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Post by rioneonroger on Jun 19, 2011 17:53:15 GMT -5
I am a newbie here, so this may not be in the best possibble location. If so, I apologize. My question is this: If it is such an advantage for microphones to be low-Z, why is it that electric guitar makers do not put circuitry in their instruments to convert the Hi-Z pickup signal to Lo-Z and route it to an XLR-type jack for output? Seems like it would make sense. By the way, I have spent the last two hours reading various threads and I would like to say that this forum seems to attract sensible people with a good sense of humor. What a joy!
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Post by newey on Jun 19, 2011 18:28:24 GMT -5
rnr-
Hello and Welcome to G-Nutz2!
Sorry, but I had to move your post. There are several places it might have gone, but since it is neither a reference article nor a link to a reference article, it had to move. Since it's more of a general question, I chose the coffee shop for it.
To answer your question, I believe it has been done, usually with low-impedance pickups to start with, but I believe from high to low as well.
Gibson's Les Paul Recording of the early '70's was a low impedance set-up. The first ones just had a single output with a Hi-Z/Low-Z switch, but later models used 2 outputs, and I believe the low impedance was an XLR out.
There are other examples out there as well.
Of course, that's also what a DI box is for- and in most live situations, a guitar signal is going into the PA via that route, and before any long cable runs as well.
EDIT: Well, I meant to put it in the coffee shop, but I guess my trigger finger was itchy . . .
EDIT: #2 No, I now see that sg intervened and moved this yet again!
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Post by sumgai on Jun 19, 2011 20:50:33 GMT -5
(newey - sorry to pull rank on you, but this is a legitimate pickup question that can apply to any guitar.) ~!~!~!~!~!~ RR, Hi, and  to the NutzHouse! If it is such an advantage for microphones to be low-Z, why is it that electric guitar makers do not put circuitry in their instruments to convert the Hi-Z pickup signal to Lo-Z and route it to an XLR-type jack for output? The quicky answer to your overall question is this: In the long run, a guitar's tone doesn't change just because the impedance was high or low. In fact, the only benefit to having low impedance pickups is that by using the required low impedance cable, you pretty much eliminate any noise from the guitar's signal, as it heads out towards the amplfier. But those cables are expensive, comparatively speaking. So if we leave the higher cost of the low impedance cable out of the equation, then what? And the answer to that is, still, cost. No, not the cost of a pickup, but the added cost of yet another part. The impedance-changing transformer to be installed would: a) Cost as much as a pickup (a loooong hunk of wire, and a significant amount of time to wind it all up); b) Incur a labor cost for installing it; c) Need more wood hogged out - these things ain't the tiniest components; d) Introduce yet another point of possible failure; and e) Violate the First Law of Leo - If it doesn't add to the player's tonal palette, then don't put it in there. Except where cost is of no concern (as demonstrated by the aforementioned Les Paul models), it's generally a good idea to leave a few bucks in the wallets of buyers. That way, they'll come back a bit sooner, rather than later. Oh, and humorous answers cost extra. ;) sumgai |
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Post by 4real on Jun 21, 2011 17:30:04 GMT -5
Welcome to GN2 I don't agree with my esteemed college there on the above 'reasons' though worthy of consideration... There are a few products about that do the job, for instance lets not forget EMG's and other miniature active electronics that change the impedance. But, back in the day and to remain passive, perhaps the transformer required might be a bit of extra components but they weren't that big even back then. You don't necessarily need a special cable or a balanced line out to run a Low-Z system...nor do innovative designs need to take more work to create...  In this Lace (a manufacturer that have explored low-z passive designs in various ways) Alumitones is a good example. The "coil" is effectively a 'single turn' of the body and magnet structure, in this HB version, you can just see under it the tiny transformer. It is a lot easier to machine wind such transformers than it is to wind an elongated pup coil. More and more bass players are going active and so Low-Z and even active tone controls... ... It is an interesting question...I think related to the kind of head scratching that Leo himself felt when he replaed a lot of his 'valve/tube' models for the latest in tech, the transistor...offering unsurpassed hi-fi sound and reliability...well yes Leo I love Leo and it is fascinating to see how he reacted to such things, but the market frequently didn't see his view on things...but then he wasn't a guitar player. Les Paul, the man, and father of multitrack knew of the benefits of Low-Z pups and such, but the market didn't folow and he really only got his 'signature recording models' of the LP to secure his name back to the gibson, 'the firm'. (remember when the LP was taking off in the 60's, Gibson didn't even make them any more and were forced to take the LP name off of the replacement by LP the man...and so the SG)...all a bit convoluted. Of course we live in a world for better or worse where all the amps and effects expect a Hi-Z guitar input impedance now...but that is not a reason not to... ... hmm...what was the question again? Oh right, cheers roger 'neon' rio They have tried but in general it hasn't caught on...and in general low-Z's clarity and hi fi like forte is not what people want in a guitar sound. There are some though that do, a lot of metal guys love the EMG's for the clarity that they get and extreme low noise in super hi gain situations. Sure, you need a battery, but they will last a long time. Of course, once you plug into an effect, it is generally Low-Z from then on. ... So...it's the old solid state amps are more reliable, more compact, better clarity and pound for pound far more powerful...yet we still covert the sounds of an ancient technology (tubes) that barely survived in any other technology. Typical guitar pups is probably the easiest way to get 'that sound' so that's where it is going to stay I imagine. Are you after that Low-Z sound yourself? |
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Post by ashcatlt on Jun 21, 2011 22:11:37 GMT -5
Low-Z requires neither a special connector nor a special amplifier. All the active guitars and basses pretty much prove the fact.
