Dunlop/MXR M-101 Phase 90

October 30th, 2014

DunlopMXR-Phase90

What is it?
Dunlop/MXR M-101 Phase 90. Guessing on the serial number, this unit may have been manufactured around 2003 or 2004.

The classic, original MXR Phase 90 is a fine specimen in vast number vintage effects that have earned their milestone status in guitar effects. So it is a classic for good reason. However, the greatness ended when original MXR went bankrupt in mid 80’s. Later, Dunlop Manufacturing bought the rights for MXR brand and sunk their hands into the catalog of great designs. I’ve heard stories where one well known guitar brand from the western world was producing lower quality instruments than their daughter brand, which manufactured guitars in asia. So these cheaper sticks were simply way better than the ones the mother company was able to produce. So what do you think was the mother company’s solution? Order the daughter company to lower their quality, so they could keep selling their product, which had a brand of higher value. This resulted in tarnishing of daughter brand’s reputation. Now you might ask how does this have anything in common with this pedal? I’ll tell you. In one way. These Dunlop/MXRs have very little to do with original MXR pedals.

I know a number of people who have made a decision to never touch another MXR pedal after they have tried Phase 90. The board inside these current production is not the same board we find in pre-Dunlop era MXR Phase 90. I’ll get to the sound of this box a bit lateer, but here’s a photo of the board. Modern, with amount of layered ground fill that will blow your mind.

DunlopMXR-Phase90-guts1

Basic design doesn’t differ all that much between pre- and post-Dunlop era boxes. But it differs enough to transform the sound to something completely different. No. It’s not the ground fill i mentioned. It’s not the use of modern through hole components like metal film resistors and multilayer ceramic capacitors. It’s the circuit topology. The four JFET based phasing stages are intact. Excellent design in vintage units have a nice, smooth, lush phase to them. Someone at Dunlop thought that the classic could be better if there was a path to feed the already phased signal back to the beginning of the phase stages. Sure. This will make the phasing effect more drastic. Maybe even deeper. In this case it does kill the original beauty of the design. Completely.

DunlopMXR-Phase90-guts2

As you can see in the photo above, there’s a resistor missing right above the output jack. That’s the “feedback resistor” that makes the modern Phase 90 what it is. That resistor is easy enough to remove, but how would you feel about buying a mid price range pedal and having to mod it to get it even remotely useful? For me, i can say with absolute certainty that i’m not going to buy current production Dunlop/MXR Phase 90 as a new unit. Never. In reality, they are selling you an image and feel of this good old effect, but the insides are not up to that image. I’m not going into the fact that Dunlop also sells “Script” versions of these circuits. For a premium price. Of course.

Oh. A fun fact. Danelectro Pepperoni Phaser is 1:1 circuit copy of this badly modernized phaser.

How does it sound?
Before removing the R22 resistor – horrible. Mids get boosted due to this internal feedback and the circuit isn’t designed to handle this boost. And while it simply can’t take, we get very ugly distorted overall tone that can’t handle even the low output vintage styled single coil pickups. This is where everything goes wrong. Kid in your neighborhood has read in guitar magazines that his/her guitarist idol used MXR Phase 90 on the record he/she loves. Next thing you know, this kid needs to get a Phase 90. And when it sounds nothing like the one used on that album, what do you think this kid’s reaction will be? Maybe he/she just hates MXR for his/her misfortune. After all, that’s what it says on top of the box. MXR.

But if (and when) we snip the R22 out of the circuit, we get rather close to the unspoiled tone of the original Phase 90. The distorted mids are gone and mellow swirl takes over once again.

Conclusion – as stock? Horrible and not worth the 30-50 money units these sometimes go for as used. As modded? Way better. Still not exactly great, but good.

EHX Octave Multiplexer (RI)

October 26th, 2014

EHX-OctaMultRI

What is it?
Electro-Harmonix Octave Multiplexer Reissue. Made in USA around 00’s.

For starters, EHX Octave Multiplexer was originally an apparent move to compete with all the other octave divider boxes that started to emerge in late 70’s and early 80’s. I have no idea when the very first down octave effect was produced and by who. Still, the basic idea of driving a flip-flop circuit over the top produces the analog octave down effect we know and love today. Sure, the technological advances have bumped us to the point where small footprint pedals can produce polyphonic octave down effects. But there’s still nothing like trying to get these flip-flop based octave dividers to track your signal properly. As a caveat, this type of circuitry can easily miss the note you wanted to add the effect to. When that happens, the tone produced is just wild and completely senseless. This behavior is something that can’t be digitally modeled. And it is a feature, love it or not. So is a modern polyphonic down octave better than its analog counterpart with its own flaws? I’d say no. Musicians have created a tons of great sounding guitar tones for tons of great albums with effects like these. To love the mistracking means that you have to be a person with adventurous mind.

