Posts Tagged ‘Overdrive’

Danelectro CTO-1 Transparent Overdrive

Monday, 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.

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.

DOD FX100 Even Harmonic Overdrive

Wednesday, July 23rd, 2014


What is it?
DOD FX100 Even Harmonic Overdrive (with Integrated Tube (TM) Technology. Made in USA in 1997.

Of course i was curious about this new and exciting thing called Integrated Tube (TM), or I.T. (TM) technology. What it actually is – it is how marketing department takes random words, put them one after another and place (TM) after it. Sure. It sounds very good and interesting to many to see new technologies arise and be put in use. And in this case, what does the I.T. (TM) really mean? There is a JRC4558 dual opamp in there. So my next question is, “Are you kidding me?!?”


Actually, the two dual opamps it this late ’97 or early ’98 unit are JRC4560Ds. So apparently the I.T. (TM) doesn’t mean even that. Now let’s put the disappointment aside and check the schematic. Your guitar’s signal journeys trough a FET buffer and reaches a gain stage with Drive control on it. Then we have another FET/BJT gain stage followed by a strange world of single diode clipping (note to self – do not pay big money for FX101, as that is the same circuit, without I.T. (TM) and with a single diode added). Journey continues through a dual gyrator circuitry, which also is a home to Lows control. On the path comes a passive highs filter with a pot on it. This is also the place where we’ll have the volume control. After this, the journey is about to end. We have only make-up gain stage and amp simulated output stages left.

So did this journey warrant any claims for new and exciting technologies? No. Was it really worth it to get (TM) status to something that’s already been done over and over by just about every manufacturer?

Further reading on America’s Pedal website

How does it sound?
Ok sounding overdrive with sluggish output level. I’d say the level is insufficient for anything else but very low, vintage output single coil pickups. Clipping doesn’t feel broken, but nice, warm and harmonic. Even. Lows and highs are controlled nicely, but this just isn’t a very good pedal. Oh. Yes. It’s just my opinion. It doesn’t mean that the unit would really suck. It just means that after the marketing department had its way with me, then come the real issues. Makes me wonder i should just solder that missing diode in and pretend this is a FX101.

Digitech DSB Screamin Blues

Thursday, July 17th, 2014


What is it?
Digitech Screaming Blues Overdrive/Distortion from “D”, or “Distortion” series. Made in china around mid 00’s.

When DOD seized to produce the later versions of the famous overdrives like FX50B, their closest successor would be the DOD FX102 Mystic Blues overdrive. When DOD seized to exist, the next step for the design was the Digitech Screaming Blues. In retrospect, the design analogy would be somthing like OD250 -> FX50 -> FX50B -> FX102 Mystic Blues -> DSB Screaming Blues. So is it a direct descendent of OD250 overdrive/preamp? I’d say sort of. Not that direct, but descendent nonetheless. Granted. The design differences between OD250 and Screamin’ Blues couldn’t be more a part, but then again, the FX50B isn’t that close to either one. All this may be be speculation, but the timeline matches.


Modern, dull traces on a board where there’s room to do anything. Once again, this shares the electronic switching part of the board design with all the other “Distortion” series pedals. The buffers and in/out section appears to be the same too. As we can see from the photo below, the gain pot is dual gang, while the EQ section doesn’t differ that much from a Bad Monkey.


Standard mix of panasonic and mylar caps with all SMD resistors and semiconductors. Not too eye-pleasing, but the reason for the units greatness doesn’t come from the design. It comes through use.

How does it sound?
Defined, clear overdrive. Where as the Bad Monkey takes the prize with honking mids alá Tubescreamer, this one stays way more transparent and natural. Where does the “Blues” part in the name originate, i can’t say. But its armed with fairly versatile EQ section, ranging from thin and piercing to blasting lows and literally screaming highs and the drive control range is rather pleasing too. It surely goes from mild overdrive to big distortion. I don’t have a lot of bad things to say about this unit. It’s not super great, but it isn’t bad at all.

For the current market of used units, you should be able to score one for peanuts. It never hurts to have a usable, defined sounding pedal – may it be rather generic – in your bag. Especially when it sets you back a 20 bucks.

DOD FX91 Bass Overdrive

Wednesday, July 9th, 2014

DOD-FX91-BODWhat is it?
DOD FX91 Bass Overdrive from DOD FX-series. Made in US around year 2000. No serial or battery door in tact, even though this late enclosure version has the door attached with a rod.

