Nice vari-cap find

[roadtonever]

For those out there who like me felt they neglected the significance of cable capacitance here's a nice part that allowed me to quickly reek the tonal benefits and get the best tone possible out of my pickups:
cgi.ebay.co.uk/Poly-Film-Variable-Tuning-Capacitor-Broadcast-Band-/300560312295

You add the part before the jack. Additionally an LCR meter and a short patch cable is used to determin the most pleasing resonance and finally a custom cable is made that matches the capacitance value required for said resonance. For this knowledge of the cable capacitance (pF/ft) is needed. A small cap may be added in parallel to one of the pickups(usually bridge) when favored resonances differ. Don't forget to count in the capacitance the patch cable and plugs.

The main downside is that if you happen to misplace your custom cable you'll be at the mercy of capacitance value of the susbstitute cable.

Also If you like a bright Fender-type tone and yet happen to have distorsion-type humbucker you'll likely have to cut the cable very short.

If any of the above seems unclear feel free to ask about it and I'll be glad to oblige.

[ijustwannastrat]

Cable capacitance? Are you trippin'? If you said resistance, I might be more willing to listen. I didn't think that a cable would add capacitance.

[sumgai]

Ooooh, what's that smell?






(Apologies to Lynyrd Skynyrd.)

[newey]

ChrisK's Pickup Coil Response Tuning thread. Note that ChrisK's diagrams have gone away; there were graphs showing the response characteristics with the various cap values.

RTN-

Why put it in the cable? Ascertain the value(s) needed for a couple of different cables (say, for a 10' and a 25'), then use a switch to choose those values or none. (c.f. : The link Chris posted to his "Proper Telecopy")

IJWS-

No trippin' involved. If you want proof, use an A-B switch to select a 25 foot cable versus a 5 foot cable, you'll hear a distinct loss of high end with the longer cable.

The difficulty with this is that cable manufacturers rarely list the capacitance per foot of their products, and LCR meters are expensive.

[ijustwannastrat]

Well, you learn something new every once in a while, don'tcha?

So, is 18 feet of cable going to wreck my tone?

[sumgai]

May 30, 2011 23:35:37 GMT -5 ijustwannastrat said:

So, is 18 feet of cable going to wreck my tone?

Depends on what your definition of tone is......

[sumgai]

Hmmmmm.....

After several years of us talkin' all over this place about caps across the pickup(s) in order to reduce the high frequencies, I fail to see how adding a cap to a guitar's innards benefits one's tone.... unless it was too shrill to begin with. Imitating a cable is not what I'd call "best practice" in terms of getting all you can out of your axe.

Next point - exactly why am I making a custom cable again? Is it simply cut to some defined length, or are there other parts soldered into it that also affect the tone?

Third point - An LCR meter can be found for cheap, in analog form (and that's usually good enough), but if you have this already, you don't need to insert external components that imitate "the real thing" - simply use a cable in the first place! If anything, I'd be inserting some inductance in the line, in order to try and reduce the level of the low frequencies to match the loss of the highs. That would get me closer to a "flat" frequency response, doncha think?

And for the record, 'flat' isn't desirable here, not by a long shot. I don't think I want to add anything, in terms of trying to change the frequency response. In point of fact, the only way to reduce cable crapacitance is to buy better cable in the first place. Not only does that let you "get more tone" from your axe, it works with every guitar you might pick up to play.

Not to mention that better quality cables will not only sound better, but probably last much longer to boot. But for Gawd's sake, don't be going out and spending Monster-sized money on, what else.... Monster cable. A good RG-174 from most electronic supply houses will do the job nicely, for about a twentieth of the cost, on a per-foot basis.

That's all, over and out.

HTH





sumgai

[ashcatlt]

+1^

Of course, the only way to get true vintage tone is with that coiled cable that Jimi used...

Somebody maybe ought to play around with JohnH's guitarFreak ( too drnk to link) or a spice program for a minute. Then ask again why cable capacitance matters.

