Archive for August, 2014

Boss OD-2 Turbo Overdrive

Friday, August 29th, 2014


What is it?
Boss OD-2 Turbo Overdrive from Boss Compact series. Made in japan, march 1986.

The OD-2 was apparent attempt to create a follower for the classic OD-1 which already had a vast user base with lots of hype going for it. In all its simplicity, the OD-1 was pretty much Boss’ venture to kill DOD OD250 and MXR Distortion. Ẃhile it may not be as widely recognized as its older competitors, it’s still a cult classic. And for a reason. The original Turbo Overdrive was manufactured from 1985 and it got replaced by OD-2r in 1994. OD-2r is supposedly the same effect as this one, only with added remote switch jack for the mode switch.

So creating a follower that would sell well and be as recognized as its predecessor wasn’t a simple task. And this is what the Roland/Boss engineers came up with. The board is pretty crowded and it has the feel of the old japan designs.


First thing that you’ll notice is that there are no opamps or any other types of integrated circuits in there. Once again, there is very comprehensive and good page dedicated for this circuit up at  The page has a schematic and a semiconductor listing available. There are three gain stages, each made up with two JFETs and one PNP BJT. Not completely unlike the “discreet opamps” we seen in some designs (the BD-2 blues driver to mind at first…) The gain pot is dual ganged and controls the gain factor for two of these gain stages. The first one acts more like a boost and the second has asymmetrical clipping diodes on it. While the driver stages are pretty complex, at least when compared to very old school like tone and level controls, the wow factor doesn’t end there. Just take a look at the power supply section in the schematic.


There are two different supply voltages which are balanced by transistors, one for buffers and one for discreet opamps. These two supply voltages have their own vref voltage networks, one for electronic switching reference voltages and other for discreet opamp reference voltage. So yeah. It is pretty complex design for being an overdrive.

Well then. How did they succeed in the mission of bringing a successor for the OD-1? Can’t say for sure about the sales, but OD-2 and OD-2r were on the market from 1985 to all the way to 1999. If it had flopped real hard, it wouldn’t have stayed on the catalogs for 14 years. If you mean soundwise?…

How does it sound?
It does have a nice vintage overall feel to its sound. Tone and level controls are well balanced and the gain works pretty well too. Nice driver tones, but with massive mid-honkin’ feel. I’d say this sounds a lot closer to SD-1 than OD-1, without being too close to either one. I’m thinking this may have acted as a base when the engineers were drawing up the BD-2.

Sure it sounds ok, but i just don’t see myself using one for anything. The reason being that i find the OD-1 and the SD-1 to simply sound better.  And there are always tons and tons of Tubescreamer derivatives which can take this sound on any time of the day.

Boss OC-2 Octave

Monday, August 25th, 2014


What is it?
Boss OC-2 Octave from compact series. Made in taiwan, april 2001.

Another classic from the Boss compact catalog. The OC-2s were originally housed in much lighter brown enclosure with the label “Octaver” on them. The name changed to “Octave” in 1984, meaning that the original ones were manufactured in japan from 1982 to 1984. These first issues are nowadays highly sought after and in one word, rare. And in another, expensive. The board on this unit is definitely a later revision. There’s not much left from the old school japanese design, and has been replaced with modern autorouted feel on overall board.


There’s a schematic with good semiconductor listings up at and you should check it out. This same page shows also the original board layout with original traces. There are one single  and one dual flip-flop IC on the original board design, but that has changed on later revisions. As we can see, the board of this 2001 unit has two CD4013 chips in the lower right corner of the board. There are other changes in the layout too, so the differences between a 1982 unit and this one are more than just minor.


The two octaves down are using two channels of the flip-flops and the one down is using one. So the leftover one on the modern board is unused. How do these changes affect the tone? Don’t have a clue as i haven’t had the pleasure of comparing the modern one with the original design. Features are quite simple. We have three knobs which control the levels of clean, buffered signal, one octave down and two octaves down. There are two opamp channels driving each down octave settings. These controls maxed will result in wild, not so good tracking of the down octaves. The analog feel is strongly present.

How does it sound?
The tones this one produces are very good. Where as most old school down octaves tend to feel low on down octave levels, this isn’t a problem for OC-2. The tracking on OC-2 is also very respectable. Although, once the octaves are maxed, the guitar signal still feels a bit weak to keep the octaves in tact, resulting in brain melting, uncontrollable mistracking. Paired with a compressor before OC-2 will help to keep the tracking in line. While we’re at it, a fuzz of distortion before this will also give out very nice results. I think the most well known instances of hearing OC-2 in action are the CKY albums from the 00’s.

