Super Simple Pedal Mod Question- delay time.

[pinkjimiphoton]

something like 5ma can kill you.
doesn't take much.

an average 9v battery is putting out about 500ma on average....different types may be higher or lower.

[Nyklus]

im getting ready to wire the mod now and looking a the trim pot it says
m20k 5N?

so i know whar 20k means of course its 20k resistance maximum,
whats 5N?
also is this 20k the max delay time this pedal can handle.
i know scgematics are usually needed for this sort of question but i thought id ask anyways.

[pinkjimiphoton]

i just replaced the delay time pot on my archaic seiwa analog delay with one twice it's size...went from 50k to 100k
and doubled the delay time. worked great.

there's a bit more degradation on the longer delay settings, but i'm a weirdo, i LIKE that.

a super fuzz on the octave up setting into it makes it freak out and create all kinds of harmonics...

echoes that are harmonically related, but NOT the same pitch. it's probably broken, but it sounds @#$%in' cool as hell!!

so i'd say go for it. double the size of the pot. triple it even. see what you can get, i don't think you can hurt anything.

[timd]

i just replaced the delay time pot on my archaic seiwa analog delay with one twice it's size...went from 50k to 100k
and doubled the delay time. worked great.

there's a bit more degradation on the longer delay settings, but i'm a weirdo, i LIKE that.

a super fuzz on the octave up setting into it makes it freak out and create all kinds of harmonics...

echoes that are harmonically related, but NOT the same pitch. it's probably broken, but it sounds @#$%in' cool as hell!!

so i'd say go for it. double the size of the pot. triple it even. see what you can get, i don't think you can hurt anything.

I agree - I replaced a 100k pot on most echos will leave those echos ragged and distorted and they go on forever...

[Nyklus]

great so heres what im thinking.

i have my 20k pot
momentary switch between
min. lead and middle for wild foot controled speed delay
and switch between the (min. and max pot leads) the two outer ones
that will route the current through a larger resistor.

[Nyklus]

Ok guys!!!

Say I wire a 500K pot in parallel with this 20k pot, that makes the resistance 460K??
also

if i wanted to all three leads to the three leads of the origonal trimpot which lead would i put the on/off switch between to turn off this elongated delay function?

[Jdansti]

500k and 20k in parallel would give you ~19.2k! 

Here's the formula:



When you have a relatively large and small resistor, the large one has little effect and the small one "controls" the result because you are using the inverse of the values. For example 1/500k is 2e-6  (0.000002) and 1/20k is 5e-5 (0.00005). When we add these in the denominator, we get 5.02e-5 (0.0000502). Hardly any change from 5e-5.  Does this make sense?

[Nyklus]

i follow, so
what about wiring them in series?

[Jdansti]

Just add the values.  500k + 20k = 520k

[Nyklus]

should i add the switch coming off the neg pold in series with the new pot or after the pos of the new pot headed back to the origonal viriable resistor?
this is of course to turn of this fantasticdelay manipulation.

[Jdansti]

I apologize, but I can't picture your question in my head. Can you find a schematic, mark it up and post it?  If not, at please draw a picture and post it.

[Nyklus]

http://sphotos-b.xx.fbcdn.net/hphotos-snc6/215740_10151195382665753_1611068514_n.jpg
sorry im an uber noob at html.

soo

i imagine i could keep the 500K down to  min  when not in use.

what sayeth you?

[Jdansti]

I sayeth thou inquiry raiseths questions.

1) What is the original (factory) wiring for the delay pot?  Looking at the delay pot and PCB very carefully, show me how each lug on the pot is connected to the PCB.  For example, lug 1 of the pot might be connected to pin 3 of IC lmxxxx, and lug 2 of the pot might be connected to the ground trace on the PCB.


For reference for the next two questions, here is your drawing:


2) Looking at your drawing, are the (+) and (-) symbols on the board: (+ )= positive voltage from power supply, and (-) = negative/ground, or something else?

3) Do understand what the lug connections of pots "do"?  You have the "Mod Pot's" 1 and 3 lugs connected to the circuit and nothing connected to lug 2. This causes the pot to become a fixed resistor. Moving the wiper (the wiper is connected to the #2 lug and moves along the fixed resistor when you turn the shaft) will have no effect on the circuit.

