Echo Base - a new PT2399 delay

[slacker]

Ok, so I've studied it a bit and thought a stereo pot (or the 2nd one) should substitute R2 in the add-on board,

Assuming you mean this layout? http://www.diystompboxes.com/smfforum/index.php?topic=60662.msg560977#msg560977 then yes you  can replace R2 with a pot or a stereo pot to control both chips at once. You don't need to change anything else.

The feedback is taken from the output of the second chip and then fed back into the first one, so the repeats are the same length as the total time from both chips.

[slacker]

1) What are you guys doing to combat the clock noise? Can I swap out the "level" pot with a different value to maybe restrict the overall level? The noise only gets bad when the level pot is at 75%+

If you want to lower the maximum volume of the delay, then trace from the wiper of the level pot , the signal goes through a 100n capacitor and then a 10k resistor, sorry I don't know which one it is on Taylor's board. If you make the 10k resistor bigger that will lower the maximum volume of the delay. Changing the value of the pot won't do very much.

2) Is there a way to clean up the repeats, or is it a limitation of the PT2399? I know it's intended to be a low-fi effect but wondering oif that's a result of the circuit or chip.

The repeats should be fairly clean at short times on longer times it gets a bit muddy, but that's mostly a limitation of the chip. You need to filter out more highs otherwise the noise gets really bad.

3) anyone experience this: pedal will pass dry signal in both modes (bypass and on) but I get no repeats until i unplug/re-plug the power?

I haven't heard of this problem before. I know if you make the resistance between pin 6 and ground too small the chip can do this, but I've never had that problem with either of mine. If you set the delay time somewhere in the middle before you turn the pedal on does that stop it doing it?
With what you've said about the noise problem as well as this I wonder if you have a bad PT2399 or a bad connection somewhere around pin 6.

[Taylor]

If you want to lower the maximum volume of the delay, then trace from the wiper of the level pot , the signal goes through a 100n capacitor and then a 10k resistor, sorry I don't know which one it is on Taylor's board. If you make the 10k resistor bigger that will lower the maximum volume of the delay. Changing the value of the pot won't do very much.

It's the 10k directly to the left of pin 1 of the 4066.

[DLC86]

Assuming you mean this layout? http://www.diystompboxes.com/smfforum/index.php?topic=60662.msg560977#msg560977 then yes you  can replace R2 with a pot or a stereo pot to control both chips at once. You don't need to change anything else.

Yes, I meant that layout, I forgot to specify

The feedback is taken from the output of the second chip and then fed back into the first one, so the repeats are the same length as the total time from both chips.

That's exactly what I wanted to know, so I could put all the add-on boards I want... But another doubt is coming... I think it could be deduced by your answer but I havent enough knowledge to do it, so...
I can totally control the feedback using one pot, right? Or is there a default fixed resisitor in the daughter board that I could substitute using a stereo pot (like R2 for the time pot)?
thank you very much

[Leftwing73]

1) What are you guys doing to combat the clock noise? Can I swap out the "level" pot with a different value to maybe restrict the overall level? The noise only gets bad when the level pot is at 75%+

If you want to lower the maximum volume of the delay, then trace from the wiper of the level pot , the signal goes through a 100n capacitor and then a 10k resistor, sorry I don't know which one it is on Taylor's board. If you make the 10k resistor bigger that will lower the maximum volume of the delay. Changing the value of the pot won't do very much.

2) Is there a way to clean up the repeats, or is it a limitation of the PT2399? I know it's intended to be a low-fi effect but wondering oif that's a result of the circuit or chip.

The repeats should be fairly clean at short times on longer times it gets a bit muddy, but that's mostly a limitation of the chip. You need to filter out more highs otherwise the noise gets really bad.

3) anyone experience this: pedal will pass dry signal in both modes (bypass and on) but I get no repeats until i unplug/re-plug the power?

I haven't heard of this problem before. I know if you make the resistance between pin 6 and ground too small the chip can do this, but I've never had that problem with either of mine. If you set the delay time somewhere in the middle before you turn the pedal on does that stop it doing it?
With what you've said about the noise problem as well as this I wonder if you have a bad PT2399 or a bad connection somewhere around pin 6.

Thanks for the help, ian. I'll throw in another PT2399 and see if the issues clear up.

[slacker]

That's exactly what I wanted to know, so I could put all the add-on boards I want...

Yes in theory you can connect as many of the add on boards as you like. In practice it would probably get too noisy to be useful though after not very many.

But another doubt is coming... I think it could be deduced by your answer but I havent enough knowledge to do it, so...
I can totally control the feedback using one pot, right? Or is there a default fixed resisitor in the daughter board that I could substitute using a stereo pot (like R2 for the time pot)?
thank you very much

Yes you only need one feedback pot, the signal just goes through however many add on boards you want, then you take the feedback from the last one and feed it back into the first one. You could also add feedback pots at any of the boards outputs and send it back to any of the previous ones to different length repeats.

