To make such a chart, you would need to know the pickup impedances. Most pickup manufacturers provide, at best, the DC resistance values and very often not even that.
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
Ceramic Capacitors?
- Thread starter 25oclock
- Start date
To make such a chart, you would need to know the pickup impedances. Most pickup manufacturers provide, at best, the DC resistance values and very often not even that.
there are quality ceramics for around the same price as the cheap out of tolerance junk. the Kemet gold series Invalid Link Removed they are also great bypass caps for power rails.
Not only that, but impedance is frequency dependent. You would have to decide upon a reference frequency. In short, it is way too complicated to come up with any meaningful chart.
Speakers have the same difficulties but you can simulate the frequency response, impedance vs frequency and many other things from only a few parameters. Why couldn't someone do the same with pickups? They should actually be simpler as you don't have to worry about the mechanical issues of speakers.
Last edited:
Same problem as already mentioned. Manufacturers don't provide enough (or any) information to enable any kind of meaningful simulation.
The attached is an extract from my own spreadsheet file. The two tables look the same because the volume pot setting is 100%. Because P and J are wired differently, different setting produce different cut-offs. Also, I have other pages that accommodate the interaction of the two volumes in the J setup, but that would be giving too much away
As @line6man says, any charts such as this should be used as guidance rather than gospel, but IMO they do give a sense of what you might expect from a given combination.
Last edited:
Thank you!The attached is an extract from my own spreadsheet file. The two tables look the same because the volume pot setting is 100%. Because P and J are wired differently, different setting produce different cut-offs. Also, I have other pages that accommodate the interaction of the two volumes in the J setup, but that would be giving too much away
As @line6man says, any charts such as this should be used as guidance rather than gospel, but IMO they do give a sense of what you might expect from a given combination.
Fantastic! Thanks.The attached is an extract from my own spreadsheet file. The two tables look the same because the volume pot setting is 100%. Because P and J are wired differently, different setting produce different cut-offs. Also, I have other pages that accommodate the interaction of the two volumes in the J setup, but that would be giving too much away
As @line6man says, any charts such as this should be used as guidance rather than gospel, but IMO they do give a sense of what you might expect from a given combination.
You can use a cap in series for the bass cut and yes you can do a passive mid cut, I'm not sure how though.
Any idea how large those are? I've been looking for some and it seems like all the Orange Drops are HUGE!!
A 'treble bleed' or 'bypass' cap is just that - cap in parallel with a resistor (a small part of the volume control) both in series with the signal that kicks in when you roll back the volume knob a little. Paradoxically, they cause problems in a VVT setup - when using one pickup solo the cap on the 'off' volume control acts as a fully backed-off tone control so you lose rather than enhance the top.
Yep. A cap in parallel to cut highs and a cap in series to cut lows together leaving mostly mids
Two-Band “PTB” Tone Control: Useful, Easy, Cheap & AWESOME! « tonefiend archives
With my VVT I prefer to do that with a phase switch. Think about a Jazz bass. Both pups full on and in phase gives a mid scoop. Put them out of phase and all you get is the middle, albeit weak. But by rolling back one or the other pickup (I roll back the neck pickup) a little there is a small range where the volume comes back, the mids become far more apparent but the low end remains weaker. Then roll off the very top with a tweak on the tone knob with a low-value (0.022u) cap and there you have it - honksville! YMMV, but with my particular pickups it seems to work.
This is what I like to call "Leo's last circuit". It's in the G&L L2x00 basses for example. I do find it awesome, even though it takes some getting used to for those used to standard active EQ bass and treble controls. It's important to note that the 1 meg bass pot has a reverse taper! You can buy them from the G&L store if you want to experiment. The treble pot is standard like any passive tone control.
I rather like to use a little "treble bleed" on passive basses so you can roll back the volume a tad without rolling off some tone. But the idea is far from perfect. Not only is the there the VVT problem, but the amount of "bleed" really needs to be variable rather than fixed. So what happens is that for things to sound right you can only roll back volume to say 80%. Any more than that and you are getting too much treble bleed through.
Well most of us like the volume full up sound anyway, adding a nice 20-25% play zone at the max of the volume pot is sort of a plus even though it isn't good over the whole volume range, so I often add the bleed caps. But it's really hard to get an all passive circuit to do everything you want exactly right.
