Echo Base - a new PT2399 delay

[Coda]

I built one of these during the last couple of weeks, using V1 of anon... PCB layout (I etched the board before I realised there was a V2 with better noise performance). Anyway it works great, I just have to mod it for v2 style buffers, and add a couple other things (like punch-in, great idea). Also, I think the time pot is wired backwards (in my head, delay time should increase as you turn the pot CW, on my build, CW decreases the delay time).

Anyway I'm mainly posting just to say thanks to Slacker for a great design and for the amazing number of years you have been helping people with their builds.
(And also ありがとうございます to anonymousfacelesscoward for the nice layouts).

[flagada]

Hello, sorry for digging upo this old post. I am building the echo base Version 2 (from 30/03/2010). I am making the vero board version. I was wondering if there is a schematic available for this version?

[garcho]

I am building the echo base Version 2 (from 30/03/2010). I am making the vero board version. I was wondering if there is a schematic available for this version?

There is a schematic for it. And good you dig this thread up because this is still one of the best DIY projects on the forum. Thanks Slacker! (and RG, Andrew, Francisco, et al.) This is how I search for something in long threads here, via search engine like DuckDuckGo:
"echo base version 2 schematic site:diystompboxes.com"

[flagada]

Thanks Garcho,

And thanks for the search-tip! I did not know it was possible to search like that in long topics.  I am even thinking of throwing out Google as my standard search engine. Is DuckDuckGo as good as Google?

[duck_arse]

Thanks Garcho,

And thanks for the search-tip! I did not know it was possible to search like that in long topics.  I am even thinking of throwing out Google as my standard search engine. Is DuckDuckGo as good as Google?

duckduckgo has a problem searching for "images of a certain type" (wink, wink) if you know what I mean. it did last I tried it, anyway. worse censorship than chinese googoo.

[Lumenus]

Hi! I am new to your forums. I did the pedal, but the modulation it is not working correctly. Voltage op-amp U3  4558
1 - ~
2 - 5v
3 - 5v
4 - 0
5 - ~
6 - 5v
7 - ~
8 - 8v
Transistor BC560. Prompt where to look.

[ropucha]

Hi all!
I've build v1 Echobase, and now when I tried it out, I have a few questions:
- I've expirienced some noise and hum when echobase is on, I suppose its some low quality capacitors or such, am I wrong?
- When I put to input some low frequency sound (from synth), it does not sound as same as from the synth itself (even with bypass). It lacks bass! I wonder if its a bug or a feature... What can cause this?

Can you please help me with those two "bugs"?

Thanks

[jan007magic]

I built one of these during the last couple of weeks, using V1 of anon... PCB layout (I etched the board before I realised there was a V2 with better noise performance). Anyway it works great, I just have to mod it for v2 style buffers, and add a couple other things (like punch-in, great idea). Also, I think the time pot is wired backwards (in my head, delay time should increase as you turn the pot CW, on my build, CW decreases the delay time).

Anyway I'm mainly posting just to say thanks to Slacker for a great design and for the amazing number of years you have been helping people with their builds.
(And also ありがとうございます to anonymousfacelesscoward for the nice layouts).

do you have a link to the v2 layout?

[Mad Science]

What could cause the LFO to not work?  My echobase was dropped, hard.  A few wires came loose and the chips came out of their sockets.  I put it all back, and its pretty much ok, but the LFO isn't working.  Light won't pulsate, but the depth knob seems to add chorus.  The speed knob does nothing.  Unwired the LFO switch, no help.  Once in a while this thing has acted funny (noisy, distortion) and unplugging and plugging it in makes it work correctly (before dropping I experienced this).  I wonder if the PT2399 chip is bad...  does the LFO depend at all on the PT2399 chip?   Possibly the TL072 is bad in the mod section? (light still works but no pulsing anymore and the Mod speed pot does nothing now)

what a mystery... such a cool effect though.  I've tried everything and i'm stumped.  Anyone have any ideas? 

[slacker]

I would check all the wiring and solder joints around the LFO section, could just be a loose connection. You could also try swapping the opamps in case the LFO one is damaged.
If that doesn't fix it if you could post the voltages for the LFO opamp that might give some clues.

[Mad Science]

seems like it was the opamp.  I switched the two opamps and the LFO started working again, but now the volume is very low, which is the problem I had after it was dropped.  Gonna go pick up a couple TL072 chips and replace both.  I was reading somewhere that TL052 is a better quality chip that can be used, has anyone tried those instead? 


and, while I have you attention, is there a cap that I can change somewhere that will allow more low frequencies into the delay circuit?  Seems like (to my ears) nothing below about 300 or 400 hz is getting into the delay circuit due to a HPF designed into this circuit.  Sounds pretty cool as is, but if I could dial in more bass I would like to try it.  Been scratching my head over that one for a while but I am a musician, not an engineer 

Thanks so much Slacker!  This is an amazing pedal that you simply cannot buy anywhere.

