Equinox: Easy PT2399 Reverb

[sanjay dubey]

Hello,
I have built the Equinox II and it has a real good reverb  thank you merlin . I wanted to make the pedal as an 'always-on' reverb unit so thought about removing the jfet and its switching circuitry. And got into a doubt . Should I also remove R9, C4, C5 as they seem to me, components for the Jfet switching? If one removes the jfet what else should one eliminate from the circuit? thank you

[Groovenut]

All you really have to remove is the JFet and then jumper the drain pad to the source pad. It will then be always on.

[merlinb]

If one removes the jfet what else should one eliminate from the circuit? thank you

As Groovenut said, you don't have to remove anything except the JFET. But if you do, you can also remove the diode connected to the JFET, and everything else connected to that diode, if you want to. (D3, C30, R22, R23, D2)
http://valvewizard.co.uk/equinoxII.PDF

[Beach]

Dear forum

I built this circuit and I like it. So much I´d like to design an Eagle PCB for it. However, maybe someone else already drawn up the circuit and/or board in Eagle. I´d like to have this file in that case. I am planning to order a few PCB´s. Is anyone interested in a PCB? The more the cheaper! I´l try and fit it within 50x100mm (probably much less than 100mm so it will fit in a standard box)

2nd: Did somebody draw up an Eagle library for the PT2399? Would you share it with me?

Pls let me know

[Beach]

Dear forum

I think that the two 1uF decoupling capacitors can be shorted, because both PT2399 are at 2.5VDC. Any (other or supporting) opinions on that?

I am close to a layout, 50x70mm. No one is interested in a board? Probably some 5 EU/pc ex shipping.

[~arph]

Dear forum

I think that the two 1uF decoupling capacitors can be shorted, because both PT2399 are at 2.5VDC. Any (other or supporting) opinions on that?

Yes, ac does not equal dc. The input and output of a non inverting op amp normally sit at the same dc level, this does not mean you can connect them. All the dc level tells you is that the average value is 2.5 volts ( vcc/2 ). It tells you nothing about what happens in the time domain. You need to know more about the internals of the ic to be sure you can connect them. Why would they break out two separate pins on the ic if they can be connected??

[colonias]

hello, i need a little help, i had a first version of equinox, and i want to use it in a parallel amp fx loop, how can i add a switch to remove the dry signal?

[~arph]

Given the schematic here

http://s81.photobucket.com/user/merlinblencowe/library/Equinox%20Reverb?sort=3&page=1


Disconnect one side of R4 to remove the dry signal

[colonias]

i tryed to do it, but i get no signal

[colonias]

problem solved, it was my amp fx loop, thx for help

[colonias]

when i put the reverb in my amp fx loop with drive on the sound gets distorted, is it normal? w clean sound no problem

[bluebunny]

I would guess that your loop is running at levels higher than guitar/pedalboard levels (which is what the pedal is expecting).  So you might need to attenuate the loop (probably not a great idea), or put the Equinox between the guitar and amp.

[colonias]

yeah, i will try to put some attenuation in the loop, thx for help

[bluebunny]

I should have said that if the levels are mis-matched and you do attenuate the signal coming from the amp, you'll likely need to boost it back to a level the amp is expecting on the loop return.

[animal]

hello friends, it is the first time i write in the forum about a problem, but the truth, no longer know how to fix, and i need your help.

I built version 2 of Equinox and the effect works, i can hear, but behind it there is an annoying noise increases as you turn the knob, i have reviewed all possible errors, like a bad solder, bridges between tracks, error component values, etc., but the truth is that everything is as it should, also review the sections of LPF and LFF but all this as shown in the diagram; i experimented with several PT2399 but i get the same result, also to make sure change the TL072, but nothing changes.

I have always this annoying background noise, i leave a sample video and photos of the pcb.

Check the voltages of the PT2399 but i didn't see nothing unusual, got voltages between 5 and 2.5 volts in the respective pin as usual, if you need more details of these let me know.

I've been already 3 days trying to make it sound as it should be but the truth is i don't know what the F...!!! is wrong!

As a last comment i inform you that i made a bridge in the JFET to test the pedal and this always on, but do not think this is the problem, since the "clean" signal sounds perfect, the problem is when the signal is incorporated with the effect

perhaps the picture is somewhat deceptive, but I assure you there are no bridges between tracks

[Govmnt_Lacky]

@animal

My first suggestion would be defective 2399 chips. I know you mentioned that you used several chips during testing however... problems with these chips is rampant and I have read no less than 10 different posts on different forums about them. Where did you buy them from?

On another note... I can appreciate the single finger salute that you gave the circuit in the end of your video. Been there myself many, many, many times 

[thomasha]

It remembers me of the infinite repeats mode on a rebote delay,

the sound keeps repeating and increasing volume and in the end it sounds like this noise, but very loud.

To stop it I always need to reduce the repeats.

Considering this, I would look for bridges that would feedback the signal, and verify the circuit with an audio probe to look very this noise starts.

Also consider checking every capacitor going to ground around the pt2399, there are some pins of the PT2399 where the signal is very noisy and the bypass capacitors remove this kind of noise.

Or it could also be the pt2399 chip, but I bought all of mine from Tayda and never had a problem like this.

[tommycataus]

It's a long shot, but I had a similar problem. I was using a cheap 9v power supply to provide the 9v but had built my own filter to remove noise. I hadn't put a heat sink on the voltage regulator in the filter and subsequently it made the effect sound like crap. Couldn't work it out and then I tried a different power source. Voila!

[animal]

Hey guys thanks for the answers

@animal

My first suggestion would be defective 2399 chips. I know you mentioned that you used several chips during testing however... problems with these chips is rampant and I have read no less than 10 different posts on different forums about them. Where did you buy them from?

On another note... I can appreciate the single finger salute that you gave the circuit in the end of your video. Been there myself many, many, many times 

I have a dealer who brings me the components (I'm from Chile), He told that he get it from "SmallBear" / ...and yeah... that middle finger is classic jejejeje 

It remembers me of the infinite repeats mode on a rebote delay,

the sound keeps repeating and increasing volume and in the end it sounds like this noise, but very loud.

To stop it I always need to reduce the repeats.

Considering this, I would look for bridges that would feedback the signal, and verify the circuit with an audio probe to look very this noise starts.

Also consider checking every capacitor going to ground around the pt2399, there are some pins of the PT2399 where the signal is very noisy and the bypass capacitors remove this kind of noise.

Or it could also be the pt2399 chip, but I bought all of mine from Tayda and never had a problem like this.

check if it had bridges, but found none. / check capacitors and everything is fine, i will change them all to make sure

It's a long shot, but I had a similar problem. I was using a cheap 9v power supply to provide the 9v but had built my own filter to remove noise. I hadn't put a heat sink on the voltage regulator in the filter and subsequently it made the effect sound like crap. Couldn't work it out and then I tried a different power source. Voila!

I tried with two power supplies and battery, but the same result 

[dschwartz]

Looks like the diode is disconnected from the circuit, i see an unsoldered pin on the bottom right ..

Man that soldering job is NASTY.. I think you should do it again, and get 1mm or thinner drill bits