4 pt2399's in series / long clean delay..

[loylo]

i'd like to make a 2M pot... instead of having a 1M pot and then switching in a 1M resistor.

If you can't find a proper 2M pot, a dual-gang 1M pot seems the easiest solution to me, as Samhay suggested.  



For the modulation circuit, I really like the concept of the Sway control of Jack Deville in his Dark Echo, which inversely controls depth and speed. So on low depth, it's fast (at 0, there is no modulation since depth is at 0, so there is no need of a modulation switch), and vice versa.

[deadastronaut]

cheers loylo, i managed to find some 15-16mm 2M metal ones on ebay...just means i'll have to wait on them though..



thanks man.

[deadastronaut]

well its been a while...and a lot of head aches..but i'm on the final leg of this epic bastard of a 3 month or so journey into the realms of delay madness....phewww...

anyway, i knocked up this in diylc, if my measurements hold up to scrutiny it should squeeze into a 1590bb (upright)

i now need to go over this node by node to make sure its ok...i drew it from the breadboards layout really , so there is no final schemo etc..

i figured if it works, then it works..

i did away with lfo on/off switch as when they are at minimum they are off anyway..(log pots reversed)

i also did away with the 1M switch as i have some 2M pots on order..(so it can smoothly go from fast to loooooongggg.....( the very longest delay will still be noisey but thats about 2 seconds-ish , but the shorter (not short at all) are really pretty clean...

i left the option to have it really long (but noisey) in as its pretty cool with self oscillation etc...quite synthy...  

i altered the feedback so it can semi-loop so it can be played over when bypassed too...which is nifty too.

overall its a pretty cool unit,and am at the stage where i just have to build it,  especially with the modulation chorus/warble/warp...very nice.

i settled on using certain values for the chip 'jumping' so the secondary repeats werent kicking back at me too much, and when all are 'jumped' it didn't go to wild..

however i have these resistors in pink on the diagram and would suggest socketing those to your particular taste.  (lower values = louder secondary repeats.)

so now its

5 pots / 3 switches and a foot dpdt.

as you can see it involves my traditional heaps of off board stuff, but hey if it works it works right...    (i'm no eagle expert )



back later when i have gone over this a bit more and double checked everything.  

[~arph]

Well that's quite a squeeze    nice work!

[samhay]

wow

[deadastronaut]

yeah, it took 3 days to get it to fit...

lots of uprights, and squeezing...but phewww hopefully it'll work..

i'm getting mrs astro to print it off big so i can check it over later..

edit: i couldv'e got it way smaller if i stuck with ceramics (2 holes) but figured sod it go for it..

[Jdansti]

You've outdone yourself!  I'm really looking forward adding this to my collection.  Thanks!

[deadastronaut]

cheers john, yeah so am i..

it'll be nice to not have this rattling around in my head night after night arghhhhhh...its really took it out of me this one....but hopefully i'll get there soon.

be nice to have my bare breadboards back ready for the next onslaught...

next on the list is an npn booster

[loylo]

Great great job, Rob!!! 

I don't know if you have heard about the Dark Echo by Jack Deville. It has a very interesting modulation circuit with only one pot, called SWAY, which controls depth and rate in interaction.
SWAY at 0, it shuts off the modulation. With SWAY set low, the LFO speed is high but the depth is minimal. With SWAY cranked up, speed is lower and depth is greater.

It may be interesting if you want to get rid of one pot. To my ears, it sounds more natural to have a modulation less present when the speed is high, it is a better emulation of the wow and flutter of a tape echo / disk echo.
But for those who prefer the possibility to achieve heavy pitch shifting and other sci-fi effects, you'd better keep the depth and rate pot.  

[deadastronaut]

hi loylo, i'll take a look at that anyway..

but yeah i quite like the krell music side of it too..


edit: yep i checked that out..cool, 450ms is moody though..

mine goes gradually darker on repeats too, which i wanted so its still a full sound when bypassed to play over..

its pretty neat.  the lfo is better off having both pots really as you can set it nicely according to the time slow/fast  etc...

anyway, i'll go over it all later on, and if all checks out i'll make a pcb up and test..(stil have to wait on my 2M pots though..

[deadastronaut]

funny thing..

i missed the cap that makes it dark on repeats...

and now another switch has re appeared in the form of a dark and bright switch.. might as well eh..

[haveyouseenhim]

next on the list is an npn booster

An npnpnpnpnpnpnpnpnpn booster 

[Jdansti]

Rob, I'm about to place an order and want to make sure I include the parts to build this sucker. As such, it's time for stupid questions.  

SQ#1.  Is the "In/Out" IC an op amp?  If so which?

SQ#2. Is the "LFO" IC a TL072 like the one in the Rebote LFO?

SQ#3. Are the four Qs JFETs?

I'll wait for your final testing before I build it, but I just want to avoid making multiple orders. Thanks!

EDIT: Went back and looked at page 1 and it appears that both chips are TL072 and the Qs are JFETs. Correct?

[psychedelicfish]

On the layout above, 2399s 2-4 don't appear to have their grounds connected to the ground rail...

[bluebunny]

On the layout above, 2399s 2-4 don't appear to have their grounds connected to the ground rail...

There's the tiniest green (invisible!) trace connecting to the yellow jumper to ground for #2 and #3.  #4 has its own ground connection under the chip to the ground line on the right.

[deadastronaut]

@john, i kept it simple both are tl072's.. and npn 2n3904's..x4 / there is 1 fet for switching/bypass . i'm using  2n5457.

the hardest part will be getting a 2M lin pot probably.. (i found some on ebay)


@marc: yep..incy wincey tiny tiny green traces..

thats how i keep track of where i am in diylc i layout my grounds/vb/9v etc...in different colours..otherwise its a nightmare..for me anyway.

when it prints its black though..


got a little bit of re jigging/tidying up,  to do..but otherwise looks ok so far...ive added the dark/bright now...a cool option. 

[bluebunny]

An npnpnpnpnpnpnpnpnpn booster 

I heard you scored a stash of Germaniumiumiumiumiumium trannies for that. 

[deadastronaut]

build a shoshoshoshoshoshoshoshoshoshoshoshoshosho ..

anyway, i got my 2M pot today...yay!...works a treat.. well worth holding out for..


going over the layout now meticulously....if all looks fine its pcb time.. yay!

should get my 16pin dil's tomorrow too.. , then i'm up n running.

been designing a nice etch for it too...

[Jdansti]

@john, i kept it simple both are tl072's.. and npn 2n3904's..x4 / there is 1 fet for switching/bypass . i'm using  2n5457.

Thanks, Rob!

[deadastronaut]

for those interested,  prototype pcb etched...

drill and pop later..

LOTS of off board stuff/wiring etc, so may take a while to verify/build etc ....see you on the flip side...............beep................................................beep.................................................