Basic theory of an octave fuzz? Is there a Geo article?

[strassercaster]

hello i just made a PE COB . for a friend. I started building pedals 7 months ago and it was my 45th build to date. I started out years ago in pinball machines and restorations. i had a tech that was a cool guy and he taught me a lot about electronics.He taught me well it got to the point he hated coming because i had serious tough issues ha ha. i really got into it for several years buying and selling about 80  machines spanning 6 decades. I prefered the 90's machines because of the challenge and profitability ha ha. I no longer have any pinballs and decided to get into pedals.So i know some basic theory and do really well at trouble shooting but most of what i know has nothing to do with tone audio or sine wave/triangle waves or how these circuits come together.Pinball is more about switches ,connectors,timers, clock chips and cpu issues.

i have read most of the Geo articles . i have built univibes,chorus ,compressors,delAys, fuzz ,rangemasters,flangers ,all on stripboard except the flanger and univibe which i am in the process of doing.

I havent seen a good article on the technology of an the octave fuzz. I love the way RG goes into each circuit. My addiction started with modding my wah back in december. the wah article is a masterpiece
.could someone walk me through this circuit .I know its splits at some point but how or where is the octave coming from? I know its q3-4 but what going on there? while i have studied all the RG Geo fx articles .I have to read them several times and sometimes i still cant wrap my brain around some of the more complex stuff.i admit i am still painting by numbers in a lot of ways and realise I dont know much.I saw a comment RG made on the prescription electronics build and it got me thinking.

The build i just did i started with  the reccomended 2n3904 and it was like circus lemonade. it was mild And nothing to get excited about. they were all at 330-355 hfe. so i upped them to 2n5088 550-590 hfe and i was pleasently suprised. So i saw where he said that q3-4 were the octave section so i upped those to 2n5089 and it was really octaving but also noisier and some unwAnted distortion. so i backed q3 down to a 2n5088 and it was right where i wanted it. just on the verge of insane with the octave knob at 9 and insane  totally dimed.

i read that a few people match  these transistor pairs as close as possible. i was wondering because i already mailed it to him . Did I mess up . it sounds good bit could it have been better had i matched the sets as close as possibel? i did like it better with q4 being hotter but its a quirky effect doesnt do much below the 9th fret.

Thanks in advance and I am 90 percent done with mine I just need to hook up the 3pdt switch which ill do in a couple of days. i am pedaled out  I built a fuzz face and a small clone chorus today on stripboard plus the second C O B of the week.Thanks again

hey Billy, Its me john . the COB sounds great. I am going to build me one soon. I might even have parts on hand already, and if so, i can put one together by tuesday ..i like this one much more than the green ringer I am using..seems to have a more pronounced octave effect and the ringer is really bad outside of the sweet spot for much of anything .

Billy , you are way ahead of the curve. your stuff looks like you been doing this for 5 years already ..those pinball machines are like computers/atches and old radios ..full of physics and math lol

Thank you John .mitsna cool corcuit. I was going to start on a Foxx or tycho brahe one afternoon and my friend requested the clean octave blend which i never heard of. i was pleasently suprised after i did some tweaking. i would have never known . I have owned boss pitch shifters and whammy pedals. they always sounded sterile or cold to me kind of fake. these fuzz octavers have a warm fuzzy feel ha ha. It a definite keeper and Ill be building the octavia soon.

its good to know its verified - cozy traced it and you built it ..Im good to go !

I got the tycobrehe working and didnt like it ..I may have made an error in the build but it was some nasty tone destroying fuzz and not much octave lol

tag board has two new ones up ..a liquid phaser and a tap tempo trem. I saw the huge phaser board and thought of you haha

i saw those as well. i finished the univibe on a srtipboard layout. its really nice. i went to far with it though. i put a rotary switch for the 4 phase caps. i did set 1 univibe setting 2 voodoo vibe (not as goid and setting 3 pahse 90 total failure.bsounds like a detuned tremolo. ha ha.overall i am happy with it but it has a volume drop. i have about 12 hiurs in it and i will tweak it soon.thankd goodness it fired rightup. i can do a lot of buils start to finish in 2 and 1/2 too 3 hours iff i drill and paint first .

after the univibe build i am not doing anything mega for a while. i have orders backing up a few tonebenders and other germanium circuits to do for some semi famous players.