Posts Tagged ‘Phaser’

Big Jam (Multivox) SE-1 Phaser

Tuesday, July 26th, 2016


What is it?
Multivox Big Jam SE-1 Phaser. Designed in Hauppauge, New York, made in Japan. Most likely made late 70’s.

It was a cold and dark late winter night. Ok, it may have been closer to spring or early summer, but anyway. I was chatting with a friend who had spotted an ebay listing of four defunct pedals from germany. And the price for the lot was rather appealing. Since i was completely out of cash but still wanted more pedals (obviously), i suggested that he bids on the deal and i’ll pay around 40%, fix the lot once they arrive and he can choose what he takes first. Not a perfect deal for me since the better pedals of the lot were, well, better – and thus, an obvious choice for the one who gets the first pick. Anyhow. The deal went down, i paid my share, fixed all four and was left with one overdrive pedal (which may be covered here at one point too) and this unit. The faults with this one were quite modest. The switch rubber had fallen off (gladly this wasn’t lost!) and the metal plate doing the switching was gone. Battery door and the slide pot knobs were missing as well. So the unit was in no condition to call it collectible or even working. Since the swtiching matrix itself was in working order, i made a new metal switch out of a washer and used heavy duty two-component glue to put the rubber mat back to its place – and what do you know, it works. Due to missing battery door i removed the battery leads as the unit would be next to unusable with a battery anyway. Now the unit was just left with missing battery door and slider knobs. I don’t think i’ll be able to locate either of those, so this’ll be the state this pedal will stay. At least for now. But in a case a duplicate was to appear…


Before anything, the aesthetics usually play a huge role how o perceive pedals. Just look at the hand pointing to the power jack receptable! That is the kind of thing that always brings the smile and good vibes. Just like this wasn’t enough, removing the bottom plate shows a circuit board that is true work of beauty. Beautifully assembled board with soldered strips and so on. One negative thing is clear though. The board can be removed from the enclosure by either breaking or unsoldering the in/out jacks. One will suffice, but break or unsolder nevertheless.


With extremely flat housing, not much higher than a 9V battery itself, this and its peers from the same series are true beuties, but still these manage to remain as weird birds of all pedals. These seem to get their high lisitng/asking price from the age alone. Not so much due to the aesthetics or designs. Which would be way more interesting factors.  For some reason this unit and series simply doesn’t feel solid enough to warrant the usual high asking prices. And remember kids. Detachable battery door is always a f*n stupid idea. Avoid those at all cost. Otherwise, Multivox engineers did not go under from where the fence was at its highest. These pedals exhibit heart warming examples of engineering of their day. When the size is taken as a factor, these are very beatiful pedals indeed.

By the sound, controls and fact that i saw the component side of the board (and didn’t realize to snap a photo at that time), i’d go as far as to call this a derivative of EHX Small Stone. Which does mean a few things as is..

How does it sound?
Fat, slushy, twirling, psychedelic and not hurt by its relatively sluggish control range consisting of only LFO rate and effect depth. Still the overall tone is not just powerful but sweet as well. I don’t have much negative pointers for the unit in any way. The battery door design may be the biggest one, when talking about issues of Multivox Big Jam pedals. Maybe one could also argue that the floating plastic jacks are another issue. If that was argued, i’d remain dormant and just maybe nod my head as a sign of silent agreement.

To sum it up, Big Jam pedals are beatiful specimens of design and manufacturing of their day. Not so much usable stuff for todays guitarists or keyboardists. I’ll definitely keep my eye out and get more of these, if the price is right.

P.S. If Multivox is unknown brand to you, i suggest you check out wikipedia.

Marshall RG-1 Regenerator

Sunday, March 8th, 2015


What is it?
Marshall RG-1 Regenerator multi-modulation effect. Made in china, possibly around early 00’s

Digital chorus/phase/flange multieffect in the small metal series? Apparently yes. And once we open it up, there’s very little doubt of what the design is all about. Yup. It’s exactly the same board as seen in Echohead and Reflector.


All these three are sisters with the same topology of TI DSP, Atmel and BSI chips. As we’ve seen with many other modern digital designs, the electronics are all the same, but the code burned n and the label on the top are the only differentiating factors.


Mostly the pedal is well made and definitely represents the top quality of current chinese manufacturing. It could be that the Marshall quality control is strict, or at least stricter than for what we find in many other current chinese made brands with a low price point.


I recently saw a same enclosure used with completely different brand on eBay. Sort of like when Daphon started to sell their own “soundtank-like” pedals as E10-series. Wonder how the british mother company feels about that. Anyway. The pedal has decent set of features and while the digital point makes the sound boringly predictable..

