Little Angel problem

[Elijah-Baley]

[...]
I'm sorry, what 47uF cap you meant? Near the 78L05, the 1N4148 or the opamp?

About this?

About the depth pot what I should to do? There's the toggle switch connected, it is a bit difficult.

And about this suggestion?

And I had joint Speed 1 & 2, and Depth 1 & 2. I had seen this connection in another layout and I found weird to have disconnect those lugs, so I thought was correct joint them.

And this could be important?

It is just to have more thing to check in case I need. I am a bit pessimist about this circuit.

Reading my notes I think I didn't try to replace the IC, I'll try. If what anotherjim says about the NE5532 is true, it could be help, if that is really the problem.

Thanks!

[duck_arse]

I was thinking of the bias supply for the opamp, so the 47uF connected to the 10k//10k//330k. disconnecting the depth pot was the easiest way I could see to remove the modulation from the audio, just to eliminate it from the equation.

both the depth pot and the speed pot are shown on the circuit diagram with a "N/C" (no connection) connection. so you should connect one end to the circuit, and the other end to the wiper, and then to the circuit. you onely need two wires from the board to each pot. so if you have joint 1&2, your board wires will connect to "1&2" and "3".

[Elijah-Baley]

Use such as TL072 or RC4558 instead of NE5532 in this one. The 5532 is an excellent hi-fi amp, but becomes very noisy with high resistor values. I wouldn't think the 5532 is the best choice for the LFO either. Perversely, even the MC1458 or LM358 would be better than the 5532 in this particular effect.

The vibrato mode is all PT2399 output, so less noise then is probably due to the filtering in the delay lines own op-amps making the hiss less noticeable.

I tried to replace my NE5532 with a RC4558 and a TL072, but no changing. So I left the NE5532 for the moment.

Now I want to insert a DC jack and use a Boss PSU.

Meanwhile...

I was thinking of the bias supply for the opamp, so the 47uF connected to the 10k//10k//330k. disconnecting the depth pot was the easiest way I could see to remove the modulation from the audio, just to eliminate it from the equation.

both the depth pot and the speed pot are shown on the circuit diagram with a "N/C" (no connection) connection. so you should connect one end to the circuit, and the other end to the wiper, and then to the circuit. you onely need two wires from the board to each pot. so if you have joint 1&2, your board wires will connect to "1&2" and "3".

Forgive me duck_arse, my english failed
Maybe i got the "technical part", but I didn't understand if in my case I have to leave connected 1&2 of the pots like I did (but the layout doesn't show) or I could try to interrupt 1&2 like this layout seems to show.

Thanks!

Update: using the Boss PSU instead of the battery the noise is almost off, I could even finish it, but I'll try something more. That is better now.

Update 2: I change my mind. I think after a while the noise come back, the sound become dirty as early.
Sorry, I'm still testing.
Tomorrow I'll try to replace that 47uF (damaged or something?).

[Elijah-Baley]

Bump

Still noisy. Still not change the 47uF cap, but I'm not much sure about that will remove the background noisy when I play.

[ElectricDruid]

In "Vibe Mode" it is noiseless.
Could somebody tell me why? What I bypass in VIbe Mode, and what I include in Chorus Mode that could be responsible of the noise?
This is the schematic, more or less. This is not the exactly version I built, but it has the switches.

One thing that occurs to me is that because of the passive mixing, there's a potential feedback path from the output of the PT2399 to the input - when the "Vibe/Chorus" switch is closed. There's a couple of 10K resistors in the path of the signal, but the input to the PT2399 has 10K too, so 30K against 10K isn't that much of a difference. If there's unexpected feedback, it might be noisier than it's supposed to be.

HTH,
Tom

[Elijah-Baley]

Thanks!

So? Is there something I can modify? Or I have only to keep it like that?
The noise is not much strong, and in high speed setting I can notice it barely- I heard it in a second test, but if I hit the strings harder I can hear it very well with the sound. It is a bit annoying, because I know that is there.

[ElectricDruid]

I dunno! It was only a thought.

If the noise disappears when it's in Vibe mode, then the noise isn't coming form the PT2399, at least, not on a single pass.

