audio:audio_by_van_alstine_work
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audio:audio_by_van_alstine_work [2019/05/22 04:47] – [RB-RC] mithat | audio:audio_by_van_alstine_work [2023/01/02 21:52] – [DVA Digital Preamplifier] mithat | ||
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====== Audio by Van Alstine work ====== | ====== Audio by Van Alstine work ====== | ||
- | I have done quite a bit of consulting work for [[https:// | + | I have done quite a bit of consulting work for [[https:// |
- | The focus of my work with AVA has always been to bring the highest standards of audio engineering to the company while fostering | + | The focus of my work with AVA has always been to bring the highest standards of audio engineering to the company while helping to foster |
===== Transcendence Five ===== | ===== Transcendence Five ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | New vacuum tube line stage to replace AVA’s existing design originally derived from the Dyna PAS 3. |
- | **Discussion: | + | **Contribution: |
+ | |||
+ | **Discussion: | ||
===== Transcendence Six ===== | ===== Transcendence Six ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | Low-cost hybrid line stage using a computer-optimized 12AT7A gain stage and IC buffer output |
- | **Discussion: | + | **Contribution: |
+ | |||
+ | **Discussion: | ||
===== Transcendence Seven ===== | ===== Transcendence Seven ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | 12AT7A-based premium hybrid line stage using a computer-optimized 12AT7A gain stage and optimized power-MOSFET buffer output stage. |
+ | |||
+ | **Contribution: | ||
- | **Discussion: | + | **Discussion: |
===== "T7 CF" ===== | ===== "T7 CF" ===== | ||
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c. 2002 | c. 2002 | ||
- | **Contribution: | + | All-tube buffered line stage using a computer-optimized 12AT7A gain stage and 12AU7 buffer stage. |
- | **Discussion:** While working on the Transcendence Seven, I was able to take a deep dive into the tube/MOSFET architecture covered in the AVA Fet Valve patent. One result of this is that I could not find a convincing reason why a power-MOSFET was better suited to buffering the gain stages than a cathode follower, but I was able to come up some reasons a MOSFET might be worse. So I developed an iteration of the Transcendence Seven design using a 12AU7A-based circuit to replace the power-MOSFET stage. | + | **Contribution:** Concept origination and development. |
- | At the time I wasn’t given the go-ahead to prototype and test this design. My understanding is the AVA wanted to maintain a commitment to their patented architecture as they felt this gave them marketing distinction. However, this circuit | + | **Discussion: |
+ | |||
+ | At the time I wasn’t given the go-ahead to prototype and test this design. My understanding is that AVA wanted to maintain a commitment to their patented | ||
===== Active power supplies for tube and hybrid electronics ===== | ===== Active power supplies for tube and hybrid electronics ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | All-new power high-voltage supply regulation circuits for use with all AVA tube and hybrid products. |
- | **Discussion:** To address a concern AVA raised regarding the audibility of B+ power supply shifts caused by line voltage variations and other factors, I developed an active regulation architecture using voltage references and high-voltage power-MOSFETs. The approach was simple and cost-effective enough that several independent regulation stages could be be used to better isolate the individual stages that comprised an entire design. AVA felt that the subjective improvements resulting from the regulated power supplies warranted the adoption of the scheme in all tube and hybrid products. This resulted in the [[https:// | + | **Contribution:** Concept origination, development, and implementation. |
- | The Ultra preamplifier ([[https:// | + | **Discussion: |
+ | |||
+ | The Ultra preamplifier ([[https:// | ||
===== Remote control ===== | ===== Remote control ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | Remote controlled volume circuit adaptable to all existing AVA preamplifiers. |
+ | |||
+ | **Contribution: | ||
- | **Discussion: | + | **Discussion: |
- | My original | + | My expectation was that AVA would offer the remote as standard equipment on all “big body” preamplifiers. Instead it was offered as a relatively costly option, which they justified because the remote control transmitters were costly, which they were because of the small quantities they ordered them in, which was the case because remote control was offered only as an option. |
===== Ultimate 70 and Ultravalve power amplifiers ===== | ===== Ultimate 70 and Ultravalve power amplifiers ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | Revision of AVA’s low-power tube amplifier circuits for the Dyna ST70 chassis. |
- | **Discussion: | + | **Contribution: |
+ | |||
+ | **Discussion: | ||
===== DAC core for Vision and Vision Hybrid DACs ===== | ===== DAC core for Vision and Vision Hybrid DACs ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | Next-generation S/PDIF decoder and DAC board |
+ | |||
+ | **Contribution: | ||