[colinrobot]

Here's something I've been working on for a while, it's a PT2399 based delay called Echo Base. It started out with some ideas for mods for a Rebote, but after playing around for a while I thought I might as well start from scratch and design something new.

The main features are:-
1. It's got an LFO that modulates the delay time for chorus/vibe/tape flutter effects, a bit like a DMM.
2. Shock horror, it's not true bypass, that's because....
3. It can do delay tails, where you bypass it and the delays die away instead of being cut off instantly.

Here's the schematic

The bypass is done using CD4066 switches and works like this. The signal goes through the input buffer which sends the dry signal straight to the output buffer, the signal also goes through the first 4066 switch (A) and into the PT2399. This section is mostly from the appnote on the datasheet with a few values tweaked, but with the output taken from pin 14 like on the Rebote 2.5, doing this taps off just the delayed/wet signal. The wet signal then passes through another 4066 switch (B) and gets mixed with the dry signal via the Level pot.
When the effect is on both of these switches are open. When it's bypassed one of the switches closes depending on the position of the Tails/Boss switch. In Tails mode the input switch (A) is closed, cutting off the signal to the PT2399,  the wet sound then dies out naturally.
In Boss mode the output switch (B) closes so the wet sound is instantly cut off, the input to the PT2399 is still open. This is how Boss pedals work, hence the name.

The modulation is a simple triangle LFO hooked up to a PNP transistor in series with the delay time pot. It took quite a bit of experimenting to get this working nicely but I think it's a neater solution than using a LED/LDR combo.

Here's some sound clips, they're just guitar >> Echo Base >> Condor >> Soundcard.

Slapback Bypassed then effect
Rhythmic repeats Bypassed then effect
Chord stabs showing the longest delay time
Chorus Bypassed then effect
Heavy vibe Bypassed then effect
Slow vibe Bypassed then effect
Pitch bending
Delayed vibes
Example of delay tails This starts with some (bad) distorted lead then the distortion and the delay are turned off and you can hear the echoes dying away behind the clean playing. The switch pop is from the distortion pedal.

Here's a guts shot of the finished pedal, vero layout to follow shortly



Thanks go to R.G. and The Tone God for their electronic switching articles and Francisco Peña because if it wasn't for the Rebote I wouldn't have built this.

Enjoy

Hi , just seen this but the schematic link is dead do you know how i can get hold of a copy? Just learning and just made a simple PT2399 circuit (pcb already made) want to go to next level and eventually make a cv controlled one . Thanks for your time!

[thomasha]

The version with some mods is a couple posts before yours. This changes normally are for better...

Fast search showed other versions with minor changes:

[garcho]

Hi! I am new to your forums. I did the pedal, but the modulation it is not working correctly.

no offense, but looking at the solder side of your board makes me think there are some loose connections, cold joints, or solder bridges. i would triple check all the solder points. удачи!

I've expirienced some noise and hum when echobase is on, I suppose its some low quality capacitors or such, am I wrong?

how did you build it? taylor's musicpcb.com board or etch or vero? how are you powering the effect?
if you have no/bad caps filtering the power supply, you'd most likely get some 60Hz/50Hz hum.
for the most part, in guitar pedal universe, caps either work, or don't work; "quality" is not a linear continuum with caps the way it is with wine or fabric or wood. regarding guitar pedals, the quality of a cap would be how long it lives. don't tell that to the hi-fi crowd, unless you have a few spare hours and a high tolerance for BS.

What could cause the LFO to not work?  My echobase was dropped, hard.  A few wires came loose and the chips came out of their sockets.  I put it all back, and its pretty much ok, but the LFO isn't working.  Light won't pulsate, but the depth knob seems to add chorus.  The speed knob does nothing.  Unwired the LFO switch, no help.  Once in a while this thing has acted funny (noisy, distortion) and unplugging and plugging it in makes it work correctly (before dropping I experienced this).  I wonder if the PT2399 chip is bad...  does the LFO depend at all on the PT2399 chip?   Possibly the TL072 is bad in the mod section? (light still works but no pulsing anymore and the Mod speed pot does nothing now)

wires shouldn't "come loose" from dropping something, no matter how hard you drop it. is your circuit board mounted? was there a battery inside the enclosure flying around? just like seat belts, one of the reasons to bolt things down is not just to protect the thing being bolted, but to protect everything else from said thing violently flying around free.

the depth knob is "adding chorus" - at any delay time?