To sum it up. This is the octave effect to have. Even though OC-2 was discontinued in 2003 and replaced by more modern OC-3, the cult reputation and usability of this all analog down octave monster is well warranted. Definitely one of the best Boss boxes around.

Boss ML-2 Metal Core

Friday, August 22nd, 2014


What is it?
Boss ML-2 Metal Core from compact series. Made in taiwan in january 2009.

Sure, i was interested in this due to its reputation. This is supposedly the meanest metal distortion there is and i’ve heard good things about it from people who i share a lot of opinions on sounds. So i grabbed one. I’ll get to the sound part later, but even though i agree on pedal tones with only few people.. This isn’t one of those where i agree. This unit took me by surprise. First question mark rose when i opened the bottom plate.


And the second one when i turned the board over. I would have never guessed by the demos and the praises i’ve heard that this would be a digital distortion. Constructed in the most boring way with all SMD and powered by what appears to be Roland branded DSP processor. The crystal clock is placed right beneath it. There are a couple of 1458 opamps in there too, but most of the design goes way over my head.


As for controls we have standard level and distortion knobs in addition to high and low controls. I’m not sure what the designer was after and why this design ended up this way. Maybe it was to recreate the designs that became classics by updating them with a digital counterpart? The EQ may be the best part of the circuit, but…

How does it sound?
I’m sad to turn to my prejudice on digital drive designs, but this time it is warranted. Even though the EQ controls try their hardest to mimic the gyrators of HM-2 and HM-3, the crushing and soaring this one tries to produce makes me feel uncomfortable. There is enough gain and while marketing suggests this to be answer to modern, next generation of metal players tonal needs, i can’t do anything else but disagree. Metal distortion, yes. Good sounding one? No. The sharpness and unnatural honk of all digital and/or modeling drives is present. No wonder guitar music is at its all time low.

Paired with a delay and used for those 80’s german detective tv series anthems – maybe (Although, you’ll get closer to that with Digitech RP-6). For anything else? Try HM-3 or MD-2.

Boss RV-3 Digital Reverb/Delay

Tuesday, August 19th, 2014


What is it?
Boss RV-3 Digital Reverb/Delay from compact series, made  in taiwan. Serial number on grey label points to june 1991. But since the units were apparently manufactured from 1994 to 2002 and the label was changed from pink to grey in early 1999, i think it’s safe to assume this follows similar error on serials as early taiwanese HH-2 Heavy Metals – being a decade off. This would mean that this unit is really manufactured in june 2001. Which makes a lot more sense.

RV-3 is a second generation of Boss digital reverb pedals. Sharing the color with the ground breaking RV-2, but housed in standard compact pedal sizes enclosure. As it’s predecessor, the full blown SMD design was expected. Where the RV-2 had two boards stacked the RV-3 has only one. It is as tightly packed on both sides though. The circuit footprint is way smaller and the features are doubled. Who doesn’t like to live in the future.


There’s a schematic up at FIS, if you’re interested. It shows pretty standard buffering and mixing with simple splitting for the stereo outputs. The digital part creating the reverb behind the mixing is pretty complex. Apparently the same digital setup can be programmed to do other things in addition to reverberation. The schem has “PS-3” printed on it, so my guess is that they have been using the same board for these two different effects. Maybe even more pedals share the same DSP architechture.


Board design is very modern looking. There are 11 reverb and delay modes with reasonable controls over the main parameters. Mix control for all modes. Time and feedback controls for the delays and reverb time with tone to control the high end damping of the reverbs.

How does it sound?
Very good with lots and lots of usable modes and the stereo output also adds to the usability. The digital signature that usually takes the edge off from so many designs is practically nonexistent. It’s not harsh sounding but a lot closer to natural. There’s even a feel of the expensive rack mount effects present. Wouldn’t call it “warm” or analog-like, but still pretty good. Most negativity comes from standard Boss facelessness. Not too personal and not the greatest pedal ever made – but still. Very very good. And this will see use as it’ll suit many situations of use, easily.

Colorless writings, part 14 – Overcoming the shortcomings

Sunday, August 17th, 2014

So what shortcomings are we talking about this time?

