Aion Azimuth - pass thru and LED. nothing when engaged.

[Slowpoke101]

Here's some things to do for the DS-1 clone (Comet Distortion ).
You have built it as a vintage unit but you are using a modern DIP8 OP Amp. You need to change the following;

Install R23 (47K ) and R24 (1K ).
Remove R11 (27K ).
Remove C6 (150pF ).
Change C4 to 68n.
Change C5 to 100pF.
Change C7 to 470n.

Do these mods and the pedal may work....If everything else is OK.
Let us know how you go.

[broomhandle]

So, I started this pedal with the 7 pin "vintage" IC chip. and it did not work (because I thought it might be fake). I pulled the chip and installed the 8 pin IC. and added a cap...

Is there any way to test the 7 pin original chip? to see if the IC is ok? I would rather keep it vintage. that was the whole point of this build.

[broomhandle]

Over 1200V is uncommon in the stompbox world.

so what would be the culprit for that on both?

[broomhandle]

Here's some things to do for the DS-1 clone (Comet Distortion ).
You have built it as a vintage unit but you are using a modern DIP8 OP Amp. You need to change the following;

Install R23 (47K ) and R24 (1K ).
Remove R11 (27K ).
Remove C6 (150pF ).
Change C4 to 68n.
Change C5 to 100pF.
Change C7 to 470n.

good catch... I feel dumb...  I am a mix of vintage and modern... just like real life.

I would rather go back to my vintage build. DO you guys know how to test a Vintage IC Chip? If so, I will put everything back to vintage. and test...

[willienillie]

Over 1200V is uncommon in the stompbox world.

so what would be the culprit for that on both?

It was a bit of a joke, I assumed you meant to include decimal points somewhere in those numbers.  If you really have 1200+VDC present, every component is fried and you're probably dead.

[Slowpoke101]

I would rather go back to my vintage build. DO you guys know how to test a Vintage IC Chip? If so, I will put everything back to vintage. and test...

The quickest option is to remove the modern option parts then put the components back in for vintage, put the TA7136 back in and try it. But consider this, the TA7136 is rather rare and hard to obtain. Is the one that you have known to be genuine - did you buy from a reputable supplier? The same question applies to the IC you used in the Zen Drive.
If they were obtained from eBay there may be a good chance that they are not the ICs that you think they are.

Also from your voltage measurements - Is your meter missing a decimal point? 1200 Volts would be very entertaining to deal with in a stompbox  ....so I take it that 12.00 Volts would be the true measurement 

[broomhandle]

I would rather go back to my vintage build. DO you guys know how to test a Vintage IC Chip? If so, I will put everything back to vintage. and test...

The quickest option is to remove the modern option parts then put the components back in for vintage, put the TA7136 back in and try it. But consider this, the TA7136 is rather rare and hard to obtain. Is the one that you have known to be genuine - did you buy from a reputable supplier? The same question applies to the IC you used in the Zen Drive.
If they were obtained from eBay there may be a good chance that they are not the ICs that you think they are.

Also from your voltage measurements - Is your meter missing a decimal point? 1200 Volts would be very entertaining to deal with in a stompbox  ....so I take it that 12.00 Volts would be the true measurement 

I am a novice for building pedals. I thought it would be cool to build my own and have them sound awesome. And the ones that work are way cool.

as for the chip. I bought the TA7136 off ebay. It is hard to tell if it is real. and how would anybody know?

the zen is from Mammoth. But I have used IC from Tayda on other builds. I was unsure about those...

Is there any way to know if the TA7136 is real? or working before I build it back to vintage?

[Marcos - Munky]

Do you know how to do an audio probe test?

[broomhandle]

Do you know how to do an audio probe test?

I do not.

http://diy-fever.com/misc/audio-probe/

[broomhandle]

Over 1200V is uncommon in the stompbox world.

so what would be the culprit for that on both?

It was a bit of a joke, I assumed you meant to include decimal points somewhere in those numbers.  If you really have 1200+VDC present, every component is fried and you're probably dead.

I am using a cheaper volt meter. There is not a decimal. maybe its 12.xx I am not sure...

[Marcos - Munky]

http://diy-fever.com/misc/audio-probe/

Yep, that's the most basic audio probe you can make, and one of the most useful tools you can use. Do you have the stuff to make one? You don't really need an alligator clip, it does indeed makes it easier to use but it's not really necessary. Also, any ceramic or polyester cap will work, as long as it's value is around 47nF-470nF. Then I'll guide you on how to use it and find where's the problem on your zen drive build.

[broomhandle]

Probe made. I used a 1uf cap. positive side is basically wire with solider at the tip.  And thank you! This is great!

[Marcos - Munky]

Great! So let's use it right now!

Turn all the pots to about middle of the rotation. Press the switch so the effect is engaged. Connect your guitar to input, turn the guitar volume to maximum and put the guitar somewhere near you. Connect a cable to the jack of your probe, the other end of the cable goes to your amp. Connect the alligator clip of your probe to a ground point on your circuit (the output jack is a nice place to do it). Turn your amp on, touch the positive tip of your probe (let's just call it probe from now) and turn up the volume of your amp until you hear a nice but not so loud buzz.

Now, let's check the schematic of your circuit and identify the path the signal flows. I already did this for you:

Basically, we just put aside everything that's connected to ground or VR. Signal enters fom "in", then goes thru C1 and enters the IC via pin 3. Then, it exits the IC via pin 1. From now, forget all the parts below IC1A, you can see they just send the signal back to the IC via pin 2. From pin 1, the signal goes thru R4, then thru tone pot, enters the IC again via pin 5 and exit the IC via pin 7. It goes thru C5, then R5, then volume pot.

