Build Report: Echo Base - EXCELLENT

[chi_boy]

Thanks to all for posting the layouts.

[alfafalfa]

And another thanks  from me to Pravudh and the others for this excellent project.

One more question : is the 800 ms  possible without distortion on the part of the  delaychip ?

In my  rebote 2.5 I get a definite hiss/distortion when I go beyond  I think 350 ms !

Now I look again I can't find the 800 ms claim anymore , Am I mistaken ??


Alf

[dschwartz]

alfalfa..
no..you can´t get more than 400mS w/out serious distortion..
you can add more lo pass filters to mask the distortion, but the trade off is a muffled delayed sound..

try using 2 pt2399 in series sharing the delay time pot and maybe you can get to 800ms or so more cleanly.

[slacker]

no..you can´t get more than 400mS w/out serious distortion..

I don't agree with that, with the right amount of filtering you can get close to 800ms. You lose some high frequencies and there is a bit of background noise but it's still a very useable and nice sounding delay.
The 3rd sound clip on the 1st post of the original Echobase thread is the maximum delay it can do and it's about 700ms. Sounds alright to me

[Valoosj]

try using 2 pt2399 in series sharing the delay time pot and maybe you can get to 800ms or so more cleanly.

How exactly would you do this? putting an IC in series must be harder than putting resistors in series 

[slacker]

It's not that hard.  If you get the datasheet for the PT2399 it shows how to wire the chip up for "surround sound", you build the first chip like that. Then you take the output of that into the second chip which you build like in a Rebote or any other delay pedal, except instead of the feedback pot feeding the signal back into that chip you feed it back into the first one.
You could use a dual pot to control the delay times of both chips or use LDRs or transistors to control each one driven by one pot. Or you can just make the first chip switchable between a very short delay time and about 400ms and just make the second one controlled by a pot with the maximum delay set to about 300ms. That would then work like the mode switch on a DD3, with the first chip on a very short delay you would have delays upto 400ms and with it on the 300ms setting you'd get delays up to 800ms.

[Valoosj]

I know this might seem easy to you butI  really don't have a clue on how to make transistors regulate the chips delay time.
I just thought I could hook the output of chip one to the input of chip 2 and be done with it

I'd like to get up to about 1000ms of delay with both chips working together, both at a max of 500ms, seeing as you can get 700ms clean delay from one.
Is that possible?  A simple schematic would be enough, then I could make an add-on pcb for this option. Or are there more things to consider on the main pcb that would need alteration?

[michal_k]

big thanks to Michael Allen and Pravudh for their layouts. I've already etched boards and I'm starting soldering tomorrow.

pic to show how nice looking layout it is:



due to the poor quality of picture, color of PCB is not visible - it's vintage beige or sth alike. I'm waiting for some tropical fish caps, hope it's gonna look killer 

[Michael Allen]

wow that was fast! looks great!!

[Michael Allen]

Hey michal_k,

I fired up another one of these today, and found an error in the layout. Pin 10 of the 4066 is connected to nothing on the layout, when it needs to have a connection to the .1uF cap and 1M5 resistor directly out from it. There is a ground pour field between pin 10 and the trace it needs to connect. The trace runs perpendicular to the new trace out from the pin 10, you see? 

Just so you're not scratching your head like I was!