Reverberation DBA by MOONN ELECTRONICS

[pawrog]

Hi there,
Maybe someone had the same problem or know where it comes from.
So Space is fun pcb from Moonn electronics.
First I had tant. caps installed because I read somewhere that they are great for audio, turns out they are not and it was opinion from audiovoodoo site.
But main issue, howling low noise, that I can hear even when all the nobs are turned left (of course I have to turned up vol on my amp).
The noise is even when I pull out the IC tlc27m4cn.
I changed the caps to elec.caps checked the film and cerm caps. still cant figure out whats going on.

 

[Synchrony Pedalworks]

Hi there,
Maybe someone had the same problem or know where it comes from.
So Space is fun pcb from Moonn electronics.
First I had tant. caps installed because I read somewhere that they are great for audio, turns out they are not and it was opinion from audiovoodoo site.
But main issue, howling low noise, that I can hear even when all the nobs are turned left (of course I have to turned up vol on my amp).
The noise is even when I pull out the IC tlc27m4cn.
I changed the caps to elec.caps checked the film and cerm caps. still cant figure out whats going on.

I do not know if this is the issue, but I had this problem with another pedal.

Your power regulator is different from the suggested part. Make sure that the pinout is correct.

 

[pawrog]

I do not know if this is the issue, but I had this problem with another pedal.

Your power regulator is different from the suggested part. Make sure that the pinout is correct.

Well I try 78l05 but it was overheating, and not really much changed. But i turned 180 a L7805cv and it work, but it's little overheated and i hear it 'pops' now and then when not played.

 

[Synchrony Pedalworks]

Well I try 78l05 but it was overheating, and not really much changed. But i turned 180 a L7805cv and it work, but it's little overheated and i hear it 'pops' now and then when not played.

If it is over heating, the issue maybe related. I would check the voltages on it.

 

[jwin615]

Is C18 touching the tip of the input?

 

[Feral Feline]

In the photos the regulator looks like its centre-pin is not very well soldered.

I'd also take a DMM and test for continuity where there shouldn't be any — may be a short somewhere that's not easily eyeballed, such as under the IC-socket.



I'm curious about your capacitor observations and choices. There are no Electrolytics in the signal path, so whether you use tantalum or electrolytic shouldn't affect the sound. I've also read tants sound better than electros; I've used Tants in a few builds to save space, in the audio path, and not had any issue with the sound quality.

Caps C2, C6, & C14 are each 1µ and go to ground, still not in the signal path but given their 1µ value you could sub them out for box-film caps if you feel it will make a difference in sound. As an aside, you can get even larger box-films in 2µ2 and 4µ7 sizes.

In the power section caps C17 & C18 are both 100µ and the only caps in the build that really require being electrolytics due to their size-value.
If I needed to save space I'd use 100µ Tants for the power filtering, even if there's enough space for electrolytics, the Tants would last longer (from what I've read) though they are more expensive than the electros.

Bear in mind, too, I'm just a hobby builder and a pro-electronics guru might have more solid info on the whys and what-fors.

 

[PJS]

The regulator only powers the Belton brick. The datasheet for the brick says that it draws typically 60mA, and 100mA at maximum. The 78l05 can deliver 100mA, so by rights it should power the brick OK. The larger regulator can deliver 1A. It will probably need a heatsink to deliver that current, but should be running pretty cool delivering only 60 to 100mA. If you are getting those regulators heating up I do wonder of you have a short somewhere either from the 5V line to something else, or somewhere in the brick wiring that is causing it to draw too much current. You could always lift the output leg of the regulator and measure the current as a test.

 

[pawrog]

Is C18 touching the tip of the input?

No, checked.

 

[pawrog]

Well, i change the ic, it doesn't overheating but the noise is still there. I audio probe pcb and starting from IN on pcb and R1 from side of IN is clear ane the noise starts from other side. I change resistor as i was i thinking its bad but the noise is still there. Changed also c1 and c5 but still there