octave up sick box not expected to survive the nite :(

[pinkjimiphoton]

hi guys,
gus had thought i might dig his OUSB, so me being a highly paid, trained professional, i figured i'd give it a shot.

so i worked this up:



i DID miss one cut at k 17...

but i can't seem to get anything thru this thing. it's late, so i don't wanna get too crazy with the audio probe etc...my household will shoot me at sunrise if i start making noise now.

this is the schematic i used:



i don't have any 5532's, so i tried tl072/82, 4558, etc...basically whatever dually oa's i had kicking around. the gain knob makes horrible noises, and the volume pot works...

but i can't get any guitar thru it. i did look up the pinout of the 5532, it's a standard dual opamp.

i have looked this layout over side by side with the schematic, and i can't find the issue!! basically all i get is noise, oscillation and hum;

i did sub a couple resistor values; 220 for r1 instead of 270r, 240k for 220, and a 1 meg for the volume, as i was down to my last 100k pot and i figured for a volume pot, that should be fine at the end of the circuit.
multiple chips...all read basically the same:

1  4.98
2  4.90
3  4.79
4  0.00
5  4.84
6  4.94
7  4.95
8 9.76

interestingly, touching my meter lead to pin 3 nukes most of the noise.

any ideas?

thanks!!

[petey twofinger]

this is a really lame suggestion , but , i am sure you counted all the jumpers / cuts .

thats my favorite personal thing to screw up ....

also , do you have a quick and dirty yet ?

i swear man , those things are indespensable , grab a crap chassis from slavation army , like a pc data switch , or a lil candy tin ... total cost is under 10 , by far . i made the error of omitting a battery , but i got one in there now . best tool in the bunch .

good luck .

[Gurner]

The opamp voltages look right (I'm not familiar with this particular cct, so that's from a generalized perspective).

If you don't have a scope, you could lift the 10uf right hand legs (the leg attached to the 33k resistor) & listen if you've got a decent audio output into your amp up to there - I'm figuring you likely will....then it comes down to those diodes - are they definitely in the right way....what voltages do you have on them?

edit: D4 on the layout looks to be in the wrong way...the cathode should be facing R6 - it isn't (in fact same with D10!)....try reversing them.

[pinkjimiphoton]

hi gurner,
the diode clipper is right. if i reversed the diode you're talking about, the clipper can't work. d 4's cathode is connected to ground, it's anode is connected to d3's cathode. d5's anode connects to d6's cathode, d6's anode connects to ground. the clipper is definitely ok...as long as each series pair of diodes is opposing, it doesn't matter which way either pair is oriented.

stumped....will audio probe it later to see what's what. suspecting if the voltages look ok that my small stockpile of duallys are cooked. i'll pick up a couple others today. i've looked at this thing til my eyes were burning!! lol

[Gurner]

hi gurner,
the diode clipper is right. if i reversed the diode you're talking about, the clipper can't work. d 4's cathode is connected to ground, it's anode is connected to d3's cathode. d5's anode connects to d6's cathode, d6's anode connects to ground. the clipper is definitely ok...as long as each series pair of diodes is opposing, it doesn't matter which way either pair is oriented.

this is peskier thatn it ought to be to discuss (cos your schem hasn't the component numbers on...and that's where this confusion has arisen...because of a layout error I initially thought your D3 was what you're calling D1), but if you follow pin 7 out...it goes to a 10uf cap (C4)...the other leg of C4 is connected to a diode D4...earlier I only paid a cursory glance earlier but now noticed  it's also connected to D1 cathode (which I'm now figuring is the correct diode...since it's cathode *is* facing the right way!) so there's an error there....D1 cathode in your schem is shown *not* directly connected to D4 (nor D3) they're meant to connect via a .47uf cap...I think you're missing a track break to the right of D1's cathode

[Quackzed]

+1 yep, checked , there needs to be a cut trace to the right of D1's cathode...

[pinkjimiphoton]

hi guys,
if ya check the vero, you'll see both anodes of d1 and d2 both connect to the .47u output cap as they should. it LOOKS funky cuz i tried to compact this a little more than i had to, cuz i'm trying to get it to fit in a single button fender footswitch case, one of the trapezoid shaped ones with the square led.

but...and yes, there is the one cut i did miss on the bottom, row, which i will correct as soon as i get a chance and fix this layout and re up.

this thing DOES work. the issue is that i was testing it standalone, not boxed...and the casing of the volume pot needs to connect to ground. THAT'S IT.

works GREAT. i don't know why the pot casing should make a difference, but it did.

octave up all over the neck, insane sustain and compression, totally reactive to touch and guitar knobs. i am impressed!!

gonna box it up today at some point...and up the corrected, verified vero for this that i did.

stupid pedal trick to come soon.

[pinkjimiphoton]

OK!~
here's the corrected, verified layout.

[deadastronaut]

octup all over the neck?.....@#$%ing nice...we gotta hear this!!!!!...

[slacker]

Yep all over the neck, at low gains it's about as clean an octave up as you'll find, crank it up and it's mental. My absolute favourite diy pedal.
Jimi there's a nice mod that disables the octave and turns it into a massive fuzz. From memory I think you lift the ground connection to one of the 33ks, well worth a try.

[Gurner]

Well this octave up version certainly one looks fairly simple   ....a full wave rectifier followed some clipping diodes (Rob....if you get your sustainer working, an 'octave up' effect should be a fun combo ....feed your 'sustained' guitar signal into it. Octave shifters crap out as the string signal fades and drops below the threshold level ....but with a sustainer....no signal fade)

[deadastronaut]

@slacker:  already done a layout of this, i was bored this morning..not sure if this is the switch you meant...took a lucky dip on that..but can easily be re-arranged

@G :  yep that sounds excellent..been looking for a good all over oct up...with a sustainer and harmonic that'll be @#$%ing brilliant....

heres my layout...



i'll post pcb/layout pdf's when that switch is confirmed?..if anyone wants them ok....

thanks for the inspiration jimi...

one question though, whats the deal with the volume pot lug 1 with th a+ symbol?...

[arma61]

one question though, whats the deal with the volume pot lug 1 with th a+ symbol?...

could it be the word "out" written by hand!!!       it's the only word missing!!! 

[deadastronaut]

arghhhhhhhh of course!..i need more coffee....

i'll slap myslef..

i don't get why jimi had to put it in a box to get it going though...weird!

[slacker]

Yeah the switch looks good to me Rob.

[arma61]

OT slacker a there's a guy that need help with a Rebote!!

sorry m8s

Ciao

[deadastronaut]

hold on missed the 4.7k coming off the pin 5..

sorted!..


@ian: cool!..

above image ammended....

[deadastronaut]

ok heres the ammended pcb/layout pdf's. ...ive checked it over, looks ok to my eyes.....

anyone see any problemo's?...

https://dl.dropbox.com/u/7464107/OUSB%20LAYOUT.pdf

https://dl.dropbox.com/u/7464107/OUSB%20PCB.pdf

[pinkjimiphoton]

octup all over the neck?.....@#$%ing nice...we gotta hear this!!!!!...

rob,

this think is freekin' sick. yes, all over the neck. even open chords. flick to the neck pickup, it's pure clean octave, flip to the bridge and it resembles an arp synth...it blooms. if ya team it with other dirt pedals, you can make it "swell in" like a slow gear...depending on knob settings, everything from crunchy overdrive to ring mod destruction.

i loved my octavia. i love my bobtavia. but this thing blows all the rest away.

[SISKO]

Wow!! Any sound clips?