Differences

This shows you the differences between two versions of the page.

--- audio:audio_by_van_alstine_work [2019/05/22 04:29] – [Vision DAC improved] mithat
+++ audio:audio_by_van_alstine_work [2019/05/22 04:47] – [RB-RC] mithat
@@ Line 121: / Line 121: @@
 **Discussion:** Phew! With the Vision DAC incapable of effectively supporting newer in-demand digital audio formats, AVA asked me to design for them a product that would. The original design brief specified support for up to 192kHz PCM sample rates and DSD64. I insisted on a design that provided support for DSD128 as well and that had the infrastructure to support DSD256 once that format matured. (AVA released official support for DSD256 in 2018.)
-Working closely with application engineers at AKM, I was able to develop support circuitry for the AK4490EQ that provided improved low-frequency reference voltage stability; this in turn reduced the low frequency nonlinearity appreciably over more conventional approaches.
+Working with application engineers at AKM, I developed support circuitry for the AK4490EQ whose low-frequency reference voltage stability was significantly greater than the circuits used in AK4490EQ reference designs. This in turn reduced the low frequency nonlinearity of the DAC appreciably over more conventional approaches.
-This would be the first time AVA would use in-house burned microcontrollers --- and it did so in a big way: I ended up using three independent microcontrollers in the final product, one for each of the DAC’s core functions: input selection and control, DAC control, and the user interface. Also notable in this design is the scale to which SMD technology was adopted and the high level of build integration. These required introducing significant changes to AVA’s manufacturing workflow, but this has brought AVA’s production methods more in line with modern approaches.
+This would be the first design that required AVA to use microcontrollers they would burn in-house --- and it did so in a big way: I ended up using three independent microcontrollers in the final product, one for each of the DAC’s core functions: input selection and control, DAC control, and the user interface. Also notable in this design is the scale to which SMD technology was adopted and the high level of build integration. These required introducing significant changes to AVA’s manufacturing workflow, which in turn has brought AVA’s production methods more in line with modern approaches.
 ===== Vision SLR, Fet Valve CFR =====
@@ Line 131: / Line 131: @@
 **Contribution:** Concept origination, development, and implementation of a fully remote-controllable chassis and supporting circuitry. New for AVA is minimal-path relay-controlled input selection, custom user interface design and microcontroller programming, and improved manufacturability over the previous generation's less capable chassis. Industrial design subject to AVA’s production and styling constraints.
-**Discussion:** I had two main goals with this project. The first was to bring the remote controllability of AVA preamplifiers up to feature parity with the competition as quickly as possible, and the second was to move AVA away from the costly turnkey remote control solution I adopted for their initial remote control offering. An additional goal was to simplify the assembly of preamplifiers. I had originally planned to work on the first of these goals immediately after completing the volume-only remote control design back in 2004; I had even gotten as far as producing prototype PCBs and a prototype build using relay-controlled input switching. But AVA opted for different priorities at the time, and this work was tabled. In 2017, the case for developing a fully remote-controllable platform was, to put it mildly, somewhat less undeniable.
+**Discussion:** I had two main goals with this project. The first was to bring the remote controllability of AVA preamplifiers up to feature parity with the competition as quickly as possible, and the second was to move AVA away from the costly turnkey remote control solution I adopted for their initial remote control offering. An additional goal was to simplify the assembly of preamplifiers. I originally planned to work on the first of these goals immediately after completing the volume-only remote control design back in 2004. I had even gotten as far as producing prototype PCBs and a prototype build using relay-controlled input switching. But AVA opted for different priorities at the time, and this work was tabled. In 2017, the case for developing a fully remote-controllable platform was, to put it mildly, somewhat less undeniable.
 ===== RB-RC =====
@@ Line 139: / Line 139: @@
 **Contribution:** Concept origination, development, and implementation of a low-cost remote controlled volume circuit adaptable to the existing RB chassis.
-**Discussion:** With the availability of a less costly remote control transmitter option that I established for the SLR and CFR chassis as well as the newly founded ability for AVA to burn custom microcontrollers in house, it was natural to apply these toward stripped-down remote control functionality for their RB (Real Basic) preamplifer chassis. The new design replaced the previous volume-only remote control implementation with a significantly less expensive solution. Once again I expected AVA to adopt the remote control as standard equipment on the RB chassis, but they again decided to offer it as an option, albeit not as costly as the solution it replaced.
+**Discussion:** With the availability of a less costly remote control transmitter option that I established for the SLR and CFR chassis as well as the newly founded ability for AVA to burn custom microcontrollers in house, it was natural to apply these toward stripped-down remote control functionality for their RB (Real Basic) preamplifer chassis. The new design replaced the previous volume-only remote control implementation with a significantly less expensive solution. Again I expected AVA to adopt the remote control as standard equipment on the RB chassis, and again they decided to offer it as an option, albeit not as costly as the solution it replaced.
 ===== The future =====