vero layout and noise

[Frank_NH]

While exploring the internet on an unrelated topic, I came across the follow very interesting document:

Electronic Construction Techniques

On page 4 is discusses methods for reducing noise in veroboard builds.  Here are the techniques they advocate:

* Signal connections run on strips for the minimum possible length. Always break strips carrying signals as soon as possible to reduce the radiation and pickup.

* Do not position strips with inputs and outputs next to each other.

* Use multiple strips in parallel for ground connections to minimise impedance. In fact it is good policy, if hf performance is important, for all unused strips to be wired together and connected to ground  so making a sort of distributed ground net that approximated to a ground plane.

* If necessary protect inputs from outputs with guard strips in between which are connected to ground.

I was wondering what others thought about this.  I like the idea of adding more cuts to the board in the prep phase in order to isolate unused tracks.  I never thought about grounding unused tracks.  Separating input from output is something that I see is usually done in the vero layouts here,but using grounded "guard" strips is something new.

Anyways, some ideas to contemplate.  I may play with my Sabbra Cadabra build and see if more track cuts helps squash some of the noise.  

[motterpaul]

Frank - I have noticed a lot of  people mentioning noise in their builds, and I also have it in my Sabra Cadabra, but that circuit is also unusually interactive with the guitar's pickups - far more than most. When I turn my guitar volume knob all the way off I actually get a loud hum out of Sabra circuit. (I have never seen another circuit do that).

In any case - about the article you posted. With the "ground plane" concept it implies a large amount of copper connected to ground is ideal - and that with vero it is a good idea to connect any unused sections to ground. It later mentions this is more critical in digital applications and when dealing with circuits using over 50 kHz (well above audio specs - but that doesn't mean a circuit designer was careful enough to avoid creating a signal that high, thinking it wouldn't be audible anyway).

It is worth looking at - and Sabra is a good one to work on.

But also - I have noticed that most people recommend having a straight line for ground. That article seems to be saying to go ahead and just connect as much as you can to ground, like a spider web. I don't know if it makes much difference really, but it is pretty hard to design a vero and also try to ground every unused piece of copper in a straight line. Would you go for the spider web approach?

Anyway - on a different topic  for which I have a different thread here (so I don't steal this one)

I was wondering about ceramic caps, and if someone could answer in my thread about ceramic caps, I would appreciate it. But the two topics seems to be closely related. I just read this in another article about caps:

[quote]Ceramic capacitors are generally not recommended for use as AC coupling in audio. They are attractive because of the size, cost and low ESR. However, when most ceramic capacitors are biased, the capacitive rating can decrease by as much as 50%! The higher grade (X7R) types suffer less from this, but you should be aware that a 1 uF might be acting like a 0.68uF in the circuit. We have also found that ceramic capacitors suffer from microphonic effects: the audio passing through the part will actually physically resonate and cause distortion! I would only use ceramic capacitors in the audio path where performance is not an issue, but size and cost are your higher priority. NP0 and C0G are the best of the ceramics, however I don't think you will find these types available in appropriate values.[/quote]