BOM :- https://www.lookmumnocomputer.com/s/BILL-OF-MATERIALS.zip
im working on the page over the next. couple of days. a video will be going up about this project also, and hopefully a functioning stripboard layout!
fuuuuuukk yeah! really looking forward to this!
Absolutely gorgeous!!!
Damn, that’s nice!!!
I understand RV1, RV5, and RV9 control how much of the delayed signal is mixed with the input to be fed back to the PT2399. RV4, RV6, and RV8 control the delay time. RV2 attenuates the CV.
What do RV3, RV6, and RV11 do?
so how the feedback and mix works in the pt2399 echo circuit is a case of getting the right level. in essence the feedback is more of a fine tune of the level. RV3,RV6,RV11 completely zeroed means the feedback amount of the delay with the mix from half way to max is relatively low in comparison. when you turn up feedback you go into territories where your straddling between minimal echo and self oscillation.
the mix isn’t a true mix and the feedback isn’t a true feedback, the feedback on zero stops the circuit going to super delay town and feedback extremes.
http://www.princeton.com.tw/Portals/0/Product/PT2399_1.pdf
if you check the data sheet, its how they have it setup, and I felt no need to change it as its a delay type and topology I have worked with for many years, a lot of pedals and stuff use this method with singular pt2399’s so its just building on it and just looking under more rocks in the stream of lofi delay forest.
when your fiddling with them you’ll see why they are both needed.
The PT2399 datasheet’s pretty minimal, there’s more detail here:
https://www.electrosmash.com/pt2399-analysis
yeah of course! that page helped me with a weird power problem.
also just a heads up! this is the first module I think is worth making cross format because of its funky sound. so im putting together a pcb that is small enough to fit behind all modules, however it will be panel wiring!
Hey @lookmumnocomputer, looks like these components are pretty easy to source!
Can you confirm if this is the right IC:
https://www.taydaelectronics.com/pt2399-2399-echo-audio-processor-guitar-ic.html
https://www.taydaelectronics.com/2n3904-npn-general-propose-transistor.html
Quantity: 7
https://www.taydaelectronics.com/10-pin-box-header-connector-2-54mm.html
Quantity: 1
https://www.taydaelectronics.com/lm7805-l7805-7805-voltage-regulator-ic-5v-1-5a.html
Quantity: 1
https://www.taydaelectronics.com/tl074-quad-operational-amplifier-j-fet-pdip-14-tl074cn.html
Quantity: 1
https://www.taydaelectronics.com/14-pin-dip-ic-socket-adaptor-solder-type.html
Quantity: 1
https://www.taydaelectronics.com/pt2399-2399-echo-audio-processor-guitar-ic.html
Quantity: 3
https://www.taydaelectronics.com/16-pin-dip-ic-socket-adaptor-solder-type.html
Quantity: 3
https://www.taydaelectronics.com/mini-toggle-switch-dpdt-on-on.html
Quantity: 2
https://www.taydaelectronics.com/100k-ohm-linear-taper-potentiometer-round-shaft-pcb-9mm.html
Quantity: 10
-edit- as these are already in short supply, here is a link to the thread for this part specifically.
As well as links to the suppliers mentioned int hat thread for reference:
https://www.taydaelectronics.com/test-group-2-2762.html
Need:
Type | Quantity
* 100k - 11
* 1k - 14
* 15k - 9
* 30k - 1
* 24k - 1
* 47k - 1
* 10k - 12
* 4k7 / 4.7k - 2
* 10R - 2
https://www.taydaelectronics.com/40-pin-2-54-mm-single-row-pin-header-strip.html
Quantity: 1
Quantity: Pick 5 from below:
https://www.taydaelectronics.com/led-5mm-yellow.html
https://www.taydaelectronics.com/led-5mm-red.html
https://www.taydaelectronics.com/led-5mm-green.html
https://www.taydaelectronics.com/leds/round-leds/5mm-leds/blue/led-5mm-blue-lens.html
https://www.taydaelectronics.com/test-group-2.html
Need:
Type | Quantity
* 100nf - 16
* 2.2nf - 3
* 470pf - 6
https://www.taydaelectronics.com/10uf-50v-105c-radial-electrolytic-capacitor-5x11mm.html
Quantity: 7
https://www.taydaelectronics.com/4-7uf-16v-105c-radial-electrolytic-capacitor-5x11mm.html
Quantity: 4
https://www.taydaelectronics.com/47uf-50v-105c-aluminum-radial-electrolytic-capacitor-nhg.html
Quantity: 1
https://www.taydaelectronics.com/6-35mm-1-4-stereo-phone-jack.html
Quantity: 3
Small Quantity: 9, Big Quantity: 1
(Pick your poison, keeping in mind the shaft diameter should be 6.35mm) Sam says to get big bigs and some smalls too.
https://www.taydaelectronics.com/potentiometer-variable-resistors/knobs.html?p=1
Here are some of my picks:
Quantity: 9
https://www.taydaelectronics.com/potentiometer-variable-resistors/knobs/boss-style-knob-black.html
https://www.taydaelectronics.com/potentiometer-variable-resistors/knobs/aluminum-knob.html
https://www.taydaelectronics.com/potentiometer-variable-resistors/knobs/aluminum-knob-3191.html
Quantity: 1
https://www.taydaelectronics.com/potentiometer-variable-resistors/knobs/34417-dup-aluminum-knob.html
https://www.taydaelectronics.com/potentiometer-variable-resistors/knobs/39133-dup-aluminum-knob.html
Is there really an R36? It’s 24k in the BOM but I don’t see it on the schematic.
This is turning out nice!
-Fumu / Esopus
check out the leg of rv4. its basically just a resistor that sort of makes it all a bit more manageable at the bottom end of the knob twist, I found too small the pt2399 crashed and turned off in too much of the knob travel. too high you dont get the full selection of garbage mode
Ah, way down there! Felt like I was playing Where’s Waldo.
I don’t have any 24k at the moment but looks pretty noncritical, if I don’t get any by the time I’m building this I’ll probably use a 22k or 22k+2.2k if need be.
You’ve figured out some good replacements already, but this calculator can be useful for people in this situation:
https://files.northcoastsynthesis.com/spcalc/
(the parallel variants it produces are often more interesting – often easier to solder, but harder to calculate in your head. E.g. in this case 47k//47k (pretty obvious) and 100k//33k (less so) would work fine.)
Its UP
I think just the 22k will be fine! I was humming and aaahing over values all over this module. seems the effect is very much down to taste. so I dont think much of it needs to be bang on the quoted values
ooooh very nice. ill be bookmarking that link.
That is excellent news! I have nine PT2399 so I’ll probably build at least one for Kosmo and one for Eurorack 
hey it looks about right! except for the LED bezel, thats not needed. 
