TREMMY TREMOLO

[deadastronaut]

aha...

had a mad revelation just now...

i was talking about getting the sweep but without the dip in volume (especially with distortion)..

i found a good kludge , the filter lfo's voltage divider (2x220k's) seems to be the key,

raising the 220k to ground from 220k to 1M (via a pot) stops the lfo led from dipping and dragging the vol with it,..

so a 220k as normal but with a pot in series works.....seems kinda obvious now ive tried it....acts as per normal, and sounds quite phasey now too...pretty sweet.

[deadastronaut]

ok heres what i have now...the filter depth is pretty cool now, pretty unorthadox, but it works nicely to go from deep sweep, to subtle.

[duck_arse]

there is something missing from IC1A in the N/C position. no feedback?

[deadastronaut]

well spotted...

must've been when i was swapping the switch position...cheers man.

[deadastronaut]

i was tinkering with filter caps...with a pot, but did'nt get desired results..

to sweep from fat to thin


             
         

                     10n  lug3........
signal lug2...../\                    \/
                    \/                     ..........
                     1nf   lug1......../\

then realised my pot is messing it up..

easier way?..
                 

[deadastronaut]

ok, with the help of sam,  cheers man.

i now have cap selection in the filter...

2.2n  /  4.7n  / 10n...the clips are in that order....apart from the noodly bit on the very end which is in reverse order ..


https://dl.dropboxusercontent.com/u/7464107/2.2n-4.7n-10n%20filter%20tsts.mp3


might have a little noodle around with the values still...but getting there..

[samhay]

Doesn't sound too bad. Perhaps try a 3n3 in place of the 4n7?

[deadastronaut]

will do, yeah it needs a tinker to get a nice 3 way range i'm happy with....

[deadastronaut]

2.2n/3.3n/10n...seems ok.. tried a 6.8n , but 10n seems fine now...

[deadastronaut]

our dear old friend mr switch poppo is back in town ...i thought i'd sorted that but obviously not..

typical , sort one thing then.......




edit a 1M across the switch seems to have tamed it....better way?



edit: i'm knocking up a layout in eagle..i fancy i'll get a few boards fabbed instead of my usual off board nightmares..

i'll still have off board pots though..can't be arsed to order them, or fanny about, and reduce size/cost etc...but the onboard switches will hold it nicely anyway too...hmmmm..   (if i can get eagle to behave that is )

[John Lyons]

Sounds good Rob. I'd like to try this one.

[deadastronaut]

^ sure thing man..


cap switch pop: (as schemo above)

its a strange one this time around,

sometimes it pops, sometimes it doesn't...

i'm beginning to think its a switch ground issue as when i hold the switch by the metal part the pop is almost gone..

whereas if i hold it by the plastic...pop.pop.pop...

however..

sometimes the pop is on the first click, then doesn't after...meaning the caps are now drained?....hmmmmm

tried a 1M across the switch, but the same result?...any solutions/ideas?...

just want to make sure i iron out this possible issue before doing a final layout etc...

[bluebunny]

I'm assuming we're talking about "CAPSW" in your pic, Rob?  I guess you could take a BFR from each of the "floating" side of those two caps (C11, C12) to ground, just like you do with the input decoupling cap in yer average pedal.  Not sure if this would affect the operation of the pedal, but it would allow the caps to discharge quietly to ground, rather than sitting there all charged up with no place to go.

Or am I talking B0ll0x?   

[deadastronaut]

yes you are..again

yep CAPSW..

BFR?..


edit: I tried 1M resistors to ground on both floating caps...still pops.

[samhay]

Dont take the big f**king resistors to ground - they need to go to Vref.
Not sure what this will do to the frequency response of the filter, you I guess you will find out.

[deadastronaut]

B @#$%ing Resistor... i might have known..

cool, just tried BFR 1M resistors from floating cap to vref...voila', excellente' silencio'.....sam is spoiling us..ferrero is in the post..

works a treat...brilliant.  filters seem ok too...cheers sam.

[bluebunny]

yes you are..again

Ha ha!   

Yeah, what Sam said - small brain-fart earlier: V_REF makes much more sense.  Ground would be plain daft.    Who the *£$% suggested that??   

[deadastronaut]

well after much testing i finally settled on cap values...

gives a nice bright/med/warm range  for clean or distortion...

i decided to include the 22pf (maybe 47pf)  in the switching too. to not taint the tremolo.

[samhay]

Well we're only up to page 8 of this thread. You're not done already are you?

[deadastronaut]

 

no way...

ive got a SVF to try yet... .........................maybe.