04 May 2013

Pedals: Phasers - MXR '74 Phase 90 reissue and Electro-Harmonix Small Stone Nano


Note: this entry was already published in my old Spanish version of this blog, around March/2011.
I wanted two compare two of the most typical Phase pedal effects. Both can be heard in lots of recordings.
Even that, because of my musical style, I don't often need Modulation effects, every effect has its place in some or other song so, it's good to have at least one of each type available for when it will be needed.

In the world of modulation effects, Vibe, Phaser, Chorus and Flangers are all cousins.
All them are duplicating the input signal in two paths, a clean path (or dry signal) and a signal that crosses several modulation stages (wet signal) and, in each of such stages, there is some phase shift applied to the signal, in a cyclical way.
What puts the boundaries for each effect type is number of stages, sweep range, speed range and some other particular characteristics for each type.

The Phaser effect is the simpler (conceptually, not electronically) of such effects. The wet signal changes its phase in a cyclical way, at a frequency (speed) rate selected with it's single control knob.
Such a signal is being mixed with the dry signal to produce the sound that we all can recognize.

During the cycle, both signals (dry and wet) have phase differences and therefore, during the cycle, some frequencies are bien cancelled while others are being reinforced.
This affects also to the perceived loudness. By cancelling bass frequencies, lot of energy is missed in the signal and the sound becomes hollow. When basses are reinforced, the sound fattens and growls.

In their higher speed ranges, Phasers are closer to Vibes, while in their lower speed ranges, they are closer to Flangers.
There were two iconic Phaser pedals in the market: the MXR Phase 90 and the Electro-Harmonix Small Stone and, that's why I've choosed to compare both, because they have created the basis for further Phaser effects.
Even that the Phaser effect is similar in both, their different "hearts" are very different and thus, their voices and behaviors are different and distinctive.

MXR '74 Vintage Phase 90 re-issue

Around 1974, MXR released this pedal and, achieved and immediate success. This particular unit is a reissue. Trying to be as close as possible to the original unit, MXR is using here same chips as the original one, while they don't run out of those NOS sourced chips. Therefore, this is a limited edition.

It's being wired to the old school. It hasn't a jack for the DC Adaptor and, has not a led light. Well, to know if the Phase is active or not is easy, this kind of effects are always noticeable.

During the '80 I had one of original ones (bad luck, I lost it, sell it or thrown it!) and, in fact, was one of the 5 pedals I had but, honestly, was the less used effect always.

Compared it against the Small Stone, the Phase 90 has a richer and warm voice. It's sweep is more linear. Once you set the speed control, it seems to shift the same amount of phase per time.
As per my tests, this pedal gives an useful sound during the whole speed range, with a guttural, warm and very musical tone.

Clearly, this is not exactly the same as a real vintage Phase 90 but it goes very close, while the modern take of the Phase 90 sounds to me bellow the tone of the Small Stone.

Electro-Harmonix Small Stone Nano

The original Small Stone is a bigger unit and, it's a real tone-sucker, dropping the volume of your sound and making it really thin. The Nano version of this effect solves all the issues of its big brother (that I also own) and its pedalboard friendly (it even has the typical boss barrel jack for DC adaptor!).
This is a rare case when an evolution of the original pedal goes better. Curious.
While the MXR unit seems to have a linear sweep, the Small Stone seems to behave in a logarithmic way, going slowly during certain part of the cycle and then, faster in the rest of the cycle and this, independently of the speed setting. This makes its sweep different from the sweep achieved with the MXR.

Maybe because of that, the resulting sound is more nasal, bright and metallic.
I have the impression that also the mix of signals in both pedals is different, maybe 60/40 wet/dry in the MXR and 40/60 wet/dry in the case of the EH. This, with the Color switch off.

I've found this Phaser not useful in the whole range of speeds (contrary to the MXR). As we increase the speed, the sound becomes more metallic and, in its extreme setting it sounds close to a ring-modulator, very thin and piercing. Also, at high speed settings, the sound seems digital (even than the effect is analogic), something that doesn't happens with the MXR.

With the Color switch on, everything changes. That lack of linearity in the sweep is being exaggerated way more and, that switch seems also to change the mix ratio, around 70/30 wet/dry.
The sound goes far away the sound of the MXR in this mode and, sounds more like some kind of auto-wah (buy without envelop-following). This is more notable between the 11:00 to 2:00 of the speed knob.

But this mode allows you also to experiment with sounds that we cannot achieve with any other Phaser effect and, that can be interesting. Playing with high speeds, I've achieved comical sounds or curious underwater sounds.


Very different pedals. For traditional Phaser effects, both can work really well. The MXR will bring more color and warmth to the mix, while the EH gives an smoother and transparenter sound (with Color switch off).
The MXR has a wider useful range of speeds while the Smaill Stone sounds ugly at high speeds.
The Small stone has the Color switch, that brings you some special sounds that you will not achieve with other Phasers.
I would leave the MXR on the pedalboard, since is warmer and predictable but, the interesting Color mode of the EH can be of help for certain songs, where that unique sounds are required.

Los Videos

This time, I am just comparing both pedals, without checking how they interact with other effect pedals. There is just one moment when I switch on the Vibe, just to check that at certain speed ranges, the phaser effects goes close to a Vibe.
Part 1

Talking about the Phaser effect, introduction of the units in the comparison and, tests with speed ranges up to 9:00 setting.

Part 2

Test of both units in the rest of their speed range.

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