Thanks for your interest and support, there’s a 70% chance that prototype units should be ready for coming the CES show – much depends on coding of the FPGA based modulator and digital filter and SAW resonator production issues. If I manage to meet the CES show deadline – then full production should be within 3 to 6 months.
After evaluating “off the shelf” modulators I felt it was worth pursuing my own modulator & digital filter design.
After evaluating all currently available SRC designs (from AD, Crystal & TI) all had a major impact in sound quality compared to a low phase-noise direct clock-lock system. This has necessitated the development of an ultra-low short term phase-noise VCO based upon cascaded 2-port SAW resonators. MCLK is 2048fs – fundamental mode crystals are extremely expensive at these elevated frequencies, and cheaper lower frequency VCXO with PLL multipliers introduce excessive phase-noise – especially close to the carrier, leaving SAW devices as the only viable option. Unfortunately I require 2 VCO frequencies to support 44.1 KHz and 48 KHz (and there multiples) – manufacture of SAW devices at custom frequencies is very costly – combined with long lead-times.
Some good news, I’ve just return from visiting my casework vendor in China last night – and it seems casework issues are finally being resolved – which has been one of my biggest headaches…..
Once again, thanks for your interest & support,
John Westlake
After evaluating “off the shelf” modulators I felt it was worth pursuing my own modulator & digital filter design.
After evaluating all currently available SRC designs (from AD, Crystal & TI) all had a major impact in sound quality compared to a low phase-noise direct clock-lock system. This has necessitated the development of an ultra-low short term phase-noise VCO based upon cascaded 2-port SAW resonators. MCLK is 2048fs – fundamental mode crystals are extremely expensive at these elevated frequencies, and cheaper lower frequency VCXO with PLL multipliers introduce excessive phase-noise – especially close to the carrier, leaving SAW devices as the only viable option. Unfortunately I require 2 VCO frequencies to support 44.1 KHz and 48 KHz (and there multiples) – manufacture of SAW devices at custom frequencies is very costly – combined with long lead-times.
Some good news, I’ve just return from visiting my casework vendor in China last night – and it seems casework issues are finally being resolved – which has been one of my biggest headaches…..
Once again, thanks for your interest & support,
John Westlake
Betto,
The T1 transport (Original name hey ) is CD only, however the digital amplifier supports DSD via SDIF3 (3 lines - Clock, L & R), and DSD buried within SPDIF - this is a proprietary interface format that has been developed in partnership with a 3rd party company I have an interest in.
This 3rd party company will offer a user installable board for certain DVD players that will output bit accurate SPDIF up to 192 KHz & DSD (converted to PCM or embedded "native" in a 176.4 KHz SPDIF DataStream). This is the only method I currently know of, which gives consumers access to the DSD stream for high quality playback.
John
The T1 transport (Original name hey ) is CD only, however the digital amplifier supports DSD via SDIF3 (3 lines - Clock, L & R), and DSD buried within SPDIF - this is a proprietary interface format that has been developed in partnership with a 3rd party company I have an interest in.
This 3rd party company will offer a user installable board for certain DVD players that will output bit accurate SPDIF up to 192 KHz & DSD (converted to PCM or embedded "native" in a 176.4 KHz SPDIF DataStream). This is the only method I currently know of, which gives consumers access to the DSD stream for high quality playback.
John
JohnW said:
Some good news, I’ve just return from visiting my casework vendor in China last night –
Welcome back John, I'll give you a call and will meet you this week
Cheers, Pavel
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Class D
- A question for JohnW