Hallman Labs first official products for sale will be treble bleed circuits for guitars! When you dial down the volume on your guitar (with any pickups) the high frequency is rolled off sharply.
The treble bleed counteracts this rolling off of the highs by bleeding high frequencies directly into the potentiometer output leg. Thus acting as a high pass filter for the incoming pickup signal. You dial in this simple RC circuit, depending on the resistance of your guitar volume potentiometer/s. Divide the potentiometer resistance by two and this is the usual resistor value used in parallel with around a ~.002-.001 uF (1000-2000 pF) capacitor of high quality. My revision “V2.0” treble bleed kit include a 2nd resistor in series with the capacitor, usually 10k-30k ohms.
This is the only difference between the two versions. Both will not only allow you to customize your resistance and capacitor, but you can even request a DIY kit! These will give you all the parts and you assemble it all yourself. I will have a QR code printed onto a paper inside the package. Use your phone to scan this QR code and it will take you straight to a video of me demonstrating how to build and install these kits.
(Fender Engineer Jonathan Parrish, on adding the 2nd resistor)
“What that does is creates a constant voltage drop across the circuit,” he said. “By adding that one resistor, I can take the highs and drop them down a little bit more. And by voicing them to each pickup combination on each guitar, they’re all a specific fit and sound really musical.”
I am also considering the V4.0 dynamic treble bleed design, where I use a high quality trim pot (Allen Bradley, Spectrol, Bourns, etc.) in place of the fixed series resistor. Trying to ensure my designs sound the way I want them to before producing any for sale. So the V3.0 modular and V4.0 variable kits have taken a temporary backseat to these fixed kits above. That is except for the people I have talked to about making the modular V3.0 series for, to get early thoughts/reviews. Also, see the bottom of the page for latest thoughts on the other series design decisions.
To help you in deciding what capacitor value is best for your setup, here are some general guidelines by guitar techs & stock configurations from the factory.
- PRS – 180 pF cap (500 kΩ volume pot, no parallel/series resistor).
- Bill Lawrence – 330 pF capacitor & 80 kΩ resistor
- Mojo Tone – 471 pF capacitor & 220 kΩ resistor
- DiMarzio – 560 pF capacitor & 300 kΩ resistor
- John Suhr – 680 pF capacitor & 150kΩ resistor
- TV Jones – 1 nF capacitor & 150 kΩ resistor (2 nF cap suggested for 500 kΩ pot, humbucker)
- Fender – 1.2 nF capacitor & 150 kΩ resistor in parallel, plus a 20 kΩ resistor in series.
- Seymour Duncan – 1 nF capacitor & 100 kΩ resistor
- Chris Kinman – 1.2 nF capacitor with 130 kΩ resistor in series!
- Lindy Fralin – 2.5 nF capacitor & 200 kΩ resistor
- (Note: 1000 pF = 0.001 µF = 1 nF ) | (pF = Pico-Farads, µF = Microfarads, nF = Nanofarads)
Hoping to get these posted to Ebay this weekend. Anyone who is interested in buying a treble bleed can get 20% off their purchase by PMing me the code below (on Ebay) and then make an offer at the price I reply back to you. Then I’ll accept your offer and you get 20% off! Note: I’ll need to know your choice of tone capacitor and which version kit you want (V1.0 or V2.0). I hope to have the V3.0 & V4.0 kits available within the next week or so.
I will update this article with the Ebay sale link when available to purchase! Follow what I said above to receive the 20% off discount for the first two weeks they are for sale. I’ll start a timer and place it below the promo code to show how much longer is left.
Update 1: Currently I am making a set of treble bleeds using every type of capacitor that I have more than 20 in stock. I am re-testing all of the capacitors with my BF-50 capacitor analyzer, this is made to test ceramic/silver-mica and paper-in oil/molded. In other words, it is a rare instrument that can test capacitors that are usually too low in value to use a modern ESR meter. I did however use the ESR meter to validate the capacitors inside of the Cornell Dubilier BF-50, which is quite a few! Surprisingly only one of the capacitors had noticeable capacitance drift (di-electric breakdown) or leakage current detected.
Current Capacitor List:
- Molded Blue AJAX
- Mallory Tropical Fish
- Mallory Orange Drop
- Sprague Orange Drop
- Cornell Dubilier Black Cats
- Cornell Dubilier Silver Mica
- Hi-Q Ceramic
- Sprague Tantalum
- FAST Polyester
- Mallory Wrapped Foil
- Special: Sprague Bumblebee
- Special: Mullard Mustard
- Special: Astron Molded
The more I thought about the variable V4.0 design, I have decided to stick with a fixed resistor in parallel to match the guitar pots and use a trim pot for the resistor in series. I realized that using 2 trim pots does 2 things I noticed off the bat, one having both of the values being variable only matters if you plan to use the kits in more than one guitar (if you do, just replace the parallel resistor if the value is too far off from the current volume pot). In using 2 trim pots we lose the advantage of our precision Dale resistors and only having to use one trim pot cuts down on the confusion of operations. Everything was pointing me towards using a fixed resistor + 1 trim pot for V4.0 variable treble bleeds.
Electrical Engineering student (Jr year) with a background in IT. Such as dealing with large scale network infrastructure upgrades at Lowe's HQ and former lead hardware tech for the NC Government.