e-licktronic Forum

Hi,

I just built a 1.02. Got thru a lot of small issues and seems to be good except I have one issue with the ride. It sounds and works ok, but when the pitch is at its lowest, I can hear a high pitched sound (~8-10khz) playing until the gate closes. The pitch of this sound follows the knob so turning it just a little up and the sound is gone because it's no longer audible. I don't have this issue on the crash.

It's kind of subtle so I'm having trouble using an oscilloscope just looking for any hints or suggestions or if anyone had this problem.

I checked around and I have so much noise on the scope I can't really see where the noise is coming from. Checked the eprom in the crash circuit and it is fine. I took out the sound eprom and when the sound triggers I hear just the noise. I've been using the crash as a comparison, but everything is kind of looking the same.

I just tried a lot more stuff and still can't find the problem.

I replaced or swapped ic 64, 52, 55, 57, 56. q69, q68, c130. I can kind of see a ringing on ic 58 pin 9 and 15. But one pin is ground and one is the trigger. I can also see the noise on both sides of r435, but doesn't seem to come from the accent on the sequencer section from what i can tell. but im using the schematics which are for 1.0l. Is there a significant change between the revisions?

I guess I can try to replace ic 58 and ic 53, but im running out of ideas.

cs1729 wrote:I just tried a lot more stuff and still can't find the problem.

I replaced or swapped ic 64, 52, 55, 57, 56. q69, q68, c130. I can kind of see a ringing on ic 58 pin 9 and 15. But one pin is ground and one is the trigger. I can also see the noise on both sides of r435, but doesn't seem to come from the accent on the sequencer section from what i can tell. but im using the schematics which are for 1.0l. Is there a significant change between the revisions?

I guess I can try to replace ic 58 and ic 53, but im running out of ideas.

It could also be an issue with the DAC or the MUX_SH boards. Try to change IC118. Or you have a bad EPROM (IC 62). Insert the Crash or Hat EPROM and check if you still get that noise. If not, it is very much likely the EPROM. Also check for solder bridges between IC53 and RA12D, E and F. Good luck!

I did check that it wasn’t the eprom by swapping them. I also tried to unplug the mux boards and that didn’t help.

I will check again ic118 and double check for solder bridges

Thanks

tried swapping ic 118 and no change. i just checked again and i really cant see any bridging. ive even been cleaning as much flux as i can in case it was being caused by that but still no change.

also tried a new ic 53 still no change.

its hard to use the scope because i have so much noise on the ground, but the noise i can see when i hear the tone i can see on the 5v lines going to the chips.

i ended up changing all the chips without any change. im starting to think there is some kind of bleed into the 5v. i can see the noise a lot on the 5v on ic 53, 54, 55. On ic 58, i can see something but it looks different, like a pulse. i noticed the 5v trace goes under c130/r440/r441 where the clock signal is. Anyone seen anything like this?

I just can’t figure this out. I tried adding some decoupling caps to see if it would help and no change. Tried changing almost every part. Do other people have this issue and not notice it?

The pitch of the tone changes with the tuning knob and the pitch only plays when the ride would sound. I see some noise on the 5v that happens while the tone is playing.

I also realized I can hear the crash bleeding a small amount into the ride.

I have been trying to track thru the circuit taking out parts to narrow down where the clock noise is coming from. I got it so I hear the noise with with the following components out of the circuit: r446, ic64 and the ride vol pot. so i guess that means the clock noise is bleeding somewhere between the ride vol pot / ic 64 out and the 4 pin output header? I can hear the noise probing directly to the 4 pin header when it's disconnected from the output board.

Further, I connected an audio probe and when I get close enough to ic 58 ride pins, I can pick up the tones without touching the pin. If I run the tip of over top of the pcb by the vias under the ride vol pot I can pick up the tones, so it seems like this is how it's bleeding into the ride volume. How can I fix this and why is it happening? Is it a problem on other boards?

cs1729 wrote:I have been trying to track thru the circuit taking out parts to narrow down where the clock noise is coming from. I got it so I hear the noise with with the following components out of the circuit: r446, ic64 and the ride vol pot. so i guess that means the clock noise is bleeding somewhere between the ride vol pot / ic 64 out and the 4 pin output header? I can hear the noise probing directly to the 4 pin header when it's disconnected from the output board.

Further, I connected an audio probe and when I get close enough to ic 58 ride pins, I can pick up the tones without touching the pin. If I run the tip of over top of the pcb by the vias under the ride vol pot I can pick up the tones, so it seems like this is how it's bleeding into the ride volume. How can I fix this and why is it happening? Is it a problem on other boards?

Download the top layout file http://www.e-licktronic.com/en/nava-par ... clone.html and check if all the ride ground points are connected to the ground. I assume you already checked for broken traces?

All resistor values are definately correct?

Yeah, all values definitely correct. I even measured them with my meter. Is it possible could you record me a sample of your ride at the lowest tuning? Or anyone reading. I just want to hear if this is a common thing from the board layout. After obsessing over it all week, I put the eprom back in and realized it is a quite low sound compared to the ride itself.