Oncle Archibald gypsy jazz trio

In the already large array of button-style piezo transducers, a small German company came out with an interesting solution to the most typical problem that this type of sensors present,  wich is the placement of the sensor itself on the soundboard.
Depending on where you place the pickup, it will capture a certain fraction of the vibration pattern of the instrument’s soundboard, giving a slightly different sound with each different placement. The intrument’s overall sound will be reproduced, of course, but anyone who has used this kind of pickups know that certain tonal differences, can definitely be obtained placing the sensor in different spots. Sometimes a certain position will give you a deep sound, but with a feeble attack, while another placement can produce a crisp but hollow voice. Sooner or later the optimal spot can be found, but at Marvin Pickups thought that increasing the number of sensors can also increase the richness of the amplified sound.
The “doppel pickup”, as it is called by this small artisanal company, has two sensors, one slightly bigger than the other, wired together in a rugged connector jack, also fitted with safety lock.

In my old Eko BA4 acoustic bass I fixed the jack to the tailpiece with two Velcro cable ties, since the weight of the massive jack connector, if left dangling, tended to raise the two sensors from the soundboard. The sensors, like in any pickup of this kind are attached with a simple adhesive paste similar to putty.

The yield of this system is quite good, simply because two sensors can detect a more complex vibration pattern than just one. Obviously, even with this kind of pickup you should at least experiment with different positioning of the two pads. There is always the risk -for example- of placing the two sensors on two spots that are reciprocally on opposite phase, and the result would be a damping effect on the overall sound. Let your ears be the judge.
One flaw that I can point out is related to the thickness of the sheath that protects the pads’ wiring.
As shown in the photo, the sensor’s surface has a kind of step, because of the aforementioned protective sheath. The thickness of the putty applied to attach the pickup to the instrument’s soundboard kind of levels everything out, but I’d prefer a sensor with a perfectly flat surface, just to ensure a homogeneous adherence.
The company that makes these interesting pickups also seems a bit mysterious, lacking a true website and having a Myspace page only. Although still very small-scale, it might be wise to give it more visibility and appeal, because the products it offers are pretty good and also pretty cheap (the doppel pickup costs 44 euros, and I bought it through Marvin Pickups’ eBay store).

Alessandro Arcuri

Oncle Archibald

Not always the equipment that a musician uses has to be made especially for a given instrument.Sure, there are amplifiers, effects and accessories specifically desinged for guitar, bass and so forth, but often the so-called “all-purpose” equipment can be a real ace up the sleeve.A simple, and therefore very effective pre-amp like Presonus’ Tube Pre, is a fine example. I noticed its versatility when, one day, my Trace Elliot GP12 SMX bass head showed serious problems in the input jack; naturally, during the soundcheck for a concert! (As I later learned some pins that connected the input jack socket to circuit board got unsoldered and went loose). Unable to use standard instrument input I realized that I had in my suitcase  the Presonus preamp (which I usually use to “warm up” the signal from the piezo upright  bass pickup) and I decided to plug in with my electric bass into the preamp. From there my signal went into the effects return of the head, therefore bypassing the entire section of the Trace Elliot EQ and compressor, and going directly into the power amp section.

The result was a sound with an incredible dynamic range and broader timbre than I was used to; but then -you know- the less you process the sound with EQs, filters, etc etc, the better.

The Tube Pre is indeed a very simple tube preamp (its valve is a classic 12AX7) with only two controls, one level and a gain control. The other buttons on the front panel are just a small level attenuator (20 dB, which is useful if the input signal is already high by itself), a low-cut filter, which attenuates the frequencies below 80 Hz (needless to say, I do not use it), a reverse phase button (handy in case of feedback) and a phantom power switch, which is useful if you connect a condenser microphone, for example. A practical gauge needle shows the level of the input signal.
On the back panel there are the inputs and outputs, both balanced and unbalanced. You can therefore use the TubePre with a normal amp, plugging it in the amp’s input with a normal audio jack, and also as a DI, using the balanced output.

The transparency and dynamics of this pre-amp make it suitable for many applications, both in studio and live context, especially where the least “coloration” of your instrument’s sound is needed. I’d say that using it with an acoustic instrument is a wise choice, either with a piezo transducer, or with a microphone. Perhaps the only flaw is its peculiar voltage rating that at 16 volts makes it almost mandatory to use its proprietary transformer. In case of failure it is very difficult to find another adapter that can replace it and you’ll probably have to buy the original.

Alessandro Arcuri

Oncle Archibald