Hughes & Kettner Warp Factor

September 16th, 2014


What is it?
Hughes & Kettner Warp Factor from early 00’s.

The unit here has seen a lot of use before landing in to my collection. There are good reasons for pros and cons and both are weighting more than with usual pedals we see. Since the positive notions are all mostly on the sound, i think it’s best too look at everything else first. Opening the bottom plate shows a massively sized modern board with lots of joints.


Flipping the board over. Everything is board mounted and number of through hole components is high. Not a bad looking board design, but as i am a huge fan of symmetry, it doesn’t mean that much. Note the four 2200µF filtering capacitors. That’s what we’ll need when the design calls for 12V AC power supply. The supply is rectified to DC on board, which does explain a part of the board and enclosure size. The schematic can be found on the web (try, but since it isn’t behind simple image search, i’m not posting it for now.


Design is rather huge, and the power supply section spews out +15V and -15V, with reference voltages per each polarity. We could say the unit runs at 30V. So this time there is a fairly good reason for running the effect with 12V AC supply. Circuit design and supply together, however, make the pedal big. And to have a need for 12V AC supply may also be a hassle. But then again, the 30V swing offers headroom that we won’t reach with with 9V DC supply.

As for features, we have electronic bypass switching, level and gain controls, plus a deep tone control called warp. The sub switch boosts lows and low mids to a degree which is rather impressive.

Now, if the size was a bit smaller and this accepted more usual power supply…

How does it sound?
F*n awesome. From Marshall 2203 JCM800-styled massive rock overdrive/distortion to sheer metal madness, this unit sounds great on any volume level. From bedroom practice amp level to loud rehearsals and gigs. I’ve been a fool for many metal distortions before, but  none of them has ever left a impact of this size. Usually the drive/gain setting for metal distortions works in maximum setting or in some cases at minimum as well. For this one, the control range is simply usable all the way of the sweep. Added low frequencies from the sub switch make Boss HM-2’s crushing lows feel like a mosquito passing by. While the usability may be limited, we still have a colorful range from rock overdrive to rock distortion to metal distortion to massive metal sounds. Very impressive pedal.

EHX Holy Stain

September 13th, 2014


What is it?
Electro Harmonix Holy Stain from XO series.Made in united states in 2010(ish).

Once again. Put a pedal, any pedal, for sale with a broken switch and a price tag around 20% of a new unit. You bet i’ll be there, bombing your email and throwing the little money i have against the computer screen. This was one of those. Simply swapped the defected 3PDT bypass switch and did a little cleaning. Unit works as it should. Or at least close to it.

Checking out the insides shows a DSP based big board. All done in current, dull EHX manner. I’m guessing the drive/fuzz/distortion is done with transistors and the rest is digital. It’s sort of like a modern hybrid.


Let’s talk about the features a bit. To begin with, the Holy Stain looks like a cross breed between a Muff and a Holy Grail Reverb, with a few added extras. The main stomp switch is our bypass that sets the overall effect on and off. The basic side is controlled by two rotary switches, a tone control and a volume control. The first rotary selects between clean, fuzz or drive modes. The second selects overall tone color between bright, dark and warm. Tone control acts pretty much like the one on big muff pedals and volume is rather self-explanatory. All that is used to set the base tone.

Then we have the rest. Foot switch selects the digital effect mode between room reverb, hall reverb, a pitch shifter and a tremolo. These four modes share the two controls for all of them, the mix and amount. Mix sets the blend of this extra effect against the clean/fuzz/drive tone coming from the first part. The amount acts as a decay time setting for both reverbs. It also sets the frequency of the pitch shifter mode and the rate of the tremolo. Amount can be rocked with a external expression pedal, which makes the tremolo mode a lot more interesting and the pitch shifter to have similar features to a Whammy.

Limited, but still quite a set of features. These usually come pretty cheap, even as new. But if you think about the features and compare them to what you actually use – or want to use. For me, i would probably gone for separate drive and effects sections with a stomp to engage/disengage the effects other than the drive side. Sure there is notable amount of outside the box thinking when the designer has set the features, but…

How does it sound?
I’ll start with the good and go on about the bad a bit later. The Fuzz mode is actually good with its crisp lead sounds. On fuzz mode, the color settings are usable too, even though i tend to leave it on warm. Both reverbs are ok too, with a slight note explained further…

Off to the bad. First off, to me (yup, may be heresy, but i’m talking about my taste) the clean and drive modes are just bad. First thing that comes to mind is the horrible distortion section found in Digitech RP6 multi-effect. Color and tone controls won’t save those, no matter what. Other reason why the RP6 pops up to mind is the latency. All the digital effect modes are fine if you have your mix control below 35% mark. Higher than that, the guitar signal has already gone out of the speakers before the verbs/shifter/tremolo even think about touching the signal. Similar digital lag as heard on RP6.

