I wouldn't waste my time either way. I'd shield over the pots with copper foil or a copper plate and use insulated wire as appropriate.

I say this over and over again, in this case, Strat pickups themselves do not get shielded yet it is the pickups themselves which are the biggest culprits for regularly sucking in and amplifying the noise, barring any abnormal antecedent conditions such as but not limited to, lousy house wiring, florescent lights, etc. Doing all the other superfluous stuff ramps up the capacitance, creates eddy currents and weakens the signal albeit, to varying degrees.



Copper is an infinitely better conductor than aluminum or carbon and would be my choice on the pickguard. As to the body, the barrier from the top plate or foil in conjunction with the shielded wire is sufficient again, barring any antecedent conditions.



The aforementioned has served me well with no complaints for over 40 years now.

You're welcome!

_________________
You dig?

Hi Martian,



Intriguing!

I've read several of your previous posts regarding shielding, but have always presumed that those topics were referring to the effects of additional shielding to cavities which already have (in most cases) conductive paint. I totally see your point and it makes perfect sense but......If its OK with you, I have a few more questions for you on cavity shielding (forgive me if you've posted similar info before, but I've found the search function less than helpful on several occasions)

Would I be right in thinking that the above would still apply to a guitar with active electronics? Its just that I've spoken to a couple of qualified electrical engineers on this subject and both recommend creating a “shielded box” for any component part (within reason), that's not currently protected in some way. For example an on-board PCB for an active pre-amp Neither have the extensive experience in this specific field as you do and I'd very much appreciate your thoughts on this. If it would help I can post a wiring diagram of the circuit in question.



Excellent! Just so I've got this, would I be right in thinking that the shielding should only cover pots and switches and would potentially hinder the performance of the pickups, should the entire underside of the pickguard be shielded?



Thanks for taking the time out to post the above. Its very much appreciated (i'm sure the “person in question” will give you a big mention in their thread )

Andy

_________________
Pending Greatness

Active circuits have their own built in buffers, etc. Having said that and in this context, it has been my experience that active circuits require no more consideration in terms of shielding than a passive circuit does. Remember, the crux of the whole issue is you are going from high impedance (passive) to low impedance (active) so of itself, the circuit will naturally be significantly quieter; again, in this context.

FWIW: I have no idea what a "qualified" electrical engineer is.



Empirically speaking, where I stop is most adequate.

Continuing to pile up the conductive elements in a high impedance circuit as you are stating will usually do just what you surmise. The conductive quality of these elements shall also be a factor too. It all depends on how much 'overkill' in terms of shielding is really involved which in turn, will vary the degree of audible attenuation. This is not true with low impedance circuits though as this is part and parcel of why there's a preamp involved in the first place where once again in this context, the preamp maintains the circuit at a certain level above and beyond the capabilities of any passive circuit. Look at it this way: It is common knowledge that one shouldn't use a cable from the input jack to the amp that exceeds say, 18 feet because this shall cause signal degradation in any high impedance circuit. This is the exact same thing that is going on with too much shielding in a passive circuit. Now, with an active circuit, you can use a 100 foot long cable because the preamp is maintaining the signal with no degradation. Remember, with a passive circuit, you can only take away. In other words, once the pot is on '10', you can only turn it down. With an active circuit, it makes the circuit's capability like it is on '50', so to speak. So, if you want to use 10 pounds of copper foil to shield a low impedance circuit, not only will it be an exercise in futility but it will not degrade the signal. On the down side, in the case of the power source of the preamp being a battery, it will drain it faster as more 'juice' is required to maintain the continuity of the preamp.



I'm glad to help and I thank YOU for bringing this topic out into the 'spotlight'. Not only is it a rather popular one but you've asked all the right questions in order to really delve into it on an intelligent level.

As to your stated, “person in question”, admittedly, you've lost me.

_________________
You dig?

This is great stuff Martian!


No worries! That just my poor attempt at wit . I best come clean. “I” am planning a build thread which will involve building a Strat body and pickgaurd from scratch and as part of the process, I'm very keen to highlight the common issues with cavity and pickgaurd shielding. With your permission, I like to quote your posts as part of the thread. Of course You'll get full credit.

Marvellous! Just what I was after.

By “qualified” I am referring to an educational or industrial institution recognising an individuals acumen in their chosen field. In this case both individuals had reached Charted Status as an Engineer, their chosen field being Electronics.

Makes perfect sense!

Your mention of the potential benefits to prolonging battery life (however slight they may be) for an active circuit saves me asking any further questions on the subject. I am more than satisfied. This is Forum Gold IMO!

Thanks Martian. I'll be completely honest, I've found your above posts fascinating and extremely valuable. I've thoroughly enjoyed our conversation and look forward to applying what I've learnt here to my build.

Thanks again for your time and insight

Andy

_________________
Pending Greatness

Andy,

Glad to enlighten, etc.

You don't have to bother quoting me, it's not like I invented this stuff.

As always, you're quite welcome.

_________________
You dig?