Phase 90 Clone Rate Mod Help

[mickeybellinello]

Hi to all,
I recently built a Phase 90 clone using a musikding PCB.
I want to add a rate led so i tried to connect a led to pin7 of lfo but i get a blinking led without a smooth transition.
I tried to built the mini pcb that i found on madbean nomnom pdf reference.
Unfortunely it doesn't work.
I haven't got a j112 fet so i used an 5457 (i searched and i saw that this is an equivalent fet).
Is my problem caused by the "changed transistor"? Any ideas?
Thanks

[Rob Strand]

Do you have a link?

It could be because the LED current is coming off the zener "Vref".

Another possible reason is the VP of your added JFET is different to the other JFETs.  Too low and the LED is stuck on, too high and the LED is stuck off.

OK I found the link.
http://www.madbeanpedals.com/projects/_folders/FilterMod/pdf/NomNom2015.pdf

From that I can see it should work.

What R29 did you use?    R29 is on the main schematic not on the LED board.
Did you use the 1uF cap?

Also check the pin-out of your JFET.

[mickeybellinello]

OK I found the link.
http://www.madbeanpedals.com/projects/_folders/FilterMod/pdf/NomNom2015.pdf

From that I can see it should work.

What R29 did you use?    R29 is on the main schematic not on the LED board.
Did you use the 1uF cap?

Also check the pin-out of your JFET.

Thanks for your Help Rob.
For the r29 I used a 1Meg resistor.

I used this way to connect it:


The schematic of my pedal is this:


While the nom nom schematic is this:

Last thing, I ordered the J112 transistor because I hadn't at home and I tried with a 5457 instead. could be the different transistor the problem?

[Rob Strand]

I want to add a rate led so i tried to connect a led to pin7 of lfo but i get a blinking led without a smooth transition.

Last thing, I ordered the J112 transistor because I hadn't at home and I tried with a 5457 instead. could be the different transistor the problem?

Highly likely the change has upset things.  Given it sort of works.  What I think you need to do is tweak the 560 ohm resistor.  Perhaps decrease it until you can see smoother blinking.   If the LED becomes too dim you might need to decrease the 1K and then re-tune the 560ohm.   Like I mentioned in your other thread, sometimes these simple circuits need helping along and that also make them sensitive to what  parts you use.

[Rob Strand]

I just occurred to me this method does not tap off the triangle wave.  It taps off the square-wave and kind of "fakes" the dimming effect.   So what you might find is at slow speeds it doesn't quite dim as slow as the LFO and at high speeds it tends to stay at some level of brightness.    You can tune the 1M resistor to tweak its behaviour to favour the slow or fast side.   The 1M + 1uF already there doesn't look too bad as a starting point but if you don't like it increase the resistor or the cap to slow it down.

The LED might be dim also, so you may need to increase the value of the 560 ohm resistor (opposite to what I said above).

At the end of the day, what I'm saying is you have to tweak everything.

EDITED

[mickeybellinello]

Thanks so Much Rob!

I'll try to what you told me!

Last thing... I found this schematic too...



What do you think about? Is it better or not?

Thanks again

[Rob Strand]

What do you think about? Is it better or not?

It's kind of the same idea.   Maybe a little easier to get going.

Just like the JFETs circuit depend on the JFETs characteristics
that one has a small dependency on the HFE gain.

I suspect the 100nF is going to be too small. You roughly need 220nF to 330nF to get the same "slowness" as the JFETs.

You just need to choose one and play around with it until you like it.

[mickeybellinello]

What do you think about? Is it better or not?

It's kind of the same idea.   Maybe a little easier to get going.

Just like the JFETs circuit depend on the JFETs characteristics
that one has a small dependency on the HFE gain.

I suspect the 100nF is going to be too small. You roughly need 220nF to 330nF to get the same "slowness" as the JFETs.

You just need to choose one and play around with it until you like it.

Here I am with good news.
I made a lot of tries and the best solution is the one that suggested to me deadastronaut:

https://deadastronaut.wixsite.com/effects/faze-filter

In the pdf document You can see the schematics and the circuit he made for the led blinking method.

The only thing I added is a 470k resistor between "pin7" and the transistor to have a better result in slow sweep.

Thanks again for the support!

[Rob Strand]

Here I am with good news.
I made a lot of tries and the best solution is the one that suggested to me deadastronaut:

The only thing I added is a 470k resistor between "pin7" and the transistor to have a better result in slow sweep.

Cool.

You connected the 470k to the capacitor instead of pin 7?  Like deadastronaut's  schematic?

Adding the 470k is very similar to just changing the 4.7k LED resistor to around 5k6 to 6.8k.  So you could probably do the same without adding the resistor.

FYI, using a transistor in that position changes the timing of the LFO especially on the slow speed setting.
The time of the up sweep becomes longer.  Normally you might get 4 second up and 3.5 seconds down.   Without the 470k that changes to about 5.2 seconds up and 3 seconds down .  Adding the 470k helps
bit dropping that to 4.8 seconds up and 3.1 seconds down.    If you use a very high transistor like a 2N5088 it will reduce the problem more.

However there's another way to fix the timing.   For a 2N3904, add a 2.7M to 3.3M resistor from the base of the transistor to the +9V rail.  For the 2N5088 that resistor will be a bit higher.

The MOSFET method on reply #7 doesn't affect the LFO timing,

https://www.diystompboxes.com/smfforum/index.php?topic=122672.0

MOSFET=2N7000.

To match the LED current you have on your transistor version the LED resistor would be about 1.8k to 2.2k.

[mickeybellinello]

You connected the 470k to the capacitor instead of pin 7?  Like deadastronaut's  schematic?

No, I connect It to lug3 of the rate pot.  Does it change the LFO timing even in this position?

The MOSFET method on reply #7 doesn't affect the LFO timing,

https://www.diystompboxes.com/smfforum/index.php?topic=122672.0

MOSFET=2N7000.

To match the LED current you have on your transistor version the LED resistor would be about 1.8k to 2.2k.

This Method isn't clear for me. I mean, in link 1 and link 2 what do I put?

Drain-> 9V
Source-> Resistor + LED
Gate->15uF LFO cap.

Sorry for this question, and thanks for help

[Rob Strand]

Quote from: Rob Strand on Yesterday at 07:23:05 PM

    You connected the 470k to the capacitor instead of pin 7?  Like deadastronaut's  schematic?


No, I connect It to lug3 of the rate pot.  Does it change the LFO timing even in this position?

With that connection the LFO timing is not affected.   However, the LED just switches off and on.   From the other thread I thought you wanted the LED to turn on and off softer?

With 470k + 4k7  the LED is off and on but it is also a little dim.

This Method isn't clear for me. I mean, in link 1 and link 2 what do I put?

Drain-> 9V
Source-> Resistor + LED
Gate->15uF LFO cap.

Sorry for this question, and thanks for help

Yes that's it.   The whole idea of that circuit was to give softer turn on and off of the LED, more like the LFO.  It does not affect the LFO timing.  Trim the resistor to suit your taste.

[mickeybellinello]

Yes that's it.   The whole idea of that circuit was to give softer turn on and off of the LED, more like the LFO.  It does not affect the LFO timing.  Trim the resistor to suit your taste.

tried and wow! now it's really perfect! Thanks so so so Much Rob! You're a genius!

[Rob Strand]

tried and wow! now it's really perfect!

Cool.

I wrote this small note showing the pro & cons in case it comes up again.

[mickeybellinello]

tried and wow! now it's really perfect!

Cool.

I wrote this small note showing the pro & cons in case it comes up again.

That's Great!!! I'll save it immediately! Thanks So So So Much!!!