One very good mode with almost usable multi-effect section – if you keep the mix down enough for it to work right. Otherwise… no.

Colorless writings, part 15 – Fuzz vs. Overdrive vs. Distrtion

September 13th, 2014

I found myself in very weird situation. Today, i simply had nothing to say. But i can’t pass on a colorless writing, as that would mess up my OCD. I did start on one more demanding subject, but i realised i won’t be able to finish it without messing up my schedule. So i just needed to drop that topic (it’ll be featured as part 16)  and write something else instead. I needed a subject that would be easier to cover. So why not bring up this age old question about how to categorise the effects that produce distorted tones.

Fuzz versus Overdrive versus Distortion?

Exactly. How do we tell which one is which? How can we be certain that a Tubescreamer is in fact a overdrive effect rather than a distortion? We can’t. It’s more likely all in the marketing speak than in real world electronic designs. Let’s start with the early days of distorted tone. Legend has it that certain guitarist for a group called The Kinks used a razor blade to slash a cheap combo amp’s speaker cone to get that distorted sound for one 60’s hit recording. Later in the sixties we were blessed with a ton of fuzz effects that were designed to mimic that broken speaker cone. The most basic fuzz design was (and still is) called a shunt-series feedback amplifier. The circuit was well known before any fuzz pedal was  ever produced. The fact that a guitar’s output is enough to push this circuit to sweet distortion wasn’t exactly mentioned on the text book the circuit was originally from. But there you have it. A very first electronic guitar effect that gives out a distorted tone.

In early seventies other types of pedals started to emerge. Some were called boosters and some were called distortion boosters, but they were still mostly boxes with fuzz sounds coming out of them. Later in the seventies, the dawn for Tubescreamer, DOD OD250, MXR Distortion+, Boss OD-1, DS-1 and ProCo Rat widened the spectrum of distorted tones available. That may not be complete list of units that suit the bill, but it’ll get us going. It must have been in those days when the split happened.

Let’s look at the OD250 and Dist+ first. These two pedals share the circuit topology with each other. Main difference is the type of hard clipping diodes after the gain stage. OD250 uses Si diodes with lower voltage drop and more volume, while Dist+ has Ge diodes with higher voltage drop and less volume. This means that the sound of these is very close to each other. Nevertheless, the former was (and still is) marketed as Overdrive/Preamp and the latter as a Distortion. You guys must now be getting my point?

Boss DS-1 works in same principles as the two, but it has more driving stages. ProCo Rat has similarities too, although its gain control isn’t even close. I’d like to point out that some Rat versions had a text “fuzztones for connoisseur” printed on their circuit boards. So is the classic Rat a Distortion or a Fuzz?

The debate may still be going on which one was the first to take clipping diodes to the feedback loop of non-inverting amplifier and creating softer clipping. Usual answers to this 40 year old debate would be TS808 and OD-1. I have no idea which was the first, so i’m not going to waste my time in speculating about that. There are hundreds and hundreds forum posts about this subject to be found on the interwebs. In case you are interested. These pedals with soft clipping are usually referred as overdrives. Although, there are numerous distortion designs out there with similar clipping diode arrangement.

To sum it up?

A fuzz. This should the easiest one to point out. No clipping diodes and no opamps. Just a bunch of transistors driving the hell out of each other in order to create clipped or distorted signal. But is it that simple? As usual, no. Take a EHX Big Muff Pi for example. This design (and its hundreds of derivatives) is often referred to as a fuzz. Another nice examples would be Anderton’s tube Sound Fuzz and Colorsound Tonebender reissue from the 90’s. I’d call all of those distortions or overdrives rather than fuzzes.

Going forward with the Distortion. This one may be simpler. Hard clipping diodes. But even here, this may not always be the case. There are pedals like ZVex Distortron that is usually considered a distortion, but to my ears it sounds (without going any further on its electronics) a way more like an overdrive. As the earlier example with OD250/Dist+ shows, the design with hard clipping could also be called just about anything.

Overdrive? Now this leaves us with soft clipping and thus, these should be easier to identify. But no. If we take a look at good ol’ Way Huge Red Llama overdrive, we’ll see it’s way closer to Anderton’s Tube  Sound Fuzz than any other OD we’ve seen. There are a number of JFET-based overdrives too. These may not have clipping diodes in them at all, but they will still offer full soft clipping sounds.

