Echo Base - a new PT2399 delay

[slacker]

Problems 1 and 2 are probably related, sounds like something is wrong between the LFO and the PNP transistor that is causing the transistor to be off all the time, this would give the long minimum delay times. I would start be checking all the connections to the PNP transistor and the mod depth pot, make sure all the connections are good and that there are no blobs of solder or anything shorting the connections.

No signal in bypass with the "clean kill" mod is normal. If you want bypass to work with the mod then use a DPDT switch for the bypass switch using one side for bypass and wire the other side across the clean kill switch so that in bypass it shorts out the switch. If that doesn't make sense let me know and I'll draw a diagram.

If the pedal self oscillates with the feedback on maximum but the dub madness doesn't work it's probably a wiring error. If the pedal doesn't self oscillate then you have some other problem.

[lizardking]

THANKS!!!
I'll start with 1&2 first.  I assume you're talking about the BD560.  I'll check that first.

I'll probably need a diagram for the switch.  I understand what you're saying, I just have a hard time visualizing it as I'm just getting started in the DIY world.  I probably should have picked an easier project to start with.  My next project is a Tremolo and that is already much simpler.

[soloarchitect]

First of all, thanks Slacker for all of the time and patience you have with everyone in helping and answering questions, including all the other helpful members here who have done the same. This is an awesome pedal and I really appreciate you sharing your efforts for the DIY community. I have built this a few months back and it sounds great. My memory sucks, but I recall doing a couple of mods to combat the tick or "flup flup flup" noise I get with the pedal. If I recall I had put a 100ohm resistor and also changed the feedback value from "stock" so it would not get the self oscillating phenomenon too quickly. I read somewhere about changing caps on a couple of pair of pins on the pt2399. My pedal was built on vero from the Sabrotone website. I did omit the humbucker switch(if this is the pedal that had that, darn memory) I have sifted through most of these pages but there are so many and my connection rather slow that I get burnt out and by the time I get back to this I end up forgetting my decisions, lol. I have kept some condensed notes but still I end up spending time comprehending what I was going to do. Last I recall I had looked at the caps that were discussed and tried to figure out which caps on the veroboard to match up what to change, but it had seemed like those were already the values discussed. All in all, I really do not know enough about it and basically see several suggestions but am looking to narrow down to one or two areas that need changes and/or possibly cap trials to get rid of the noise. It doesn't come through when playing loud, but it isn't satisfactory if I need silence, and it is there and has a slight tone suck even if the pedal is off(tone suck is bearable and not a big deal but the noise I would like to do away with) Thank you for any input.

[goatboy]

  I'm very keen to start on this today and wondered if anyone could tell me where to connect the jacks for a dry loop?

[goatboy]

  Sorry, accidentally posted without completing my question! I'm using this layout http://www.sabrotone.com/wp-content/uploads/2011/05/EchoBase.gif
     
     

[slacker]

Not sure what you mean by a dry loop, if you can explain what you want I can probably tell you how to do it.

[goatboy]

 :)Thanks Slacker. I mean the FX loop! I should sift back through the thread but became impatient sorry!
     Also in Sabro's layout for C2, if I use an electrolytic cap which side is positive?
       Thanks

[stratprince]

good day! Im searching for its correct pcb layout (Echoebase). where can I see it? the correct and final one?

[garcho]

good day! Im searching for its correct pcb layout (Echoebase). where can I see it? the correct and final one?

Not to brown-nose, but if you have $14, Taylor's PCB is very high quality, comes with an extensive PDF, and will save you time and headache. It'll take you less than 10 minutes to populate the board. Considering it's a slightly complicated circuit and vero board isn't the cheapest, this is a great way to build the Echo Base.

[slacker]

Gary's right Taylor's PCB is great, if you want the latest version of the Echo Base then as far as I know that is the only PCB available. The layout for the earlier version is here http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=44171

[Chris oej]

I'm going to attempt to build an Echo Base with almost every mod - not quite every, but most. I've bought a pcb from musicpcb.com and will put in all the mods suggested on the documentation (clean signal kill, diode lift, dub madness and wave shape pot). Simple enough - however i want to also add a taptation Tap tempo control and a Hi / Lo pass filter switch.

Firstly - does anyone know where i can get hold of a taptation chip?

Secondly - i've read that you just put the taptation circuit in place of the time pot, how does this work with the modulation part of the echo base circuit? Does anyone have a schematic of an echo base with a taptation circuit included, without having to loose the modulation part of the echo base circuit?

For the hi / lo pass filter im going to base the circuit on the tone part of a big muff pi, but using a 2P3T switch instead of a pot. Am i right in thinking that the 10K resistor coming off of pin 14 of the PT2399 and the 15n capacitor that follow it and goes to ground are what gives the Echo Base repeats the low pass filter? Therefore, If i remove these 2 components and make them switchable with different values i should be able to alter the tone of the repeats.