Shortcomings of a classic fuzz circuits. Sure i could rave on about hundreds and hundreds of boosters, overdrives and distortions that simply can’t overcome the unity level of your guitar. In my books that’s a shortcoming. But maybe i’ll reserve those for another part of my writings. Let’s just go with the fuzzes for now. To get to the bottom of this behavior, we must understand what the guitars were like 50 years ago. The term “vintage output” for pickups does have a meaning. DiMarzio was the first manufacturer to offer aftermarket pickups. Meaning that before 1972, swapping the pups for better ones wasn’t exactly an option (for the word better, we’d need to define what’s better, but you’ll get the idea). Swapping pickups on existing guitars and paying more attention to those became widely popular later in the eighties. Which means that all the classic effect pedals from 1966, all the way to beginning of 80’s were designed to work with old school standard pickups that were shipped with sold guitars. Usually having  low or lowish output pickups. Think about PAF style humbuckers for example. They have very nice tone, but the output is still low. I’ve noted before that once your pickups have high enough output, that can turn the effect to sound mushy, and simply put, bad. Other chance is that the output is too high for the circuit design to add any real current to the signal.

To me, it’s very annoying to notice that otherwise good sounding re-issue of Fuzz Face can’t boost the signal coming from my favorite humbuckers. Now, these humbuckers give out highish output and they sound reasonably good without being too harsh. When i play with clean sound for most of a song and want the upcoming lead to stand out, i simply can’t choose this Fuzz Face re-issue to be the pedal to do that. Not by itself, at least. I’ve seen this same behavior with many other effect designs from the past too.

Got it. So how to overcome this issue?

Breaking every single rule i ever had for my colorless writings, here’s a schematic for very generic silicon fuzz face. (Sure, these images have no color except for black and white, so i can let it slide)


You can find about a hundred similar schematics with internet image search. There is also very comprehensive article published by R. G. Keen. But i’m talking about simple silicon version with common negative ground power requirements. The 47R resistor from Q2 emitter is there to tame some of the hiss, oscillation and excess noise that high(ish) gain silicon transistors in this configuration can be prone to emit. The TR1 is a trimmer for tweaking the bias voltage for the transistors. I always tune bias by ear rather than using some known voltage. Every transistor is unique in their gain factor and the pickup signal is another factor for the correct bias,  so one exact voltage for all situations won’t cut it. Plus the controls on the classic pedal are, in one word, crap. 1k linear pot for fuzz control means that all the usable range is in the last three percent of the sweep. And i don’t want to go further to the volume control. To sum it, both controls have one usable location. That being maxed. Anyway. This is the circuit that sound very nice when played on single coils with vintage output. Circuit can do some boosting in this scenario. But since it simply cannot do that with modern pickups. If you have ever tried a clean booster after a FuzzFace in you effect chain, you know that will sort the problem. It isn’t very convenient solution though. To change from your base sound to soaring lead, you would need to jump on two stomp switches. So why not take a simple one transistor boost circuit and place that after the standard fuzz as an internal post boost? This way we’ll have most of the original tone and frequency response in tact, but we are addressing the low output.

Here’s my evolved Fuzz Face. Standard fuzz circuit with a bias trimmer and everything exactly as before. Minus the reverse logarithmic taper for the fuzz pot. The output has been dramatically improved.


There is nothing exactly new or special about it. If we look at some details, there are your modern standard 3PDT stomp for true bypass, including a 1M pulldown resistor at the input to address possible pop side effects caused by mechanical switching. One could, of course, use way higher value for that resistor to prevent it from loading the input. This switching method also grounds the circuit input when bypassed and there’s a 12k resistor for bright white LED too. DC connection is wired for standard battery (which i never use for my builds) switching, which takes the battery connection out once the input jack has been disconnected. Power supply section has a 47µ filter cap and a series polarity protection (taken care of by low voltage drop Schottky). The base topology for the fuzz is in tact with its 2µ2 input cap, bias trimmer and a swapped reverse logarithmic fuzz control pot. There are other ways to gain reasonable sweep for this control by creating a custom taper, but for this drawing we’ll settle for rev. log. Some might have noticed that the fuzz output cap value in both of my drawing is 100n. Many similar designs have a lot lower value in that position, which leads to more tighter, trebly and nasal overall tone, especially when the level control is maxed. Personally i like the feel of a fatter tone, so 47n or 100n for me. Now all up to this point will produce the same tone as the smaller, more generic example.

The rest of the circuit is not completely different from one classic one transistor booster marketed by one Electro-Harmonix. It is a simple one transistor amplifier with low parts count that colors tone tone only a little. The output of this amplifier is coming to a 100k trimpot which acts as a Master Level trim.

Why do you have the level control for the fuzz where it originally was? Why not use that Master Level as an level control?

