APL01 Special Edition

Notes

There are a lot of reason why the APL01-SE can be considered a very special

design. The first point is that everything, in this design, is optimized for the pure musical result and not (only) for technical results. This optimization has concerned many aspects, not just those that are usually considered: follow some examples.

The circuit. It is an All Tube, pure class A, Zero Feedback circuit. This circuit gives high technical performances and exceptional musical results. It is an SRPP of 6350/6463 designed and optimized to achieve the “aural” shape of distortion that makes it absolutely transparent for the human ear, as we do in any other Riviera design. No other preamplifier circuit is designed for this goal. Speaking of distortion, pay attention: we do not try to “add” some “nice sounding” distortion, like someone does. Our goal is an absolutely natural result. We do any effort to reduce the distortion as possible, but mostly we try to keep its shape closest to the human ear’s one. To achieve this goal we do not use feedback and optimize any detail, from the working point of the active devices to the best mix of passive components and much more.

The power supply. No switching PSU: it is a traditional and over-sized linear power supply, thanks to its “over 200VA” power transformer (just this “detail” is not usual in a preamplifier). But this is not the point. The point is that also the power supply is designed for music; it makes use of unusual and very elegant solutions. In example the filter: it is a double-PI filter, using choke. The anodic power supply is regulated, but not by a standard series regulator: it is a parallel regulated power supply, with an original design. Overall there are 6 regulated power supplies in the preamplifier.

True Balanced Inputs are made using ultra high quality transformers, with mu-metal core and mu-metal shielding.

The volume control. It is a top quality TKD motorized potentiometer, with an internal LADDER configuration that makes this component different from any other on the market. The result is similar to the best switch solutions, but with the graduality and smoothness of a real potentiometer. It is elastically isolated from chassis to avoid transmitting vibration from the motor.

The balance control. It is made by 2 separate potentiometers on the output, not on the input. This solution avoids the standard “cascade” of two potentiometers on the input (the volume pot and the balance pot), because in our opinion this implies an important degradation of the sound.

The (only) capacitor on the signal is not just a single component but is the “mix” of 3 different size caps using 3 different technologies, tuned by listening tests for the best result.

The balanced output: it is made using custom, extremely high quality transformers. Since we believe that the result obtained is a “reference” result, we have used the transformers also in the unbalanced output. In this way we can ensure that the result of the balanced and unbalanced outputs is absolutely the same.

The chassis. It is our opinion that the mechanical behavior of a device, especially a preamplifier, has an important influence on the musical result. This is why we have paid extreme attention to mechanical construction of the preamp and this is another side of the optimization we mentioned earlier. The APL01-SE weights over 25kg, 25kg of machined aluminum: we don’t think we need to add anything else.

When we refer to listening test and optimization, we mean that we do not try to maximize just ONE aspect of the result (maximum resolution, maximum dynamics, maximum impact, deepest low freq, maximum sharpness, maximum speed, maximum transient response and so on). Our research aims to give the best balance between all aspects, because every part is important in the music. When you maximize just one aspect, you will lose the balance, the harmony and then you will lose the music.

Our goal, with every Riviera product, is to give you the more natural music, like in a live concert.