IMPROVE TONE QUALITY - Change The Low Pass Filter Cutoff From 3.6kHz To 20kHz     

       HEIGHTEN AUDIO CLARITY AND REDUCE NOISE - Replace Two Op‑Amp IC's For Superior Audio

       RAISE VOLUME OUTPUT - Increase Output Gain For The Left And Right Audio Outs

       BATTERY REPLACEMENT - Internal Battery Removal And Replacement

       POWER SWITCH - Replacement Part Numbers And Specs

       DOCUMENTS - FB‑01 Secrets, SysEx Control, 1986 Intro, Gatefold Sales Brochure. Ghosts In The Machine Part 1 & Part 2

       PATCHES - 3000+ Free FB‑01 Patches In SysEx Format

       EDISYN / FREE FB-01 PATCH EDITOR - One Of The Very Few Free FB‑01 Patch Editors Available For Mac OS X, Windows And Linux
FROM 3.6kHz TO 20kHz

Listen To "Before/After" Audio FB-01 DIY
Background: The original FB‑01 schematics show four capacitors with a value of 3.3nF. During the assembly phase and for unknown reasons, Yamaha installed four 18nF capacitors instead. This unfortunate substitution reduced the audio spectrum causing high frequency tones to be "muffled" and less pronounced. If the capacitors inside your FB‑01 are 18nF (seen labeled here as 183), you should consider performing this mod which updates the audio filter circuit to the original specs. It effectively raises the lowpass filter cut‑off slightly over 20kHz
How: Replace four capacitors (C4, C9, C14, C16)

(4) 3.3nF Polyester Film Capacitors, 50V*

647-QYX1H332KTP - mouser.com       or       A-414 - taydaelectronics.com
Cost: 4 x 36¢                                                   Cost: 4 x 10¢

Note: I chose Nichicon P/N: QYX1H332KTP because it is a high quality capacitor and has the same 3.5mm lead spacing as the original. Any brand 3.3nF polyester film capacitor will work as long as it has a DC voltage rating 50V or greater. Because this is for an audio circuit, I highly recommend using a quality brand name like Panasonic, TDK, WIMA, Nichicon, or Kemet (a.k.a Arcotronics)

* Update: One year after posting this mod, I've received eMails from DIY visitors who have decided to substitute 6.8nF or 10.0nF caps instead because they say the 3.3nF caps produce a sound which is "too hot" for their use. Of course, everyone has different tastes. I mainly use my FB‑01 for Industrial, Sound FX and Unusual Noises so for me... the hotter the better!  FB-01 DIY

I suggest using Single Column DIP Sockets for these four capacitors. Changing the capacitor values will be very simple and allows you to find the right one for your musical tastes. Single Column DIP Sockets are available from taydaelectronics.com - P/N:  A‑1605

Listen To "Before/After" Audio FB-01 DIY
Background: Just about every online review of the FB‑01 mentions issues about noise. Some FB‑01 owners like the noise for recording tracks with that "industrial" flavor while others do not. Yamaha sourced JRC4556D op‑amps for the FB‑01 which are low priced and have a Slew Rate* of 3V/µs. Imagine if these were replaced with some hi‑fidelity, high‑performance op‑amps with a higher Slew Rate to eliminate noise! I chose to use mid‑priced OPA2134PA op‑amps at $6/each which are higher quality but not too pricey. The OPA2134PA has a slew rate of 20V/µs. This is nearly 7x greater than the factory installed JRC4556D op‑amps. Another op‑amp with a Slew Rate of 20V/µs is the LM4562. The LM4562 may also work but, I can't verify this since I have not tested that part number

*IC's with limited Slew Rates can cause noise and distortion at high output frequencies and amplitudes. This is why IC's with a higher Slew Rate are more desirable and more expensive
How: Replace two IC’s (IC1, IC4) + add two IC Sockets

(2) OPA2134PA Op-Amps

(2) 8-Pin Tooled IC Sockets

595-OPA2134PA - mouser.com       or            A-856 - taydaelectronics.com
Cost: 2 x $6.15                                               Cost: 2 x $4.00

575-199308 - mouser.com               or           A-857 - taydaelectronics.com
Cost: 2 x 50¢                                                  Cost: 2 x 12¢

Listen To "Before/After" Audio FB-01 DIY
Background: FB‑01 owners have always complained about low gain from the audio outs. A factory stock FB‑01 has an output gain level of 3. This mod replaces two 4.7K Ω resistors with two 10K Ω resistors to raise the output gain level to 5 with no clipping after effects
How: Replace two resistors (R6, R13)

(2) 10K Ω 1/4W Metal Film Resistors

660-MFS1/4DCT52A1002 - mouser.com       or       A-2203 - taydaelectronics.com
Cost: 2 x 17¢                                                            Cost: 2 x 2¢


* Update: After this mod has been online for a couple of years, some purists have commented that this additional volume mod adds a level of extra distortion to the total volume output. That it does! I don't use my FB‑01 for Piano and Violin sounds. I use it for Industrial and Sound Effects so I like it LOUD! I suggest using Single Column DIP Sockets for these two resistors. If you don't care for the additional volume output, changing the resistors back to their original values of 4.7K Ω will be very simple. Single Column DIP Sockets are available from taydaelectronics.com - P/N:  A‑1605
The YouTube channel of Jiří V. has an excellent comparison on the oscilloscope of the "Before" and "After" showing the upgraded performance value

