Echo Base - a new PT2399 delay

[slacker]

Once I'd decided I wanted tails and therefore it wasn't going to be true bypass I decided to use electronic switching, I did toy with the idea of using mechanical switching but I didn't see any particular advantage over electronic. The CD4066 method also allows remote and momentary switching which mechanical switches wouldn't, having said that not many people have made use of those features.

Not sure exactly what switching method you're proposing, if you mean  this http://www.diystompboxes.com/smfforum/index.php?topic=95632.msg829073#msg829073 then that still needs part of the CD4066 switching or a transistor switch as well.

If I was going to do another version I'd do it like this http://www.diystompboxes.com/smfforum/index.php?topic=90460.0 or go with Merlin's method to keep the true bypass fanboys happy.

[Kesh]

This kind of thing. Much simplified, I've left all components out except the switching. the bold line shows where the dry/bypass signal goes (with 2 op amps) the rest the switching

[slacker]

Yeah that would work, from memory that's what I thought about using, except I think I had a DPST for tails/no tails shorting out either the send or return section of the on/off switch.
Somewhere back in this thread someone posted a similar arrangement with a DPDT centre off or maybe a rotary switch for the tails switch that gives a third bypass mode where both the send and return are cut in bypass. The same mode could be added to the existing switching as well.

[Chris oej]

Thanks for the advice Slacker - I've made the Echo Base and implicated the mods on the pdf.It sounds amazing! I've rigged up the hi / lo pass filter switch too. The lo pass filter sound great - really dark, although the feedback gets a bit carried away - maybe i need a higher value resistor than the 20k i'm using?

The hi pass filter doesn't work at all - infact, it seems to bypass the delay completely and i just get the unaffected guitar.

Here's the schematic of the switch



I haven't hooked up the taptation yet - want to get this bit working first.

Thanks

[slacker]

Try doing the high pass by putting the 22k resistor in series between the 3.9n cap and the switch, I don't think it will work like you have it because the resistor being connected to ground will mess with the bias of the opamps in the PT2399.

Yeah the feedback can be tamed by making the 20k resistor bigger, a lot of people like 100k.

[slacker]

Just had another thought, it might be your values, you've got the frequency set at about 1.8 KHz, with the low pass filtering elsewhere round the PT2399 there won't be much signal left that high.
Try 22n and 10k which gives about 720 Hz.

[cattmampbell]

Does anyone have a drill template for the pedal using PCB mounted pots? Does anyone have a diagram on how to make an fx loop with the EchoBase? I'm fairly new to DIY pedals. Any help would be fantastic. Thanks!

[Vince_b]

I don't have a drill template but I can tell you how to add an FX loop.

1) You need to break the connection between the middle lug of the Level pot and the 100nF cap.
2) Solder the tip of the Send jack to the middle lug of the Level pot.
3) Solder the switching lug of the Send jack both to the 100nF cap that was previously going to the middle lug of the Level Pot and to the tip of the Return jack

[slacker]

Yeah, that's it. You can do the same thing with the repeats pot, this gives you an FX loop where the first repeat is clean but subsequent ones go through the loop each time they repeat.

[Chris oej]

Thanks again Slacker - putting it in series in the hi pass worked a treat. I experimented with a few reistor values till i got one that sounded right.

I've wired in the taptation circuit now but am having problems. I bought the pcb from the the below link:

http://www.jmkpcbs.com/JMK_PCBs/Store_files/%20Mini%20Taptation.pdf

I having trouble though - now the delay has just got really slow. The delay pot and tap do nothing. The LED does nothing. I accidentally made a bridge between the 9v input to the board and the pin 6 input. The taptation board started working although there was no delay signal. After releasing the bridge the delay was at the new tempo. I measured the voltage of the voltage regulator (78L05) and it's only giving 2.3v. Should it not be closer to 5v?

I'm really baffled as to what the problem is. Am i right in thinking that the momentary switch for the tap should be open and the beat of the tap is the closing of the switch?

Thanks for all the help.

[soloarchitect]

{Posted by Slacker Reply #299} I'd do it like this. Put the second pot in series with the original one, wired the same way. Then use a SPDT switch and connect the middle lug to where the pots join and the outer lugs to the outside of the pots, like this
           
Pin6----1---Pot-2--Pot--3--    Numbers are switch lugs

That way the will change between the 2 pot values without any break in the connection.

