Rebote Delay 2.5 built, revised, fine tuned

[Fp-www.Tonepad.com]

Official release of the rebote2.5 delay.

I have just finished fine tuning the prototype and the updated project pdf is available at tonepad.

http://www.tonepad.com/project.asp?id=51

I decided to keep Rev.1 status since the previous releases were experimental.

If you have downloaded any of the old revisions, please download this one (Rev.1.Sep.30.2005). (966 downloads for the previous versions).

I encourage people who have built rebote2 to build this one and post your results.

Enjoy!
Fp

[Mark Hammer]

If any grit in the signal at longest delays strikes you as objectionable, you can consider a .015uf to .0022uf cap in parallel with the .01uf cap to ground just before the repeat pot.  This will roll off some more high end in the delay path and make any grit less obvious, although the filtering is already pretty serious.

[Fp-www.Tonepad.com]

My objective with this build was to stretch out the capabilities of the PT2399 chip without going into 'compander' territory. A minimalist design, if you will.

I think I succeded, but time will tell when more people build it.

I also thought of making the delay time pot a dual one and wire the other one of the resistive elements to an aditional low pass filter with variable rolloff frequency that would be lowered when the delay time is increased. This way you'd have nice higher fidelity on lower delay times, and less treble in higher delay times... but I'll leave that one to the more skilled tinkerers.

The filtering IS pretty serious, but the repeats sound very nice. I will try to add sound clips in the next weeks.

Fp

[lovekraft0]

Are you going to have boards available any time soon? I like the idea of this one, but I hate etching my own!

[Fp-www.Tonepad.com]

I will. Really soon

Drop me an email.

Fp

[Ethan]

Hi Francisco. glad you have a new version.  Took a look at your new schematic and was wondering why, for the straight sound,  you have a non-inverting buffer feeding an inverting amp? Aren't you inviting phase problems?  Also, I have built the PT-80 and breadboarded the Reboot2 and was wondering if this happens to you or anyone else:
Plugged into a high gain amp, I roll back the volume on my guitar to get a clean sound.  The delays then become real gritty, not in a good way.  This does not happen with PT80. Do you think this is the effect of the compandor?  It could also be breadboard related, but that's why I was hoping someone else could verify this.  The compander is expensive and hard to find in SMD version.
-ethan

[Fp-www.Tonepad.com]

Actually, now that you mention it, I was thinking of going back to the inverting input (as in Rebote2).

I haven't observed any of the issues you mention in my builds. I doubt it has to do with the compandor, and I don't see how/why that would happen. Then again, you're using a breadboard, and you must understand it's limitations, both in terms of circuit functionality, but specially because it's easier to make a mistake.

I hardly breadboard entire circuits anymore. I preffer making the pcb and swapping parts (when designing/tweaking).

Fp

[soggybag]

I was wondering about the choice of using the non inverting input stage? It seems (to my uneducated mind) that the output should be phase inverted in the new version.

[Fp-www.Tonepad.com]

You guys are right, I should've continued to use the input section from the Rebote2. I changed it because I was aiming for less parts.

I certainly preffer the clean signal to be in phase with the bypassed signal. I'm going to change that opamp input stage back to inverting to keep the output in phase (in a few days).

Fp

[labs]

I'm going to change that opamp input stage back to inverting to keep the output in phase (in a few days).

Fp

Any progress on this phase inverting issue on 2.5 yet? I'm about to start building a delay pedal but I'm not sure if I should build Rebote delay 2 or wait the upgrade of 2.5.
I understand you've been busy with Boss CE-2 and stuff, but I can't wait to start building... sorry about my impatiency 

-Lauri

[Fp-www.Tonepad.com]

It's ready.

Go ahead and download Revision 2 dated today (october 18th 2005)

Fp

[chokeyou]

can somebody do me a huge favor and email me a known working pdf? For some reason the robote series has ALWAYS given me errors in acrobat, i have no idea why. email: tylerromo at gmail.com

[Fp-www.Tonepad.com]

please download the latest version of adobe acrobat reader.

Fp