Bass overdrives are a fun genre. I’ve seen a few and nearly all of them are pretty standard overdrive circuits with no cut on the low frequencies. Which means that the designs may be slightly too fat for guitar, but i still think these should be tried on guitar too. America’s Pedal has some info about the unit. It apparently shares the circuit board with FX102 mystic Blues overdrive. There are more features for this version, which explains empty pads on both effects.


There is a schematic up on the web without the switching part. The drawing shows a buffer at the input, which passes the signal to pretty standard clipping amp and on to a Blend control which mixes the clean signal with the output of that clipping amp. That is followed by a tone stack and a recovery amp and a volume control. simple, but decent design.


Interesting little fact about these units is that at least some of the units have a factory error. The R3 should be 1K resistor, but some units have a resistor with 200R value on its place instead. This change adds a noticeable amount of gain coming out of the clipping amp, and it shifts the frequency around too. You can read more about it at DIYStompboxes forum.

How does it sound?
Fat and useful. Serves well as bass overdrive and the blend control works also well. There’s enough gain to get soaring blast sounds out. I’ve played with this with a bass and a guitar. Bass is obvious choice to use this with, but it offers very nice boost features for a guitar too. Reasonably  good effect.

Maxon OD808 Overdrive

Friday, June 27th, 2014


What is it?
Maxon OD808 Overdrive. Reissue, made in japan around 2008.

Another Tubescreamer? Well. Sort of. Apparently the design for Maxon OD808 has varied a lot over the years, depending on the “re-issue”. Some schematics available show the input and output buffers to be implemented with a LM1458 opamp instead of NPN transistors. This unit isn’t per that schematic due to only one dual opamp being used. So this unit is apparently the latter re-issue, which is pretty much 1:1 with Maxon designed Ibanez TS-808 Overdrive. From what i can tell, the board layout is not the same as in either original Maxon TS808 or Ibanez TS-808, but something different.


I do like the idea of fastening the board to the enclosure with several screws. This method should last a long time of careless (ab)use. The component side is neat and laid out evenly, offering more smiles in terms of aesthetics. Even the plastic shell protecting the bottom of the box from touching the board is fastened with screws. Solid boxing design.


Controls are housed on their own board and much of the outboard wiring has been done without any sockets or other methods that reduce the labor. There’s a lot of hand craft for pedal that’s this modern. This is one great factor to consider, when you’re after a TS variant for your board and you’re confused about the pricing.


Well made as every other Maxon box. And since the design is 1:1 with Ibanez TS-808, this is the closest you’ll get of having a brand new Ibanez TS-808. As for the hand drawn schematic (link above), the schem is exactly the same as TS-808 in all the component values. Only thing that differs is the electronic switching. This unit doesn’t have  the standard Ibanez flip-flop switching, but electronic equivalent based on a latching switch and a buffered bypass. Which is better, you might ask? Well. They are different. If you do have a strong opinion about which is better, i suggest you leave a comment with your justification for the choice. No. Really. I want to hear it.

How does it sound?
Surprisingly bright and open. Which makes me suspicious. Every single time i can hear a difference between two same circuits i’m puzzled. In terms of electronics theory this pedal should sound more or less like my 00’s TS9 reissue. But it doesn’t. Differences are subtle, but still noticeable. For the mid honk, that always makes me feel bad for the humble TS9, this one has it, but it isn’t as muffled as in, well, all the other reissues and derivatives out there. I’m forced to admit that this simply sounds better than most TS clones/derivatives i’ve played with. Why? I wish i could tell you why. If the original TS-808s sounded like this when they came out of the factory back in 1980, i sure am getting the cult reputation. Which was a deep mystery to me before this landed on my desk. It is a Tubescreamer. No denying that. But it is simply better than most other TS’s.

The different switching could explain some of this, but it shouldn’t. Puzzling.

Nevertheless. This is very good sounding Tubescreamer. If not the best i’ve played with, then its sitting in tight with the others in top three.

Barber LTD Silver

Monday, June 16th, 2014


What is it?
Barber Electronics LTD, Silver edition. Made in USA, 2005.

Barber pedals pretty well known for high quality in their designs, as well as for their build quality. This unit is the first Barber pedal for me. Got it in a trade, played with it for a while and opened it up. Yup. There are only a few of these modern “boutique” brands that are not likely to get ridiculed on builder/analysis/diy forums. Opening the bottom plate gives you the first clue why Barber is one of those. Although there is not much eye pleasing symmetry on the board design, everything has its place and all the parts are connected neatly. In essence, this is a prime example how i would like to see more of the bigger name “boutique” pedals done. Barber has posted a schematic for this design on his page.


