Archive for the ‘9-Series’ Category

Ibanez SD9M Sonic Distortion Mod

Sunday, March 8th, 2015


What is it?
Ibanez SD9M Sonic Distortion Mod from the modern 9-serie “reissue” line. Made in china, early 10’s

I still haven’t been able to score the original, classic Sonic Distortion for a reasonable price, but i did manage to find this one a while back. And as usual, i needed to see what it’s made of. The box  is a modern version of the familiar classic with a battery door and four screw fixed bottom plate. Followed by a insulating plastic between the circuit board and the plate. The circuit is fastened to the box with another screw. What  comes to the board itself, this looks like all the modern 9-serie boards. More modern than vintage units, but still quite neat.


Similarities with the other new niners continue once the main board is lifted. Everything is board mounted, but still keep the feel high. Offboard wires are connected with plastic terminals to keep the manual labour in reasonable scale. As with 7-series, all the different parts have their own circuit boards. One for main board, one for control pots and one for each in/out jack. In this case, even the two toggle switches have their own PCBs.


What comes to the design, there is a traced schematic (sans switching circuitry) up at Aion’s page. When compared against the original, non-mod version, there are a number of differences, while a few key parts are in tact. Both versions have a transistor based input buffers, followed by a gain amplifier opamp channel. Next up, tis version has a gain switch which sets the gain from normal no amplification in one position to the second which has 10 times the level. After those it’s the hard clipping diodes shunt to ground and the tone control. The not completely different to big muff tone stack section has also a switch for swapping a cap value for the one that handles the low pass filter.


After those, the mod version has a half of an opamp for output buffer, which is not present in the original. In other words, the modifications to the original circuit are more than just added two switches which are the most visible changes to the pedal. These are gain and mids modes that alter the signal level before the hard clipping stage and the low pass filter on the tone stack. In a sense the design is clean boosting opamp driver stage, followed by a Rat styled hard clipping, followed by a Big Muff style tone control. Rest of it isn’t affecting the tone as much as those building blocks. What’s more interesting is that…

How does it sound?
While i do not have the original SD9 at the time writing this, i’ve played around with the circuit on a breadboard and cloned it. If my aural memory serves me even remotely right, there is still the same powerful and neat distortion present for both models. Soaring and definitely usable. But for the added gain and versatility for this mod version, we have a very nice distortion tones that are very much relevant today. High gain mode can still boost the modern high output pickups while still sounding great. And the non-boosted mode will give the sound and feel of the original SD9. Although it’s all relatively simple and there isn’t any super high wow-factor in the design, i was blown away when i first tried the circuit. It may be due to its simplicity, but man it sounds great. Recommended pedal to try out.

Ibanez BB9 Bottom Booster

Wednesday, September 3rd, 2014


What is it?
Ibanez BB9 Bottom Booster, from modern 9-series. Made in china around 2010 or so.

There are only a few Ibanez designs that are more like meh. This is definitely not one of those. I had interest for this for some time, before i spotted one for reasonable price tag on one auction site. This particular unit was apparently a demo unit for some store. Very little wear and nice near mint condition with original  box and papers. Played with this for quite some time once i received it. There is a beautiful traced schematic up at Dirk’s page, so there were no rush in seeing how it is made. Reason for opening it wasn’t as usual as for most pedals.

That reason being a small mishap on the studio floor. I had just recorded all base guitars for 11 tracks of 12 for the album we were doing. I thought i needed to add a bit of reverb for the other effect line. I took my previously repaired Boss RV-2 out of the bag and chained it with all the other pedal in that chain. This resulted in nothing more but a hiss. Something went terribly wrong and my BB9 was dead. I figured it had to be some sort of power surge, but since i (obviously) didn’t have suitable tools or spare parts with me, i had to make due with other solutions for the second effect line on the last track.


Once the unit was back at my desk, the fault was easy to track down. No power. This is where Dirk’s schematic came in really handy. Don’t know how that surge occurred, but it burned the DC-DC converter (a.k.a. charge pump) chip. As you can see in the (crappy) photo below, the chip on top left is socketed. I almost never use sockets for anything, but since the charge pump on this one *can* die, i figured it’s best to have it socketed. After swapping the chip and polarity protection diode as a precaution, the box rocks again.


To get going on this post, the design of the BB9 is solid Maxon quality with modern board design and manufacturing method. If you checked the schematic linked above, you’ll see a power supply section that creates a bipolar +9/-9 volt swing with LT1044 DC-DC converter. This means that the pedal runs actually on 18 volts, using ground’s zero volts as a reference voltage.  For me and my fix, i only had ICL7660S chips at hand, but these are pin-to-pin equivalent and they can be used as a drop-in replacement for each other.

