danelectro dan echo de-1 r10 mod for infinite repeats

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danelectro dan echo de-1 r10 mod for infinite repeats

Postby tabbycat » 01 Nov 2014, 20:32

danelectro dan echo de-1: r10 infinite repeats mod.

have done this mod two ways and thought i would post a description and some pictures. it’s a stupidly simple mod.
basic mod is to remove (or clip one leg of) resistor r10 (see pics) so it is no longer part of the circuit (it limits repeats). then jumper the solder connections to re-complete the circuit without it.

i tried this and it works great and as expected. the point at which self-oscillation starts is very finely tuned in on the ‘repeat’ knob. 3pm and you are in a world of lush and dreamy everlasting repeats. past that you go into swirling parallel-universe self-oscillation, which has its own beauty and uses.

as the whole reason i originally bought the dan echo was because it was perfect sounding as standard (to my fussy ears), i decided that i would put the original r10 resistor across the top two lugs of a mini dpdt switch, a wire jumper across the bottom two lugs, and join the wires to and from the original r10 solder connection to either side of the middle lugs (see pics).
so now i have modded or unmodded at the flick of a switch, which saves me having to redial the original settings in every time i want to switch back to unmodded sounds.

the big advantage of this in practice is that it allows me to leave the repeats on max in unmodded mode for maximum dreamy but not self-oscillating, then flick the switch for a bit of chaos, and then back, easily.
without the unmodded/modded switch you have to fiddle around ‘safecracking’ the dial to find the sweet spot again, in the midst of a self-oscillating storm.

ultimately i’d like the switch on a stomp, but not sure where to put it so it wouldn’t be too close to the on-off stomp or to the knobs. as the pcb is huge a rehouse will take some planning.
there are other things i am looking at re modding this (truebypass, modding buffer, don’t care about the modulation mods so much) but am very happy with it as is for now. which is the point.

anyway, here are some photos for reference.

r10 mod small 1.JPG


r10 mod small 2.JPG


r10 mod small 3.JPG


r10 mod small 4.JPG

tabbycat.

ps. one final thing i did was to put sockets into the r10 solder points and soldered the wire ends of an old breadboard jumper onto the wires from the switch. the wires are a snug fit in the sockets so still a good connection. but this means that if/when i play with the board in the future i don’t need to take the switch out with it and have it dangling around likely to break off.
"be a good animal, true to your instincts" (d.h. lawrence).
"there is no excellent beauty that hath not some strangeness in the proportion" (francis bacon).
"ni dieu ni maître" (anarchist slogan).
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Re: danelectro dan echo de-1 r10 mod for infinite repeats

Postby POGART » 10 Dec 2014, 01:57

I was hoping someone here could help me out. I was aiming to do the r10 mod to my dan echo pedal and when I opened it up there is no resistor that I can see in the r10 spot. There is just "r10" and a blank space with no holes or resistor. I noticed it is not even in the same place as some pictures I have seen as reference from other peoples mods to the pedal. Any suggestions?
Thanks
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Re: danelectro dan echo de-1 r10 mod for infinite repeats

Postby tabbycat » 10 Dec 2014, 05:29

POGART wrote:I was hoping someone here could help me out. I was aiming to do the r10 mod to my dan echo pedal and when I opened it up there is no resistor that I can see in the r10 spot. There is just "r10" and a blank space with no holes or resistor. I noticed it is not even in the same place as some pictures I have seen as reference from other peoples mods to the pedal. Any suggestions?
Thanks
POGART

hey pogart, welcome to fsb.

if you could post a decent pic of both sides of your pcb i may be able to see what is going on. photos of mine are above, does it look anything like that?
if it's the pb&j rather than the dan-echo the basic mod is the same but the resistor is in a different place. i've done that mod too, so i can post pics if you want. let me know.

tabbycat.
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"ni dieu ni maître" (anarchist slogan).
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Re: danelectro dan echo de-1 r10 mod for infinite repeats

Postby POGART » 10 Dec 2014, 16:36

Thanks for the speedy reply. I think I figured out the pb&j issue. Looks like I do not have a full connection between the two resistor sockets. I may have killed the pedal, this little resistor chips are so small and I think the one below the r10 is buried somewhere in a glob of solder so it is not connected to anything anymore. If possible can I jump the two sockets together with wire even if the resistor is gone?. I hope the pictures are clear enough for you to get an idea. I appreciate the help.
The second and last pic is the pb&j. I noticed from your pics that my dan-echo board looks different. It is smaller and seems to have resistor "chips".
POGART
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Re: danelectro dan echo de-1 r10 mod for infinite repeats

Postby tabbycat » 10 Dec 2014, 22:00

hi pogart, thanks for the pics. it seems danelectro have completely redesigned the pcb since mine was made.

if you look at this website (just saves me opening up mine all over again) you can see that there is a big long chip with pt2395 written across it in big letters. that is the main delay chip.

http://www.e-basteln.de/harp/Images/lar ... boards.jpg

full webpage here with other pics and mods for the dan-echo. http://www.e-basteln.de/harp/

i can’t quite read what they have replaced it with (it looks like a combination of chips working together to do the same thing) but (as you can see from the whole layout of the board) it’s a completely different design to yours. and as part of that redesign they seem to have replaced most of the normal size components with smc (surface mount components, the little silver chips you mentioned).
i don’t know when the redesign happened. the only pics i can find of google are of the boards like mine, which were made in the late 1990s. yours are the first pics i’ve seen of any new design for it.

