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Discussion in 'Pickups & Electronics [BG]' started by vindy500, Sep 18, 2006.
obviously i could easily search this.. but search is down, so what do you guys have in ur p?
Standard value is.047uF. Other common values are .1uF and .022uF, which give darker and lighter tones respectively.
and should you want more high cut than what a .047uf cap delivers, but a .1uf cap is just too much ...
solder a .047uf and .022uf cap in parallel for an effective equivalent of a .069uf cap
all the best,
A good .047uf Poly cap
to be clear, there is no need to spend big $$$ on boutique caps from high end electronics dealers if all you are utilizing it for is on a passive tone control pot. everything that passes thru the cap is filtered to ground. you will never hear the signal frequencies that pass thru it. period.
for this application, it is also pretty much irrelevant which flavour of cap you plan to utilize. again, paying high $$$ for boutique caps for this application is a waste of your funds
the only significant need for a cap besides its value is that it have good solid leads to solder to.
now if this cap was going to be used on a volume pot to keep the high end from being lost as the volume is turned down, then it's a completely different story. in this latter case you will hear the signal that passes thru the cap - you do want to make sure you have a high quality cap for this specific application.
to sum it up, there are two main cap applications. the main application is for a passive tone control, where you are selecting the frequency at which everything above that point will be bled off to ground (earth.) since you will never hear the portion of the signal that is bled off, there is no need to waste money on high end boutique caps for this application.
'tis the facts on caps
all the best,
its just teh standard tone ap, am i right in thinking that at an open position (knob right up so as trebly as we go) it doesnt matter what capacitor is being used? so a .1uf cap will have a larger range?
a 0.1uf cap will allow you to bleed highs to ground at a lower frequency knee than a 0.047uf cap will
the audible amount of highs bled off are determined by the rotation of the tone control pot, and the cap serves as the regulator for where the frequency cut-off point is. a full on pot will allow all of the signal to flow, thus making your cap choice irrelevant. it's only when you start exposing the signal to the cap that the highs are bled off
0.022uf is typical on many J-bass bridge p/u's
0.047uf is typical for a P-bass
0.1uf is pretty low, but still usable
all the best,
I would disagree, since anything that the cap doesn't filter out will still be heard. You still have a portion of the signal going through the cap, and the other part going to the output. So, even though one doesn't hear what goes through the cap, one does hear everything that does not go through, making the cap quality nearly as important as in a treble bleed application (although, in a tone setting, the highs will be removed, which give more of the characteristics of a bass's tone).
I just found in an alley next to a music store an Erie .047 uf capacitor. It's one of the old style plastic case big capacitors. It sounds better than the ceramic one that used to be in there. I like film stlye capacitors for tone controls rather than the ceramic.
BTW, a capacitor is always in the circuit unless a "no-load" stlye tone control is used. The tone control just puts more resistance between the pickups and the capacitor. At 10, there is maximum resistance, but it still is filtering some signal. It makes a difference. That is why you see a lot of people here put in JUST a volume , or wire straight to the jack.
While you're welcome to disagree, but you should understand what's happening in the circuit before making such a statement. Let's look at the following wiring diagram for a P bass
notice that the hot lead to the jack comes from the volume pot. note also that the hot lead from the pickup goes to the volume, and that it also parallels over to the tone pot.
now note that the tone pot has the cap wired to its middle lug and that the other end of the cap is connected to ground. note that the jack is also connected to this common ground
the signal flows from the hot lead, and into the input jack without flowing thru the cap (there is no way for it to travel thru the cap and into the jack.)
note that the cap positioned here is to allow a frequency set to be filtered off of (removed from) the output (by providing an easier path to ground than running thru the jack and to your amplifier), but it in no way is in the direct signal path TO the jack - it sits idly by waiting for you to turn your tone pot to expose signal to it so that it can then let the highs pass to ground and leave anything lower than its frequency point retained in the signal that will is directed to the jack.
since the cap is NOT in the direct signal path, it has NO effect on the signal properties that do not pass thru it - it simply cannot due to the design of the circuit.
So in conclusion we can now say with certainty that the myth about using a high $$$ boutique cap having a direct impact on the non-filtered sound is BUSTED
all the best,
Sorry, Rodent, you have missed the fact that the capacitor is isolated only by a resistance, not an open circuit. So it is still doing something, albeit a small amount.
