Archive for November, 2014

EHX Octave Multiplexer (XO)

Friday, November 7th, 2014


What is it?
Electro-Harmonix Octave Multiplexer from XO series. Made USAaround late 00’s

No. I’m not writing everything about this again. Just check out the post about EHX Octave Multiplexer Reissue. The main points for the design are written in there. There are a few differences between these two units, mainly on construction methods – that’s why i’m posting these separately.


From electronic point of view, this is exactly the same effect as the big box reissue. Only differences are the manufacturing methods and the type of components. While the reissue tries to stay true to the vintage Octave Multiplexer, the XO series version just tries to add more user value to the design.


The main difference in features is the “Dry out” jack placed next to the “Wet” output jack. This allows the user to split the signal to two paths. First for the sort-of bypass and second for the processed signal. Nice feature, but has few applications. Supports experimentation though. And that’s not a bad thing.

How does it sound?
Exactly like the huge box reissue. Both of the versions sound exactly like each other, so in reality there’s not much point in having both. Unless you love down octave divider effects and are a pretentious asshole, also known as the collector. Again – For a bit more in depth article on this circuit, check out my Octave Multiplexer Reissue post.

Ibanez TK999HT Tube King Distortion

Tuesday, November 4th, 2014


What is it?
Ibanez TK999HT Tube King Distortion. Made in china, late 00’s.

Not sure if the TK999HT is currently in production anymore. Ibanez site doesn’t list it and many european internet shops don’t have it on their listings. At least not any more. This high gain distortion is somewhat impressive by its appearance. The box is huge and heavy. The rubber pads on the bottom plate are something like 40mm in diameter, while the box itself measures 15x15x5 cm. Enclosure isn’t aluminium.

As the features go, we have the usual drive/level controls, a three band EQ with low/mid/high controls and a presence switch. Since the amount of gain is very high, there’s also a “Void” control. This is your noise gate. Other Ibanez boxes have had the same feature, name some high gain distortions from 7-series. The box feeds itself on a 12V AC power supply and has its own transformer and rectifier diodfe bridge inside.


In a sense, this configuration reminds me of those hybrid guitar amps that exploded in popularity in the 90s. In fact, this comes pretty close, minus the output amplifier. Dirk Hendrik has drawn a schematic of this one too – here. Even without the noise gate and power supply section, the design is taken one step further from the basic boxes we see more often. In essence, we have input buffering, followed by driver amp and gain control. After those there’s two tube driver stages, a buffer to decouple the tube. After that, there’s presence switch and tone controls. All three tone controls have their own cutting/boosting gyrators. Followed by output buffering. Void circuit in on mode, is attached in parallel with the effect circuit. Dirk’s schematic doesn’t disclose what’s the voltage being fed to the tube, but it sure isn’t the same 12V DC being fed to to rest of the circuit. Complex and somewhat impressive.

If i was to come up with one, biggest negative side to the design, it would definitely be the location of the tube. The ventilation is sufficient, but the previous Tube King boxes had the tube in plain sight, making it simple to swap for another type of tube if desired. This time the tube is placed so that it’ll require disassembling most of the insides to get to the tube. Somehow reminds me of older cars versus newer cars. One should be able to change the burned out headlamp by oneself. At least in my opinion.

How does it sound?
Modern High-Gain. Maybe slightly too modern and too high-gain for my personal taste. Due to amount of gain, the noise gate (or Void) is a good thing to have. While this may be a bit too much in distortion department, the output level is high enough to use the unit as a soaring lead monster. Due to it’s nature, i don’t see myself using this for base sounds on any set of settings. But as a solo distortion? Yup. In that scenario the pedals shines. And bright.

EHX Germanium OD

Saturday, November 1st, 2014


What is it?
Electro-Harmonix Germanium OD, “Vintage Overdrive” from XO series. Made in USA around late 00’s.

Creativity. A threat or a possibility? Sometimes it manifests itself as both. And at the same time. I got mine as used for a fair price with velcro on the bottom. By the way, you can use the detached strip to get the residue glue off the metal. Anyway. The internet had only a few guesses of how this circuit was made. This was one of motivators in play when i decided to buy one. Opened it up as usual.


And traced it. If you take my drawing and mirror it vertically, there are some similarities with Arbiter Rangemaster – but not much. The point of the design is PNP transistors reversed with negative ground and odd controls that affect resistance on both, emitter and collector side of the main transistor. Which looks a lot like remake of NKT275. Or possibly even a re-branded NKT275.


Everything about the circuit and the build quality is more or less on par with all the other modern new york manufactured EHXs. No handwiring involved and most of the circuit is made with SMD components. I brought up the creativity in the first paragraph, because this design falls easily into “drunk or genius” category.

How does it sound?
Unusual. Wouldn’t call it good, but it offers that broken 60’s tone when applied in front of a decent tube amplifier. But folks looking for an overdrive.. This may feel like an awful mistake if you are not exactly sure you know what you are getting into. OD may not be a perfect description for the sound this produces, in my opinion. I’d rather call this Germanium Warmer. If considered as a “warmer” instead of an overdrive, this might be a useful tool to nail that sixties teenage garage punk clean tones. Think of this as a Rangemaster style treble booster with full frequency range and less boost. With rather senseless controls, of course. That should land you in the correct park.

Not bad at all. But i still wouldn’t call this an OD.