Skreddy Echo [gut shots]

[monkeyxx]

oooh nice! can't wait for this one. skreddy is "the man" in my mind, when it comes to effects design

[Damon Jonesta]

I need at least another forumite to help me get this schematic right. If you have the Echo, even better for comparison purpose. Let me know if you're interested. I have 90% of the values and presently trying get the schematic onto Eagle. This will take 2-3 weeks on my off time to do.

[Moustache_Bash]

So, was anyone able to make a schematic out of this? I would be very grateful for it.

[Skreddy]

If I start seeing Skrecho clones on eBay or Chinese sweatshop versions, I'll be pissed. Forgive me for not being all rah rah, but this happens as a direct result of this site on a regular basis as I have seen, "non-commercial/educational use only" disclaimers notwithstanding. The Echo is a product of a year's worth of my own development time and represents a unique value of my brand, not a simple clone of other people's work.

Everyone has a legal right to tear them down and share their findings; but the benefits of public disclosure seem to redound to unethical cloners as opposed to any greater good to the DIY community, in the case of one person's unique work as the Klon for example. There are no fundamentally new things to learn here; only my own unique work product of fine tuning and employing common technologies in new ways.

The LFO is a simple, 1-transistor (the EA Tremolo), driving an LED/LDR for modulation of the delay line.

The unique Skreddy Echo limiter section is composed of 2 networks: 1 very subtle diode soft-clipper at the input of the delay chip, and 1 very subtle mosfet soft-clipper at the output.

There are multi-pole filters in the delay line's output path, which utilize inductors and resistors and relatively small capacitor values, which are tuned to remove hiss and fizz but retain the essential guitar tones.

The input/output stages are typical inverting gain stages with very minimal filtering and just enough gain to offset their impedance drag and could very probably be improved from a noise standpoint by re-designing into non-inverting, very-low gain stages.

Learn all you like, but please don't create DIY projects of this to encourage fast-buck, shirt-tail-following cloners.

Please? Thank you.

[madbean]

Sounds like a reasonable request to me. Thanks for sharing some more info. I'm really liking the inductor approach...sounds like you spent a lot of time working that out. Cheers.

[Skreddy]

Sounds like a reasonable request to me. Thanks for sharing some more info. I'm really liking the inductor approach...sounds like you spent a lot of time working that out. Cheers.

Thank you! You're a gentleman and a scholar.

[madbean]

Sounds like a reasonable request to me. Thanks for sharing some more info. I'm really liking the inductor approach...sounds like you spent a lot of time working that out. Cheers.

Thank you! You're a gentleman and a scholar.

Ha ha, more like a curmudgeon and a hack, but thanks for keeping up the illusion.

[Moustache_Bash]

Learn all you like, but please don't create DIY projects of this to encourage fast-buck, shirt-tail-following cloners.

Please? Thank you.

I just want to build stuff for my own amusement, cloners for profit can suck a fatty.

[Skreddy]

Sounds like a reasonable request to me. Thanks for sharing some more info. I'm really liking the inductor approach...sounds like you spent a lot of time working that out. Cheers.

Thank you! You're a gentleman and a scholar.

Ha ha, more like a curmudgeon and a hack, but thanks for keeping up the illusion.

For some reason, my first reading of that word was "cunnilingus." The actual word you used makes much more sense.

[iq01221]

Thanks for sharing your own work +

Learn all you like, but please don't create DIY projects of this to encourage fast-buck, shirt-tail-following cloners.

Totally agree!! Group hug!!
Is there a way to do something about it? I mean, DMCA or something, but not for fsb, just to those jilly-cloners

[Jack Deville]

Thank you for confirming my assessment of the circuit, Marc. Neat ideas, nice approach and most importantly, good tones.

[Skreddy]

Thanks for sharing your own work +

Learn all you like, but please don't create DIY projects of this to encourage fast-buck, shirt-tail-following cloners.