Is that what you call a sum of the subject?

Well. Maybe not. But it does show us one thing. There isn’t one clear, or even fuzzy logic to when we call a  circuit a fuzz, overdrive or a distortion. It’s all in the head of designer at first – then in the heads of the people at the marketing department and after that – in our heads.

Sure it would be easy for me to think that these pedals are fuzzes, these  pedals are overdrives and these pedals are distortions. But that won’t do. We can’t define something that’s completely undefinable. And since there is not a way to define which is which, we all may face the situation where our newly bought a) fuzz sounds like a distortion, b) fuzz sounds like an overdrive, c) overdrive sounds like a fuzz, d) overdrive sounds like a distortion, e) distortion sounds like a fuzz, or f) distortion sounds like an overdrive.

I’m going to leave you with one summing thought – there is no way to define or categorise which is which, from electronic point of view. It’s all in the marketing and in our heads.

This does easily apply to all the other pedal genres as well.

Systech Phase Shifter

September 10th, 2014


What is it?
Systech Phase Shifter. Made in USA in mid-70’s. Pot date codes considered, the unit has most likely been built in 1974.

I’ve got this unit more than a year ago and after initial testing it just sort of was forgotten to a spot on my museum shelf (for the units manufactured before 1980). As the testing didn’t raise much more but eyebrows, this didn’t get much more attention. But about a month or two ago a friend from nearly across the globe acquired one after decades of not having one (yeah, Pink! I’m talking about you!). His memory was that the unit was really good sounding and extremely deep phaser, almost pushing the limits of a phase shifter.


Sadly. He wasn’t correct about the pedal. Or he was. But not about this pedal per se. It did come as a surprise to me too. These phasers have apparently three different revisions of the Systech Phase Shifter. According to the dedicated forums, the first unit was in similar silver/yellow/black housing like this one, and the circuit design in those were pretty standard 4-stage phaser. According to same sources, this board revision is the middle one. Similar enclosure, but eight phasing stages. Not completely different to MXR Phase 100. The third one is the winner. This is the one with silver/red/black colored enclosure and optical design instead of JFET phase stages.

All three versions have a ramp feature for the LFO speed, which is very nice feature. There’s also an independent rate control for both foot switchable rate settings. Ramp works very well and has very nice gradual speed up and down.

How does it sound?
Sadly. Quite dull. This would stay behind just about any phaser if it wasn’t for the ramp. There is some notable personality to its overall phase, but still it is dull. Well working controls and there’s still some usability in there. Like most Systech pedals, this is a classic and highly collectible. Nice thing to have, but will this see much use? I doubt it.

Danelectro CTO-1 Transparent Overdrive

September 8th, 2014


What is it?
Danelectro CTO-1 Transparent overdrive from Cool Cat series. Made in china, late 00’s.

It seems that CO-1 and CTO-1 from the series are becoming rare. There was a time one could snatch one of either one for peanuts through auction sites. I believe these two were manufactured in very limited numbers and follwed by their successors, CO-2 and CTO-2 respectively. Quick replacements may have been due to the ciruits being really close, if not exact clones of other manufacturers designs. So without further due, let’s check out Danelectro’s Timmy.

Once the box is opened, the standard Dano universal jack and switch board stare at you. Nothing special there.


Judging by the size of the circuit on the board, i see nothing special in why modern chinese rip offers can squeeze similar circuit in miniature box. One dual opamp, four clipping diodes and a few other parts. Mostly SMD, but as with many CC series boxes, there are a few metallized polyester caps in the mix. If you are interested in a schematic, i suggest you do an image search for Paul Cochrane Timmy and omit the switch for the second diode pair.


I got mine through an auction site with reasonable price as it was defected. Missing knobs and DC jack was torn off the board. Quick fix for the DC was just to resolder the jack. I tried to source original knobs through my country’s importer, but the answer was no. Apparently Dano isn’t in the business of selling spare parts for any of their pedals. With little a ingenuity i tweaked couple of the knobs i had to get the controls to look relatively close to the original ones.

Onc e again, the biggest downside to this effect is the concentric pot for Bass/Treble. It’s not like you need to tweak those controls all the time, but turning one usually tends to turn the other at the same time.

How does it sound?
Like Timmy. Usable and neat sounding overdrive. Shines on lower gain settings when used to push an amp. Treble and Bass controls have usable range, although the minumum settings are not that usable. There is some clear mid hump present, but it keeps the guitar’s tone pretty well in tact. Nice thing to have.

Carlsbro Minifex Flanger

September 6th, 2014


What is it?
Carlsbro Minifex Flanger. Possibly made in asia around late 80’s.

