Will a mini phone plug & jack be sufficient for an electric-acoustic guitar?
Electric guitars and their cords have always used standard (1/4") phone jacks and plugs. Pickups for acoustic guitars follow suit and use that size. Thus if one installs a pickup in an acoustic, and wants to have the jack mounted in the endpiece of the guitar body, it’s necessary to remove the strap button from the endpiece and ream its hole out to make room for the jack. (The jacks made specifically for this function as a strap button as well.) But if the guitar is collectible, this modification can reduce its value - a purchaser may want it to be in factory trim.
I’m thinking about installing a mini phone jack (1/8") in the strap button itself (strap buttons are readily replaceable). It would be easy enough to make an adaptor for standard cords, and the mini phone jack and plug could be gold plated. The question is, would this work properly, or would it negatively affect the signal compared to a standard, non-gold plated phone jack and plug?
From an electrical POV, there should be little, if any, difference in the sound quality. Where you might run into a problem is that the mini plug will be much more likely to pull out or become loose, especially if you move the guitar around a lot.
I think I can solve the physical problems. A short adaptor cord could plug into the jack and be fastened to the guitar strap, with the regular cord then plugging into the adaptor (the end of which could also be clipped to the strap). There shouldn’t be any stress on the plug that goes into the guitar. My concern was the electrical/sound quality aspect.
Well, you are aware of the difference between stereo (trs) and mono (ts) cables? Guitar signals work on the mono ones, and most 1/8" cables/jacks tend to be stereo. You would need to make sure you are using mono (TS) 1/8" cabling.
Also, most 1/8" cables aren’t meant to be swung around and dragged like 1/4 cable is. Plus, it may not be as well shielded from outside things like noisy power adapters and crt monitors. So you may get more noise with the 1/8 setup than with a 1/4, unless you buy special cables that are meant to be used with guitars or guitar-like signals. Because there is a big difference between normal line-level signals that usually get sent thru 1/8" and RCA cables (tv audio, recievers, cd changers, etc.) than the type of signal that gets sent thru a guitar.
Not really. If memory serves, guitar outputs fall somewhere between mic level and line level signals in strength. A 1/8" jack should be fine for this application so long as the physical issues of fragility and the like are adequately addressed. While the contact patches on an 1/8" jack are slightly smaller than the contact patches on a 1/4" jack, the 1/4" is already a crappy jack in terms of contact size and it’s obviously perfectly adequate for this purpose. There will be a very slight increase in resistance in the circuit due to the smaller contacts. This will be no more significant than using a slightly longer cord, which has precisely the same effect.