Totally agree!! Group hug!!
Is there a way to do something about it? I mean, DMCA or something, but not for fsb, just to those jilly-cloners

Absolutely not without a patent. Years ago, a wise man (now I forget whether it was Jack Orman, R.G. Keen, or Mark Hammer) once said that the best way to protect your IP is simply to publish it. Folks will copy, but at least you'll get the credit. Well, I kind of want to forestall the copying as long as possible. There is honor and good will shared among the DIY and small-time builder community. We all learn from one another, and there are plenty of unique ideas to create powerful market niches for whoever wishes to take his hobby to the next level without needing to resort to "me-too" style product development and marketing.

[culturejam]

Thanks for the insights, Mr. Skreddy.

Learn all you like, but please don't create DIY projects of this to encourage fast-buck, shirt-tail-following cloners.

There isn't really any point now in doing a 100% clone, as you've told us how the different functional blocks work. There's enough info now that with a PT2399 data sheet, EA Trem schematic, and some reading up in "The Art of Electronics", I think someone could come up with something functionally similar.

That, to me, would be a far preferable outcome, as it would yield an "original" (as original as things can be) work-alike that nobody could reasonably claim is a "Skreddy Echo clone" in their shitty ebay auction.

[Skreddy]

The last thing that sets the Skreddy Echo apart from the others that hasn't been mentioned here is the mix control. It goes from 100% dry to 100% wet. It's a bit lossy, so that's why extra gain is needed to achieve unity. You can look at the schematics of the old tube Echoplex EP2 to see how this is done. Basically, you send both signals (dry and wet) through to the output stage via pairs of resistors with the mix pot set in the middle of them like the cross-bar of a letter "H". The wiper of the pot goes to virtual ground.

[monkeyxx]

Thanks for the insights, Mr. Skreddy.

Learn all you like, but please don't create DIY projects of this to encourage fast-buck, shirt-tail-following cloners.

There isn't really any point now in doing a 100% clone, as you've told us how the different functional blocks work. There's enough info now that with a PT2399 data sheet, EA Trem schematic, and some reading up in "The Art of Electronics", I think someone could come up with something functionally similar.

That, to me, would be a far preferable outcome, as it would yield an "original" (as original as things can be) work-alike that nobody could reasonably claim is a "Skreddy Echo clone" in their shitty ebay auction.

that is a great idea. I might go for this, given the necessary gumption (motivation), wonder if anyone else will do the same and share their results on here. I like the basic ideas but tweaking the tone and controls might lead to something unique and fun. there are so many ways to use and customize a delay, more than some other basic circuits like fuzz, that if you know what you like and what you're doing you could really achieve something great I think

[Skreddy]

If anyone wishes to add a delay-line-only effects loop, you would make a definite improvement over my design by adding a proper buffer in front of the "send" terminal. Once that buffer is part of your intrinsic design, you'd of course tune the feedback control and the mix control accordingly. Then, when a customer uses the effects loop, the delay signal won't suddenly get louder and want to feed back like crazy (because the impedance is suddenly high and with a healthy signal level). My space-saving workaround to this is a 100k trimpot on the "receive" signal, to attenuate when an effect is used. It's a hack, and could definitely be improved.

[~arph]

The last thing that sets the Skreddy Echo apart from the others that hasn't been mentioned here is the mix control. It goes from 100% dry to 100% wet. It's a bit lossy, so that's why extra gain is needed to achieve unity. You can look at the schematics of the old tube Echoplex EP2 to see how this is done. Basically, you send both signals (dry and wet) through to the output stage via pairs of resistors with the mix pot set in the middle of them like the cross-bar of a letter "H". The wiper of the pot goes to virtual ground.

Look up 'panning for fun' at geofex for that type of mixing.

[roseblood11]

The chinese know how to clone IC's, cars, medieval castles, complete production facilities, whatever.
If they really want to clone a simple delay pedal, they'll buy it and retrace it themselves.

This whole "FSB helps the gangsters" discussion is nonsense...

[Damon Jonesta]

how do you know i'm not chinese?

[culturejam]

The chinese know how to clone IC's, cars, medieval castles, complete production facilities, whatever.
If they really want to clone a simple delay pedal, they'll buy it and retrace it themselves.

This could be its own topic. Think I'll start it now in Member's Corner.