EHX-OctaMultRI-guts1

The unit we’re looking at here is the 00’s reissue of the original 80’s Octave Multiplexer. The circuit has similarities to its predecessor, but there are modernized parts to it. The sub switch is not present on the original and this is the biggest difference between a reissue and the vintage unit. This switch takes the low octave in and out of the processed signal. If taken out, the “High Filter” control lets one use this as a up octave. Sort of.

EHX-OctaMultRI-guts2

The low octaves are created with a 4013 16-pin flip flop circuit. As seen in most of the effects in this genre. EHX couldn’t have done a better or worse job with their circuit, since it’s all about the 4013. The tracking aspect can vary with the rest of the circuit and in my opinion EHX does this remarkably well. Actually the Octave Multiplexer ranks at least as high as Boss OC-2 in my personal favorites list. The way this flip-flop works is that the signal pushed through it has to be huge. But if it’s too big, the tracking won’t work right. And if the signal is too weak, the octave divider doesn’t work. One can, of course push a massive fuzz through the flip-flop like done in MXR Bluebox, but to create all analog, distortionless, well tracking octave down effect isn’t as trivial as one might think. Some people prefer to use a compressor in front of this kind of effects to help the tracking. It works to a degree.

EHX-OctaMultRI-guts3

Board design and manufacturing methods look exactly like all the other reissues in EHX catalog. Not a pleasure to look at, but not ugly by any means. Massive sized box will definitely keep a few future fans away. But for that, there is XO-series version with otherwise the same electronic circuit. Just made with baked-in SMD components instead of the real deal.

How does it sound?
Wild and mean with a decent tracking. I think the size and the of the box may have been contributing factor to why Boss OC-2 has always been considered as a classic and EHX Multiplexer hasn’t. To my ears the Octave Multiplexer sounds at least as good, but with added craziness in the form up octaves as well. It sure is a beautiful sounding octave down. Every time i need an octave down when recording it’s either this or the XO version i take with me. Unless it’s a dirty down octave that is needed. Then the choice is DOD Buzz Box. Not much sense in trying to feed clean down octaves with wild distortions. So. For clean down octaves. EHX Octave Multiplexer is the king.

Tone Freak Effects Abunai

October 25th, 2014

TFE-Abunai

What is it?
Tone Freak Effects Abunai. Made in USA,2008.

More like a boutique brand, the Tone Freak Effects apparently gained some recognition in the latter half of the 00’s. However, the little respect from the diy community turned into a frown pretty quickly. For those who do not see it, i can point out already – it is obvious why. For this particular unit, i got it in a trade as a defunct pedal. The interest for the brand and designs marketed on it did not exactly warrant the purchase of a new unit which is considered higher shelf boutique thing and is priced accordingly.

As always with broken pedals i get, the first thing was to debug the issue and find a cure for it. Opening this one up revealed somewhat ugly PCB design and all handcrafted board. Board design does not look very appealing and the plastic plate, in credit card thickness, says it all. Abunai 808.

TFE-Abunai-guts1

Found the issue pretty quickly. A burned out polarity protection diode. Swapped that and the pedal was rocking again. You got your socketed opamp and switchable clipping configurations. Otherwise, the topology is pretty much a Tubescreamer. Now, those who didn’t understand why the brand’s profile isn’t as high as it could be. This is the reason.

TFE-Abunai-guts2

Do we really need a new, slightly modified Tubescreamer derivative every month? Do these really sell well enough to warrant their existence? No matter what way you look at it, it is still nothing more but a slightly modified Tubescreamer. These modifications may, and usually will, make the unit sound better than the TS9 reissue you can buy from just about anywhere. This unit incorporates the modifications that are quite usual, clipping options, more bass and more gain. Main reason that  makes this dull is that you can go out and get yourself a TS7 for less than 1/4 price and get the same “TS on steroids” sound. It wasn’t just this model on the Tone Freak Effects catalog that made the brand look far from great. It seems that most of the brand’s designs are slightly modified versions of known designs. If the board design looked even a bit more interesting, the hand made part would appeal a lot more to me.