On the topology, is one half of JRC4558 acting as input buffer. Then we have dual gang potentiometer setting the level of signal passed to gain recovery and the actual gain of the clipping amp that is paired with a static gyrator that sets the boosted frequencies. After these we have active tone control to have nice control over the treble content. This leads to level control and output. Not too conventional way to create overdriven boost.


What comes to box design, it surely ain’t as aesthetic as the 30 year older 9-serie units. It isn’t ugly though. Sort of reminds me a bit of build methods we can find in Marshall small metal series pedals. Pedal follows the original series on the enclosure and carbon film resistors, but not much else. Here we have four separate boards to ease the manual labor. Neat and beautiful on the outside, but pretty dull on the inside – except for the circuit design.

How does it sound?
So good that no words are enough to match it. BB9 offers mild overdrive tones with really, really good sounding frequency response. It is not a distortion nor a classic overdrive in sense of tubescreamers or others, but something that brings your tube amp alive in a manner that can only be matched by few others. Also, it’s not a clean booster. It is a pedal that will give out better, no matter how subjective that term is, overall tone. Little bit of grit and boost combined. Even the voltage swing has a strong emotion-like feeling of great amount of available headroom. This is definitely one of the greatest sounding Ibanez branded boxes. Ever.

Ibanez TS9 Tube Screamer (Reissue)

Thursday, October 10th, 2013


What is it?
Ibanez TS9 Tube Screamer Reissue, made in japan. According to my guess on the serial, this is probably made in 2008. Got it used but in fair condition.

This must be one of the pedals with most information written. Sad thing that the reissues aren’t getting as much attention. No one seems to care about dating back the serials on these. Oh well. Teared mine open, and the box is exactly like the original 9-series boxes from the early 80s. The bottom insulation is better and non-removable though. The sight that welcomed me was like meh. Modern looking traces on modern thickness board. Not the acidy cool traces, nor the thick board that spreads confidence. All three of my Soundtank TS5s has thicker board than this specimen.


Components are close to the original, which makes this function like the older units. This specimen even has the JRC4558D chip in it. Not sure if there really is an audible difference between 4558 and TA75558. I’ve modded couple units before and tried both on with a DIP8 socket. Slipping in to heresy section, i personally believe that NE5532 is the best suited chip for this circuit.

Once again, refer to GEOfex article for more information on the circuit itself.


This one will surely get modded if i come across another unit for reasonable trade or price. Designwise this reissue is really nice pedal. Soundwise…

We could have a debate on if this design gets better with true bypass. My personal view is no. True bypassing buffered effects with electronic switching should only be done when there is something very wrong with buffering or there’s too low input impedance which leads to pickup loading and therefore oscillation. Hype of true bypass just isn’t worth it. I’ll talk more about this issue at some point. Maybe on some Colorless writings chapter…

How does it sound?
Well. What can i say? The cold dead hands slaps you on the top of your head. Unless. You have super sucky pickups. Then this puppy rocks. Sounds exactly as it should. Mid-honkin, bass-strippin medium overdrive with medium output. For live situation to get your mids heard over everything else. Not for anything else. A classic one trick pony. Prime suspect for modding the inverting input for more bass and gain.

Ibanez AF9 Auto Filter

Wednesday, August 21st, 2013


What is it?
Ibanez AF9 Autofilter. Made in japan in early 1980’s.

Even though i don’t see myself as a huge fan of autowah/envelope filter genre, i happen tohave a few specimens. The way envelope filters, aka autowahs usually work, is that there’s an driver part that triggers the filter when certain input level threshold is achieved. Then the filter sweep is mixed with the incoming signal. I do believe this design works in the same manner. Quick googling around did not give me the schematic. Because of this (and in part because i haven’t had the time to analyze the circuit more deeply),  i can’t offer deeper understanding of the circuit at the moment. Reliable sources tipped me off that this should be close to Ibanez AFL, the Auto Filter from the Ibanez L/Master Series.


Older Maxon/Ibanez PCB layouts are just beautiful pieces of art, don’t you think? The traces are like perfectly aligned acid trips. Just beautiful. Even the joints are beautiful.

I find all the controls useful. Sensitivity affects how easily the filter sweep is applied to the signal, Peak then takes care of how hard the sweep affects it. The slide switches alter the filter type between low pass, band pass and high pass, all of them affecting the different parts of the frequency range. The sweep can be driven from up to down and down to up with a switch. And finally, Range setting makes this usable with bass.

Apparently these boxes have quite a lot of user and collector value.

How does it sound?
Greatest sounding autowah i’ve ever played. Versatile, yet simple. Schoolbook example of how autowahs/auto filters should be made. It can do wild, almost synth-like sweeps and standard funk sounds. From rhythms to leads. Useful, even when your music isn’t funk.

The range of settings are good. None of them kill the signal or behave badly in any way. This unit makes me feel good in so many ways.