My Echo Base version (schem)

[Morocotopo]

Hi people, I´ve recently built an Echo Base, and reading the corresponding thread and various others, I came up with/implemented some mods in my build.

My schem:



What I did is this:
- I replaced the input buffer with a JFET buffer, to minimize noise (mainly hiss). That left me with an unused opamp, wich I used to make a direct , or dry, out.
- I added a "wet only" switch, to get at the FX output only the delayed signal. This to be able to send (in conjunction with the dry out) the dry signal to one amp and the delayed signal to another one, for example.
- I modded the value of some resistors to make it more "humbucker friendly", I mean, to minimize distortion in the signal path.
- I added a 1/2 voltage reference for the audio opamps and switches, because the 5V reference was shared by those and the PT2399, and slacker mentioned somewhere that this added noise in the signal. So now the 5V is used only by the PT2399 and the LFO opamps.
- Added a 2u2 cap to the LFO to minimize (actually there´s none) ticking in the signal
- Added a waveshape pot to the LFO, suggested in some thread, to vary the LFO from triangle to square. Actually it doesn´t produce a square, more like a "stairsteped square" thing.

Well, those are my mods, hope I´m not forgetting something. It works very well, the only thing to keep in mind is that the signal path is inverting, so if used in a parallell config you might get cancellations.

No PCB, sorry, I made it by hacking the available one...

Audio:

http://www.zshare.net/audio/63981179d011e0e7/
http://www.zshare.net/audio/63981281bb1f54a0/
http://www.zshare.net/audio/6398130127ba54b2/
http://www.zshare.net/audio/63981322cd64196f/
http://www.zshare.net/audio/63981391dffcb934/
http://www.zshare.net/audio/63981411f3f42af0/
http://www.zshare.net/audio/63981502a37d3934/
http://www.zshare.net/audio/639815614022addd/
http://www.zshare.net/audio/639816223dca7f7a/

Hope you like it.

[slacker]

Nice work with those mods. Sounds very cool

[Morocotopo]

Thanks Slacker, and thanks for making your work available to us! Hope you don´t mind that I used your drawing to show my mods. Neat little thing this FX!
And, by the way, I´m already thinking about an Echo Base with 2 PT2399´s in series to have double delay time... hehehe...

[slacker]

Hope you don´t mind that I used your drawing to show my mods. Neat little thing this FX!

That's fine, I don't mind if people use my stuff, so long as they share it

And, by the way, I´m already thinking about an Echo Base with 2 PT2399´s in series to have double delay time... hehehe...

There's some information in the main Echo Base thread about this, including some schematics and a layout for an add on board.

[arma61]

Hi there

is the schematic picture gone ? or am I having problem with photobucket ? can't see it.

Cannot find the copy I've saved when I re-drawed it with ExpressSCH, and need to check components values before starting to populate my PCB.

Thx a mil m8s
Armando

[arma61]

Hi there

is the schematic picture gone ? or am I having problem with photobucket ? can't see it.

Cannot find the copy I've saved when I re-drawed it with ExpressSCH, and need to check components values before starting to populate my PCB.

Thx a mil m8s
Armando

Ok, got it with my Pc at home


Armando

[puretube]

This one ?



(http://i68.photobucket.com/albums/i5/Morocotuco/echobase-schem-MODS.jpg)

[arma61]

This one ?

(http://i68.photobucket.com/albums/i5/Morocotuco/echobase-schem-MODS.jpg)

yes, that's the one thx m8

[alfafalfa]

- I modded the value of some resistors to make it more "humbucker friendly", I mean, to minimize distortion in the signal path.

Which ones did you mod ?

I would like to try that.

Alf

[Morocotopo]

Alfalfa, I don´t remember wich ones I modded, compare my schem with the original one, as I remember they were in the area of the PT2399 output. I got the info from Slacker´s thread.
One thing: I found out that my schem eats a bit of highs, even in bypass. It´s more noticeable when using distortion, because you get more harmonics than with a clean sound. Maybe by tweaking some caps in the in/out buffers it can be solved...
Another thing: the level control doesn´t fully mute the wet signal at minimum, another thing to watch. Maybe using a larger value pot it will work better.

Some day I´ll try to solve this small issues, when I have time. Or if someone makes my schem, you can try...

[arma61]

hi there

a quick ?

is using all 2M2 res instead of 1M5 affecting the bypass ciruit?, it's not working properly always "on" and it sucks tone when fx is engaged.

thx m8s
Armando