Carlsbro effects have been around for a long time. Carlsbro as a company is better known for amplifiers, but their pedal ventures started all the way back in beginning of the 70’s. First units Carlsbro was selling were OEM’d Sola Sound designs. Later there were the “Alu” series of massive enclosures and following those, the Minifex series.

There is very little information available on these units. I’d be interested to know who designed these, who manufactured these for Carlsbro and even more importantly, when. Designs of the two stacked boards seem like japanese origin (just a hunch), but the board manufacturing methods look a lot like early pedal boom at chinese factories. It could be manufactured in japan or korea too, but for some reason i find that hard to believe.


Notable things designwise are definitely a SAD512 BBD and a “roll-your-own” style optoisolator. My guess would be that the CD4007 is acting as a flip-flip for the bypass switching, but design doesn’t look too familiar.


Pots are shaftless type and the knobs are simply pushed inside them. Every IC is socketed and there are tons of things that i find, for some not so obvious reason, fascinating. Sure there are some caveats. All plastic box with super cheap feel to it, plus it only runs on a battery.


Traces look like they have been produced with cheapest methods available. This isn’t too big of a problem, but it keeps the unit from getting my complete attention. Solder joints are looking neater than what one would expect.


Pedal has reasonable build quality for the price range. One of these plastic peculiarities that may have been sunken to the void for a reason. I personally like it, even though it is what it is. It would be very interesting to get my hands on other boxes from this series…

How does it sound?
Pretty standard with nothing too special . Still pretty slush with some personal character to it. For the plastic feel of the box, the sound is surprisingly good. For those massive airplane flanges, look elsewhere. This has the vintage slush that many players want from their flangers. It is definitely not the worst flnger around. If these were growing in trees, i would probably rehouse one with true bypass and modern power jack to get the sound with me. With battery operated plastic box? No. I’m not taking this anywhere from home. The sound is still better than with most current production analog flangers.

Danelectro CM-1 Metal

September 6th, 2014


What is it?
Danelectro CM-1 Metal from Danelectro Cool Cat series. Made in china late 00’s.

Another metal distortion. While Dano’s Cool Cat series has pleasing and personal enclosure, most designs seem to be simple rip offs with very little original in them designwise. Currently i’m not sure what this particular unit based on, but everything about it is pretty much on par with all the other units in the series.


We’ll find three separate boards inside. One universal for 3PDT stomps switch, one for in/out/dc jacks. These boards are, like i said, universal and the same ones are used throughout the series. The bottom board is the effect. Construction is mostly SMD with couple of the caps being metalized polyester. Three oapms are running the show.


I’m pretty sure this is a slightly modified derivative of some other pedal. Just can’t point my finger to any directions right now. While it may look pleasing, the control knobs are horrible. Sure they are meant to be “set and forget”, but that set once part is killing me. Dual pots with stacked concentric knobs are not a bad thing if executed like in many boss pedals. Here, the turning of the either level usually results in both setting being shifted. Annoying.

I’d be rather interested to find out what this is based on. If you have any solid information, drop a line in the comments. I may study the connections at one point. If i happen to get interested enough.  To sum it – Standard metal distortion. Not bad, but not too great either.

How does it sound?
Like so may other motal distortions. EQ section is powerful and gain plus level setting are sufficient. The overall tone reminds me a bit of Boss HM-2, but here we have separate mid control. I do find this usable metal distortion, but it’ll always stay behind HM-2 and HM-3. I’d say this goes to the same category with DOD American Metal and Death Metal. Again, not bad, but not too great either.

Ibanez BB9 Bottom Booster

September 3rd, 2014


What is it?
Ibanez BB9 Bottom Booster, from modern 9-series. Made in china around 2010 or so.

There are only a few Ibanez designs that are more like meh. This is definitely not one of those. I had interest for this for some time, before i spotted one for reasonable price tag on one auction site. This particular unit was apparently a demo unit for some store. Very little wear and nice near mint condition with original  box and papers. Played with this for quite some time once i received it. There is a beautiful traced schematic up at Dirk’s page, so there were no rush in seeing how it is made. Reason for opening it wasn’t as usual as for most pedals.

That reason being a small mishap on the studio floor. I had just recorded all base guitars for 11 tracks of 12 for the album we were doing. I thought i needed to add a bit of reverb for the other effect line. I took my previously repaired Boss RV-2 out of the bag and chained it with all the other pedal in that chain. This resulted in nothing more but a hiss. Something went terribly wrong and my BB9 was dead. I figured it had to be some sort of power surge, but since i (obviously) didn’t have suitable tools or spare parts with me, i had to make due with other solutions for the second effect line on the last track.