[mth5044]

Yes you only need one feedback pot, the signal just goes through however many add on boards you want, then you take the feedback from the last one and feed it back into the first one. You could also add feedback pots at any of the boards outputs and send it back to any of the previous ones to different length repeats.

Getting into Arnoud's nifty echorec-esq delay 

[slacker]

 

[DLC86]

That's exactly what I wanted to know, so I could put all the add-on boards I want...

Yes in theory you can connect as many of the add on boards as you like. In practice it would probably get too noisy to be useful though after not very many.

But another doubt is coming... I think it could be deduced by your answer but I havent enough knowledge to do it, so...
I can totally control the feedback using one pot, right? Or is there a default fixed resisitor in the daughter board that I could substitute using a stereo pot (like R2 for the time pot)?
thank you very much

Yes you only need one feedback pot, the signal just goes through however many add on boards you want, then you take the feedback from the last one and feed it back into the first one. You could also add feedback pots at any of the boards outputs and send it back to any of the previous ones to different length repeats.

Thank you very much, now everything's clearer

[nick d]

                   Hey , just finally got this working!! (after numerous debugging hours - not really suitable for my second build!!).
                    All I can say is  --AWESOME!!!!!!!   Ian , you are a genius , thanks mate!! 

[DimebuGG]

My echo base a week ago suddenly died(for about a year of usage), a dead PT2399 and the 4066 CMOS. I don't know how did it happened. It's giving me headaches really during live situation before it died. It exhibits some weird noises(such as LFO ticking) and switching malfunctions. Luckily, I got a spare PT2399 chip and decided to revise the layout and use JFET(J113) switching in place of 4066, a separate voltage dividers of the in/out buffers and the LFO. Delay trailing feature is still there. I would like to post the layout if someone's interested.

[DLC86]

My echo base a week ago suddenly died(for about a year of usage), a dead PT2399 and the 4066 CMOS. I don't know how did it happened. It's giving me headaches really during live situation before it died. It exhibits some weird noises(such as LFO ticking) and switching malfunctions. Luckily, I got a spare PT2399 chip and decided to revise the layout and use JFET(J113) switching in place of 4066, a separate voltage dividers of the in/out buffers and the LFO. Delay trailing feature is still there. I would like to post the layout if someone's interested.

I'm interested

[DimebuGG]

http://www.filefactory.com/file/b38ce0b/n/echobase.PDF

PCB measures 5.4cm x 5.7cm.

[DLC86]

http://www.filefactory.com/file/b38ce0b/n/echobase.PDF

PCB measures 5.4cm x 5.7cm.

Thank you, very compact layout
It's already verified, right?

[DimebuGG]

Thank you, very compact layout
It's already verified, right?

Of course.

[DLC86]

Hi DimebuGG, could I use a j112 in place of a j113 in your layout?  I saw the datasheets and the differences are in drain current, G-S cutoff voltage and D-S resistance. will it work properly? If not, could you suggest me a valid substitute for this FET?
Thank you again 

[Barcode80]

Dumb question, but I would assume the 2SK113 will work in place of the J113, correct?

[DLC86]

Hi DimebuGG, could I use a j112 in place of a j113 in your layout?  I saw the datasheets and the differences are in drain current, G-S cutoff voltage and D-S resistance. will it work properly? If not, could you suggest me a valid substitute for this FET?
Thank you again 

I've found the answer on your signature site, I can even use a common j201. Thank you anyway

Dumb question, but I would assume the 2SK113 will work in place of the J113, correct?

I don't know if they are the same (I think so), you can check the datasheet

[DimebuGG]

I'm no expert in electronics but I suppose those FETs will work. Better yet contact the electronic gurus in here.  . I only used J113 since it's the only available FET I had which I removed from an old DOD pedal and also the only one with the "D S G" pinout(facing flat side). I could have used 2SK30's or 2SK184's which are commonly used in Boss pedals.

could I use a j112 in place of a j113 in your layout?

I think so. 

[edd101]

hi there,

First of all I would like to thank Slacker for this cool project! I etched my own pcb using anonymousfacelesscowards layout, also tried all the latest mods (thnx Taylor for all-in-one pdf, had to do a little trace cutting and extra wiring). The effect is great, the flashing light is sexy !
My PT-80 delay didnt sount that good the decay was gated, so i'll be boxing EB instead. I had some distortion with my dimarzio pickups, so i replaced two 47k with 22k, that solved the distortion problem but it also made the repeats sounding thin. Next thing i'll do is try two 33k insted of 22k maybe it'll bring some life in to them

Ed