FLANGER (weird hiss issue)

[Rob Strand]

( i'll stick a resistor between the pot and wire that goes to the 33k to (add value) test.)

That would be good start.   The other way is to decrease the 3M3 (R17) on pin 12 of the 4046.  Both work but it's more a matter of not stuffing-up the way the unit works when the Manual isn't set fully CCW.   Perhaps increasing R19 is the least change.

Jim's comment about removing the diode clipper is the most accurate in terms of why the clock frequency is lower now compared to the JH design - well spotted Jim!    The clipper diode characteristic might actually smooth out the sweep a bit by rounding off the bottom of the LFO.

[anotherjim]

We know the TL072 can't swing to 0v, the only thing that's letting pin9 of the 4046 going too low are the x3 connections in a row to 0v of the Sweep/Manual controls.
I would suggest clamping those connections at a higher voltage. Instead of the 0v rail, put x2 diodes in series down to 0v. That should get a minimum of about 1.2V on the VCO control due to x2 diode drops.
So...
Put x2 1N4148 or similar in series with the cathode end to 0v. Connect Sweep lug 1 and R19 to the diode anode end instead of 0v. The cap C9 negative can either stay at 0v or move to the diode anode.

[deadastronaut]

''Put x2 1N4148 or similar in series with the cathode end to 0v. Connect Sweep lug 1 and R19 to the diode anode end instead of 0v. The cap C9 negative can either stay at 0v or move to the diode anode.''

hi jim, gotya....i'll give that a go....nice one man...

so sweep pot 1 and bottom of R19 go to the Anode of the 2 x 1n4148's in series, then the cathode to ground, if i read that right. 

[deadastronaut]

hi guys, well i did the the 2 x 1n4148's thingy....

no hiss, but hardly any flange now ....change R19?...

[antonis]

So Rob, you want both flanger action and no hiss..

Are you serious..?? 

[deadastronaut]

i know, how demanding am i ffs...

funny i swapped the R19 for my resistor sub box so i can change values, and it makes a lovely chorus...and flange....but its deffo not as strong as it was....

[Scruffie]

hi guys, well i did the the 2 x 1n4148's thingy....

no hiss, but hardly any flange now ....change R19?...

Your control voltage can't go lower any more, so to get the width back now the only way is 

[antonis]

Maybe you should try to leave R19 as it is and wire C9 between R19 and Pot..

[11-90-an]

try using one diode only and place a trimpot (say, 100k) in place of the second diode... You can fine-tune the voltage...

[deadastronaut]

maybe i should cover the pcb in sausage meat and bake for 20 mins...

after tinkering with it, the flange seems quite acceptable.....

i guess its a balancing act...diodes..resistor...

but yeah 1190an i might try that too..

[bluebunny]

seems quite acceptable.....

Hang on a minute.  What about the other twenty pages??   

[deadastronaut]

dont worry plenty more pages to come...

right guys, just noticed this.....when i touch the ''mix'' pot shaft with my finger, it hisses like hell...like a static hiss and crackle...

no other pot shaft does it, only that one...im guessing it needs a cap before it?..

when fully ccw hiss goes....hmmmm...so this could have been the issue?....

[antonis]

Are lugs 2 & 3 actually shorted or did you try it according to your notorious lazyness..??

[deadastronaut]

yes i am a lazy bstd 

EDIT: crackle sorted.......

however at certain settings i get a tick along with audio....when audio dies, the tick dies too......

this fckng flanger lol. its fought me every step of the way ha ha...

[bluebunny]

Decouple the power for the LFO?

this fckng flanger lol. its fought me every step of the way ha ha...

Or else get one of Druid's chips, gunk up the innards, and pass it off as the Astroflange.   

[deadastronaut]

i might just do that.....lol... he wont know eh ha ha.... 

(only joking mr druid) 


going to crack open a bottle of ice cold home made wine ...this 35 degree heat is too much , and think about it..... 

[anotherjim]

The heat was shocking today! Came out of Aldi's (we usually complain it's too cold in there) and the heat shock was like woa! Car was too hot to wait for the air con to kick in. Open all windows!

Anyway, a quick try for LFO tick - got a TL062?

[deadastronaut]

ooh i might have one......i'll swap it over...

yep this heat is mental....i try to get my car journey stuff done before the sun comes around and burns my interior..and butt..and hands...

EDIT:  swapped it for a 062....still ticky...hmmm....well its actually more of a distort and ticky .....hmmmm

[anotherjim]

Does the distortion have a ringmod flavour? Tick is hf, clock is hf - result audible hash in time with the tick -  if that's what it is.
Put C14 after D2 and power the LFO +9v from C14 (I don't think the bypass LED needs C14). Rest of circuit stays after R29.
You may not totally fix all noises on the breadboard.

[deadastronaut]

hi jim, back again, been busy...its a distorty tick,  but also adds distorting too overall when both man/sweep are around 12 o'clock....

ive put a 100uf to the right of the 47r (r29)

so basically move top of R25 to the new 100uf and power the lfo from there then....ok.

EDIT: yep done that, still distorting.....hmmmmmm