Once the unit was back at my desk, the fault was easy to track down. No power. This is where Dirk’s schematic came in really handy. Don’t know how that surge occurred, but it burned the DC-DC converter (a.k.a. charge pump) chip. As you can see in the (crappy) photo below, the chip on top left is socketed. I almost never use sockets for anything, but since the charge pump on this one *can* die, i figured it’s best to have it socketed. After swapping the chip and polarity protection diode as a precaution, the box rocks again.


To get going on this post, the design of the BB9 is solid Maxon quality with modern board design and manufacturing method. If you checked the schematic linked above, you’ll see a power supply section that creates a bipolar +9/-9 volt swing with LT1044 DC-DC converter. This means that the pedal runs actually on 18 volts, using ground’s zero volts as a reference voltage.  For me and my fix, i only had ICL7660S chips at hand, but these are pin-to-pin equivalent and they can be used as a drop-in replacement for each other.

On the topology, is one half of JRC4558 acting as input buffer. Then we have dual gang potentiometer setting the level of signal passed to gain recovery and the actual gain of the clipping amp that is paired with a static gyrator that sets the boosted frequencies. After these we have active tone control to have nice control over the treble content. This leads to level control and output. Not too conventional way to create overdriven boost.


What comes to box design, it surely ain’t as aesthetic as the 30 year older 9-serie units. It isn’t ugly though. Sort of reminds me a bit of build methods we can find in Marshall small metal series pedals. Pedal follows the original series on the enclosure and carbon film resistors, but not much else. Here we have four separate boards to ease the manual labor. Neat and beautiful on the outside, but pretty dull on the inside – except for the circuit design.

How does it sound?
So good that no words are enough to match it. BB9 offers mild overdrive tones with really, really good sounding frequency response. It is not a distortion nor a classic overdrive in sense of tubescreamers or others, but something that brings your tube amp alive in a manner that can only be matched by few others. Also, it’s not a clean booster. It is a pedal that will give out better, no matter how subjective that term is, overall tone. Little bit of grit and boost combined. Even the voltage swing has a strong emotion-like feeling of great amount of available headroom. This is definitely one of the greatest sounding Ibanez branded boxes. Ever.

Boss PH-3 Phase Shifter

September 1st, 2014

One more Boss before moving on…


What is it?
Boss PH-3 Phase Shifter from compact series. Made in taiwan, april 2008.

PH-3 marks a very first digital phaser in the Boss catalog. All the previous ones, released before the year 2000, were more like all standard phasers from any other manufacturer – BBD based analog phasers. PH-3 introduced couple of quite innovative modes to the world. Basic modes are digital recreations of four, eight, ten and twelve staged phasing. Modes that were next to groundbreaking at the time of release are rise, fall and step modes. Rise and fall modes are also known as barber pole modes. Step mode sort of randomizes the sweep, resulting in unexpected phasing sweeps.

See. The new ideas on this one were so exciting that i simply skipped my normal pattern and ran straight to the features. Getting back to basics.. Board bottom looks like something that i haven’t seen in the compact series before. All  components are on the other side and the second side traces and vias look modern, but still quite new to me.


And once we flip the board over, we’ll have Roland branded digital signal processor. There’s a schematic floating around at Photobucket. To sum the design, there are analog buffers at the input and output. Connected to the mixing amplifier is the AD/DA converter chip. Which is then connected to a DSP and a CPU running at 4.233MHz. In  retrospect, a slightly faster processing speeds than what we’ll find in Super NES. Sure, i’m psyched about the geekiness of the fact. Way more than by the design itself.


Can’t help myself. These computer-like pedals can offer some reasonable tones and sometimes even something completely new. Still i’m left cold and somewhat bored by the designs. It may be just current me talking, but analog designs are the ones where the real magic happens. I see little value for a VST plugin in a stompbox. This stance may change someday. But i’m fairly certain that day won’t be any of the 365 days of 2014 or 2015.

How does it sound?
Like most well designed/programmed pedals of the modern, digital world. These things get the job done without degrading the guitar’s sound too much. Actually, little enough to go unnoticed. The modes are new and exciting addition to the pedal sounds people crave. Even though it sounds good and the old school modeling modes also sound good, there is something missing. It just doesn’t feel like a guitar effect.It feels a lot more like a generic studio tool. Exactly like a VST plugin in a stompbox. Nice thing to play around with. But. Pre 2000 Boss effects are more my cup of tea.

Boss OD-2 Turbo Overdrive

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.