Stateline Amp 2

• Inputs: 5x line-in RCA, SPDIF-RCA, USB-A
• American walnut feet
• Treated with additional OsCon caps, e-pads and Maestro finish
• minimalist, stylish design
• Stainless steel cabinet and glazed front panel

HiFi high-end amplifier- The Stateline Amp2 is the result of years of research in which we have optimized every detail of the circuit topology, as well as the selection of the optimal components in each place according to our understanding of music. In an integrated amplifier with DAC, line-stage and power amplifier, this is quite complex, as there are many interactions to consider. The advantage on the other hand is that we can create an integrated device with very coherent characteristics.

Line Stage

In the Line Stage, following Einstein's statement, "Everything should be made as simple as possible, but no simpler," we started with a one-transistor circuit, with no negative feedback. This sounded nice with an extreme selection of active components, so it worked properly as intended. THD are mainly second order in the 0.2% range, which we personally prefer to a lower percentage of distortion if they are third or fifth order. In any case, lower distortion means more real information - if it is not accompanied by higher transient intermodulation due to negative feedback. So we have obtained a circuit with two transistors, where the second transistor works as an error correction amplifier, not in the actual signal path. We have no feedback from the output of the line stage to the input with all its negative aspects, but we were able to reduce the distortion of this stage to 0.001%, keeping the aspect of distortion mostly second order.
Listening comparisons show that there was much more musical information with this concept, as it was two orders of magnitude further from the distortion level.

Power amplifier

As we are usually friends of discrete transistor circuits, in this case we decided to take advantage of the shortest possible signal path of an integrated solution.
The output stage runs in a bridge circuit mode, which means that there are two amplifiers per channel, and the plus and minus terminals of the speakers are connected between these two amplifiers.
So there is no current flow on the ground plane, which is very positive for low level resolution, since ground is the reference point for all signals.
Another aspect is improved damping of the speaker, which is pushed and bound by two amplifiers.

Volume control

Remotely controlled custom Alps Pot with linear characteristic, which has a much better matching between channels than any log pot. It has special taps where by adding a resistor with a specific value we can perfectly match the characteristic to the characteristics of the human ear, without the disadvantage of poor channel matching that is in the nature of a log pot.

Power Supply

The power supply is another fundamental component with significant sonic impact on the overall sound. After trying various topologies here, it turned out that a professional switch-mode power supply developed by was a perfect match and sonically outperformed various transformer-based solutions as well as other switch-mode power supplies we tried.
All stages are decoupled by 5 different voltage regulators, using low-noise discrete circuits for the line stage and the DAC. The total power supply capacitance besides the base SMPT is more than 36000μF, combined by different types of caps selected for their sonic performance at each location.

DAC

The DAC is a non-oversampling concept that offers bit-perfect performance and can be fed via SPDIF or USB. The Stateline Amp 2 accepts sample rates up to 96KHz.

In conclusion, it shows that the Stateline Amp 2, despite its small size a HiFi high-end amplifier all honor.

Review