Posts Tagged ‘Chorus’

Rocktek CHR-1 Chorus

Thursday, April 24th, 2014


What is it?
Rocktek CHR-1 Chorus. Made in china around early to mid 90’s. Housed in brittle, all plastic enclosure.

Noticed a lot of two Rocktek pedals, listed as broken on eBay. First one was this one and the second was the Metal Worker distortion. Sniped the lot for decent price and waited with enthusiasm to get the units on my bench. I’ll write another post on the Metal Worker later, so we can focus on chorus on this one. I do enjoy sharing these straight-forward repair reports…

So the unit was completely dead. First, i took it completely apart and noticed two faults that looked a lot like the unit had taken a quick flight and stopped suddenly at a wall. With all the cables attached. The input jack had been totally shattered and the DC jack was torn off from the solder joints, taking an important chunk of the ground strip with it. Basically, a new board mounted input jack, new joints for the DJ jack and a crude, almost brutal fix for the broken ground strip. That was it. The circuit was running like me, ten years ago. Fix was pretty simple and i happened to have suitable parts at hand.


Effect offered other surprises. I’m not sure where the design is ripped off, but the board design is looking a lot like ten year older japanese designs. The design itself is a standard MN3102/MN3207 chorus with LM358 acting as an LFO and a JRC4558D as a mixer amp. Very good looking board and nice analog chorus design. True. There isn’t that much in there to be throwing wow factor around, but overall design does keep all the mehs away.


Electronic switching and all the things around it will keep this unit far away from most desired old pedals. Sucky, not too well designed buffering won’t response to people who require modern pedal standards. I do find this one interesting.

How does it sound?
Very nice and usable. Soft analog chorus with reasonable control range. There’s nothing special about the sound, but overall feel is pretty close to all the other unit from 80’s and 90’s with same choice of BBDs. The MN3102/MN3207 has a nice, clear, yet personal chorus sound. Well worth getting this unit, even though it won’t be a prime suspect for your board. These seem to be selling cheap, so for an good sounding analog chorus for your recording needs, this may be a very good choice.

Ibanez SS10 Session Man

Saturday, February 1st, 2014


What is it?
Ibanez SS10 Session-Man Distortion/Chorus from Power series. Made in japan between 1986-89.

Mid 80’s was a perfect time to try out stupid things like to combine distortion with other type of effects in small pedal enclosures. DOD did it, Boss did it and of course, Ibanez did it. The idea of mixing distortion with chorus seemed like something that i wanted to try out. The great thing with the Session Man is that there’s a switch that places the chorus in parallel or in series with the distortion to create different soundscapes. The bottom knobs control the distortion with standard parameters (level, tone, gain) and the upper knob determines the level of chorus mixed with the distortion. The chorus doesn’t have any controls, other than the mixer level. Sure, there are trimmers for those parameters inside, but it is basically fixed to one depth and one speed.


For all analog distortion and chorus delay circuitry, the board looks like it’s well used space. Turning the board around reveals crowded and crammed circuit with a lot of components. The yellow trimmers are for tweaking the chorus. I couldn’t find a schematic to see everything there’s going on.


From these crappy photos and being inside my unit, i can tell that there’s a BBD pair handling the choruses timed delay, one opamp acting as LFO ans SIP opamp driving the distortion. The SIP may be a good choice, since  there’s a lot of stuff going on on the board.

These seem to be somewhat collectible units. As a niche novelty items, i think the value is correct. But as a usable, unique sounding guitar effects? Not so sure.

How does it sound?
First of all, the distortion isn’t too bad. Quite open and dynamic, without the flattening compression that most distortions offer. Now, when we engage the chorus in parallel, i’m like “why?” The chorus is so mild that it hardly does anything, even when maxed. Anything good that is. The chorus is a lot more overwhelming in series mode, but still. Why? The parallel setting is a thing of its own, but if i wanted to chain a chorus and a distortion after each other in a studio environment, my choice would not be SS10. For a live setup maybe. But even then i’d rather use a utility box to engage both with a single stomp.

These combination pedals are nice curiosities. As these come, the SS10 isn’t the worst of them by far. It could even serve a purpose on some situation.

Morley CCB Crystal Chorus

Sunday, December 1st, 2013

Yeah. I know. it’s december already, but this is the last uncovered chorus pedal in my collection for the moment. I want to cover it now – so that i don’t have to write about choruses for a while…


What is it?
Morley CCB Crystal Chorus from Jewel Box series. Made in US around 1995-98. Serial number maimed by velcro (grrrr!).

