Variable treble bleed mod

[Tommorichards]

Im having a go at making this for a friend, however, i am unsure of the values used.

V-Treb Variable Treble Bleed Circuit For Guitar & Bass

If anyone has one, or knows the values, could you post? Also, where to find the variable resistor, it would be a big help.

I have done the treble bleed mod before, but not with a variability option.

[Steve Conner]

Hmm, "patent pending", I wonder what on earth is patentable about it.

The little variable resistor is called a "trimpot" or "trimmer". You can get them from any electronic parts supplier, Mouser and the like. The value is printed on it, but they've photoshopped the image so it just says 000. 1M ohms would be a reasonable value, and for the cap just use whatever value of treble bleed cap you normally would.

[Chuck H]

My guess, based on personal experimentation, is that there is a cap and resistor in parallel and the variable resistor is a series resistor. It's a good circuit, and self explanitory, but doesn't allow for adjustment of the cap value. Which is a critical part of tuning such a circuit. You could easily make a similar circuit from parts you likely have on hand. And I'm with Steve. What's patentable about it I'm not sure. I've used that exact circuit though the series pot was temporary for adjustment and then replaced by a fixed resistor. I admit that I haven't seen a variable circuit like this for sale though. So it might stick?

For classic rock and blues distortion levels, using a combination of humbucking and single coil pickups and 500k pots I use a 220pf cap paralleled by a 220k resistor in series with a 47k resistor. For high gain I use a 180pf cap, no parallel resistor and a 100k series resistor. Either of these setups seems to allow me to get a decent clean tone down from the indicated gain settings with the guitar volume control backed off. So it seems to me a good "tweener" arrangement would be a 220pf cap parallel with a 470k resistor and a 68k series resistor.

[leofan]

Lindy Fralin recommends a .00025 cap paralleled with a 220KOhm resistor on the volume pot. He does not list the pot value but I'm going to assume this is for a standard audio taper 250K pot since so many of his wiring diagrams pertain to Strats and single coil pickups. You can always use these values as starting points.



I think that most times the best thing to do is start with values like Fralin suggests and vary from there. Also, I think it's a good idea to try linear taper pots, too, as many players actually prefer those once they try them. (If you do volume swells with your volume pot then you probably won't want linear taper pots.) The other thing is that the typical pots used with guitars can vary greatly in value, including CTS. So, what one person finds to work for them may not work as well for the next person. That might sound silly, but it's very true.

Recently I've been using the Bourns non-sealed variety of pots. They are inexpensive, silky smooth, and tapers seem more consistent than others in the under $5 apiece price range. Antique Radio Supply sells these. I've used the 250K and 500K pots.

[Phostenix]

Hmm, "patent pending", I wonder what on earth is patentable about it.

I can only guess that because it's a packaged assembly ready to install, it's a patentable idea? PRS' website says that the 513 is patented. They patented a 3-way switch to control coil selections? Really? I'm hoping what they got patented was the whole package of pups & selections. Even that seems far fetched to me....

[Phostenix]

My guess, based on personal experimentation, is that there is a cap and resistor in parallel and the variable resistor is a series resistor.

That's exactly what it is.

It's a good circuit, and self explanitory, but doesn't allow for adjustment of the cap value. Which is a critical part of tuning such a circuit.

That's the downside I see in it, too.

[David Schwab]

Lindy Fralin recommends a .00025 cap paralleled with a 220KOhm resistor on the volume pot.

It says .0025µF in the diagram.

[David Schwab]

PRS' website says that the 513 is patented. They patented a 3-way switch to control coil selections? Really?

Did you read the PRS patent? The 513 has tapped coils, so when in single coil mode you get the full output, and then in humbucker mode they are using part of the coil to match the coil next to it. There's a bit more to it than a 3-way switch. That was for the coil tapping.



There have been many switch wiring schemes patented, some by Bill Lawrence.

[Phostenix]

Did you read the PRS patent? The 513 has tapped coils, so when in single coil mode you get the full output, and then in humbucker mode they are using part of the coil to match the coil next to it. There's a bit more to it than a 3-way switch. That was for the coil tapping.

[ATTACH=CONFIG]14306[/ATTACH]

Interesting. It looks to me like each pickup (which look like single coils) has 2 coils inside it - both of the same magnetic polarity - with a coil tap lead between them. So, the pickups look like this:

A is L1 & L2
B is L5 & L6
C is a non-split single coil L26
D is L14 & L15
E is L18 & L19

The 3 positions of the 3-way give you this (ignoring pup C which never changes):

1. Both coils of A in series with both coils of B & both coils of D in series with both coils of E
2. One coil of A in series with one coil of B & one coil of D in series with one coil of E
3. Both coils of A only & both coils of E only

The idea of a split within the single coil is different. but aren't you still getting twice as many coils in the full humbucker mode than you are in either of the splits? I would expect the typical volume drop for the splits. Am I missing something?

I've attached a pic of the switching as I see it.

[Phostenix]

There have been many switch wiring schemes patented, some by Bill Lawrence.

I can't imagine there's much left to try that hasn't been on some internet forum for several years.

Like the topic of discussion here: Packaging a treble bleed circuit in a convenient stick-on circuit board that makes it dead simple for the average guitar player to try is a great idea, but I'm not sure what makes it so unique as to be patentable. The circuit certainly isn't patentable, so it must be the packaging. How different does packaging have to be avoid patent infringment? Re-arrange the components?

[David Schwab]

I can't imagine there's much left to try that hasn't been on some internet forum for several years.

Like the topic of discussion here: Packaging a treble bleed circuit in a convenient stick-on circuit board that makes it dead simple for the average guitar player to try is a great idea, but I'm not sure what makes it so unique as to be patentable. The circuit certainly isn't patentable, so it must be the packaging. How different does packaging have to be avoid patent infringment? Re-arrange the components?

I doubt that has been patented. Theres another one that is three switches on a circuit board that gives you series/parallel and phase reversal for two pickups. It might even be from the same company. They say that's patented as well. I really doubt it is. I think it's just talk.

But if you came up with something a while ago before it was all over the internet, you certainly could have gotten it patented.

[jrfrond]

The word "patented" has been used in ad-speak ad nauseum, and the US Government isn't about to tackle piddly little MI manufacturers for using it in court, so to me, it's just BS, unless it's backed up with a patent number. Do you REALLY think that someone is going to file a patent, a process that costs thousands of dollars, on a little gadget like this???

Same goes for copyrights. Do you really think that all internet content that sports a "C" mark is copyrighted? Most are implied copyrights, because most content wouldn't outlast the time required to grant a copyright.

You can't believe everything you read. You can also freely search patents and trademarks at USPTO.gov.

[David Schwab]

Same goes for copyrights. Do you really think that all internet content that sports a "C" mark is copyrighted? Most are implied copyrights, because most content wouldn't outlast the time required to grant a copyright.

Just saying it's copyrighted and putting the © implies a common law copyright. That is actually legal, but is harder to defend.