the ‘infinite repeat’ mod may still be possible if the new circuit has been redesigned to do the same thing, which i’m supposing it does in a way (or it wouldn’t be called an echo). but the r10 (short for ‘resistor number 10’ in the original circuit) might be resistor number 11 or resistor number 9 in the new design circuit. the only way to easily work out if it is possible would be if you could find a circuit diagram (called a ‘schematic’) for the new circuit to compare to the old one.

as for the original circuit design for which this mod works, i’ve highlighted the circuit path (in pink) on an image of the board to show how the mod works in that circuit. (ignore yellow arrow, that is to do with another mod).

r10 mod danecho copy.jpg

basically the circuit signal comes out of the middle lug of the ‘repeat’ control potentiometer (‘pot’ for short), goes into resistor 10 (r10) which is 15k, it then goes into the negative lead of a 1uf electrolytic capacitor (‘cap’ for short) and goes from the positive of that into another (non-polarised) cap labelled c30 (which i don’t have the value for as it’s not written on it, and i can’t measure it unless i unsolder it from the circuit) and from that into the middle lug of the ‘high-cut’ pot.
when you replace r10 with a jumper (basically a length of wire) you are removing 15k worth of resistance from that path between the pots, and that small change allows the pedal to go into self-oscillation.

if the new design circuit is very close to the old design (and only by comparing the circuit of the old and new will you know that for sure) then (in theory) it may be the case that if you reduce the resistance of that same path between the two middle lugs of the ‘repeat’ and ‘hi-cut’ pots by 15k the mod should work the same.
but it’s a big if. especially when you consider that the main chip for the whole circuit is different. when i look at the ‘repeat’ pot and ‘high-cut’ pot on your new design board i can’t see any resistor between them at all. all the components i’ve highlighted on the old design are just not there on your new one.

so to cut a long answer short, i don’t think the r10 mod that worked on the old design will work on the new. which is a shame as it’s a great and simple mod. but if you can find a circuit diagram for the new design board and post it here, i (or someone else here) may be able to look at it and tell you for sure whether the mod is possible on that circuit.

as for the pb&j, hopefully danelectro haven’t redesigned that.

again, it should have that same long pt2395 chip the old design dan echo has. except in the pb&j it goes across the bottom of the board, taking up the width of the whole board almost.
the two long rows of solder blobs going right across the width of the board (halfway down the picture of my pb&j below) are the solder pin connections that join to the pt2395 chip on the other side of the board (you have to take the board right out to see the chip itself). if your board doesn’t look like this it might be a newer design. the dan echo and the pb&j are very similar pt2395 based delay circuits, which is why the same mod works on both. but the resistor you need to change is in a different place on the pb&j board.

i’ve highlighted the jumper wire i soldered into place where the resistor was on mine.

pbj r10 mod.jpg

and here is a close up.

pbj r10 mod 2.jpg

i’m not sure where the resistor is that you have tried to solder in your pic but it is definitely not the same one. if you study my pics and this video you will see which resistor has to be jumpered to do the mod.

you can see the whole mod (such a small thing that it is) being done in real time here.

Link

i don’t know why he leaves his pedal on while he performs the mod. a bad idea. always unplug before taking a look inside a pedal. he puts a blob of solder across the two solder points he removes the resistor from, but the wire i used does the same job. basically that resistor has to be removed from the circuit, and the gap left by it has to be filled with solder or wire to complete the circuit.
if you are not confident about what you are doing it may be best to find someone who knows a bit more about soldering and circuits to do it for you, or to help you do it. electricity and heat are dangerous things. with the details here someone who knows what they are doing should be able to do it for you in less than a minute, as the video shows.

anyway, i hope this message helps? i’ve tried to be as detailed as i could. sorry it doesn't seem to be good news re the new dan echo board.

tabbycat.
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Re: danelectro dan echo de-1 r10 mod for infinite repeats

Postby POGART » 10 Dec 2014, 23:08

Excellent information buddy. Thank you so much. Unfortunately I think my pb&j is toast now. I reworked the solder "blob" with wire jumpers and still not a peep from the pedal. It turns on but there is no delay at all. I salvaged the smc's but I am pretty sure they are fried and reslodering those little guys is really tough : ) The board was different than yours and by the time I realized it was already into it lol. I dig the sound of the dan-echo as is so I will keep an eye out for an older one to mod. I have another pb&j delay that is the correct board design. I may mod that one but will keep looking for another one to "test" on. Thanks again for the quick reply and detailed info. I will surf the net and see if I can find a schematic of the dan-echo I have now.
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Re: danelectro dan echo de-1 r10 mod for infinite repeats

Postby elcomplicado » 13 Nov 2016, 14:26

Hey there,

I'm planning on doing this mod later in the week although I was wondering if there was a slightly different method. I want it so that when I stomp the momentary switch it goes straight into infinite repeats regardless of where the pot was previously. If I'm right in thinking, the method of jumping the r10 resistor only makes it go to infinity when the pot is in the further position. So I'm thinking if I take what is going into the 1st leg of the pot and jump from there to after the R10 then it'll effectively act like an infinite switch straight off the bat. Would that be right in thinking?
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