Click on images to enlarge
Component Location Detail

Schematic With Notations

Detailed discussions about all modifications shown above are here, here and here

SUPER JX Battery Replacement DIY

Power Rating: 6A @ 250V AC
Type: Solder Lug - DPST (ON/OFF)
Panel Opening: 13mm x 19mm
* The original FB‑01 rocker switch has a solitary dot as its actuator marking on the face. After evaluating all three switches, I prefer the higher quality switch from Mouser. I've posted two alternative switches from Tayda because of the low cost and the high visibility of the red switch A‑5092. These have the same power rating as the Mouser switch and will work equally well. As of August 2021, the price for the Mouser switch was $3.31 (USD) and the price for the Tayda switches was 29¢ and 26¢
There was a great article in the January 1989 edition of Electronic Musician Magazine titled "Secrets Of The Yamaha FB‑01". This article covers a lot of "hands-on" applications using SysEx to unleash the FB‑01. This article is a must read if you have any interest in controlling parameter changes using SysEx codes
SUPER JX ZONE   Secrets_Of_The_Yamaha_FB-01
Yamaha User's Group Magazine Aftertouch from July 1986 featuring an article titled "Introducing Yamaha's MultiTimbral, MultiMIDIChannel FM Tone Module"
SUPER JX ZONE   FB-01_Introduction    (Note: This document is housed on a very slow server)
Yamaha User's Group Magazine Aftertouch from September 1988 featuring an article titled "Percussion Secrets Of The FB‑01"
SUPER JX ZONE   Percussion_Secrets_Of_The_FB-01    (Note: This document is housed on a very slow server)
Yamaha's 6page gatefold sales brochure from 1986
SUPER JX ZONE   FB-01_1986_Gatefold_Brochure
I have added this document to the webpage since it covers a wide range of Yamaha series synths (DX, TX, RX, QX, FB). Two articles from the May 1989 and July 1989 editions of Electronic Musician Magazine titled "Ghost In The Machine". These articles discuss test routines inside synths and samplers which might help save you a trip to the repair shop. Some of the other brands featured are Roland, Oberheim, Kawai, Ensoniq & Korg
SUPER JX ZONE   Ghost In The Machine - Part 1 & Part 2
The FB‑01 is not the easiest synth on which to create new Patches. No knobs to turn and no sliders to be found anywhere. Patch editors for any current O/S are uncommon. The best alternative is to load‑up on Patches from a free source. The MAZES Psychoacoustic Haze Blog has a selection of 3000+ FB‑01 Patches online at this link available for free downloading

      SUPER JX ZONE   http://mmmazes.blogspot.com/2010/05/fb-01-patches.html
FREE !!!

EDISYN from developer Sean Luke is a synthesizer editor that gives you control over the FB‑01 (and more than 60 other synths!) via custom made MIDI editing synthesizer templates. It also has unlimited levels of undo, CC and NRPN mapping, real‑time updates, test notes and chords and some MPE support. Sean has also built‑in a range of creative tools to help with patch generation. These include randomization, patch merging and blending of random patches, pushing patches closer towards other patches (very interesting), morphing interpolation between four patches and more

      SUPER JX ZONE   Edisyn FB-01 Patch Editor
ANIMATED_STAR I think these two topics are important enough to place on all of my synth INFO webpages


1) I buy a lot of broken synths on eBay and I'm able to fix about 90% of everything I find. It's usually a simple fix. If you have a synth with no power or intermittent problems after it warms up, it's probably due to the fact that back in the 1980's Roland and other synth makers used sub‑par solder and/or not enough solder to hold components in place. After 30+ years, the solder begins to break down and hairline fractures appear. This occurs at a higher rate for components which generate a lot of heat like Bridge Rectifiers, Power Transistors, large Electrolytic Capacitors, power input jacks and audio jacks which get a lot of use. The best approach is to use a magnifying glass and carefully inspect the backside of the circuit board. If you spot any suspect areas, re‑flow a hefty amount of NEW solder

2) I receive a lot eMails and field many questions at synth related forums and also on Facebook. The most common question I get about problems with a synth has to do with errors when trying to load Patches and Tones. About 99.9% of the time, the problem always turns out to be a crappy MIDI interface. If you have a cheapo MIDI interface which looks similar to the one shown on the right... throw this piece of shit in the trash! Do It Now. Seriously! This thing is total junk and you get what you pay for. Inexpensive MIDI interfaces like this are unable to properly regulate the buffering of MIDI data. They will work fine with simple messages such as CC, Note On, Note Off, etc... however, when you try to send SysEx messages which are much longer, the SysEx data cuts off after only sending a few bytes. Investing in a higher quality MIDI interface will solve Load/Save errors and other communication problems
All of the modifications shown above were compiled from discussions I have found on the Internet. I have performed all of these mods on two FB-01's I own. They are completely revitalized and sound better than ever

Safety Precautions and Disclaimer:
Modifications made to any factory stock equipment will always pose an element of risk. Sometimes mistakes are made which are irreversible. Improper soldering and handling of electricity can cause serious injury and damage the FB-01. Use caution when handling static sensitive devices and the PCB. Make sure you are properly grounded, working on a static-free workbench or table and wearing eye protection during any soldering tasks. The author is not responsible for any damage or injury resulting from this DIY info. Use this DIY information at your own risk. And, I can't stress enough, the importance of wearing eye protection while soldering. That stuff flies everywhere sometimes!
Other Synthesizer And Sampler Homepages I Maintain


If you find some of this DIY info useful, please consider donating a small amount. All donations are used for future DIY synth and sampler development. Thanks! SUPER-JX ZONE

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