Kelso Signature Dac

Kelso Dunes, Mojave National Preserve, California are also a rare “singing dune” field. The National Park Service describes its famous booming sound as deep enough that you can feel the vibration through your body. By leaning into our history of transformer development we were able to bring forward transformers that reflect the idea of a singing device able to transmit the deepest sonic waves and emotions. Hyperbole aside, we doubled down on our transformers and knew that only fully point to point wiring would relieve any bottle necks.

The story of the Kelso Signature DAC came about from the idea of wanting to build a DAC that fully represents the values and execution capabilities of ampsandsound. Beyond our commitment to transformers, tubes, and simple circuits, this meant doubling down on fully point-to-point, hand-wired construction and eliminating circuit boards from the analog signal path. We believe how a circuit is physically built matters, and hand wiring gives us control over component placement, grounding, wire routing, lead length, and the relationship between the delicate audio signal and power supply that simply cannot be approached in the same way when a circuit is designed around mass-produced PCB construction. Every connection beyond the digital section is made by a person on our own custom turret boards, with every component and signal path visible, accessible, and intentionally placed. There is also a larger idea represented in this approach. PCB construction is exceptionally good at producing thousands of identical devices efficiently, but Kelso was never intended to be a mass-produced idea. We believe the human touch remains superior for the type of equipment we build, where the person constructing the device is participating in the execution of the circuit rather than simply assembling parts around a board. Just as importantly, this method creates a device that is near-infinitely repairable. There are no multilayer boards containing inaccessible traces or proprietary assemblies that require the entire device to become obsolete when one part fails. A skilled technician decades from now should be able to open a Kelso, understand exactly how it was constructed, identify an individual resistor, capacitor, wire, tube socket, or transformer, replace what is needed, and return the DAC to service. Hand wiring isn’t nostalgia and it isn’t simply about making something more difficult to build. It represents our belief that high-end audio should be built deliberately by human hands, optimized for sonic performance rather than manufacturing efficiency, and constructed with the expectation that the device should remain both relevant and repairable for generations.

The digital section remains the trusted single chip NOS R2R solution that is theAD1865. All wiring beyond the digital is down on our own custom turret boards, to employ our custom circuit.

Our DAC strategy calls for a Resistor Ladder DAC architecture as opposed to the more common Delta-Sigma computer processing style DAC. Rather than using feedback loops and high frequency oversampling clocks. R-2R DAC turn on each required bit in the digital ‘word’ and the exact amount of current will flow from the chip to reconstruct the analog waveform. The method is perfect in its simplicity is closest to an analog sound.

The founding idea is a robust power supply with multiple points of active and choke regulation but devoid of any integrated circuits or regulators. The idea is the power supply feels more alive by removing the regulators and their nasty by byproducts.

The IV transformers are proprietary to ampsandsoudnand tuned considering the total performance of the dac not the theorecticeal ideal. Delicate analog current signal that comes out of the AD1865 chip is run through a high quality resistors to create a voltage representing the audio signal – this signal is then transferred through a 1:1 (I/V) transformer which allows this ultra delicate signal to land on the line stage fully intact. Our approach doesn’t just chose the closest best choice based on a spec sheet but both measured performance and extensive listening tests to pic the final design that expresses our voice and yields max performance.

Once past the IV transformers the audio signal is amplified in the output tube stage which comprises of a 12au7 input tube and an ECC99 output stage.

Fully point-to-point hand wiring is central to how we believe high-performance audio equipment should be built. Rather than forcing the circuit to conform to the fixed traces of a PCB, hand wiring gives us direct control over component placement, grounding, lead length, and signal routing, allowing us to optimize the circuit for sonic performance rather than manufacturing efficiency. More importantly, it places the human builder at the center of the process. Every connection is made and inspected by a person, and every resistor, capacitor, wire, socket, and transformer remains visible and accessible. The result is a device that is near-infinitely repairable. Decades from now, a skilled technician should be able to understand the circuit, replace an individual component, and return it to service without depending on an obsolete proprietary circuit board. Hand wiring isn’t nostalgia; it represents our belief that the human touch remains superior to mass production when building equipment at this level, creating something intended to perform exceptionally and remain serviceable for generations.

The final part of the output stage is our custom output transformers. For those who know ampsandsound reputation for custom absolutist transformers, these outputs are no different. They are wound by the same team that winds outputs for our amps and places tone and performance above all else.  

Specs:

Output tubes: 12au7 / ecc99

Power Supply 6CA5, ECL82

Line stage – Jupiter copper film+Silver bypass.

DAC Board CS8414 receiver , AD1865 analog conversion

IV transformers with nickel core laminations

Output transformers 200% oversized and wound with significant interleaving for extended frequency response.