Danelectro CTO-2 Transparent Overdrive V2

October 22nd, 2014


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.


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.


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.


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


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.


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.


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.


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


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.


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.


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.


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


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.


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


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.


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.


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


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.


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.


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.


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.

Ibanez DE7 Delay/Echo

October 1st, 2014


What is it?
Ibanez DE7 Delay/Echo from 7/Tonelok series.  Made in china around 1999-2002.

Couple of Ibanez delays hold a few remarkable places in my personal favourites. The DE7 ranks very high on that list. I set up photos with two separate units, side by side, since while the electronics remain the same on both units (DE7 and DE7C), the pink one is limited edition and the standard grey is the basic version. I have no idea what the manufactured numbers are, but pink ones tend to be seen rather rarely. In case of comparing how often different DE7 models come up for sale, that is. Both cosmetic versions are relatively easy to find through auction sites and the prices being asked have not (at the time of writing) gone through the roof. Not sure if they ever will, but if you are interested in having one.. You should probably grab one now.


The boards on both versions are exactly the same. Two-sided, modern traces and soldering quality on par with every other Tonelok-series pedal. I’m not aware of the manufacturing factory of this series, but i would not be surprised if it was the same factory behind the Marshall small metal cased series.


Construction with mostly through hole components and a few surface mount chips on the bottom looks like a killer. On the other hand, the number of links on the board.. Seems like the design is based on dedicated digital delay circuitry, rather than on DSP.


What comes to features, there are your standard Delay Time, Repeats (aka feedback) and effect level knobs. In addition to those we have two slide switches, first one setting the delay time range. There are three ranges that vary from 30 milliseconds to 2600 milliseconds. 2,6 seconds is rather long time and this may even scare the DD-7 folk. On the other features, like tap tempo and whatnot, DD-7 takes the cake, but the price range is completely different. The second slide switches between Delay and Echo modes. Delay being closer to modern standard digital delays and Echo is modelling the vintage echo sounds. Simple features ensure ease of use.

How does it sound?
Next to perfection. Even the digital delay sounds are not harsh, but remind one of smooth analog sounds. Without the noise and with long delay times. On echo mode the sounds are even more mellow. The attack for both modes make you forget that you are using a digital pedal. Natural sounding delay with massive delay times. What’s not to like?

EHX Small Stone EH4800 Phase Shifter

September 28th, 2014


What is it?
Electro Harmonix Small Stone EH4800 Phase Shifter. Made in USA, possibly in early 00’s.

This wasn’t the first and certainly won’t be the last pedal i’ll buy as a broken unit. Sure there have been units that were beyond repair and those will always hurt, but usually i tend to be able to fix them. This particular unit has all the OTA chips socketed. The symptoms were that the pedal only worked with a battery, but not with a power supply. True. This was the case. But even though i suspected a broken connection from the DC jack, the truth was that everything started to work right once i pressed the ICs firmly back to their sockets. Which makes me wonder why all the chips are socketed in a unit that’s manufactured in this scale. Who knows, maybe not all the chips work perfectly in this circuits and they need to be swapped around.


Since the early versions of the 70’s, the design has always been using OTA chips to create phasing. There is a distinctive difference in sound of JFET-based phaser when compared to OTA-based design. According to the internet, the early units had CA3094 and CA3080 chips in them. The later versions, due to obvious reasons, are done with LM13600/LM13700 chips. If the reason is not yet obvious to you, the CA3080 was discontinued about 10 years ago, and the CA3094 even earlier. While there are a number of CA3080s available through auction sites, the price and availability isn’t exactly right for manufacturing of this scale. LM chips are still in production, even as surface mount chips.

As for most classic circuits, there is a schematic floating around the web. This one’s drawn by Bernandduur and as always with his work, it is a pleasure to look at it. There’s a quad opamp for in/out buffering and LFO, plus two dual channel OTAs for the phasing. Basic manufacturing methods on these units look ok.  Neat, but not too pleasing.

How does it sound?

A deep wobbler with definite personal sound. Decent range on the rate knob and depth of the phase goes way beyond what we are used to. Even though the sound is very good, don’t expect to get soft and mild slush out of this. This is a lot more like a shock effect than ambient phaser. Prime example of good EHX design. Something that’s not exactly like all the others, and successful at that.

ProTone Pedals Body Rot II

September 25th, 2014


What is it?
ProTone Pedals Body Rot II Distortion. Made in USA around early 10’s.

Once again, a pedal that the original owner put up for sale as defected unit, for peanuts. And once again, i had no choice but to grab it asap. I do not own too many small brand boxes, so i must admit being excited. There wasn’t much information about this particular pedal available. Just the marketing speak, which was more of a typical attempt on hype raising than actual good and informative product description. So all i had to begin with was a marketing praise and nothing else. So without hesitation i opened the unit up as soon as it arrived.


Ok. Handcrafted  from start to finish. Lots of work put on those offboard wires. All pots handwired. All industry standard Alpha pots, except for one (which definitely does not feel like all the others). Standard chinese 2PDT stomp switch controlling a millennium bypass. At this point i needed to know what was wrong with it. LED lit up, but there was no signal passing through the device. First thing i noticed, was a 220µF power filtering capacitor. Rated for 10V. This puppy looked like a puffer fish. So i obviously swapped that for a new one, rated at 16V. The heart of the design is a single 2N5088 transistor, followed by a LM386 power amplifier. Traced my way from the input to that power amplifier and its output was dead.


Swapped the chip for a new one, and yes. The pedal was back to its original  glory. Since i had the unit open already, i snapped a few photos and posted them to a known stompbox forum. One kind soul called Manfred traced the unit from these photos and component values i picked up. It was quite interesting to find out that the pink component that looks like a resistor in weird color, is actually a capacitor. You can find the schematic from Freestompboxes.org, if you have an user account there.


Best part for the last. Just look at it. And not to mention that this “groundbreaking, all new” design is actually a few component values away from another well known german high gain metal distortion design. Somehow i knew it. If the marketing is all about raising hype, then there must be something wrong with either the manufacturing methods or the design found inside. I think this pedal will easily take years of use and abuse, but it still doesn’t feel that professional to me.. It’s not all bad though.

How does it sound?
Actually, very good. I do find that minimum settings for gain is killing the signal pretty stupid (as i do find all the designs that go quiet with anything else or more than the volume knob). I haven’t played with the design this is obviously based on, but this one sounds good. Mean, super high-gain, with very nice EQ section. Did i already mention it offers a lot of gain? Good metal distortion, either way. If you really want one, i’d suggest contacting the manufacturer instead of getting one from the store. The store price for a new unit seems a bit steep.