Good question. And i have a simple answer. To keep the frequency responce of the fuzz as close to the original as possible. Since the boost amplifier colors the tone only a little, we don’t want its output to change the frequency response in the same manner as the fuzz’s level control does. Instead of this arrangement, we coud use a JFET or even an opamp to boost the ouptut, but former would be better off with a bias trimmer and the latter would need its own refence voltage network. To keep everything simple and neat, its not a bad practice to go with this solution. Ah. There would be so much more to talk about what’s going on with this circuit. But i’m going to leave you with the information above and two notes – Breadboard it. Fuzz face is a highly tweakable and good sounding tiny circuit. There is always room for more and more tweaking. You should try to make it better for yourself. And another; want one? Sure, i can build you one..

Boss PSM-5 Power Supply & Master Switch

Thursday, August 14th, 2014


What is it?
Boss PSM-5 Power Supplu & Master Switch. Made in japan, november 1982.

There has been a time place for everything. Daisy chaining, or dedicated power supplies were both practically unheard of until this new and exciting device hit the market. What surprises me more is that the pedal was actively sold from 1983 all the way until 1999. I thought the interest for the features offered would have been way gone by 1999. This unit has seen use and it has the orginal black label on its bottom. The label explains the main features as well.


The nice looking old school style board houses the boss standard flip-flop switching and an effect loop (’cause that’s what the pedal actually does). These were originally shipped with a power supply and a splitter cable for up to seven effects. Since my specimen is from the year 1982, you can take a guess if either of those have survived. Quick search produced a schematic, which confirms that the design for the loop is simply four buffers, controlled by electronic switching – an effect loop if you will. Schamatic also shows that the power supply is only splitted for the out going 9VDC.


One other thing noted in the schematic. The operational amplifiers should be NJM4558DD, or in other words the classic JRC4558D. Seeme like mine has been modded at some point in the pedal’s life. The ICs have been removed and replaced by sockets, which now have two LF353s, high grade audio chips in them. Rest of the semiconductors seen on the board are two BJTs for the flip-flop, another two BJTs for LED control and four JFETs to take care of the actual switching of the loop.


These older Boss boards are mostly a pleasure to look at. Acid trip traces but annoying lack of symmetry. Plus an acre of free land to grow your tomatoes.

How does it sound?
It works as an effects loop, so it should not have a sound of its own. And furthermore, it doesn’t. I do understand why someone wanted to swap the opamps for “better” ones, but as they are acting only as an unity amplifiers (or we could say buffers), i strongly feel the improvement in sound is next to nothing. This being there’s not much i can say about how it sounds. It is a relic, which makes it rather interesting.

I do believe this had lots and lots of user value back in eighties and in the beginning of 90s. Using one now? Not a chance. There are tiny hardwired true bypass loopers and extremely high quality standalone buffers in existence, so at least for me, the choice would be very simple and clear.

Boss TU-2 Chromatic Tuner

Tuesday, August 12th, 2014


What is it?
Boss TU-2 Chromatic Tuner from compact series. Made in taiwan, june 2004

The workhorse. I’ve heard stories that these nearly didn’t make it to production at all, since the designers were sure that there would be no market for a pedal tuner. Well. I do get it. After all, the Arion and DOD had flopped pretty hard with theirs. But the TU-2 made it to production and if i’m not completely wong, it sold very well. So well that Bossarea page calls it an instant hit.


There are different tuning modes as features, but i must confess that i’ve never used any of those. Not even to try them out. The standard chromatic mode that picks up the note you play has been sufficient. For years.

Pedal is made of two separate boards, a mix of digital and analog circuitry. Nothing too eye pleasing with autorouted, tasteless and scentless feel to overall construction.


But then again, who buys a hammer for its looks? Metaphor for a hammer isn’t as far as you would think. As you probably have seen, there are pink and tiny designer hammers in existence, but no one in their right mind would pick up one of those if they were to build a proper wooden wall. No. They would pickup that old, rusty heavy thing that is a real hammer.


Boss TU-2 is (or was) a hit for several reasons. User can see the display on the darkest stage without disturbance, the accuracy is good enough and.. Well. It simply gets the job done. TU-2 got discontinued due to TU-3, which has more features and, i believe, is aimed to take on TC Electronics tuners in the market, which consequently have even more features. Come what may, the TU-2 will stay and enjoy its cult status. Less features sometimes mean higher usability.

How does it sound?
As most of the Boss pedals tend to drain your signal when bypassed, the buffering on TU-2 is either better than on the rest, or i may be turning def. While this tuner doesn’t sound like anything per se, it acts a faithful buffer when it’s turned off. As a tuner, this unit is something that all other pedal tuner manufacturers should take a look at. It works.

Boss HM-3 Hyper Metal

Sunday, August 10th, 2014


What is it?
Boss HM-3 Hyper Metal from Boss Compact series. Made in taiwan, march 1993.