How does it sound?
Like all the other “TS on steroids” boxes out there. Definite TS sound, including tamed mid honk, but with clipping options on a switch, added bass and gain content. Boxes with same tonal results are out there in numbers, so what makes the Abunai stand out? Nothing. Soundwise, this is just another souped up Tubescreamer. In fact i find the TS7’s Hot mode  to sound pretty close, if not better.

Danelectro CTO-2 Transparent Overdrive V2

October 22nd, 2014

CTO2-TranspOD

What is it?
Danelectro CTO-2 Transparent Overdrive V2 from Danelectro Cool Cat series. Made in china around late 00’s to early 10’s.

This unit was the very first of Cool Cat series pedal i ever bought. Got it as used unit from one great local guitarist who had just tried it  out. The price was right so i grabbed it. For the pedals in this series it’s usual to see number of upgrades in V2 or just later versions of the pedals. For this particular unit, there are added DIP switch under the battery door. This switch lets you to change the clipping options added to the second version.

CTO2-TranspOD-guts1

Construction, board quality and design decisions are very close to all the other units in the series. The special usage of two sides, that’s not something i’ve seen too often. The board is otherwise SMD, but there is one transistor and a couple of capacitors on the other side of the board. Apparently the board is designed in a manner that it can handle these components in either through hole, or surface mount components. Idea or reasoning behind this method is unknown to me.

CTO2-TranspOD-guts2

While i can’t be sure at the moment, the design seems like slightly modified version of CTO-1, the renowned Danelectro Timmy. With added clipping options of course. These options seem to switch between four LEDs (red and blue) and four MOSFETs. The switching can also take them all of, which leaves us with opamp clipping only. And tons of output level. I must point out that while i may seem like a fan of Danelectro boxes, their board designs have not made me feel at home since  late 90’s. There is something in the looks that make it look forced somehow.

CTO2-TranspOD-guts3

Otherwise the controls are quite standard. You got your volume control, bass/treble EQ section and your gain control. Once again, the treble/bass controls as a concentric pot isn’t the best of ideas (as the knobs tend to touch each other when turning). Sufficient controls and sufficient levels of volume and gain. All this in small, thick aluminium box and armed with 3PDT true bypass. And for the price? How could this go wrong?

How does it sound?
This time it doesn’t. Very nice sounding Timmy-derivative with good controls and a sound that is very much usable. The tweakable clipping take the sound from all out booster via compressed to open distortion. Nice sounding overdrive. And for this price range, i suggest you try it out. You won’t lose much is you decide you don’t like it.

DigiPlay CH-70 Chorus

October 19th, 2014

DigiPlay-CH70-Chorus

What is it?
Digiplay CH-70 Stereo Chorus. Made in japan in early 80’s.

Saw this unit up for sale with a price tag of small pack of peanuts. What was i to do, but to get it. The switch was acting up, but simply cleaning it up with suitable chemicals did the trick. I didn’t know much about Digiplay boxes, other that they are from japan and vintage. Heck, i still don’t know much more. There isn’t that much of documentation around of Digiplay boxes. For now, the best source of extra information is Effectsdatabase. FXDB knows that the unit is basically one of those pretty generic designs that emerged in early 80’s. Apparently the box is pretty much the same as Wasburn’s most acclaimed chorus, the A-SC7. And close to Loco Box CH-1.

DigiPlay-CH70-Chorus-guts1

As with many others, there may have been one designer and one manufacturer for all these generic boxes. But why should it matter if there are about ten brands out there with the same exact effect? I do not know any reason why it should. No matter about the prestige of the brand or design, here we have extremely pleasing acid trip traces on vintage japanese style board.

DigiPlay-CH70-Chorus-guts2

Clean hand soldered board, but wait a minute? CD-chip and the BBD+clock have been sanded? Apparently sanding the markings out isn’t a new trick brought to us by bad boutique designers, but it has been around for a long time. Yes, the estimate of DIP-14 chip being a CD4000 series chip and those two DIP-8s being BBD and a clock is pure speculation. But it is a chorus, so chances are the chips are some sort of vibrator/BBD/clock combo.

DigiPlay-CH70-Chorus-guts3

I’m about 99,99% sure the design is all analog. Could the brand name be a hint of simpler times when everything digital was a huge advantage as a selling point? In general, the work and wiring is neat. Everything is looking like it should. This is one of those well made japanese units from early 80’s.

