of designing a non based DSP POG (complete analog device) starting from block diagrams.

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Post by DougH »

soulsonic wrote:Stupid DSP. People are amazed at what the POG can do..... it's just a computer! I wonder what the "Hazarai" opcode is?
They're still cool-sounding effects, but the DSP thing kinda puts it in the same category as some kind of Digitech multi-effector, except it only does one effect. It's cool that they can do that now, but it's not exactly one for analog purists is it?
I'll give you the benefit of the doubt and assume you are being sarcastic here, as this is a great parody of the typical tube-screamin' Gear Page goofball. :wink:

Of course it's DSP, never claimed otherwise. It's essentially a digital guitar synthesizer, although its bigger brother, the HOG, has more "synthey" features.

FWIW, I love my HOG. It has an incredible amt of depth. I've had mine for over a year and have still barely scratched the surface of what it can do. Yeah it does all the organ sounds but that's a very small % of what it is capable of. One thing I love about it is that it has the flexibility and ease of a digital synth combined with a very "analog" feel. For example, instead of all the monotonous patch-editing, you just turn the dials and set the switches where you want and save it in the footswitch. Six presets is kind of limiting but for me that's a happy tradeoff for the simplicity of operation.

IMO, the POG/HOG are easily the most interesting (and on some levels innovative) guitar effects to be produced since the whammy pedal.

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Vinnie
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Post by Vinnie »

OK, I need 5 post to link an url :roll:

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Vinnie
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Post by Vinnie »

Well, here is my proposal for an analog POG, feel free to contribute, discuss, argue, what would you add? ......... please! :lol:


https://img.photobucket.com/albums/v640 ... 1190889050

Vinnie

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Post by DougH »

It's a start. I would add an adjustable LPF on the output of it. This should be an active filter with a steep rolloff. To get the "organ" sounds you need to be able to mix in the octaves and then roll off the high-freq with an LPF. Then, make it controllable from an expression pedal as an option. This will give you the ability to get some synthy textures. You also might consider some sort of envelope control as well.

Edit: One of the biggest challenges you are going to have is getting a clean octave in an analog circuit. And it will be difficult to make it polyphonic as well. You will have to track and separate all the fundamentals in the guitar signal and produce clean octaves for each. It's a tall order for analog electronics. Not saying it can't be done but...

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Post by Vinnie »

DougH wrote:It's a start. I would add an adjustable LPF on the output of it. This should be an active filter with a steep rolloff. To get the "organ" sounds you need to be able to mix in the octaves and then roll off the high-freq with an LPF. Then, make it controllable from an expression pedal as an option. This will give you the ability to get some synthy textures. You also might consider some sort of envelope control as well.
Ok, which will be the fequency range to be adjusted? and what about a parametric filter?
DougH wrote:One of the biggest challenges you are going to have is getting a clean octave in an analog circuit. And it will be difficult to make it polyphonic as well. You will have to track and separate all the fundamentals in the guitar signal and produce clean octaves for each. It's a tall order for analog electronics. Not saying it can't be done but...
Yes I know, specially for clean octave-ups ........ I understand that the topic is to alter the signal timbre, the guitar signal harmonic content and the amplitude associated to evrery harmonic ..... there I'am lost lost in a sea of ignorance :cry:

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Redhouse
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Post by Redhouse »

I know this thread is old, but I'm only gettin 404's.

Did anybody stash this stuff, and would ya mind tossing me the files?

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Post by Gila_Crisis »

do anyone still has the schem for this one?!? the link you posted doesn't ork!

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Post by Dirk_Hendrik »

Gila_Crisis wrote:do anyone still has the schem for this one?!? the link you posted doesn't ork!
I know. Some big Ork made real effort to have this stuff removed. That's why it doesn't Ork. Send me a mail and I'll reply with attachment.

btw.
You're not going to build this one after seeing that schematic. :wink:
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

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Post by Dirk_Hendrik »

Interesting...
Last week I sent this schematic to mutiple people as results of threads like this one. these threads got very very quiet immediately after doing so.... I wonder how that would come???