This has me confused, I have spent a couple of hours wrapping my mind around this and now I am tired. Pardon me if someone has already drawn a diagram or explained this more thoroughly to someone else, there are just so many pages... I have wired it up a couple of ways and from what I read, any break in the connection during switching causes overload and noise, this happens to me when I am switching from short to long feedback(or is it long to short  ) Doesnt matter, one of the ways causes noise  . I am struggling with this picture and knowing for sure what "outside of the pots" and "to where the pots join", also is pin 6 connection going to lug one of switch originally went to lug 1 of the pot, or is this a second lead from pin 6? OK time for sleep!  Thanks for your help.

[slacker]

Here's a picture, courtesy of Merlinb, hope it makes sense.

My limited knowledge and the other posts on this thread suggest that the process of switching between the two pots could result in momentary infinite resistance on pin 6 of the PT2399,
Any alternative ideas about how this could be avoided?

Here's one possibility:

[soloarchitect]

That will work! Thank you!

[soloarchitect]

OK, one more question. This schematic is showing pin six going into the side of the pot that also loops into the center lug. The one I built was on the Sabrotone site. And his pin six goes to lug one, and lugs 2,3 are connected instead. So would I simply just wire it up the exact way as the picture except reversing pin 6 and pin 4?(starting from left to right instead of right to left)

[soloarchitect]

ok , I wired it up that way and it still does it, just not as long. so perhaps its correct. The noise I am hearing is a constant white noise for about a second. But now the feedback only repeats once, so I mustve knocked something loose, time to do a little debugging, YES!, Im so excited!  I do love learning electronics! 

[kurtlives]

Getting around to building an Echobase.

Which of the mods in the PDF (or elsewhere) are worth doing?

[garcho]

Which of the mods in the PDF (or elsewhere) are worth doing?

What, don't wanna read through 70 pages of thread?  

Depends. What music are you going to make with it? Don't know? Then include all of them, none are complicated or expensive.
A 'punch-in' momentary is a MUST. The 'tails' feature is supremely celebrated with a punch-in momentary foot switch, even if you're not Scientist or King Jammy.
I ended up hard wiring a SPDT for the LFO shape, since I wasn't really fiddling with that knob. I usually just crank it to straight up square or triangle.
Dub madness is perfect for noisy/psych/dub/ambient music. You might want to tweak it to flavor - good to breadboard. I imagine it's pretty useless without a momentary foot switch.
I play with Gotoh humbuckers on a homemade strat and haven't felt the need for the diode lift. I'm not Mr. Clean, but I'm not a lo-fi garage punk either. Every once in a while...
Clean kill is great for new wave/noisy/psych kinda stuff, but I only made sense of it with a short delay and heavier modulation. One instance where the shape knob comes in handy, because it has a big effect on this feature.
Probably forgetting something.

[dongeo]

Hi!

Some time ago I built the Echo Base with the Rapidriotboxes layout . Some time after that I ordered a tap tempo kit from UK-Electronic and wired it up according to the schematic provided. By doing so the modulation part went completely silent. My question is that is it safe to wire up the tap tempo kit as the regular potentiometer was according to the Rapidriotboxes layout. My goal is to get both of them to work.

Thanks!

[slacker]

I take it you've removed the delay time pot and connected the brown wire to where lug 3 of the pot was and the blue wire next to the brown one to ground, like how they explain. If you've done that then the modulation part of the Echo Base is completely disconnected so it won't do anything.
It's probably safe to hook the blue wire next to the brown one up to where lugs 1 and 2 of the delay time pot went, this should give tap tempo and modulation. The only way to tell for sure would be with a schematic or if you trace where the brown and blue wires go on the circuit board I can probably tell you.
The other blue wire connected to the time pot and the tap switch still needs to be connected to ground.

The tap tempo probably won't be very accurate if you use it with the modulation.

Welcome to the forum

[Chris oej]

Hi Dongeo,

I'm having a similar problem with a Taptation tap circuit - if the GND of the Taptation goes to ground it shorts the modulation, if it goes to where lugs 1 / 2 of the time pot should be, the delay just got really slow. The delay pot and tap do nothing. The LED does nothing. I accidentally made a bridge between the 9v input to the board and the pin 6 input. The taptation board started working although there was no delay signal. After releasing the bridge the delay was at the new tempo. I measured the voltage of the voltage regulator (78L05) and it's only giving 2.3v.

I'm not sure that anyone else has wired a tap control to an Echo Base yet (i can't find anyone on here that's done it) so not sure if it's even possible - lets hope we can work it out.

Please let me know how Slacker's suggestion works out for you.