The younger brother of since discontinued HM-2. Similar controls and expectance for similar sounds was high to say at least. This time there is some symmetry on the board design and even those machine like autorouted traces do not bother me that much. Not exactly sure how accurate the schematic up at FIS is, but i’m thinking the base topology is correct. So we have a design that’s somewhat close to HM-2, with the triple gyrator EQ tha has two controls and three separate clipper stages.


As usual for many Boss boards, the opamps are SIP devices. The asymmetrical clipping amp with distortion control is made of one opamp channel and NPN/PNP transistor pair. Still quite similar to the HM-2. In build quality and and housing issues, this doesn’t stand out of Boss Compact crowd. Solid, but dull.


All of the features feel a lot like HM-2 Heavy Metal, but power supply requirements are updated to be more modern and well..

How does it sound?
Actually better than the praised older brother. To my ears the distortion is slightly thicker, fatter and lows feel even more crushing with its soaring highs. The overall tone manages to stay quite defined even thought the amount of distortion is impressive. If i was to use metal distortion on my board, this would most likely be it.

Boss HF-2 Hi-Band Flanger

Wednesday, August 6th, 2014


What is it?
Boss HF-2 HiBand Flanger from compact series. Made in japan, august 1988.

Japan made HF-2 is probably the most praised flanger, not only in Boss catalog, but otherwise too. While the “standard” Boss flanger may be and have been the BF-2 for decades, the HF-2 operates in slightly different manner. While most flangers mix the whole incoming signal with delayed duplicate (controlled by LFO to create the sweep), this Hi Band Flanger takes the incoming signal and splits it in two ways. Other stays as it is and the other is pushed to up octave which then has the flanging delay mixed into. Or so they say. That idea sure has some out of the box thinking in there.


The board is full and still looking rather pleasing. The old school board manufacturing methods always please the eye. The delay section of the flanger isn’t anything special. It ihas MN3102 for the clock and MN3204 512-stage Bucket Brigade Device for the delay. The schematic is available for download through the interwebs. Looking at schematic, i’m not exactly sure how that half of IC2 and Q2 are supposed to create the clean octave up, but it surely won’t act only as a buffer in front of the delay circuitry.


That being said, the HF-2 isn’t your standard flanger, but it isn’t anything too special either. Controls are very sufficient. Manual affects the Rate and Depth, while Resonanse controls how much delayed, or flanged signal is getting in the mix with original signal. The footprint is pretty common with most flangers and choruses.

How does it sound?
Don’t be expecting anything too wild. It is a very nice sounding flanger that goes from mild detuned vibrato to airplane hights. Overall tone is still rather tasteless and scentless, the same problem we’re facing with many Boss boxes. Sure it sounds good, but it doesn’t quite reach that acidy velcro flanger wildness the greatest flangers reach. It does offer slight variance to most usual flangers, which is a good thing. Controls offer good variance in terms of speed and depth. For me, the best use for this is to have it act as a vibrato. I do get whyt some folks prefer this over any other, but that isn’t me. Good but somewhat boring.

Boss CE-3 Chorus

Sunday, August 3rd, 2014


What is it?
Boss CE-3 Chorus, made in taiwan, august 1988.

Boss choruses are all praised, even though the CE-3 has less reputation if compared the obvious classics like CE-1 and CE-2. With less reputation comes a less numbers on the price tag on auction listings. This particular unit is one of the very first CE-3s to come out of taiwan plant. CE-3 is the first Boss chorus with stereo output and there are couple of interesting things on the pedal. Like the position of the three knobs. Bossarea has more information listed.


Board design is pretty with old school traces, but disturbing asymmetry on the layout. There is a schematic up on Synthdiy. Design is pretty common with two 4558s to drive the signal after the FET buffer and after the BBD modulation stage. The modulation stage is based on MN3207, a 1024 stage analog bucket brigade device. That chip is controlled by a MN3102 clock. Rate and depth are controlled by LFO, constructed with one TL022.


Stereo operation can be used to push zero and reverse phases to their own outputs, like many modern stereo choruses.

In general, everything about this unit is great. Vintage feel to the design, construction and it even offers some eye candy being as ugly as it is. And the most important part is yet to come..

How does it sound?
Soft and natural chorus. May not be as mellow and 70’s sounding than CE-1 and CE-2, but there isn’t that cold harsh detune around that, at least in my opinion, kills the usability of countless chorus designs. Depth control is sufficient, but i was surprised how slow the Rate is, even when maxed. This is a feature that makes the unit have a soul of its own.

Definitely one of the best sounding vibe-like chorus pedals in the price range.