Biasing amps "by ear" to get the perfect tone.
It’s time again to take a look at all things tonal, with the intent of giving you even more information to further your adventures in making music. This month, I thought it would be fitting to share some thoughts and advice given to me by my late, great friend, amplifier-serviceman and Trainwreck amp designer, Ken Fischer. I was first introduced to Ken way back in 1981 via telephone while working for Groove Tubes in Los Angeles. On the first day of my new job at GT, my first call was from the extremely animated and hilarious Ken Fischer, delivered in his soon-to-be instantly recognizable New Jersey accent. Little did I know at the time that I would be blessed with all kinds of tips and tricks from Ken for the next quarter century.
One of the things that Ken often mentioned was that he didn’t always do things “by the book.” Instead, he used his keen instincts and sharp eye to troubleshoot and solve problems typically found in amps needing repair. One of his big interests was dialing in an amplifier’s “sweet-spot” by using his ears – not by digital voltmeter readings. Ken would always talk about getting the most tone from the tubes as one of his prime objectives when nursing broken amplifiers back to health.
Ken would always say that there was a very fine line – a balancing point – where great tone began and where that wonderful ear candy completely evaded you. This month’s installment is really designed as a lesson in how to open up your ears to the big sonic picture and learn that there are indeed times where a few rules can be broken in the quest for your perfect sound. These observations revolve around how you can optimize and adjust your amplifier’s bias control by unusual conventions more related to tone and musical character than just electronic criteria. It’s also important to know that great sound can come out of trial and error.
You can make your amplifier sound better with a screwdriver and some experimental tweaking. You first need to determine whether your amplifier has an internal bias trimpot. This type self-adjusts without too much trouble. Some amplifiers are self-biasing and can be voiced by substituting different brands of tubes until you hear the results you like. Other amplifiers require some soldering to adjust the bias circuit. These are best left to a qualified amp technician if you’re not comfortable with the potentially lethal voltages present inside a tube amp. If you do not have the proper safety equipment or don’t feel qualified to go poking around inside an amplifier, please leave it to a professional. You’ve been alerted to the potential hazards, so please use some common sense and everything will be rocking.
My first experience biasing “by ear” involved a now vintage Jim Kelley amplifier. This amp had its bias trimpot control conveniently located for external adjustments – just turn
the trimpot with a jeweler’s screwdriver and listen carefully. What Ken taught me was tantamount to my future listening abilities. The trick is to get the amp sounding full and rich with harmonics and overtones, but there’s a catch – this is a matter of personal taste. You may like the sound of your amp running just a tiny bit hotter, or perhaps a little bit colder. There are many shades of great tone to be found in this dial.
When I bought my Komet 60 head back in 2000, I called Ken to ask him for some advice on biasing since the Komet had EL34 tubes and the Jim Kelley used 6V6s. He told me that since I was already able to bias the Kelley there was no real difference between the two – it was still matter of slowly turning the bias control and playing the amplifier until it totally rocked my world. Granted, the EL34s reacted differently than the 6V6s, but I was able to hear just where any crossover distortion was rearing its ugly head and turn the dial until it was gone – bingo!
Oddly enough, when you look again at the amp’s bias voltage with a digital voltmeter after biasing by ear, the tubes are typically within the acceptable range of operating tolerances. This technique is analogous to intonating a guitar at the 19th fret and then double-checking the 12th fret for any changes. You won’t really see any change, but you sure will hear it. This is just another method of getting closer to the sound you want.
Thank you, Ken – it was an honor and a blessing to know you for the time we shared. You will never be forgotten! Remember to make good music, have fun and be safe above all. We’ll see you next month.
Dean Farley is the chief designer of "Snake Oil Brand Strings" (www.sobstrings.net) and has had a profound influence on the trends in the strings of today
Kick off the holiday season by shopping for the guitar player in your life at Guitar Center! Now through December 24th 2022, save on exclusive instruments, accessories, apparel, and more with hundreds of items at their lowest prices of the year.
We’ve compiled this year’s best deals in the 2022 Holiday Gift Guide presented by Guitar Center.
DiMarzio, Inc. announces the Relentless P (DP299), the Relentless J Bridge (DP301), Relentless J Neck (DP300), and the Relentless J Pair (DP302) for 4 string basses.
DiMarzio, Inc. announces the release of the Relentless P (DP299), the Relentless J Bridge (DP301), Relentless J Neck (DP300), and the Relentless J Pair (DP302) for 4 string basses. The new Relentless P and Relentless J series pickups feature the Relentless cover designed in collaboration with Billy Sheehan.
As with the Relentless pickups, we removed all the hard edges from the standard P Bass and standard J Basspickups, and added an arch to the top of the pickups to bring the sensing coils and pole pieces closer to the strings. These improvements increase the dynamic range and make active circuitry unnecessary.
