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Old 20th October 2005, 12:10 PM   #1
Betto is offline Betto  Italy
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Default A question for JohnW

When your "digital" amp will hit the shelves?
Thank you Betto
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Old 20th October 2005, 02:05 PM   #2
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I am convinced that John W's amplifier will be one of the best on the market. He is working on the right ideas!
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Old 20th October 2005, 08:07 PM   #3
IVX is offline IVX  Russian Federation
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Yeah, very interesting - WHEN, or how project is going on at least? Any news? Any reviews?
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Old 21st October 2005, 02:22 AM   #4
JohnW is offline JohnW  Hong Kong
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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
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Old 21st October 2005, 03:30 AM   #5
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I'm semi confident we'll be seeing John's gear before that of Mueta

Keep at er John, Thanks for that bit of detail on it, very interesting.

REgards,
Chris
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Old 21st October 2005, 07:32 AM   #6
Betto is offline Betto  Italy
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Thank you John, very interesting.
One more question please.
Would the matching transport be able to read SACD also (ie converting DSD to PCM)?
Keep up the good work
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Old 24th October 2005, 06:23 AM   #7
JohnW is offline JohnW  Hong Kong
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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
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Old 24th October 2005, 06:55 AM   #8
PMA is offline PMA  Europe
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Quote:
Originally posted by JohnW


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
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