Two trimmers that control presence and bass response are marked on the board. This surely suggests that these are controls in addition to external ones. As the schematic shows, the design has non-inverting clipping amp stage with dual pair of Si diodes and added presence control to standard non-inverting arrangement. After that, there is a low pass / high pass filter as tone control – not completely unlike the one you’d find in a Big Muff. Although, the values on Silver edition are the key to the design being the Silver edition. Pot offers very mild tonal changes, which are meant for fine tuning rather than for affecting the overall tone in drastic measures. Presence and Bass controls do offer a lot of tweakability and one of the resistors on the following non-inverting gain stage can be swapped for a additional mids control per the shared schematic. For the tone control, one  could also swap the 150K resistor from pot pin three to ground with a potentiometer to add a “body” control. The last gain stage has interesting, but simple way for controlling the bass (and treble, in customized version of the schematic).

But i do not see a reason for tweaking this unit. It is very nice, usable design as it is. I wouldn’t mod mine for the world. As for biggest downside.. The font for the labels. Really?

How does it sound?
Organic, mild/medium range overdrive with very nice dynamics and smooth, harmonic symmetrical clipping. It offers enough sustain for leads, but truly shines as mild ovedrive, used to boost a good sounding amplifier for your base sound. The trimpots inside offer a lot of control range, while keeping the outer shell simple. In my opinion, the tone control could have been a trimpot too, as its range is limited to fine tuning the frequency response. The footprint of the enclosure is rather big for the designs, but should be counted as a con only if there are other pedals with similar overdrive features on your board. As only overdrive, this one shines bright. Simple, yet very effective, recommended overdrive.

Marshall JH-1 The Jackhammer

Monday, June 2nd, 2014


What is it?
Marshall JH-1 Jackhammer Overdrive/Distortion. Made in china in mid 00’s.

We’ve seen a few of these units that combine two popular dirt effects – the overdrive and the distortion. So far i haven’t come across an unit that would excel in both. First analogue would be Boss OS-2, which is terrific distortion, but super sucky overdrive. But. More about the sounds later. Let’s rip this puppy open and see what’s inside.


As with all the small metal series boxes, the traces are clinical with autorouted feel to them. The soldering work is very chinese from 2005. Not bad, but i’ve seen a lot better. Lots of praise comes from using through hole components. Overall feel is a lot sturdier and these units really feel like they are built to last. The off board wiring is done with terminal sockets. Looking at the component side of the board, the opamps providing the boost and gain are Marshall’s weapon of choice number one, the Texas Instruments TL072. It is a very nice sounding opamp for most occasions, like the big black Bluesbreaker. Here, the designiing engineers have wanted to take a bit too much gain out of them – resulting in opamp clipping with not-so-great decay on the release. Sort of reminds me of main stage distortion of the transistor based amplifiers. Yup. It is that good sounding. It is, of course, masked by the clipping diodes when gain pot is set at over half of its sweep. There is a factory schematic floating around the webs…


There is two pairs of clipping diodes. The first pair are 3mm red LEDs and the second pair are your standard 1N4148s. The design doesn’t seem to offer a lot of surprises. After a quick look, it seem like the OD/Dist rotary switch is basically cotrolling the clippers.

I guess the board could be tweaked to sound, well. Generally better, but this unit will never become a DIY favourite. Why? Let me tell you why. There are six pots and a switch in addition to semi-complex circuit and one of those pots is a reverse logarithmic dual gang. So anyone trying to fit a clone of this one in 1590B sized enclosure is either insane or very adventurous. The pots control gain, volume, treble, bass, frequency and contour.

How does it sound?
If we start with the distortion side, there’s not much good to say. It’s muddy and unarticulate no matter what the settings are. That is just simply bad. But. Once we turn the rotary switch to Overdrive side. That’s when to tone opens up and controls start to feel correct. Open, bright and with enough controls to match any guitar and amp combination. The overdrive is very versatile and actually very good effect. Where as Boss OS-2 sucks on overdrive mode, but shines bright on distortion, this one is exactly the opposite. The distortion is the kinda sound that i don’t think i’ll find any use in anything. But the overdrive. That’s well worth spending the $30 on this Marshall unit. Well worth it.

Yamaha COD-100 CMOS Overdrive

Friday, May 16th, 2014


What is it?
Yamaha COD-100 C MOS Overdrive from Yamaha 100-series. Made in japan in mid to late 80’s.