How does it sound?
Usable, soft and nice. But very generic and rather faceless. The sound is exactly what you’d expect from any two knobbed stereo chorus pedal of the era. There is a reason why Ibanez CS9 and Boss CE-2 are pricey classics and Wasburn/Loco Box/Digiplay choruses aren’t. One does get close with a fraction of a price and let’s face it – if you are playing gothic rock, you’d be better of with this unit than one of the highly praised ones. Not bad. Not too great either.

Ibanez DS7 Distortion

October 16th, 2014

DS7

What is it?
Ibanez DS7 Distortion from 7/Tonelok series. Made in taiwan, 1999.

One of the Tonelok series early birds. Somehow i have a feeling the DS7 was discontinued earlier than the rest of the bunch. I think i see a point in this. Anyway. This one doesn’t have any other controls but drive, tone and level. First thing that comes to mind is, could this be just a revamp of Boss DS-1? But then again. It’s Maxon/Ibanez were are talking about. Even though the designers may have borrowed certain snippets from MXR and EHX in the 70’s, i haven’t seen much borrowing happening since. Or at least after the 80’s. And once the bottom plate is removed, the board sure looks like it doesn’t have much to do with anything simple.

DS7-guts1

At this point i was like WTF. Ibanez DS7, the dullest unit of the series, and the main board looks like that? Once we take and flip the board, the sight is something completely different. Apparently some other units in the series use the same drill layout as a base and due to this the board’s bottom looks like there is hundred things going on. While in reality there are just ten.

DS7-guts2

There is a factory schematic around the webs as a floater. It can be found at least in here. These factory schematics are horrible to read and interpret (i may need to redraw it for myself as this one hurts my eyes. And brains.). But if we focus, we can read it. We have input, bypass and switching buffers, obviously. For the main circuit, there’s a driver amp followed by a hard clipping diodes shunt to ground. Then there’s most interesting part. Quad gyrator based tone control. Nope. This isn’t borrowed from DS-1. In fact, it has very little to do with any basic distortion design i’ve seen.

DS7-guts3

Rest of the box is per Tonelok series standards. Control board, jack boards and bypass board with indicator LED. Build and design quality are also on par with every other Tonelok box.

How does it sound?
Sadly. It sounds rather dull, faceles sand hollow. But due to boards being with through hole components and the gyrators are in plain sight, one should be able to tweak this to their liking. For gain and level controls, the ranges are sufficient, but nothing out of the ordinary. After seeing how the tone control is made,  i just had to give the unit another test run. Yes. Knowing gives a very different view to the tone control’s behaviour. It is powerful, but may it be how powerful ever, the fact remain. Dull, faceless and hollow. With being rather noisy. Not a bad modern distortion, but not anything great either. Falls in somewhere between metal distortions and those ugly sounding 80’s plastic things, while not being either. Strange bird. This seems like one of those units people throw away with trash. When you see one for 15€, grab it. It may not be good, but it’s definitely worth that 15€.

Colorless writings, part 16 – The Transistor

October 13th, 2014

A transistor? As in electronics 101?

Yes. A transistor. A rather simple device that we’ll find in almost any stompbox, in form or another. Transistor is usually a triode. Meaning that there are three terminals and all those three terminals have their own purpose. You know, a tri-ode. Three terminals. As opposite to diode – di-ode, which has two. Simple analogy forward to tubes that may be pentodes and so on. Transistors can be used for a few different purposes, most notably as switches and signal amplifiers. The latter one is is the one i’ll be focusing on. And we usually can find two distinct types of transistors – NPN and PNP. I’ll be focusing on NPN type, but i’ll talk more about this later. Just a second ago i said that transistors have three terminals. These are called a collector, a base and an emitter. The base is where you apply your signal. Collector collects and emitter emits. Can’t get much simpler than this. When i was introducing myself to the magical little devices, the obvious thing to assume was that the emitter emits the amplified signal and collector collects the juice for this amplification. This is not true. Emitter emits the juice to inside the device. Collector collects the amplified signal and this is the output we can get out if it. Somehow i don’t think i’m the only person who’s had this misconception when getting to know his/her transistors.

Let’s take a look at the subject in even simpler terms. Semiconductors in general work in a very simple way. The voltage and/or current is passed through the semi-conducting material in one direction, but the other. are you familiar with a diode? For a diode, we have anode and cathode as the terminals. Cathode is the end with a stripe on it.. If we apply 9V DC voltage to the anode, we’ll end up having a voltage that’s close to 9V DC on the diode’s cathode, as this is the direction the diode passes voltage and current. But if we apply the same voltage to the cathode, the anode won’t have any voltage, because the diode doesn’t pass the voltage or current in this direction. This is the fundamental, basic idea for all semiconductors. That’s what they do. Once you get this, everything will start looking a lot simpler.

