Search found 27 matches

by iampoor
Fri Apr 22, 2016 7:45 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

That looks much cleaner. You will almost always have to put in some break in the ground plane to route signals but as long as you try to avoid the current return paths, avoid running signals in parallel to each other (watch for that between layers), etc. you can usually get a good clean PCB. Great!...
by iampoor
Fri Apr 22, 2016 12:58 am
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

Well, I would get rid of the ground pours on the top layer, better to have one good ground plane. It looks like you may have some broken current return paths. See the pdf at www.ti.com/lit/ml/sloa089/sloa089.pdf on page 17-15 it appears you have things like "Version B" and you reall want ...
by iampoor
Thu Apr 21, 2016 2:12 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

frank wrote:Would be easier to look at if each layer were posted separately, can't realy see if there are any issues on the bottom layer.
Here you go. Let me know if you would like anything clarified!

Thank you for looking this over and being so helpful!

http://imgur.com/a/nxfef
by iampoor
Tue Apr 19, 2016 5:35 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

Okay, so Im convinced the problem was my layout. Nothing else would seem to make sense at this point. I have added some additional pads for bypass caps (just in case) on the plugin board, and increased the number of via's between the ground planes. Some of the pins on my original PCB were not connec...
by iampoor
Tue Mar 22, 2016 2:22 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

What do you mean by "Yet when I plug in my audio interface and ground the circuit" ? Are the audio cables not grounded? Are you adding a separate ground? Hi What I meant wa, when I plug in my audio interface and then plug my laptop power supply in ("grounding" it). Then the nois...
by iampoor
Sat Mar 19, 2016 2:29 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

Tracking down noise sources can take lots of time and can be from external things like your power supply as you discovered. "Ground" can be different things, the "ground" on a 3 prong plug is a chassis ground for safety and may not be the same as signal ground so you need to mak...
by iampoor
Fri Mar 18, 2016 4:19 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

OK, a few items to check: You only have a 1nf on the AVDD/DVDD pins on the FV-1, that should be 100nf (0.1uf). You don't have a bypass cap on the EEPROM, add a 0.1uf. Do not tie anything to pin 3 of the FV-1 other than the 1uf cap!!!! It looks like you have pin 2 tied to it in the schematic. If onl...
by iampoor
Wed Mar 16, 2016 11:19 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

Please post complete final schematic of all boards, etc. Also higher res images of the boards as I cannot zoom in on the current one. http://imgur.com/a/oNaeg Here is an album, first 2 pictures are of the plugin board the FV-1 is on. It has a ground plane on both sides. The second two pictures are ...
by iampoor
Tue Mar 15, 2016 9:18 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

Here is the schematic and board layout I used too. It is slightly different from my original post. :wink: http://imgur.com/a/uALhy Im almost at the point of buying a development board to compare against. Ive been having so many noises issues with these designs. Not sure what Im doing wrong, or if my...
by iampoor
Tue Mar 15, 2016 9:13 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

Hi Finally got the opportunity to build this I used my soundcard (Mbox 2) to pickup the output noise on the main card the fv-1 is on. Here are are the noise plots Im getting. Not sure what it is so different for each channel. This is straight off the outputs after the passive filter recommended in t...
by iampoor
Mon Feb 15, 2016 7:23 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

I don't see the filtering there to remove the high frequencies from the delta sigma converters, i.e. there is no 1K/2.2n cap on each of the outputs. Also, any filtering should be on the small board, as close to the pins as possible. Hi, its there. R7/C4 and R12/C7 on the larger PCB. I will move the...
by iampoor
Sun Feb 14, 2016 1:31 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

There are lots of possible causes of noise, how clean is your power source? If possible try a battery to power it to eliminate the power supply as the source of noise. I looked at the schematic and boards and they don't seem to match up, the top schematic seems to have only one header but the small...
by iampoor
Sat Feb 13, 2016 5:50 pm
Forum: FV-1 hardware questions
Topic: My designs are always noisy :(
Replies: 22
Views: 16831

My designs are always noisy :(

Hi I have been through quite a few different iterations of FV-1 based PCB designs. Unfortunately, they are always too noisy to be useful. I think part of this has to do with my layouts (Might be my ground plane too), but I think I have finally figured out a solution. I was trying to cram everything ...
by iampoor
Thu Feb 05, 2015 1:37 pm
Forum: FV-1 hardware questions
Topic: distortion on low output signal?
Replies: 13
Views: 10175

Okay, so fun little update. APparently this issue only exists on 1 of my bioards. Im going to try building some more powerful low pass filters In the YT video it sounds like you are getting hiss not distortion, if that is the case you might need to do some signal filtering which should get rid of an...
by iampoor
Wed Feb 04, 2015 6:54 pm
Forum: FV-1 hardware questions
Topic: distortion on low output signal?
Replies: 13
Views: 10175

Here is a video of that noise when Im sweeping through with the generator. I can cause it to stop with a cap across the input, but at lower frequencies, it is still seeping in, even with a cap across the input ( I used .1 just to be dramatic. :lol: ) https://www.youtube.com/watch?v=B7VZ5uOu6B8&f...