The aesthetics are heart warming. The box is too big, but the white sparkle coating makes amends. Knob pointers are glowing in the dark and the graphic design reminds me of something 50’s.  Stylish and very neat. Blinking LED for the indicator that shows you the LFO speed is also pleasing.


I thought i heard something that wasn’t like on most standard analog chorus designs. Taking a look at the schematic confirms my suspicion. The chip driving the 1024 stage 3207 BBD isn’t your standard timer. As always with Morley, the buffering and mixing is done with a quad opamp. Motorola MC3403 acts as a LFO and the timer for BBD is created with CD4007 and CD4047 CMOS chips. To be honest, i’ve never seen that don before. The stereo output  is just simply splitted and connects only when the first output is in use. It could have been inverted, but then the board would not have been big enough for Morley engineer.


There’s also user manual available with example setting. Those ara always fun.

Negative points come from the big box and the rate knob. And a small additional minus for the board layout. The ground strip that connects the left and right side goes under the battery hole of the board. It’s not too convincing way to ground the board.

How does it sound?
Smooth and gets quite flangerish with depth maxed. Feel of the rate knob isn’t perfect as the best part of the sweep is located at last 10 percent of the sweep. Schematic shows that pot to be a log taper one, so it undoubtedly is performing in the best possible manner. If you ever get a chance to play with one, try to place it in front of some massive distortion unit like Boss MD-2. That’ll give you something a lot closer to synth than a guitar. Soundwise, this turned out to be my favourite chorus.

Ibanez TC7 Tri-mode Chorus

Friday, November 29th, 2013

TC7What is it?
Ibanez TC7 Tri-Mode Chorus from 7/Tonelok series, made in china. Stamp on the enclosure suggest the build date to be around 2005.

Now here’s the first! There’s not a hint of blue on this box! And in other news, the three modes are quite interesting – at least on paper. There are basically two separate delay circuits for two separate choruses that are simply out of phase with each other. And there’s only one LFO driving those delays. Tri-mode in this case means that the first gives out mono chorus and splilts the clean signal to second output. Second mode is for out-of-phase stereo output and the third widens the delay time range and has both outputs active. Quite usable options.

Ripping one open shows a highly populated board with crowded joints and modern traces.


As with all 7-series boxes, the insides are made of five different boards. Well made solid build with pin terminals instead of board to board wiring to connect boards to each other.


Work is neat in many ways, which validates the point that there are good manufacturers in china. I do not know which of the companies have built these, but they probably should be credited.

Down to the design itself. Couldn’t find a schematic right off the bat, but i assume that the TL022 is used as LFO and JRC4562s are taking care of buffering, mixing and driving for the different outputs and modes. So there’s one LFO driving the two Mitsubishi M65850 digital delay chips.


M65850 isn’t that widely used digital echo/delay processor as some others. But it has quite interesting datasheet with notion to Karaoke on it (check it out on So i suspect one should be able to find those chips from inside a number of different karaoke devices.

How does it sound?
Solid and trustworthy. Nothing too special in the sound, but at the same time it does have some personal character to it. The longer delay times found on third mode have similarities to a flanger design, offerign quite wild and swirly choruses. Not completely unlike vibe effects out there. Not bad at all. The fact that the delay line isn’t your standard BBD or digital chip may be the root of the personality found here. Well designed.

If i needed to drop all other choruses from my collection and leave only three, this one would probably make it to the ones i’d keep.

Ibanez CF7 Chorus/Flanger

Tuesday, November 26th, 2013

CF7What is it?
Ibanez CF7 Chorus/Flanger from 7/Tonelok series. Made in china.

One of the more complex designs on the series offers digital chorus and flanger. No blue here either. But then again, it is a flanger too. Got mine for standard market price for used unit and almost pulled my hair off once i opened to parcel. I do not mind the nicks and scrathes, but one should never (NEVER) sell a pedal with “in good condition” label if it really isn’t so. This one had all sorts of crud and human waste on it. That can be addressed with a towel and a considerable amount of turpentine. But the lost bottom rubber and dual-lock-velcro over the serial number is not exusable. Not in any way. So the bottom is practically raped and there’s no chance of salvaging the serial nuber as it’s just a paper sticker fastened to the type plate. I did let the seller know…


The horror didn’t even end there. Just check what’s going on in the picture above. To this day i have no clue what he was trying to do with adding two more caps and soldering the wire to the solder side of the board. Could be as it is supposed to be in the original, but i highly doubt it.


