New Project at GGG - SHEcho (800mS)

Started by Dean Hazelwanter, March 31, 2006, 10:51:40 PM

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Dean Hazelwanter

JD notified me today that he has posted the 2nd of 3 projects I sent him. It's called the SHEcho - for Swartz-Hazelwanter Echo. It is a combination of my older 800 mS echo (at GGG), and Scott Swartz's superior PT-80 (300mS) delay. Scott gave his blessings as well as some input to this project. Enjoy! :)

Marcos - Munky

Cool. I still didn't had time to build your last project (the EQ). Thanks a lot.

newperson

Thank you for a new delay.

how do the repeats sound?  can/do they go into feedback?

Mark Hammer

Looking forward to this.  I won't go into detail about how I got my 8955 chips, but it was almost 6 years ago to the day and it involved perfect timing between a 3 day stay in New Orleans, the order desk at the American Radio Shack and FedEx.  For the aggravation involved, there is NO WAY I'm letting those chips lie fallow! :icon_lol:  Those and all the 256K DRAMs on those 486 boards festering in the garage!

There are plenty of satisfied PT2399 users who have been convinced that with the right filtering, a digital chip can have all the "warmth" they look for in a delay.  I think people will be pleased with what the extra half second of delay time enables one to do with a delay unit.  Not quite a looper but certainly a step in a different direction for what one does with repeats and plans around them.

Of course you realize that this calls out for a rejigging of the board to accommodate a PT2395.  The 8955 is a decent chip but offers lower sonic quality (not to mention availability and cost) relative to the PT2395.  The latter will also provide 800ms with a 256k DRAM chip.  I'll need to take a closer look at the pinouts of the two chips to see if I should retract my suggestion or not.  It may be a no brainer to move a trace here and there, OR it may be closer to a complete redraw than I imagine.  In any event, something to think about.

As always, thanks for your dedication and contribution.  Rectangular provinces rock!!

Dean Hazelwanter

Thanks, guys!

Special (and public) thanks to you Mark. As I mentioned in the 6 band EQ thread http://www.diystompboxes.com/smfforum/index.php?topic=43395.20 , I appreciate your input that other, bigger project. Although it wasn't what I wanted to hear, it's what I needed to hear, and helped me to prioritize things! :)

roseblood11

... is there a chance that anyone will make the SHEcho work with a PT2395?

Or maybe slackers echobase?

chi_boy

Quote from: newperson on March 31, 2006, 11:55:18 PM

how do the repeats sound?  can/do they go into feedback?

I need some help understanding this question.  Is a delay SUPPOSED to be able to go into feedback??

I just finished a PT80, and went through a lot of effort to eliminate the feedback when repeats was maxed.  The solution came from Mark Hammer, and did make the run away feedback go away.

But I have seen others ask similar questions as if the crazy feedback was a "feature."  Just so I can educate myself, why would someone desire such mayhem?  More power to ya if that's your thing, I'd just like to know why.

Cheers,
George
"Great minds discuss ideas, average minds discuss events, small minds discuss people." — Admiral Hyman G. Rickover - 1900-1986

The Leftover PCB Page

Mark Hammer

The runaway feedback thing has several aspects to it.  At one level, it can serve as a kind of rhythmic device when the delay time is long enough, like a mini-looper.  At another level, every repeat, unless we're talking about exquisite sampling or A/D/A conversion, tends to be lower fidelity than the previous one.  That's partly because there is some filtering in between where the delay signal begins its journey and where it is tapped for recirculation, but also because the process is generally imperfect and the errors in A/D/A conversion accumulate.  The "lo-fi" quality that emerges over time is something that some folks like to play with as another texture.

In Jamaican dub music, a common trick was to shave off some of the bass fro each repeat, so that the repeats not only got more lo-fi but more strident and shriek-ey over time/repeats.  This provided a nice contrast to the prevailing bass-drum rhythm (excuse me, riddum  :icon_wink: ) going on through the song.