Take a spare pot, and with your meter set to resistance, connect the leads to lugs 1 and 2 and watch the resistance change as you rotate the pot's shaft. Do the same with meter on lugs 1 and 3, and on lugs 2 and 3.  You need to understand how the pot works. Also, see this image:



4) Do you understand how the switch lugs interact?  You show no connection to the common (middle) lugs of the switch; therefore, toggling the switch lever back and forth will have no effect on the circuit.

Conduct a similar test with the switch as you did with the pot and learn how the six lugs interact (or don't interact) when you flip the lever.  Also, see this image:



.................................................
Now redraw your picture to show how you want to modify the original wiring.   You should now have two pictures, one showing the original, unchanged wiring, and one shown the mod.

BTW, all you have to do to embed an image is type: "[img.]" before the direct link, and "[/img.]" after. Omit the dot (.) after the "g". I put it in there to prevent the site from thinking I was trying to embed an image. Click on "quote" when you read this post and you'll see how this is done.

[Nyklus]

i forgot to photo the original circuit board. just wanted to take a stab at a correction.

I used - and + cause i was guessing, that the flow of electricity flows from - to + and throught the pot from 3 to 1.

I am learning a lot from this forum and your help jdansti,
thank you.

[Jdansti]

^ How electrons behave is interesting, but not necessary information for resolving your questions abou the pedal. It's more important to understand and use the terminology that everyone else uses. You'll pick up on all of this over time. Just continue learning.

[Nyklus]

right,
did my schematic make sense?

[Jdansti]

Not really.

It seems that you are learning some things here, so even though this has not been a "Super Simple Pedal Mod Question" it's been valuable. (Either that or someone is having a good laugh at my expense ).

Your picture is post-mod. I still haven't seen the original factory wiring for the original delay pot. How was it connected?  It's difficult to modify something without knowing how it was configured before the mod.  Draw us a new picture showing how the original pot was wired before any changes, ie., straight from the factory.

I also need to understand the goal of this mod in terms of parts, not the desired change in sound.  Is the goal to increase the resistance at + and - on the board above the original pot resistance when you press the new switch?

Without knowing the answer to these two questions, I'm in the dark and can't help you.

[Nyklus]

hey i should have taken the picture you asked for
but i put the switch in and now i have a great mod, the next i will do will be a 500k pot in series with the 20k.
basically it will be normal delaytime as the origonal pedal when the pot
is set to 0k resistance. and when i turn up
the pot it will get that cool lofi long delay.

[Jdansti]

Without knowing how the original pot was wired, I'll assume that the board just used the variable resistance between the wiper (#2) and only one of the end lugs (#1 or #3). If so, then this would have been what the wiring might have looked like. Note that the unused pot lug might have been connected to the #2 lug.

Presumed Original:


Now, if I wanted to add a series pot that could be switched in, I would wire it like this:

Mod Pot Added


The following two drawings show the path of continuity in the two switch states. The direction of the arrows doesn't mean anything. They were just a convention to illustrate the continuity

The first would be he "Normal Mode" which should sound as it did from the factory. If you are using a momentary switch, this drawing shows what the path would be if you were not pressing on the switch.  As you can see, the Mod Pot is not in the circuit.

Switch in Normal Mode


This picture shows the continuity path when you press on the switch. Again, the direction of the arrows is just to show the continuity. Here, the Mod Pot is connected in series with the original pot.

Switch in "Mod" Mode

[Nyklus]

Ok so i have questions in regards to manipulating delay time.

I have taken pictures of the main ic chips that my guyatone tube echo uses.

there are 3 4580D JRC H089Bs

there is also 311D JRC 7019B
082BD JRC H013B

a big ol SA571N FDN3021 0538op

a big tmTECH 12J 0723 T14L1024N CH70606

i have no knowledge of what chips people use for delay so maybe this is first question.
what chips is driving the delay?

ill post some pictures of the chips.








and then my second question.
and i guess it depends on what chip is used for delay.
but im trying to have two switches in series. one that when pressed will take the delay resistance to 0 and have a nice slapback sound (this is already done, i know it works) and the second switch with a 500K or 1M resistor that'll add delay spacy, super long delay.

Im just hoping that doing this doesnt destroy the chip.
heres a picture of the diagram i have in mind.