The source of all the crazy sounds is M50198 digital chip. The same one used in DSC10 and many other Ibanez digital effects. This time the designing engineer put the chip a good use and took it even further. The design has even more similarities with DSC10, but it has evolved to the next level. The “Crazy” switch seems to affect the overall delay time, but it is labeled as it is. With options for “normal” and “wack’d”.This is in my opinion a landmark in digital flangers. A flanger’s what it really is, although it can be used as a sub-par chorus as well.

As for the beaten and mistreated unit? I’m definitely on the look for reasonably priced replacement in a better condition. Once i find one, this one will have to go.

How does it sound?
In the gut of the metal worm! Blasted! Weird and good with enough options to drown you. From mellow classic chorus and flanger tones to metallic, cold chorus to shattering digital flange. Think of this as a bastard child of DFL Digital Flanger and DSC10 Digital Chorus. To me, this one is the shit. Amazing and very usable sounds for many purposes. Classic to noise.

Yamaha CH10M II Chorus

Friday, November 22nd, 2013

Yamaha-CH10MIIWhat is it?
Yamaha CH10M II Chorus from Sound Device series, made in japan. Datecodes on the components suggest manufacture date to settle at late 1984. The year of the Orwell’s instruction manual.

Can’t help it. The coin-op design box looks real good to me, which is the biggest reason for me to hunt these down. And just look at the traces. Simply beautiful. Design is your standard BBD chorus with two controls and added direct output for stereo use. Nothing new or special. Circuitwise, a standard analog chorus desing with added clean signal ouput for stereo use.


All the boards in this Sound Device series look very pleasing. Acid trip traces with beautiful freehand drawn feeling to it. Soldering is neat and the inside enclosure design is good. These are very solid and recommended effects for your everyday use. Construction is strong enough to last couple of lifetimes.

How does it sound?
Quite mellow and soft with no particular character to it. Standard usable chorus sound that doesn’t lay too far away from mild sounding Danelectro choruses i’ve covered earlier. There is something missing though. The personality and edge. With the compressor, this is probably one the most disappointing boxes in Yamaha Sound Device series. Not bad but doesn’t get too close to the top.

Ibanez BC10 Stereo Bass Chorus

Tuesday, November 19th, 2013

BC10What is it?
Ibanez BC10 Stereo Bass Chorus from 10/Power series. Made in japan around late 80’s.

As with CS5/BC5 covered earlier, the circuit is more or less verbatim with CS10. Funny. Four pedals equal one design, or the other way around. And the colour is… Slightly darker-or-more-violet-than-SC10-blue. As with its guitary brother, SC10, the BC10 has also three controls. With, Speed and Delay Time. If i haven’t written it already, the controls stand for: Width – the intensity of the LFO sweep affecting the delay circuitry, Speed – this one is changing the LFO speed and Delay Time – affecting the length of delay getting swept by LFO and BBD clock timer.


Modern board with modern traces. Very neat and professional soldering. The board size is not larger than what we find on Soundtank series, so it’s funny how the board here looks this crowded – even with LFO moved on the control board. Stereo output inverts the phase, so once again i’d recommend to try it as a stereo device.


The component side says it all. 1:1 board to SC10 Super Stereo Chorus. Some of the cap values are different, but otherwise the design is verbatim.


Upper board shows the LFO and controls. The controls are not complete workalike of SC10, with mild differences on the max speed and width. This may be diue to component tolerances and if so, the individual boxes of the same product will yield slightly different results. Damn i’m loving the analog circuits.

How does it sound?
With the minor differences on the circuits, this one sounds and feels pretty much the same as SC10. Just slightly fatter. If i place all four of these in series (CS5, BC5, CS10 and BC10), the differences are very minimal. Which is interesting and fun. Maxon engineers could have just created one circuit, preferably the one found on this one (BC10) and use that board and design for all the rest.

It sounds very good. Mellow, soft and fat(ish). Again, as with soundtank equilevant, the bass version lets more lower frequencies through, resulting in slightly softer sweep. Very good chorus to have.

Ibanez SC10 Super Stereo Chorus

Tuesday, November 19th, 2013

SC10What is it?
Ibanez SC10 Super Stereo Chorus. 10/Power series box, made in taiwan  late 80’s.

You guessed it. Blue as it should be and without the stereo output circuitry, this looks like close match to Cs5 Super Chorus. According to schematic found online, the design is almost verbatim to CS5 – or one could argue (and be correct) that the CS5 is almost verbatim to SC10. The main (and only) difference is the output section.


SC10 has splitted output unity drivers for stereo output where the CS5 has only one output driver. The boards are nothing alike in layouts, but the electronic design is nearly the same. Except the added output driver here inverts the phase of output signal for its channel, giving out the perfect bi-phased chorus output. (Sorry for super crappy photo below)


The delay and timer circuitry is created with 3102/3207 pair, and LFO is driven by TL022. Maxon engineers have apparently solved most of the possible clock bleed issues by taking the LFO on the control board instead of main board. The main board only having the mixers, buffers  and delay circuitry on it.