Since you don't have an output, the signal is getting interrupted somewhere, and we'll search for where it's getting interrupted. There are "smarter and faster" ways to use an audio probe, but let's do the most basic way, which is to follow the signal from the beginning of the path.

Hit the strings of your guitar and, while they're still ringing, touch the pad labelled "in" on your board. You should hear the sound of your guitar. If you don't, press the switch again, the circuit may be in bypass. When you check the "in" pad, you also check the left side of C1. Now, you need to check the right side of C1, to see if the signal is going thru C1. You can do it by hitting the strings again and connecting the probe to both legs of C1, or just hit the strings and connect the probe to pin 3 of the IC, since it's connected to the right side of C1.

The next thing in the signal path to check is if you're getting signal on pin 1 of the IC. Hit the strings and touch pin 1 with the probe, you should get a louder and distorted signal. Then check R4, the tone pot (lug 1 then 3), pin 5, pin 7, C5, R5 and finally the volume pot (lug 3 then 2).

Since you're not getting any sound out of the circuit, by following this signal path you can get the exact point the signal is being interrupted. Do this test and let us know where you get sound, and where you don't. Just notice you don't have to check any point after the one you are not getting sound. If, for example, you don't have signal on pin 5, you surely won't have signal on pin 7 and the next points.

[broomhandle]

This is so cool. thank you.

so...

I got a pass thru on all. and pin 5 and pin 7 is the IC correct?

I had a little trouble getting a pass thru with C1. But I think its more of because its a fat cap.

so.....

[Marcos - Munky]

Yes, pin 5 and 7 are for the IC, and C1 will drop the volume a lot because it's a big cap.

So you got sound out of pin 7? What about lugs 2 and 3 of the volume pot?

[broomhandle]

Yes. I got pass thru sound from those. I got pass thru from all.  No effect sound.

[Marcos - Munky]

So you got a sound on lug 2 of the volume pot. That says the circuit is working. Is the guitar sound overdriven/distorted or clean? Try to turn the gain pot and check if it changes how distorted the sound gets.

On the switch pcb, there's a pad named pcb out. There's a wire that connects that pad to the out pad of the big board. Disconnect the tip of this wire that goes to the small pcb and put the probe on this wire. Are you getting the guitar sound out of this wire?

[Slowpoke101]

Interesting.

Try this - Make certain that the guitar is plugged into the effect correctly and is set for maximum volume. Set the effect's controls as Volume fully clockwise (max ), Drive to max, Voice and Tone to mid-way. Make certain that power is applied and the effect is engaged - not in bypass. Test for audio (using your audio probe ) on the IN terminal and then do the same for the OUT terminal. What do you hear?

Follow Marcos' instructions first - there may be no need to try my suggestions.

On another note your TA7136P IC's picture. It doesn't look like any I've seen before. Normally the markings would be printed with a silver ink on the black body of the IC. Yours looks very different but I can't really tell from the picture.

[broomhandle]

So you got a sound on lug 2 of the volume pot. That says the circuit is working. Is the guitar sound overdriven/distorted or clean? Try to turn the gain pot and check if it changes how distorted the sound gets.

On the switch pcb, there's a pad named pcb out. There's a wire that connects that pad to the out pad of the big board. Disconnect the tip of this wire that goes to the small pcb and put the probe on this wire. Are you getting the guitar sound out of this wire?

Yes, I get sound on lug 2 of volume. The only knob that makes a change is the "voice" knob. it has a sound where it is like the tone is all the way down. and the it changes the volume. other than that, on lug 2. none of the other pots make changes.

[Marcos - Munky]

Ok, so we know those things so far:

1) your circuit is partially working:
You're putting a signal into the circuit (your guitar), and the signal is flowing thru the circuit until it reaches the end (in this case, the volume pot). So the entire main signal path is working, and some secondary paths are not.

2) the clipping part of the circuit is not working:
The entire part connected between pins 1 and 2 of the IC is not working. Why? We don't know (yet). Maybe you indeed damaged one of the diodes by using too much heat, maybe it's just a cold joint, maybe is something else. I'd bet on that 1N34A, ge diodes can be burnt easily. Anyway, check your multitester to find where's the "diode" function. There should be a diode symbol somewhere, probably near the resistance settings. Just locate the diode mode for now, let's firstly fix the reason why you're not getting sound out of the effect when using the output jack.

3) the voice and volume pots are working:
Nice! Two things to not worry about.

4) the tone volume may be not working:
Why "may be not working"? Because sometimes when the effect have two pots to set the tone (in this case, tone and voice), the result of turning one pot depends too much on the other pot setting. You may set one pot to the point the changes on the other are very subtle, and since we are "just making noises" with the circuit so far, you can't really thell if this is the case or if the tone pot is really not working. Like the clipping part, we will check this one latter.

And finally:
5) the reason your stompbox is dead quiet when you try to get sound out of the output jack is because there's something wrong with the switch part.
How do we know that? Simple. You got sound out of the volume pot, that means the signal are passing thru the circuit. What's the only thing between the volume pot and the output jack? The switch part. And if there's something wrong with that part, the signal may be interrupted.

How we fix it? Well, first thing is to find out if the problem is the switch itself or the board you used. Where did you got that board? The board may be ok but the way you put the switch may be wrong, so the whole thing is not working correctly. Or maybe you just have a bad switch. Do you know how to test for continuity using your multitester?