Echo Base - a new PT2399 delay

[sean k]

I just replaced the wrong 100nano with the proper 1nano and it all goes fine but I noticed that endless repeats were real easy to get and suffered very quickly from heavy bass, I suppose from the pick attack, coming through so I changed the 100nano after the 20k from the feedback pot to 15nano and immediately found I could get longer repeats before oscillation began with the attack noise from picking so I might just put a buffer in there with a bandpass filter so I can get lows dropped at about 1.2 -1.6k and cut highs a few octaves above that and, of course, that means I could use the same set of buffers to create a send and return path so in answer to the question above I think the point between the 20k and the 100 nano is a good place to put in the send and return. Oh the other thing I'll do is remove the 10k resistor between the input and output amps and throw a 100k - 250k log pot in there so I can cut the intial unaffected signal and just have the delayed signal at the output. With all those knobs to twiddle the original signal just gets in the way.

Oh, and an envelope filter, like a slow gear or anything that rolls up the volume from 0, is going to be great with this gizmo.

My hats off to Mr Slacker at last, lazy and impatient me realises it's all my fault that its taken so long, for a great build! 

[bent]

just a quick question 

can the circuit be powered by 12 volt instead of 9 volt ? or do i have to change some value to make it work on 12 volt ?

thank's

bent

[slacker]

It will work fine on 12 volts with no modifications. The only thing to take care of is if you're using an unregulated power supply just make sure the voltage doesn't go above 15volts or you'll destroy the CD4066.

[bent]

It will work fine on 12 volts with no modifications. The only thing to take care of is if you're using an unregulated power supply just make sure the voltage doesn't go above 15volts or you'll destroy the CD4066.

thank you very much slacker... 

cool effect by the way....

bent

[Praying_V]

Do we need "specially selected gains" for the bc560 & 5089?  Or can I just solder randomly selected ones in without a worry?

[slacker]

No need for any selecting, any will work fine.

[Gila_Crisis]

i'm all out of .1uF!!!!!! i'm also out of tlo72. I will trade an etched echo base board to anyone who can give me a bunch of .1uFs and a bunch of tl072...

where are you from??

USA, TN

mh... it's a bit too much far away from switzerland......

[omarvolta]

hey there, well this is a little offtopic but I tried getting help in it's own topic with no luck and since the idea came from the echobase I thought maybe I could try here. Since I really like the echobase with the waveshape control, I'd like to add one to my deluxe memory man if that is possible. Below the LFO section of the DMM. Any info greatly appreciated.

[sean k]

I would suggest that the oscillator is basically fine as it is but VR5 becomes depth and R57 is replaced with pot which becomes speed then R58 is also replaced with a pot, becoming triangle/square and the centre lug goes to thhe top lug of VR5 which is cut from pin 7 and the switch. I'm not sure but that would make it essentially the same as the LFO on the echobase except for the transistor that adjusts the length of pulse over the delay time setting.

[omarvolta]

hey sean k, thanks man. What value would you suggest to use?? I'll do it as soon as I get a new voltage regulator which I shorted and fried while measuring(D'oh!)

[sean k]

It ain't gospel buddy, I'm just making a semi literate guess and hoping someone else will pipe up and set us straight. Usually bigger resistance in a oscillator equal lower hertz and the same with caps, bigger caps equal longer wavelengths, so it looks like chorus should be vibrato and vice versa. The 910k could be a 1MB or a 500k with a 470k switched in or out for short and long and the others, the triangle/ square wave would be 100k I suppose with a 20k resistor in series with the square wave end which I think is pin

[sean k]

(carried on, opps) 7. Look back earlier in the thread for the schematic for the mod to the Oscillator and you'll see the similarities. But lets see if someone jumps in and confirms what I'm hoping is right.

[mth5044]

Just bought a PCB from John. I am beyond excited. 

Except I still have to manage to put together a mouser list, which will take me at least a week  stupid mouser and your confusingness.

[ppatchmods]

Just finished my echobase, but got a few problems:
1. the dry signal is not as loud as the delayed signal
2. the volume pot is not working(could be the reason for #1)
3. the delayed signal still comes through when bypassed when the boss/tails switch is in boss mode
4. lots of noise
5. the feedback oscilates infinity at about 10 o'clock

I realize that some of these problems can be related, but the best advice comes from experience!
The delays sound great, but I'm trying to troubleshoot those problems.  I am using the newest layout on a John Lyons blue board.
Thanks for any help you can offer!
-John

[Barcode80]

Just finished my echobase, but got a few problems:
1. the dry signal is not as loud as the delayed signal
2. the volume pot is not working(could be the reason for #1)
3. the delayed signal still comes through when bypassed when the boss/tails switch is in boss mode
4. lots of noise
5. the feedback oscilates infinity at about 10 o'clock

I realize that some of these problems can be related, but the best advice comes from experience!
The delays sound great, but I'm trying to troubleshoot those problems.  I am using the newest layout on a John Lyons blue board.
Thanks for any help you can offer!
-John

1 and 2 are obviously related, as the "volume" knob is actually a dry/wet mix, not an actual volume control.

3 is usually a miswiring of the tails switch. if you reverse any of the wires, then you essentially keep the delay on in one setting

4 and 5 are likely relayed too. 5 is a known issue from earlier in the thread. if you raise the value of the resistor going to lug 2 of the feedback pot, it will tame the feedback. adjust to taste for at what point you want the feedback to oscillate. the oscillation builds noise pretty quick, so this could be where you are hearing noise too.

[ppatchmods]

Thanks barcode80!  I remember reading about the feedback resistor now that you mention it.  I'll check those things and see if that does it. Thanks a lot!
-John

[slacker]

At a guess your level and feedback pots are wired wrong.  One of the lugs of each of these should be connected to ground so turning the level pot all the way down should mute the delayed signal likewise turning the repeats pot all the way down should give you just one repeat. If they don't do this that's where I'd start looking.
If your pots look like they are wired correctly check that all the grey traces on the layout are connected to ground, there's a couple of jumpers on those traces and if you've missed them that would cause the problems you're having.
Once the level and repeats pots are sorted you might find the other problems go away, if not check the voltages on the 4066 using the info a few pages back to make sure the boss/tails switch is working.

[ppatchmods]

Thanks Slacker! I have found that the volume knob doesn't seem to have any affect.  I will check the traces and jumpers tonight.

-John

[ppatchmods]

My echobase is doing some crazy modulation and making tons of noise! The delay signals are louder than the dry and I'm frustrated! I think I'm going to get another pcb made and start over!...it looks good in the case though
-John

[slacker]

Don't chuck it away yet, the layout is known to be good so if yours isn't working then you must have made an mistake of some sort. Starting again isn't going to guarantee success and everyone knows pedals that need a lot of debugging have extra mojo

Just in case you've wired it up wrong here's a wiring diagram for the anonymousfacelesscoward's board.



Once you're sure the wiring is correct turn all the controls all the way anticlockwise except the delay time, put that somewhere in the middle. That should give you no delay, if you can still hear the delay then check around where the level pot connects for shorts that might be letting the delayed signal bypass the pot. Once you've got no delayed sound turn the delay level up until you can hear the delayed signal, you should get just one repeat. If you get more than one repeat check for shorts around where the repeats pot connects. If you only get one repeat turn the repeats pot up until you get 4 or 5 repeats. These should have no modulation to them, if they do check round the mod depth pot for shorts.