How does a diode get us closer to a transistor?

I just explained how a diode works. There’s not a lot of options how that third terminal is connected inside this device called a transistor. Since i’m talking about NPN type transistors, think of the transistor as two diodes. Both anodes tied together as a base, one cathode is your collector and the other is your emitter. NPN stands for negative, positive, negative. Now, if we apply that 9VDC voltage to the base, or two anodes tied together, we’ll have near 9V on both, emitter and collector. This doesn’t amplify anything, but it shows us the idea behind the transistor. Let’s play with a thought of it doing some amplification without going into mathematics. To begin with, transistors amplify current, so we’ll need to give it some. Our guitar output is good source of low voltage AC signal and it’ll have hot and cold leads. For this example, cold is the same we have as DC ground, so  we can use just a single signal path. As we’ll need to apply some voltages to get the device doing the work, we’ll need to place a capacitor in series with the base and apply the signal to the free end of that cap. This cap will pass the signal to the base, but block the DC voltage from the base from getting to your guitar. Now it all comes down to bias. I know. It’s a concept that isn’t as clear as pancakes for most people. To get the amplification going, we’ll need to have a voltage on the base, which has to be smaller than the voltage on collector. If we take 1M resistor from the 9V supply to the base and another one with 100k value from base to ground, we’ll end up with something like 0,8V DC voltage on the base. That’ll work. For the emitter, we’ll take a small resistor from it to ground. Let’s say 470 ohm. Finally, we’ll need something like 10-12k resistor from supply to the collector and an output cap to block the near supply voltage from our real output.

What happened?

We applied low bias voltage to the base with our signal. Ground potential at the emitter and the bias, or reference voltage pushed the signal towards the collector. Which collected it and made it to pushed the signal out with way higher current than what we applied to the base. That’s the amplification of  a small signal in the simplest possible way. Four resistors, two capacitors and a single transistor. This is the configuration we’ll find inside EHX LPB-1 Linear Power Booster.Sure. This information doesn’t take you very far. But i’m hoping it’ll offer enough snack for thought, so that digging deeper may become slightly easier. There are tons and tons of good articles and videos around the internet if you feel like going further.

EHX OD Glove

October 10th, 2014

EHX-Glove

What is it?
Electro-Harmonix OD Glove from EHX nano series. Made in NYC in 2013.

An overdrive that sounds like nothing else on EHX catalog. That’s the catchphrase from the marketing material. Sure enough. It isn’t close to anything from current or past EHX catalog. But it is rather familiar from somewhere else. Take a look.

EHX-Glove-guts

The chip on the right is ICL7660S, a DC-DC converter, which doubles the incoming 9V to 18V(ish). There’s a slide switch for selecting the use of standard 9V or doubled. I suspect the 18V doubled mode will eat your battery a lot faster than the standard voltage mode, so a switch may have been a nice idea. How does it affect the operation or sound.. That’s another story. But let me say – not that much. There is a distinctive difference, but t actually hear it, you’ll need to be somewhere else than your rehearsal room with the rest of your band.

The main circuit looked pretty simple when the function of the other chip was established. Couldn’t help myself but to trace the whole thing. Here are the results. Does it look familiar to you? Non-inverting gain stage with gain control, hard clipping done with two MOSFETs (shunt to VRef instead of ground), a recovery stage and a two mode switchable, simple tone control. All that followed by a standard level control.

If you haven’t seen this before, i guess it’s time for you to get yourself a 18V running, MOSFET clipped, tone control added derivative of a Voodoo Lab Overdrive. Or in other words, a very nice and super cheap derivative of something related to an obsessive compulsion disorder.

How does it sound?
Fat and distortion-like overdrive. Very nice sound that sits well in somewhere between a Voodoo Lab OD and a MI Audio Crunchbox. High gain overdrive that’ll suit many occasions with its good controls and good range from near clean to overwhelming drive. The 18V switch adds some headroom, which lets the pedal to live a bit more than it does running on 9V. Treble cutting the tone knob does may be useful to most as well. I’ll keep this short. It sounds good.

Boss CH-1 Super Chorus

October 7th, 2014

Boss-CH1

What is it?
Boss CH-1 Super Chorus. Made in taiwan, november 2001.