Quite standard design with no surprises. Solid.

How does it sound?
If i only had this and CS5 in reversed order, i would probably love this one more. Basically because the sound is pretty much the same. But i happened to get CS5 first, so that one made a bigger impression on me. Usable chorus. The addition of delay time control opens a lot of new worlds. One can easily use this as mild and focused chorus, or tweak the delay time to make it sound monstrous. Versatile and good basic chorus.

Ibanez DSC10 Digital Chorus

Sunday, November 17th, 2013

DSC10What is it?
Ibanez DSC10 Digital Chorus from 10/Power series. Made in japan, late 80’s.

Refined chorus in 10 series with more controls than usual. And it’s digital. So prepare yourself for some iron worm action. Well. Not exactly. At first glance, this seems like very desirable unit with lots of options. In the end it sort of lets you down. The controls are “Color” and “Delay time” switch in addition to standard width and speed. “Color” is a passive low pass filter control, which i think got included because the design team wanted it to sound and feel like analog devices. The idea in this control isn’t too far away from the Rat’s “filter” control. Otherwise, from functional point of view, there are two outputs that are out of phase with each other. So stereo use is more than recommended. Letdown comes from the fact that it just tries to be one of those omni-choruses, where everything from mild ear pleaser to noise monster is possible. It isn’t.


You’ll find the schematic from Dirk’s archive of the most beautiful traces known to man. Removing the bottom plate shown the well and tightly designed layout. Packed with noticeable accuracy (again, sorry for bad photos). Modern traces can’t turn me down this time. Just look at the joints and parts placement. There isn’t much symmetry, but the amount of stuff fit in there is respectable. Now we should talk a bit about the schematic…


Motorola M50198 chip is the key here, basically just replacing the need for BBD pair in clock and delay purposes. That is one cool huge chip (i currently have no idea whatsoever how those work). The input buffering and phase inverting output drivers are your common parts. Rest of it. Not so much. In addition to the main delay circuit being a digital one, the LFO is created with JRC2904D. The 74HC04 Hex Inverter that we commonly find in electronic switching flip-flops has parts of it used as sort-of buffers between the LFO and the digital delay chip. Yeah. I know. I lost myself in there too.

As shown on the last picture, the LFO is placed at the control board, between the pots and the switch. Due to my current knowledge, i simply cannot shed any more light on the subject. But it is beautiful pedal on the inside. More than just beautiful.

How does it sound?
Meh. Sad thing really. A rare Ibanez moment of stunning beauty and nearly unusable sound. The controls and the effort on the design let me believe much more until i played with it. On maximum time/width/delay time and minimum color setting, it does get somewhat close to a flanger style chorus. The sound behind the color control really bothers me. You can achieve the same “warmth” with dialing your guitar’s tone know down. Both methods can give you something that’s close to vibe-style effect but not quite.

It does have some potential and it’s not completely in vein. But it doesn’t make it even close of the top ten choruses i’ve played. If you’re planning on getting a Power series chorus, then i’d suggest to look for SC10 or BC10 instead of this one.

DOD FX60 Stereo Chorus

Monday, November 11th, 2013

DOD-FX60-STChorusWhat is it?
DOD FX60 Stereo Chorus. Made in US around 1990-91.

For some reason i find this unit simply beautiful. Seafoam/baby blue colour and simplicity of two knobs. Even the straight DOD logo suits this look very well. For aesthetics, this is one of the finer examples why i happen to like these FX series pedals so much. There is an old factory schematic available online which doesn’t quite match this unit’s version.


3101/3007 design. Basis of the design has remained, even though there are reportedly at least five different versions of the board. At least the delay section with that particular BBD pair is the same on all of them. This unit is the second latest board design, sharing the board with FX65. Which i do find intriguing, as the stright logo label would have us to believe that the unit would have earlier board in it. Ah, the mysteries of DODs. More quirks on the FX60 and all the different board revisions/versions – read about them on the DOD information heaven, the America’s Pedal site.

Overall, it has your standard controls of width and speed. Both having nothing but usable parts on the range.

How does it sound?
Mellow and soft. Like a good simple analog chorus should. There are no extreme settings, but just plain and simple warbling mild chorus. Very usable, but with no recognizable personal character. For a cheap DOD pedal, you really can’t or won’t go wrong with this one. It does sound very good, but doesn’t make it in to the top three for me.