- | **Discussion: | + | **Discussion: |
- | AVA originally wanted to support only 44.1kHz PCM formats | + | AVA originally wanted to support only 44.1kHz PCM formats |
- | This would be the first time AVA would use predominantly SMD parts in a PCB design. The previous generation DAC had used a single hand-soldered | + | This would be the first time AVA would use predominantly SMD parts in a PCB design. The previous generation DAC had used a single hand-soldered |
I was not involved in the development of the analog stages for the first DAC products using this board. However, I was responsible for the analog circuits found in the [[# | I was not involved in the development of the analog stages for the first DAC products using this board. However, I was responsible for the analog circuits found in the [[# | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | All-tube, next-generation premium preamp line stage. |
- | **Discussion: | + | **Contribution: |
+ | |||
+ | **Discussion: | ||
===== Vision RIAA Phono Preamplifer ===== | ===== Vision RIAA Phono Preamplifer ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | Component value selection for best RIAA conformance. |
+ | |||
+ | **Contribution: | ||
- | **Discussion: | + | **Discussion: |
===== Vision DAC improved ===== | ===== Vision DAC improved ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | New reconstruction and output stage based on a discrete, class-A, solid-state gain stage I developed as an independent project. |
+ | |||
+ | **Contribution: | ||
**Discussion: | **Discussion: | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | New line stage based on a discrete, class-A, solid-state gain stage (developed as an independent project). |
+ | |||
+ | **Contribution: | ||
**Discussion: | **Discussion: | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | All-new DAC product with USB and S/PDIF inputs supporting high-rate PCM and DSD formats. |
- | **Discussion: | + | **Contribution: |
+ | |||
+ | **Discussion: | ||
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. | 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 design that required AVA to use microcontrollers they would burn in-house | + | 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 brought AVA’s production methods more in line with modern approaches. |
===== Vision SLR, Fet Valve CFR ===== | ===== Vision SLR, Fet Valve CFR ===== | ||
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[[https:// | [[https:// | ||
- | **Contribution: | + | Fully remote-controllable chassis and supporting circuitry. |
- | **Discussion: | + | **Contribution: |
+ | |||
+ | **Discussion: | ||
===== RB-RC ===== | ===== RB-RC ===== | ||
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c. 2018 | c. 2018 | ||
- | **Contribution: | + | Low-cost remote controlled volume circuit adaptable to AVA' |
- | **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. | + | **Contribution:** Concept origination, development, and implementation. |
- | ===== The future ===== | + | **Discussion: |
- | I continue to provide consulting services to Audio by Van Alstine, particularly in the areas of digital audio, small-signal analog audio, | + | ===== RC3 ===== |
+ | c. 2020--2021 | ||
+ | |||
+ | Embedded design for IR remote control sending with silicone membrane switches. | ||
+ | |||
+ | **Contribution: | ||
+ | |||
+ | **Discussion: | ||
+ | |||
+ | ===== DVA Digital Preamplifier ===== | ||
+ | c. 2018--2021 | ||
+ | |||
+ | **Contribution: | ||
+ | |||
+ | **Discussion: | ||
+ | |||
+ | The DVA Digital Preamplifier also brought forth a new design aesthetic and chassis mechanics that I originally intended as a one-off transitional one. As is often the case, it took a good amount of work to convince AVA of the merits of making the change. But once the design was released, it received, for the first time ever for an AVA product, praise in the audiophile press for its aesthetics. Likely as a result of this, AVA asked me to design or redesign faceplates for a variety of new and existing products. | ||
+ | |||
+ | What this means is that my original plan of transitioning to a brand new design program that takes updated user, business, and manufacturing requirements into full consideration will be delayed. I regard this as an odd manifestation of [[https:// | ||
+ | ===== DVA A2D ===== | ||
+ | c. 2021 | ||
+ | |||
+ | **Contribution: | ||
+ | |||
+ | **Discussion: | ||
+ | |||
+ | ===== DVA R2X ===== | ||
+ | c. 2021 | ||
+ | |||
+ | **Contribution: | ||
+ | |||
+ | **Discussion: | ||
+ | ===== The present ===== | ||
+ | |||
+ | I continue to provide consulting services to Audio by Van Alstine, particularly in the areas of digital audio, small-signal analog audio, | ||
+ | |||
+ | ===== The future ===== | ||
+ | Within audio, my work focuses on developing solutions that represent meaningful audio progress rather than chasing colorations that happen to be the current fashion. At a more general level, my design interests include a bringing greater equity to all technological realms and improving user experiences in every stage of product use. I try to bring this to bear as much as possible in my work for AVA. | ||
audio/audio_by_van_alstine_work.txt · Last modified: 2023/01/02 21:54 by mithat