Happened to score one of these in near mint condition with an original retail box from a local guitar builder guru J. Lindén. Since i’m still fond of those coin-op design Sound Device series pedals, this one wasn’t too high on my want list. But. Price was correct and due to like-new shape with nearly 30 years of age.. How could i resist? Surprisingly little information available on the unit. Your best bet would to check out the specs from original marketing material at Effectsdatabase.


Before opening the unit up, i had a huch of this being adaptation of either EHX Hot Tubes (which has a history of its own) or Ibanez MT10 Mostortion. Turns out its neither and both. I suspect that the lower IC is there for electronic  bypass switching and the part above the jacks is the effect circuit itself. There is unbuffered 4069 CMOS chip in there. I’m currently just guessing what’s going on with the circuit, but this pedal may be one of those that deserve a deeper look at the design. The board design itself is eye pleasing, but not special. Nice. Not shocking, but nice.


I’m quite puzzled how Yamaha designs have slipped through the cracks of interesting designs. Most of the effects that people find interesting from the era have factory schematics floating around. But not for Yamaha. Even the traced schematics for these are scarce. For this particular unit, i sure hope there will be interest in the future. Expect an update on this post…

How does it sound?
As advertised, the MOSFET sound is in there. Harsh, metallic overdrive/distortion with plenty of output level. Well working EQ section with separate controls for highs and lows. Pretty standard all the way, except for that MOS sound. Since there are only few of similar sounding designs, i’m forced to wonder if none of them sold well? And if so, why? For my ears these all (this, WH Red Llama, Hot Tubes and Ibanez MT10) sound very good, gritty, agressive and powerful. And we do have ZVex Box Of Rock and Distortron which both have similar characteristics in their sounds.. I’m under impression that those sell well.

Well. Doesn’t matter. To me, this sounds like a lost gem and it is a definite keeper.

Korg TNB-1 Tone Booster

Friday, May 9th, 2014


What is it?
Korg TNB-1 Tone Booster from Series 1. Made in japan in late 80’s.

Korg hasn’t produced many guitar effects, but they are well known for their high quality synthesizers and other products. In fact, the Series 1 is just a rebranded Yamaha 01 series, both manufactured by KLM. Or the Yamaha series may by simply a rebrnaded Korg series. Hard to say, but to me it seems like KLM may have been offering various designs as OEM boxes for more than just two brands. Of this i’m not sure, but the designs show a lot of resemblance to those Pearl effects. All the way to the enclosure design… (Nope! “KLM” means the board is designed and built by Korg Japan, the other manifestations of the KLM circuits in other brand pedals are OEM’d Korgs. This was just brought to my attention and i was not aware of this before, thanks to Pepe!) Got this one in near mint condition and with original box. And for a good price, so i couldn’t let it go. I had studied the schematic earlier on and this seemed like a great preamp/distortion box. Schematic has “KLM690” printed on it. I’d be rather interested to know what other brands have bought OEM designs from that company…


Really solid enclosure that is fastened through the top rather than from bottom. Relatively small board footprint and comes with dreadful asymmetry. Despite that, i think i’m just going to go with saying that the unit is very well designed and built. It’s not offering any high gloss eye candy on the board design, but i think it should handle heavy use for a long time.


To analyze the schematic, there is input buffer that splits the signal for bypass buffer and the first driver stage. The bypass buffrer outputs to DPDT stomp switch and while it has two buffers on in bypass mode, i didn’t notice any of the sucking. With a short testing, that is. Anyway. The first driver stage is non-inverting opamp stage that has similar gain control that you’ll find in OD250/Dist+, only with 1M reverse log pot. This should give out more usable sweep for the pot and it does. This gain stage can be cranked to massive distortion. The stage drives a simple two band tone control which then passes the signal to recovery gain stage and volume control. I’d say the original designer has put the TL072 in good use. The recovery gain stage is inverting, so the wave coming out is inverted. This is not unusual, but something that user might want or need to know.


I find the bypass method interesting. Simple but effective. While the bypass buffer always gets the signal in, its output is switched between effect and bypass. Other pole of that switch either kills the gain stage or lights up the LED. It may not be anything super special, but it has some out of the box thinking involved. This is a very nice unit to have.

How does it sound?
From mild preamp to massive distortion with well working EQ section. Good ouput level and usable range from unity tone shaper to singing leads. It sounds good. No denying that. I’d still call this an distortion rather than a conventional booster, it offers nice versatility in tone. Good sounding well built unit. I do not see any downsides to this one.