Once in a while this thing has acted funny (noisy, distortion) and unplugging and plugging it in makes it work correctly

IIRC that's happened to others with all types of PT2399-based circuits. not sure if there is a consensus on why/how. do a search, you'll find info.

Possibly the TL072 is bad

with the exception of reversing the polarity of the voltage going to the power pins, it's actually pretty hard to electrically destroy an op amp, in guitar pedal universe anyway. sometimes they can even live through that (don't quote me, ha!).

seems like it was the opamp.  I switched the two opamps and the LFO started working again, but now the volume is very low, which is the problem I had after it was dropped.  Gonna go pick up a couple TL072 chips and replace both.  I was reading somewhere that TL052 is a better quality chip that can be used, has anyone tried those instead?

unless you know why an IC would be "better", don't bother. the TL052 has a higher bandwidth and slew rate than the TL072. neither matters in this application.

The version with some mods is a couple posts before yours.

i believe this is the up to date schematic:

[Cjuried]

Does anyone have a PT2399 spice model available? Thanks in advance.

[1reeko1]

hi guys!

this is my first reply on this forum and I wouldnt want to waste your time if I havent already wasted enough of mine:)

Im playing around with the tap tempo option (I've built the PTAP from this threath if anyone remembers it http://www.diystompboxes.com/smfforum/index.php?topic=75740.0)

I tursted it and made it myself


and I tryed it with one of my old cavedwellers first to see if there is any response from this. notning.... did everything i should -  pin 5/6 from the  MCP40150 to pin 6 of pt2399,  then pin 2 from ATtiny to the lug 2 of the 50k Time pot.

I checked if I did a mistake with the regulator also nothing... the dweller is working as if there is no time pot... I have even started to thing that I need to programe the ATtiny with a software and some kind of board that connects chips... Im really desperate here.. so I really need to do this?

now my question: after extensively searching for any verification on this schematics for the PTAP I havent understood if it has been confirmed as working - has anyone had luck with this one on the echo base and does is work the same for all the pt2399 delays?

if so, I must be doing something wrong. if not, should I just try another option? I know there is the taptation but I dont think I can get it here in europe as fast as I would like to.


... now I also found this: http://uk-electronic.de/onlineshop/product_info.php?products_id=1797&osCsid=9f026e3ce8c7f112ecbf2f4975e25fed

PTAP kit for most of the pt2399 delays - is this my solution if the other one is not working?

I would be most greatfull of anykind of help!

thank you!

[1reeko1]

sorry for the photo...

https://www.dropbox.com/s/sik2w8cdbdf1ab5/ECHO%20BASE%20-%20PROJECT%20DATA%202.pdf?dl=0

[slacker]

Hi Welcome to the forum

I have even started to thing that I need to programe the ATtiny with a software and some kind of board that connects chips...

Yes the Attiny is a microcontroller, basically a tiny computer, you need to program it with the code for the PTAP, it won't do anything until it's been programmed. If you can find the PTAP code you could buy a programmer and program the ATtiny, I don't know if the code is still available online the project is quite old and a lot of the links in the thread you posted are broken.

... now I also found this: http://uk-electronic.de/onlineshop/product_info.php?products_id=1797&osCsid=9f026e3ce8c7f112ecbf2f4975e25fed

That is probably the easiest solution or buy a taptation.

[1reeko1]

Thanks a lot for your reply!

yes I figured it out once I started researching the attiny and how it works so I did exacly as you said.. I found a local forum with the electicians here and Im waiting for someone to reply with the positive "yes I will program it for you" 

I also ordered the ptap programed so lets see what comes to hand first.

I'm very greatfull for all the information on here and I'm learning day by day!

keep up the great work for this comunity!

I will get back to you when I have the ptap and echo base ready with photos and project report!

[1reeko1]

hey there!

me again!

so I've integrated the ptap into the Echo Base and I've cut off the modulation. To bias the flash light on the ptap I had to put a resistor on the lug 6 of the pt2399. it works ok but with a few problems.

1. the repeats are not even as half as loud as before (on the level pot 100% they are still not louder than the original signal) and the feedback doesnt get to the oscillation. ( I changed the resistor 20k after the volume pot to 8.2k and I got to the oscillation. but still the repeats seem week and not as loud as I would want them...

2. I think I'm getting a little his into the repeats too but it's not in the metal box yet so maybe that's why it seems so...



is there an easy way to fix this? where to look into to raise the repeats volume? and will that affect the feedback as well?

thanks a lot!