Another contribution by Jordan. Thanks mate!
I was playing with the Seppuku Fx Memory Loss that
you had posted and made some adjustments for more versatility. The
schematic we all have to work from is so sketchy I thought people might
enjoy a thorough series of mods to it.
S
First off I added a Mix control. It could probably be done better and would love to hear suggestions.
The C Taper for Stability gives easier adjustment over where the latch up occurs in playing dynamics.
I
set values at the Filter control. The on/off/on gives a clean delay,
dirty repeats and very dirty repeats. If you placed a 1u in either C2 or
C3 it creates a totally nuts fuzz.
I set components around the feedback and surge control to taste.
The increased Time pot is for longer delay times, why wouldn't we want longer delay times?!
I 86'd the switch for the LM386/Pins 1 & 8. I'm not going to use it but it wouldn't be hard for someone to wire it in.
The layout is not verified. It is the result of fixing the board I built from my original layout.
Hopefully no one minds a few diagonal caps.
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I'm guessing stability is modulation, is surge any particular value, and where does the time fit in? Or maybe it doesn't.. Probably all quite obvious to someone more competent than myself but I'm just confused. Would like have a go at this, potentially fun but some bits of info seem to be missing. Or is just me?
ReplyDeleteMy bad on the surge. It's a momentary switch. Normally open.
DeleteStability has been called a number of things on different versions of the pedal. It's going to control when the delay cuts out based on your signal coming in. Ccw the delay functions normally. Cw the delay chip is shorted out. It's very sensitive to your playing and effects stacked before it.
Time is the delay knob. That's just my preferred term for it.
So the filter control is an on/off/on toggle, but what type of toggle is the modulation?
ReplyDeleteModulation should have been relabelled as Stability. Stability is a C50k. Sorry for the errors. I'll update the layout and hopefully anders can upload it when he has time.
DeleteAnd yes to the on/off/on
layout is updated with the correct labeling.
ReplyDeleteWell thank you for all that, quick too! That sorts the weekend for me.
ReplyDeleteHello, comparing it with the diagram I noticed that only the LED resistor is missing, for the rest everything looks correct... What I don't understand is what about the 86 (sorry) that is connected between pins 1,8,7 of the LM 386 and the clock of the PT2399 and these pins are not connected to the board?Excuse my ignorance
ReplyDeleteon this i am only using the 'envelope' led as the on/off indicator. run the wire from Led + to the led and a wire from its - leg to the footswitch.
DeleteI think by clock you are referring to pin 5. nothing is ever connected to pin 5 on pt2399 delays. not that ive seen anyways. there is some information about why here: https://www.electrosmash.com/pt2399-analysis
the original memory loss has a distortion option on a switch. this is made possible by connecting the lm386 pin 1 and pin 8. i don't care for it so i omitted it on this build. "86" is slang for "deleted" or "removed".
Great, thank you for your complete answer, yes I was referring to pin 5 of the pt2399...now I understand about pin 1 and 8 of the lm386, it is like the clari-not- mod from mid-fi electronics, thank you very much
Deleteon my search earlier today for a particular ic i noticed i had a few pt2399 ic's doin nothing, so i thought ok, lets build this memory lapse 2 from jordan! well, it works (as is) ! i just gave it a testrun and seems very fun to play around with! thanks for the layout!
ReplyDeleteRock and roll!
DeleteRight on!
DeleteTagged.
Everything working fine except for the surge. Is this just me? Simplest part of the off board stuff and - Nada. Nice beast though.
ReplyDeleteAll I can think is make sure your connected to feedback lug 3. If your on 1 it will do the opposite of surge.
ReplyDeleteHello! Can I use another op-amp instead of the LM386? Thanks!
ReplyDeletethe lm386 is not an op amp, rather a power amplifier. so to my knowledge there are no alternative chips. Besides of course if only the prefix is different. For example the JRC386 i believe will replace it. unfortunately it isn't like the TL072 that has a dozen other alternatives. The good news is they are cheap and easy to get.
DeleteOh I see, my bad haha I thought it was an op-amp because of other delay circuits. Thanks for answering, I'll order that tomorrow :)
DeleteBtw, what effect does the 15nF capacitor have on the circuit? I don't have any so I was thinking that if it's a decoupling cap I could change it to another value, maybe 10 or 20nF ¿?
Its going to effect low much high frequency gets through on the repeats. you might was to socket the cap and experiment. My instinct is to go bigger. the world is your oyster!
DeleteThis comment has been removed by the author.
ReplyDeleteThe JRC386 is the way to go, those cheap LM386 amps are nothing but noisy!! NTE823 is also a replacement for the LM386?
ReplyDelete