[roadtonever]

ChrisK's Pickup Coil Response Tuning, indeed. I have to admit I'm a bit stoked that I found a way to put the ideas in his post into practice. The resonanace determined by external capacitance consitutes a large part of what makes the percieved tonal qualities differ from one pickup to another. Several cable manufacturers don't list picoFarads per foot but some do, check out lavacable.com for such specs. With a LCR meter there's no need to guess and it becomes easy to include plug capacitance to the equation.

To clarify, the vari-cap is'nt meant to be permanently added to the cavity, although it can. What I'm about is finding your favorite tone in a less cumbersome way via a nice gradual dial control and finally pre-seting it via cable length. A static cap can be added before the jack, if you perfer a warm distorted tone it might just be what the doctor ordered. Capacitance is capacitance no matter if it's coming from the cable or a cap, what's interesting is the amount of capacitance and it's effect on tone. If you prefer a articulate clean sound a rather short cable will be required, in some cases too short for comfort and in such case a cap in the circuit certainly won't help. A lower capacitance cable will allow a more comfortable length.

Bascially I'm about the user having control over their tone and a method to nail it in a definite and repoduceable way rather than being at the mercy of pickups and cable. At least that's what I got from.

[sumgai]

May 31, 2011 6:58:28 GMT -5 roadtonever said:

A static cap can be added before the jack, if you perfer a warm distorted tone it might just be what the doctor ordered.

Capacitors are not meant to introduce distortion, they're meant to tailor a frequency response curve, and that's all they're meant to do (in the guitar world). If a capacitor in your circuit is giving you any kind of distortion, there's a problem.

Even if you like that particular sound/tone/Mojo, it's still not the correct way of achieving it. Whyzat? Because capacitors can't be created equally - there's always some small difference in value between them, which is why we have tolerance ratings.

Capacitance is capacitance no matter if it's coming from the cable or a cap

Uh oh, time to back up and attend the mini-refresher course in Electronics 101.

Standing by itself, a capacitor is worthless - it must have other components to work with. And from that, we know that caps react in different ways, depending on what they're hooked up in series with, what's in parallel with them, etc. It all very quickly escalates into the territory of Complicated Electronics. Thankfully, for those so inclined, software programs like pSpice or 5Spice can take all the drudgery out of that kind of calculating, and give you an answer almost before you get your finger of the Enter key.

But suffice it to say, cable capacitance Does Not Equal a cap hooked across a pickup. The resultant tone between the two methodologies will be markedly different. Do I need to go into detail here?

If you prefer a articulate clean sound a rather short cable will be required

There's that bit about 'clean versus distorted' again - ugh!

Articulate as a descriptive term is subjective to the listener's tastes and actual hearing ability, not to mention that other listeners might not use the same word to describe what they hear. It's a world fraught with ambiguity, to be sure.

Bascially I'm about the user having control over their tone and a method to nail it in a definite and repoduceable way rather than being at the mercy of pickups and cable.

Laudable goal. I think it's why we're all here in the NutzHouse in the first place, eh?

In closing, let me just say keep trying, keep searching, keep discussing, and most of all, don't let know-it-all jerk-offs like me dissuade you from your quest. You may be wrong at this moment, but it's a 50-50 bet that tomorrow morning you may well come up with The Next Big Thing.

HTH




sumgai

[roadtonever]

Sumgai, for me this is certainly the next big thing. Bigger than sliced bread and what have you. Despite that you're breaking everything I write down at the seams and even putting words in my mouth I can't be disuaded, I've been blessed with great tone! If anything you're helping turn this resonanace tuning method into a secret weapon. I'd certainly acknowledge a big part of what you doing is rigourous QC of my posts which is warranted.

[sumgai]

As I think I've said before, tone is in the ear of the beholder! ;D

I think what you want to do next is write up a description of what you did, step by step. Include the tools/instruments used in the procedure, diagrams (layout or schematic), and possibly even a photo or two of a meter showing the results. It goes without saying that sound clips are de rigeur, both before and after (even during, assuming that you may have traveled down one path, tested and recorded, only to later find a different path that you liked better).