But I do agree, expensive caps really don't make a huge difference.
allowing signal frequencies to be filtered off - yes, agreed it is still in the circuit and will have a 'minimal' filtering impact even with the tone knob wide open (full signal to jack)
in the direct signal chain to the jack and having a direct impact on the quality of the signal below the knee point (gated, unfiltered portion of the signal) - no, it has no impact as it is not in the signal path
FWIW this stuff isn't rocket science, but is instead a re-use of technology developed in the early days of radio for the cleansing/filtering of noise from a broadcast signal (one of many uses)
I should also note that one reason you can hear a difference when eliminating a tone control (and even a volume control) from the onboard circuitry is that the pot itself has an impact on the signal - and this impact is determined by both the pot quality and it resistance rating (25K, 50K, 250K, 500K, 1MegK, etc ... pot ratings)
all the best,
FYI, the stock cap on the American Vintage 57 and 62 Precisions is .1uf. Seems to work quite well, at least with those pickups.
I beg your pardon, but I do have a quite clear understanding of how a tone circuit (and analog circuits in general) works. I am, after all, an electrical engineering major...
I don't think you understood my point. While the signal going to the jack does not pass through the capacitor, everything that doesn't pass through the cap is still going to the output. This means that if the cap removes a certain range of frequencies, then the compliment of those frequencies will pass to the jack.
Now, I do agree that boutique caps are overrated, and the differences between various caps of a given value are minimal, if not negligable.
Hey, ryre, I'm EE major, too.
i used to customize guitars, and I had some vintage guys having me research some "bumble-bee" caps for them. It's amazing what people will pay for foil in oil caps...
I'd try out some different styles of caps, like ceramic disc ones, mylar film, and tantalum ones (which I haven't messed with a lot). The mylar ones seem to suit my ears best...
A lot of people might say I was biased, but I just bought what was the right value when I discovered the mylars sounded better than a ceramic.
I'm not a believer at all in the boutique capacitor thing as far as a passive bass tone control is concerned at all.
However, if you're a guy like me that maybe buys one or two capacitors for few projects the cost differential between a no name disk capacitor and an orange drop cap is insubstantial and you can be assured of better tolerances which is important, since I don't have a huge bin to sort through to find the good ones. Plus they got long, beefy leads.
The few I have ordered with my other bass parts have been exactly the value they said they are compared to the one that came stock on my project bass was off by over 20% and it made a huge difference in sound to me.
20% is quite a big variation. That would make quite a difference in a passive tone circuit!
I kind of think the opposite is true - what's important is the resulting sound, regardless of how you understand the circuit to work.
That said, understanding how a bleed-to-ground tone circuit works, I think RyreInc's explanation hits the nail on the head: even though the tone cap is not in the direct signal path (i.e. it is not a direct "coupling" cap), it is still "in" the signal path by virtue of how it subtracts from the direct path.
My experience is that caps of the same value and different materials in a passive P-bass tone circuit can make a very significant difference in tone. The effect is more significant as you roll more of the capacitor bleed into the circuit, especially below 50%. The biggest differences I have heard are between modern film caps, paper-in-oil caps, and old, vintage wax/plastic caps. I haven't tried any of the boutique caps so don't know how well - if at all - they capture what an old, vintage cap might offer. But the 0.1uF plastic cap I pulled out of a 60's Kay guitar sounds fantastic in my P-bass - thumpy and smooth with the tone rolled down to 20%.
If you'd use a high-end capacitor in the tone control, the good sound character bleeds away and the bad stuff remains. You'll get more or less the opposite effect. In principle you'd be better off with a capacitor which would sound ugly when used in series of the signal.
If you use a sharp, metallic sounding capacitor (when used in series), you'll get a more sweet and mellow sound when used in in the tone control (parallel), because the sharpness is filtered out of the signal.
Same is true for resistors. In good sounding high-end audio equipment the resistors in series with the signal path are high quality carbon (sweet) and the parallel resistors are metal film (like expensive tantalum ones, these sound ugly when used in series).
I don't really see how you could make caps expensive, even if you made them by hand
which, in terms of solid state electronics, isn't always better