At one point i woke up to a feeling. I had tons of effect pedals, but zero Boss brand choruses. That felt extremely weird, as these effects in Boss catalog are usually praised pedals. So what was i to do, bet to get me some. First i scored a CE-3 stereo chorus through auction site listing (i’ve talked about that unit earlier on..) and second, i grabbed this one as used from around here. As usual, i checked the serial number against the Bossarea decoder and checked some facts about the design as well. What do you know. Just my luck. This unit is one of the very first CH-1s to exit the factory with newly revamped SMD board inside. Just a month older, and it would have been the one with a pink label and a MN3007 as a powering BBD.

Boss-CH1-guts1

The original CH-1 was apparently a derivative of CE-2/CE-3, with added blend/mix control and a tone control, which allowed the user to set the audio frequencies processed by the chorus. But since the changes between the old design and this one is pretty huge, i honestly wonder why this wasn’t marketed as CH-2? The changes would have definitely warranted that. But then again. We have DD-2 and DD-3 delays which have the exact same circuit inside, but for some reason the model number was changed. Peculiarities are sometimes fun, but… Everything about the design look even newer than the actual manufacturing date, but i guess that’s to be expected.

Boss-CH1-guts2

At the first look the board looks a bit like just SMD version of the original. We do know that DDBs come in surface mount packaging too. And the long chip could be a CMOS chip to handle the electronic switching. But no. Closer look revels that there aren’t any BBDs present. Just a digital 20K Itri Erso ES56028 echo processor chip.

I haven’t had a pleasure of comparing this against the  previous version. I highly doubt these two sound anything alike. At least the delay line is different enough to warrant this assumption.

How does it sound?
Decent chorus, nevertheless. Mix control is nice addition when we want to dial in smooth and ambient chorus tones. Tone affects the frequencies chorused, rather than the overall tone. Another feature that gives more to the sound than one would think.While all Boss choruses have a great reputation, i tend to see one fault in all of them. The range of LFO speed feels to be always from too slow to slow. Same thing here. If we disregard that, we have good controls and nice chorus sounds. Not  perfect, and i’d still choose my CE-3 over this in a heartbeat every time. If you get one for ridiculously cheap, then get one. I may keep my eyes out if i happen to run into the pink labeled version at some point. Comparison test would definitely be worth a post…

Danelectro CD-1 Distortion

October 4th, 2014

CD1-Distortion

What is it?
Danelectro CD-1 Distortion from Cool Cat series. Made in china around 2009.

The number of good sounding units in this series seems to be on the rise. Took me a while to get one and to tell the truth, this didn’t come too cheap either. But i wanted one, so i went out and got one. Simple as that. One part of the attraction was that all there was on the internet was just a couple of guesses about what the circuit could be. Usual guesses pointed out this being a derivative of the “standard” Danelectro distortion, the Fab Tone from original series. Granted, that design may have been circulating in the brand’s catalog more than enough. But. Since there were nothing more than guesses based on nothing around, i felt it like a duty to shed a little light on this subject. I’ll say one thing before going any further. The box feels and sounds nothing like the Fab Tone.

CD1-Distortion-guts1

Opening the box up, no surprises at this point. Just a standard Cool Cat series jack and switch board inside. But as we all know, the effect itself is on that other board. Four transistors and a dual opamp. At first glance, the first transistor looks like it’s a buffer, and there’s two separate pairs of clipping diodes. Nope. No clue about what’s it based on, at least not just by taking a quick look at it.

CD1-Distortion-guts2

But several hours, a multimeter, a few liters of coffee and several packs of smokes. Yup. Now we know. At first the design didn’t ring any bells, even though it should have. So, we have an input buffer, followed by a non-inverting clipping amplifier with diodes in feedback loop. Then we have hard clipping stage, followed by dual gyrator-based tone section and a buffer for output.

CD1-Distortion-guts3

Design is, in other words, pretty impressive distortion design. At the moment of my trace it really should have been obvious to me. Anyone ever heard of a distortion unit called Distortion Master? Here we have that, almost verbatim, with slight modifications on the tone controls and the gyrators they control. May that mean whatever, but still, we have $200 sound in $40 package.

How does it sound?
Very good. Not too far from those distortions that try to capture the feel of old Marshall amps pushed to the max. Not too high in gain, but well balanced and sufficient. Gain control goes from overdrive tones to big distortion sounds. EQ section works well and sounds like you really don’t have any need for a separate mids control. I would go so far to call this one of the greatest rock distortions. In one word, usable. But we should remember it is heavily based on an existing pedal that is currently manufactured. Still. Wonderful sound to have in one’s toolbox of sounds.