The Relentless P and Relentless J pickups incorporate Neodymium magnets and produce 70 percent more output than traditional passive pickups, and they’re dead quiet due to the incorporation of metal covers and foil-shielded cables. To dial in (or fine-tune) the individual string output, the Relentless P and Relentless J include eight adjustable pole pieces. These pickups also have a broad magnetic field so you can even bend notes without volume dropout.
DiMarzio’s extra shielding makes the Relentless P and Relentless J better for both recording and stage performances. We’ve mounted them onto robust .09375” thick circuit board base plates to eliminate the annoying protruding mounting screws — ultimately creating a more comfortable and consistent foundation to rest your fingers on.
The new Relentless P steps beyond the traditional P-Bass sound and can only be described as massive. It has more of everything: more volume, beefier lows, a growling midrange, and crispy highs with better individual string definition.
The Relentless J incorporates a new invention, (patent pending) parallelogram-shaped coils, offering an expanded mid-range punch, snappy highs, precise lows, and a new dimension to the sound of the Relentless series pickups.
Relentless P and Relentless J pickups will breathe new life into any bass, increase playability, and work well for any style of music from Motown to metal.
DiMarzio’s Relentless P, Relentless J Bridge, Relentless J Neck, and Relentless J pair are made in the U.S.A. and may now be ordered for immediate delivery.
Suggested List Price for the Relentless P is $169.00 (MAP $119.99).
Suggested List Price for the Relentless J Bridge and Relentless J neck is $155.00 (MAP $109.99).
Suggested List Price for the Relentless J Pair is $296.00 (MAP 209.99).
For more information, please visit our website at dimarzio.com.
Mystery Stocking is coming soon! Sign up for PG Perks below so you don't miss it.
Sign up for PG Perks on the form below to make sure you don't miss the launch announcement!
About Mystery Stocking
Each year, Premier Guitar likes to put out these mystery boxes as a part of bringing some fun to the holiday season. Remember, this is supposed to be a fun holiday treat! If the contents of this box will ruin your holiday, deplete the last of your bank account, or end your ability to see the good in humanity, it may not be for you.
- This year's Mystery Stocking will cost $44.95. ($39.95 + $5 Flat shipping)
- Each box will be guaranteed to contain $40 or more in value.
- US only. (Sorry World.)
- Make sure your shipping address is correct.
- Have your credit card ready to go before you refresh the page. Paypal is not available. Autofill may not fill in your information.
- There will be NO REFUNDS given.
- There has been a huge demand for these in the past. We really did sell out in less than 4 minutes last year. When they are gone, they are gone.
- One per household, one per person.
Q: What's in the Mystery Stocking?
A: It wouldn't be much of a surprise if we told you, now would it?
Q: Will I definitely get my money worth?
Q: Can I return it if I don't like it?
A: Nope. All sales final.
Q: What if I live outside the US?
A: Sorry, US only.
Q. How much is it?
A. $39.95 Plus $5 shipping
Q. When will it ship?
A. On or before December 10, 2022.
Q. What form of payment do you accept?
A. Credit cards only. Sorry, no Paypal for this.
Q. Can I ship to a different location than my billing address?
Q. I tried last year and didn't get one. Will I get one this year?
A. There is an overwhelming demand for Mystery Stocking. Be sure you have a fast internet connection and be ready when they go on sale. Last year we sold out in 3 min 33 seconds.
Q. I want to buy 5. How can I buy 5?
A. You can't. This year, we're limiting to one per household, so more people can get in on the fun!
Featuring the Adaptive Circuitry recently introduced on their Halcyon Green Overdrive, Origin Effects have brought us a pedal with a character all of its own and a new flavor of drive.
Origin Effects introduce the new M-EQ DRIVER mid booster & drive pedal. Based on a vintage Pultec studio EQ, this unique pedal offers a range of mid-focused tones, from a subtle mid boost to thick, resonant overdrive. Featuring the Adaptive Circuitry recently introduced on their Halcyon Green Overdrive, Origin Effects have brought us a pedal with a character all of its own and a new flavor of drive.
A choice of three mid-range frequencies ensures that you can boost just the right part of your guitar signal and, when pushed harder, can elicit a range of saturation from a classic “mid-hump” overdrive to fierce “cocked wah” distortion. Thanks to the Adaptive Circuitry, the high-end roll-off of the Cut control is reduced as the pedal cleans up. This allows for a smooth transition from warm overdrive to bright clean tones in response to playing dynamics or guitar volume knob changes.
Introducing... M-EQ DRIVER || Mid Booster & Drive
Built-in the UK to the highest standards, the M-EQ DRIVER continues the Origin Effects tradition of vintage, studio-inspired tones in modern guitar pedals. The Origin Effects M-EQ DRIVER is available now from Origin Effects dealers worldwide.
RRP: 259 GBP (Inc VAT) / 319 USD (Ex TAX)
For more information, please visit origineffects.com.