How does it sound?
It is still quite versatile sounding unit. Lacking in taste, scent and personality, but still pretty good. Two chorus modes are not surprising, as the flanger, phaser and vibe modes. The step phaser tries to mimic the random stepping of the Boss PH-3, and succeeds to a certain level. The expression pedal input is a very nice feature that adds a lot usability to the tones produced. To sum it up, this would be a nice entry level multi-modulation pedal for anyone who may need one. Nothing great, but nothing too disappointing. These are widely available and one should be able to score one for peanuts as used unit.

Ibanez PT999 Phase Tone

Saturday, February 28th, 2015


What is it?
Ibanez PT999 Phase Tone. Made in japan by Maxon around 1976.

These units apparently are not as rare as i thought. I suspect that the number manufactured was very high as there seems to be several units available in shops and auction sites even right now. Apparently the units sold very well back in the day. I had a hunch i was not going to buy one of these, since the prices around were looking quite ridiculous. Ranging from around 200 to nearly 500 euros. But, as it turned out, someone had one in a very condition and was willing to pass it over to me with reasonable price tag. The unit was and is in very good, slightly used condition with only small chip on the side panel.  Apparently someone has made it to squeeze the battery snap adapter for the power supply.. This is shown in the photo.


The board is fixed inside a plastic container. Since there is nothing wrong with my unit, i didn’t feel like forcing it open. What comes to electronic design, we have quite standard four stage JFET-based phaser. Dirk Hendrik has a schematic up on his site. The schematic shows a modern Maxon reissue, but i’m pretty sure the main circuit is the same. I’m sure that these originals from mid-70’s did not have dc jacks or indicator LEDs in them coming out of the factory at all. No other surprises, but overall feel is still stronger and prettier than what we find in similar designs. And then for the most important part.

How does it sound?
Amazing. Great soft analog feel that doesn’t spoil the tone of your guitar. While there are similarities with MXR Phase 90, the sound here is just better. Well balanced depth and sufficient speed control are basically everything that you would need. Additional dc jack and more modern switching could be in order, but those do not affect the tone. Which is just sweet as honey. Praised classic and for a good reason. Recommended phaser.

Ibanez PM7 Phase Modulator

Thursday, December 25th, 2014


What is it?
Ibanez PM7 Phase Modulator from 7/Tonelok series. Made in china, 2005

As the truly modern guitar effects go, there are usually those that designers have spent hours to design an effect that sounds great on guitar. Better than the previous takes on this same subject. Then there are these designs that try to create something completely new and something that’s never heard before. These two imaginative design methods rarely combine well. That said, the Maxon engineers behind the PM7 Phase Modulator have reached a line that’s not often crossed. The controls are loaned from flanger designs and the versatility of Speed, Depth, Manual, Feedback and three LFO waveform modes, in addition to four/six stage switch and two in/out of phase modes for the 6-staged phase, is just more than convincing. Manual can be seen at Midimanuals.


Everything is still through hole construction on five board system that is familiar from all the other effects in this series. No surprises in build quality or component selection. The phase utilizes three dual 13600 OTA chips. SO every phasing stage has it’s own half of the chip.

The factory schematic is up at Yes, since it’s 7-series factory schematic, it is a pain to read.


Buffering and mixing is done with obvious Ibanez/Maxon weapon of choice, the 4558. LFO is created with NJM2904D. I’m guessing that the choice for this chip as LFO has been made due it’s stability in case of taking more wobble out of the LFO than what we usually see in any, or at least most, LFO controlled circuits.


Solid construction and designed to withstand a hit. Thick metal housing for everything electronic that is fastened with screws. Nothing floating or other wonky in there. These will be able to take years and years of abuse on the road.

How does it sound?
From mild sweeps that remind us a little of the original MXR Phase90 to absolute noise madness that can be described better with a word monster pseudo-ring-modulator. Well, this is to be expected. If one takes out a 6-stage OTA-based phaser and equips it with more feature packed LFO than most design have, this is what you’ll get. The palette is very versatile and the sounds range from mild to extreme, while still hanging on to term usable. Overall, this is a very good pedal.

DOD FX22 Vibro Thang

Thursday, December 4th, 2014


What is it?
DOD FX22 Vibro Thang from FX series. No serial number (blue velcro on botton plate and rubber+sticker missing), but judging by the graphics, this unit is made in USA, around 1997.

Only few of DOD FX series boxes have received as wide recognition and fan base as Vibro Thang. A few more should have reached the status, but it’s no surprise why Vibro Thang is nowadays so highly praised. It’s a great, solid design that does everything from mild phasing to absolutely crazy, deep vibrato. There is some additional info on America’s Pedal, which suggests that the initial sales after the release weren’t that hot. I personally recall these units were selling for peanuts in the mid 00’s. I got mine around then. The appreciation wasn’t there at the time. Since then something has changed. The prices for these units are still very reasonable. Possibly due to high(ish) number of manufactured units.