Might it be page 3 of that schematic??

btw,

That POG schematic comes, as many of us know, form a larger archive whech was, most likely as result from harassment by a known Ork, removed. This is what's in there:

16secondschra.pdf
2880rc.pdf
qtron.pdf
bassballs.pdf
bifilterschrb.pdf
bigmuffpi.pdf
blackfingerra.pdf
deluxeelectricmistress.pdf
deluxememoryman.pdf
doctorq.pdf
doublemuff.pdf
eh4700slapbackecho.pdf
freedomamp.pdf
frequencyanalyzer.pdf
graphicfuzz.pdf
hogschra.pdf
holiergrail.pdf
holygrailrbsch.pdf
lilbigmuffrb.pdf
lpb2uberb.pdf
metalmuffrc.pdf
microsynthesizer.pdf
miniqtron.pdf
octavemultiplexer.pdf
pog.pdf
polychorus.pdf
pulsar.pdf
qtron.pdf
smallclone.pdf
smallstone.pdf
stereomemoryman.pdf
tubeeqschrb.pdf
tubezipperrevb.pdf
whitefingerschra.pdf



People hosting this stuff tend to get harrassed by the the Ork. Therefore drop me a mail if you need something.
Sorry. Plain out of planes.

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Post by Sock Puppet »

Using those filenames, it's possible to find the schematics - they're still out there.

S.

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Post by krome_magnon »

Sock Puppet wrote:Using those filenames, it's possible to find the schematics - they're still out there.

S.
Or just grab them all here...

http://sharebee.com/373969b4
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Post by Stephengiles »

There doesn't seem to be a link there.

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Post by DougH »

I don't think a schematic for DSP device without the source code is going to do you much good. But hey, have fun...

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Post by analogguru »

you only have to click either on:

Badongo

or:

RapidShare

or.....

as long as the ork doesn´t pass by...


enjoy,
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Post by Stephengiles »

Many thanks

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Post by OrionManMatt »

Is there anything else out there besides the POG and Micro POG that will simulate organ tones? That's really the only part of the POG that I'm looking to build. Or will combining two octave pedals in one (up and down) with a low pass filter accomplish anything like the POG (recognizing the DSP in the POG is substantial)?

Thanks.


I stumbled upon this forum through many google searches and have been very happy with what I have found here, both in terms of the quality of the posters and the information available.

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Post by vanessa »

OrionManMatt wrote:Is there anything else out there besides the POG and Micro POG that will simulate organ tones?
You can do pretty convincing organ "comping" by setting your tone control to full bass, add a little tremolo (or leslie sym) and a nice amount of reverb. Then comp your chords.

The tricky thing about getting organ chord tones is harmonizing. The trick is good tracking on notes and chords. Boss sells a stomp unit that tracks really well for the price. Add a little distortion, reverb and leslie sym to that and you should be getting something close at a lower cost.

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Post by OrionManMatt »

vanessa wrote:
OrionManMatt wrote:Is there anything else out there besides the POG and Micro POG that will simulate organ tones?
You can do pretty convincing organ "comping" by setting your tone control to full bass, add a little tremolo (or leslie sym) and a nice amount of reverb. Then comp your chords.

The tricky thing about getting organ chord tones is harmonizing. The trick is good tracking on notes and chords. Boss sells a stomp unit that tracks really well for the price. Add a little distortion, reverb and leslie sym to that and you should be getting something close at a lower cost.
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?

Of course all of this gets me thinking and thinking:

1) I begin to think of preferable ways to spice up a tremolo to make the effect even more convincing (and generally just plain sweet): adding a tap tempo (which few tremolos seem to have and it seems ridiculous to me that more don't); and an expression pedal input so that you can control the speed of the tremolo with your foot much like you would have control with on an organ.

2) Something a little less complex than the HOG but along the same line of thinking of dialing in harmonics through the use of faders or knobs. Using the basis of the described pedal above, adding two knobs for dialing in a "third" (with a switch for major or minor) and a "fifth."

Just brainstorming but no clue how to accomplish....

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Post by vanessa »

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.

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