You could try putting a proper op-amp mixer in to mix the wet and dry signals. If it doesn't make any noise like that, there might be some mileage in my theory. If it still makes noise, forget I mentioned it...

HTH,
Tom

[Elijah-Baley]

Thanks!
I'm not sure I got what you mean, but I tried some op-amp with no success.

I had power the circuit without a diode. Are there some clues could be some damaged components, like a cap? We had mentioned early a certain 47uF. Could really be?

[Elijah-Baley]

Tested, again.
Using PSU or Battery is the same. Noise is there.

With more volume I noticed the noise there is also in Vibe mode, but in this case is very subtle and low.
The 100nF caps close to 78L05 are one film and one ceramic monolithic  Could be important?

The sound is good, but that noise ruins the effect.
I don't know what to do except build another with different components, but I even afraid could be useless.

[duck_arse]

have you posted us a sound clip of the problem?

[Elijah-Baley]

Actually not. I could try, but I was afraid that the noise can't be heard, I cna record it with crap stuff, by old phone, or cheap mic on my ear-phone.

This noise is something weird, I can hear it just while I play. If I hit the string harder I can hear it louder. If I play softly also the noise is lower.

But... ok, I'll try to record it.

Stay tuned!

PS WOW! I start this topic: December 30, 2014, 07:37:03 AM!

[Elijah-Baley]

I decided to built it again

I'm making the bill of materials. I'm wondering about the 100nF caps, especially those around ther 78L05 (see the vero layout). Should I prefer poly, film or ceramic?

[duck_arse]

across the positive supplies (9V or 5V), ceramic disc or plcc, they are better at that job. all the others, pretty much whatever you like/can fit - but poly.

[Elijah-Baley]

Thanks!

So I could take from here: http://www.taydaelectronics.com/catalogsearch/result/?q=100nF: 0.1UF 50V MULTILAYER MONOLITHIC CERAMIC CAPACITOR, and solder it one to the left side of the 78L05 (the little orange one looking the layout) and one on the right side of the 78L05 (the big red one).
It could be good?

Sorry for my excess of zeal.
This circuit it is a kind of nightmare.

[samhay]

Before you build another of these, have you considered that you may have unrealistic expectations from the circuit? It will have some noise and be a bit temperamental.
If you want a chorus - rather than a Little Angel - then there are other options, which might suit your needs/wants better.

[Elijah-Baley]

Thanks samhay, indeed I have on my list the zombie chorus, ready to build.
But I have to admit I like the sound of this Little Angel, it adding a smooth and subtle color, with a slightly slap delay, and I like the vibe mode, too.
I was hoping to get sound it less noisy like someone else already did. How thay had did it?!

Well, I'll consider another building with more attention.
Anyway, I just to buy few caps, use some resistor I have, and recover switches, DC jack and pots. And some work.
I could be still in time to change my mind and to stock the components.

So... we'll see.

[samhay]

The PT2399-based effects do have a certain something, and if you like the slap-back aspect, then they are probably your best bet.
However, I would build another one on the breadboard first. If the noise is acceptable like that, it is unlikely to get any worse when you built it.

[Elijah-Baley]

I think that is the best thing I can do. Breadboard.
But the schematic is a bit complicated for my skills, and I have to try and study well that. Probably I need help.

[duck_arse]

EB - yes, those caps will be fine, probably for the ones around pins 7, 8, 9, 10 (etc, ? from memory) as well. [but! I wouldn't trust tadya for those 100nF greencaps, they will be MUCH bigger than the caps in the picture, even if only 6c each.]

excessive zeal is fine in moderation. also, scrapping and scrounging for parts, same method I use. and you really shouldn't have problems breadboarding this circuit, it's really not that complex. let me know if you do, I'll draw a diylc for you.

[Elijah-Baley]

Thank you duck_arse! I'll let you know.
I buy 100nF green cap when them aren't tight on the board, else I buy the grey film cap.

First time I bought green poly I didn't know how much them were big so I bought a pair of 470nF, just for try it. Huge! Never used them, I still have it.