1) Don't confuse a low source impedance with a balanced connection. Two different deals altogether. It's perfectly possible to have a Hi-Z source with a balanced connection. Any pickup whose signal wires are separate from its shield wire could (and probably should) be used in a balanced configuration.
Generally Low-Z passive pickups would have fairly low output level as well, which means that the S/N ratio will be skewed toward the direction of suck. Same goes with using a transformer to convert from a Hi-Z pickup to a Low-Z output. This will necessarily be a step-down transformer, which will reduce the output voltage and...
Either way, they should be balanced, but very few amps or stompboxes that people actually want to play through will take advantage of the balanced run so you're talking about rebuilding the whole industry.
2) Since we're looking for maximum voltage transmission from guitar to amp (it's true in most audio applications actually, but we're talking guitars) as long as we are careful to observe The (at least) 10 : 1 Rule (of thumb) everything is groovy. There is some weirdness with some stompboxes (fuzzfaces and others which depend on the tone-suck caused by loading the pickups with an under-specified in-Z), and apparently some tube amps, but for the most part there won't be a "impedance mismatch" even with very low out-Z at the guitar. The out-Z of most stompboxes (not to mention, say, JohnH's buffers) sits pretty darn low, and nobody complains...
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freddyi
Rookie Solder Flinger
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Post by freddyi on Mar 12, 2012 17:06:16 GMT -5
I think in general a low -Z pickup will have lower inductance and a higher resonance before rolloff giving a more "hifi" or "sterile" tone. I wound one 40+ years ago and used a little mic transformer to match it to a regular unbalanced guitar cable.
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Post by reTrEaD on Mar 12, 2012 19:54:39 GMT -5
Freddy, this is a little old, but since it's a question about general practices, I don't see any harm at all by reviving it. I think in general a low -Z pickup will have lower inductance and a higher resonance before rolloff giving a more "hifi" or "sterile" tone. I wound one 40+ years ago and used a little mic transformer to match it to a regular unbalanced guitar cable. Yes. The original question was about converting a high impedance signal to low impedance, but your point about inductance vs impedance in pickup winding is valid. Low-Z requires neither a special connector nor a special amplifier. All the active guitars and basses pretty much prove the fact. Yep. 1) Don't confuse a low source impedance with a balanced connection. Two different deals altogether. It's perfectly possible to have a Hi-Z source with a balanced connection. Yep. Generally Low-Z passive pickups would have fairly low output level as well, which means that the S/N ratio will be skewed toward the direction of suck. Same goes with using a transformer to convert from a Hi-Z pickup to a Low-Z output. This will necessarily be a step-down transformer, which will reduce the output voltage and... Maybe not-so-much. The voltage would be lower, but the lower impedance would do a better job of noise rejection. Probably a wash if both being compared were unbalanced, and an improvement if comparing low-z balanced to high-z unbalanced. But that improvement also assumes you have a balanced input at the other end to take advantage of the balanced output. Not so common. Yep. Preamps with low-z output are available for guitars. When coupled with a passive pickup, you can get an authentic "passive" tone, have the low-noise benefits of low impedance output, the same (or greater) voltage you would have without the buffer, and no massive "tone-suck" with long cables. But they haven't gained mainstream popularity, because of cost. Not that they cost much, but they do add something to the cost. And they require a battery. Another cost, and another nuisance. A minor nuisance, but nuisance just the same. |
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