Opening it up shows a board that’s on par with all the other US made FX series boxes. Neat design and solid construction. Now, if we take a look at the electronic design itself, we  have two LM13600 dual OTAs, equaling in four phasing stages. JRC chip is the LFO. There’s a copy of factory schematic donated to Freestompboxes forum, but you’ll need an account for the forum to see it. As a side note, the D6 thing on the America’s Pedal page is wrong. This LED is crucial part of the the LFO and it is exactly where it’s supposed to be.


The design isn’t that basic or something we’ve all seen thousand times before. The idea of having OTA stages for phase/vibe isn’t all new, but controlling how the LFO affects the phase and vibe is another story. So we basically have controls for phase stage feedback, in this case known as Regen, or Image. RPM, or Speed controls the LFO rate. Control named as Width/Drop is our vibrato depth and control called Phase/Intensity controls the phase depth. Not too obvious, but referring to the schematic it all sort of makes sense. With any given combination of Drop and Intensity, we’ll achieve beautiful and different phase/vibe tones. And what’s even more important..

How does it sound?
Any given settings sounds just awesome. It  can be wild and it can be mild. But there’s very little unusable area on controls. Sounds like a perfect vibrato and a perfect phaser. Or a perfect mix between the two. And since the design with four OTA stages hasn’t been done over and over by everyone (before like couple of the other methods of creating a phase and a vibe), the personality in tone of this effect is notable.

Usable. In the biggest meaning of the word. And for me, this pedal is important. For its sound, good controls and, well. Everything.

Dunlop/MXR M-101 Phase 90

Thursday, October 30th, 2014


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 later, but here’s a photo of the board. Modern, with amount of layered ground fill that will blow your mind.


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.


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 Small Stone EH4800 Phase Shifter

Sunday, 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.

Systech Phase Shifter

Wednesday, September 10th, 2014


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

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


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

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

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

Boss PH-3 Phase Shifter

Monday, September 1st, 2014

One more Boss before moving on…


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

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

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


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


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

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

Pearl PH-03 Phaser

Friday, July 11th, 2014


What is it?
Pearl PH-03 Phaser from Sound Spice series. Made in japan around early 80’s.

This is one if those boxes i managed to buy off from mr. Lindèn and it came with reasonable price too. The unit is very lightly used and it even has its own retail box with minimal wear. These do not come by every day. For example, at the time of me writing this, there are no units listed on eBay. According to, these usually sell for something between 50 and 100 USD. This feels a bit low as there are not that many units available. Maybe this phaser simple hasn’t had the cult status of the overdrive or octaver boxes from the same series. I personally think it should. Here’s why.


Classic hand drawn acid trip traces on a fat old japanese style PCB gives out eye candy that you can expect from similar boxes of the era. Solid quality and beauty combined. Pedal is made out of two different boards. One for bypass switching and the main board. Flipping the board over gives out a view that one did not expect to see in a phaser. I was waiting to see your standard Phase 90 derivative or something similar where phaseing is done with discrete JFETs. No. There are obvious modulation stages, done with dual opamps and an LFO, which doesn’t seem that standard either. The big chip in the has been painted black so tinkerers would have a hard time finding out what it is. Since there’s no telling what the chip is just by looking at it, i thought i’d check for a schematic if that would shed some light on the matter. There is an old factory schematic up at FIS. No luck. The schem says it’s “exclusive use”, which in pedals, usually means  that it isn’t that secretive, nor is it made exclusive for this design. Usually these are your standard parts that are just obscured. I didn’t want to stop there. I found an discussion about the circuit on FreeStompBoxes forum ( you may need to log in to see it). Anyway, someone had bought one of these as a defunct unit and found MC14069 chip where IC4 should have been. So it’s pretty obvious that someone else had already tried repairing that unit – by replacing the chip for something that clearly isn’t the right one.


User Tube-Exorcist suggest that the original chip may be a AM79C11 (can’t find any info or datasheet about it), a obsolete quad JFET. Which would definitely make sense.

The design isn’t your run of the mill phaser. The LFO isn’t anything too exotic, but the modulation stage is. May the chip be what ever, it isn’t usual to have a quad JFET DIP16 chip in your phaser. If the chip is (and it probably is) a quad JFET, that would mean that the design is in its heart a four stage phaser. Still a sort of derivative to Phase 90, but not exactly. Either way. This offers some mystery and i like it. Besides, the four effective controls are also something that every other phaser doesn’t have.

How does it sound?
Lushy and wild. Not as deep as EHX Small Stone, but a lot more powerful than your average Phase 90 and its derivatives. From mild, slow sweeps to nearly massive wobble. Feedback and manual controls offer a lot of room for variation. It is very nice sounding phaser. Probably one of the greatest ones with only four phasing stages.