Soulnote A-1 Integrated Amplifier
" No superfluous sonic artifacts ... A 'mature voice' combining an enormous amount of color, naturalness, and impressive control and authority ! "
Roland Kraft - Stereoplay / Germany
Perfectly balanced, discrete non-NFB channels
To extract the best from the unique characteristics of SOULNOTE's original perfectly balanced, discrete non-NFB circuits, we re-examined every minute detail of our amplifiers for possible improvements, like incorporating ground plane star wiring, centralizing local non-NFB regulators, implementing direct coupling routes, optimizing the tuning of the drive current, and more. This helped us achieve even more vibrancy and speed while also providing a wider sound range.
High-speed, discrete non-NFB power supply
In addition to a newly developed bifilar wound, large capacity toroidal transformer with independent positive and negative windings, we have lowered the impedance by connecting multiple high-voltage, small-capacity filter condensers in parallel and incorporating a fast recovery rectifier diode. We have also completely refined the smallest details in order to boost the power supply, such as making current loops as short as possible by placing the rectifier diode close to the power transformer. This further increases S/N and speed
Every type of connector in the signal system has been eliminated to create a completely contactless construction. A three-dimensional print board assembly results in lower impedance in the power supply lines and wiring that focuses on star wiring. This improves S/N and removes any concerns about contacts deteriorating over time.
Output transistor pairing
The output transistors feature low Cob, high Ft, and have extreme accuracy. We have selected and paired these components based on their characteristics. They work together to increase sound image focus and deepen three-dimensionality.
Other Technical Features
Relay-switching balanced attenuator
The volume control in the A1 does not use a conventional rotary or electronic volume control. Instead, it uses a newly developed relay attenuator style balanced configuration. This dramatically increases clarity, and allows the sound image to emerge in three dimensions. It also significantly improves quality at low volume levels without fear of gang errors.
Direct mechanical grounding construction
Spikes connect to the bottom of the transformer's center of gravity to directly expel harmful vibrations without interfering with the unit housing itself. This achieves both supremely vibrant musical expression and a high S/N.
Symmetrical housing with resonance control
The housing's symmetrical construction increases rigidity balance while controlling the sharpness of resonance (Q factor). This eliminates the usual sensation of sound containment in highly rigid systems and creates the high resolution, expansive SOULNOTE sound. The newly developed, heavyweight aluminum front panel design also helps control resonance.
Metallic insulators as standard equipment (when under load)
Though plastic insulators are the conventional standard, we now use metallic insulators since they promote higher sound quality.
80W rms into 8-ohms
120W rms into 4-ohms
Frequency Response (8ohm / 1W)
3Hz – 300kHz (+/- 1.0dB)
LINE 1 (Balance): 700mV / 16kohm
LINE 2, 3, 4 : 700mV / 8kohm
Less than 0.08% (30W / 8-ohms)
110dB (IHF A network)
Dimensions (W x D x H)
430mm x 418mm x 109mm
22 lbs (10 kg)
Fostex FE88 SOL
What they say ...
“…No superfluous sonic artifacts ... A 'mature voice' combining an enormous amount of color, naturalness, and impressive control and authority ! ...”
"Conclusion : Kato-san put a lot of thought into this amplifier ... so the listener doesn't have to. The Soulnote A-1 is a real sound machine with which you can experience music in wonderful liveliness and emotionality. The open, carefree nature of this integrated amplifier makes it immediately 'likeable', and allows the user to overlook the small idiosyncrasies of the device. The A-1 always gives recordings a considerable size, gives the individual elements room to develop, and thus creates an experience with a lot of depth that lets you fully immerse yourself in the music.
Despite its tonal qualities and the philosophical approach to its technology, it is completely unpretentious and as honest as its sound. This Soulnote is actually a 'real' Little Soul.”
LITE / Lifestyle & Technik Review / August 2022
"Conclusion : The precise, always energetic, exciting character of this unusual amplifier
goes hand in hand with a very deep, highly detailed sound image in front of a black background; Clarity, transparency and, above all, freedom from artifacts are extremely pronounced here - no "superfluous" sound, no unnecessary showmanship, mature - in the best sense of the word, all this combined with an enormous amount of color, naturalness, but also impressive control and authority.
Given the asking price, this device is waaay above its range ! So if you ask us : This is definitely one of these 'insider tips' ... our soul-felt compliments to Hideki Kato ! "
Stereoplay.de Review / November 2022