Thanks all

[garcho]

EDIT:
Taptation

Sorry, weird forum issues.

Read the Taptation PDF regarding pitch mod mod.

[slacker]

To hook the taptation up with the Echo Base's modulation you connect pin Pin 6 of the MCP41100 in the TT to pin 6 of the PT2399 and the collector of the PNP transistor in the EB to pin 7 of the MCP41100. Not sure offhand which of the delay time pots pads on the PCB those are but it should be easy enough to work it out.
You should note that the tap tempo probably won't be accurate when hooked up like this, the transistor adds some resistance even when modulation is turned off, the Taptation doesn't know about this so can't take it into account resulting in longer delay times than expected.

Here's some things you could try to get round this issue, this is taken from a discussion I was having with someone about this recently.

"...Here's a few things you could try to either solve the problem or get round it. First try replacing the 220 Ohm resistor connected to the base of the PNP transistor with a jumper, this might reduce the resistance of the transistor when the depth pot is turned down enough to improve the accuracy, I haven't actually tried this so it might do nothing. The resistor is attached to the wiper of the LFO depth pot, so hopefully it should be easy to find.
If that doesn't work you could wire up the Taptation with the EB modulation and add a switch from pin 7 of the digipot to ground, this would short out the transistor, which would kill the modulation but it would mean you would have accurate Tap tempo when not using the modulation.
Another thing to try would be a pot from Pin 7 of the digi pot to ground, like shown in the taptation document. This would take the transistor completely out of the circuit when turned down, over riding the original depth pot and might even allow small amounts of modulation with out affecting the accuracy too much. Obviously you don't want two separate modulation depth pots so if you try that and it works let me know and I'll tell you how to bypass the original one."

The middle suggestion will definitely work, I don't know about the other two, I haven't heard how he got on with them and I haven't had chance to try them myself.

Your tone control ideas should work, I haven't tried a high pass but that's the right place to experiment.

Good luck with it.

[gcollective]

I started making pedals late last year, and I think I am ready to try and tackle this project. I am using sabro's vero layout, but I had a few questions:

1) can I replace the 27k resistor in front of the switch for the feedback mod with a pot so that i can adjust the level of feedback, and if so should I use a audio or log pot and should I use a 25k or 50k pot?

2) I plan on making it true bypass by using a 3pdt bypass circuit between the in and the out (this will serve the same function as the tails off switch), and using a dpdt in the normal spot as an effect on/of switch (this will serve the same function as the tails on switch). My question is, should I put a jumper between tails switch 1&2 or 2&3 on the vero layout so that the tails mod is bypassed with the tails set to "on"? I am not comfortable with my understanding of IC pin outs to do this wiring without seeking the advice of the DIY pedal gurus.

Thanks to everyone who has been contributing to this project, it's going to make me look really cool in front all my musical friends.

[slacker]

Yes you can replace the 27k resistor with a pot or different value resistor, I would try a 100k pot, log or linear doesn't matter. You might want to keep the existing resistor in series with the pot to limit the maximum feedback.

If you jumper Tails 1 and 2 that will hardwire it in tails mode.

Good luck with it.

[gcollective]

Thanks for the advice. I'll have to make sure and post some pictures when I am finished with the build.

I was looking over the schematic last night and making a wiring diagram for myself and I got stumped in one spot. I am going to use the LFO wave shape mod and I noticed that on on Taylor's PCB it looks Ike the mod speed pot has lugs 1&2 jumped and on the strip board layout and older layouts it shows lugs 2&3 jumped. I'm sure as long as the pot is hooked up correctly this only effects the direction you move the pot to get a faster or slower rate of oscillation. But just for clarification, more resistance = slower rate of oscillation and less resistance = faster rate? Sorry if I am misusing the terminology.

[slacker]

But just for clarification, more resistance = slower rate of oscillation and less resistance = faster rate? 

Yeah that's correct.

I think you're right, the way the mod speed pot is wired on that layout, fastest will be anti/counter clockwise. The wiper and anticlockwise lugs should be jumpered, so lugs one and and two by his terminology.

[drummer4gc]

anyone running two (or more) footswitches and the vero layout - can you show me a gutshot of your pedal? I am having a hell of a time trying to fit everything into a 1590bb and I feel like it should be easier than this!

thanks!

[slacker]

Here's mine, this is using my vero layout, the Sabrotone layout is a few holes longer so it might not fit the same way.

[Kesh]

Is there any reason for using a 4066, and not a 3PDT and 2PDT to get on/off and tails/no tails? You can set it up that way.