Linking to a website where you found out how to do all this is acceptable in lieu of your own write-up.




sumgai

[roadtonever]

Alright, here's my little step-by-step tutorial. ;D

RoadToNever's pickup resonance tuning tutorial

Tools needed:

• LCR Meter
  
• AM-band 10-265pF variable capacitor
  
• Short patch cable
  
• 1/4" plugs and ample length of cable
  
• Assortment of caps in the sub-270pF range
  
• Alligator clip leads
  

Step One:
Add the vari-cap across the input jack with alligator leads and go straight into your amp with a short patch cable.
Set your amps tone controls for a relatively even amount of bass, mid and high, in most amps this involes turning mid up, bass and high down.

Step Two:
Select one of your pickups individually. Get ready to play guitar! Play the riffs, licks etc you love, whilst playing with vari-cap. Eventually you find a position on the dial that pleases you the most. Take your time and have fun with it.
Once you're enjoying how you sound and don't feel compelled to adjust the vari-cap any more disconnect it and bring out your LCR meter. Get the capacitance reading from the vari-cap. Make note of this value.
Repeat this step for any additional pickup/s your guitar has.

Step Three:
Now starts the process of setting your favored resonance in stone, as it were, using the values measured. Before you can determin the absolute capacitance required to achieve this you need to factor in the patch cable. Measure the capacitance of the patch cable by placing your probes on the ring on one end, tip on the other end. Add this value to the values you noted for each pickup earlier. You now have the values that determin your favored resonance for each pickup. The smallest of these values will determine the base capacitance served by the cable you'll assemble in the next step.

Step Four:
A cables length as well as it's plugs are a source of capacitance, as well as caps which I'll come back to. Plug capacitance needs to be factored in before the cable is cut to it's final length. Measuring the plugs is simmilar to measuring the patch cable, the ring probe can be placed on the shell of the plug to help steady it during measurement. The values measured off the plugs will be added together and subtracted from base capacitance before cutting the cable. Before doing so you need to get a rough idea of the cables pF/ft. One sure way of doing so is by probing the shield braid on one end, center conductor on the other end. If you have an indefinitely long cable you can cut exactly one or two feet. Either way you'll now be able to calculate how much length is required to reach base capacitance minus plugs. Go ahead a cut the cable but leave an foot extra just to be on the safe side. Now measure, cut off an inch, measure, cut off an inch and so on until you nail it. It's fun. Get your soldering iron warmed up and get ready to assemble your cable!

Step Five:
With a cable assmbled you're almost done. All that's left to do is set the capacitance for the pickups which required a higher capacitance than base capacitance. This is done via capacitors across said pickups. Subtract the preferred capacitance value to base capacitance and add a corresponding cap for each pickup.


Thats it. There's more than one way to skin a cat of course. What I've outlined here is what has worked for me. You can use dual vari-caps across each pickup in the first step if you like. You might be lucky enough and own a cable that is close enough to base capacitance(+/-15pF maybe). You might like the same external capacitance for all pickups, or you might like them hundreds of pF apart. You can also add caps across both pickups if desired and use an existing (shorter)cable. It's all about making the capacitance work for you and your ears.

Be aware that different makes of cable have varying capacitance at the same length. A lower capacitance cable(20-30 pF/ft) will allow you to use a longer length.


I'll come back on the subject of effects, true bypass and all that jazz, unless someone beats me to it. And likely other housekeeping. Right now I'm about to fall off my chair!

[sbgodofmetal]

why not just install a DPwhateverT varitone rotary switch and go wireless a decent wireless setup can be had for $49.99 at musicians friend. ;D

[roadtonever]

Just to be clear I didn't claim this was gonna be all-inclusive. What you're suggesting is certainly useful if in step one you can't settle on any particular resonanace. If you're too cheap the wireless system can be substituted by a JFET buffer, even. I'd probably love the DPxT in a half-parallel context myself.

[sumgai]

Anybody who can put up with me gets an extra +1, in addition to the normal +1 for that excellent write-up! ;D

Now, about those sound samples......



sumgai