Quote:
Originally Posted by
welwynnick 
Without divulging TUC intellectual property, this is how I understand TUC upgrades equipment. There are three main approaches, the first is
not to change the core functional components - the decoders, DACs, clocks, etc, not to change the circuit schematics, which are largely "correct". The second is to upgrade the passives, which is familiar and straightforward......
Other mod-men do this too, but I get the impression that TUC are just thorough and comprehensive. I believe its the third approach that distinguishes TUC. They ensure that every component is working to its best by providing the right environment for it to function - something like the demonstration/sample boards that SOC vendors make for qualification or evaluation. Here, the active device is not corrupted by the adverse environment created by internal and external sources.
A typical DVD player however, is a bad environment for many reasons, and this degrades the installed performance of even high quality silicon. TUC therefore use damping, grounding, shielding and filtering to minimise the effects of the adverse elements of the environment. All the DACs and op-amps that CE makers use can claim superb peformance figures when measured on a perfect test-bed, but that performance is never achieved in real-life, where there are many incompatible signals and technologies that are forced to share a box.
I recall Eric Kingdon of Sony telling me that getting the schematic right was just the start of getting good performance from electronics, and when you listen to what manufacturers say away from the press releases, there's a recurring theme. The real quality comes from tuning the design - selecting the passives, mounting parts and connectors, tightening cables, isolating, damping - I don't know - that sort of thing. It sounds like TUC use the existing schematic, and just finish the tuning job properly.
That's my take on it, and I think David Schulte has learned a lot about how to get the environment right for electronics. That's his know-how, and he really doesn't want to give it away. Having heard the results of this on the Onkyo, its clear to me that he knows what he's doing. I don't know exactly what he has done inside, and even though my background is electronic systems engineering, I don't need or even want to know - its the results that count.
Apologies for dredging up an old post, but people have been asking all along about what TUC mods are actually performed. They
are proprietary, but DS has expanded a bit more on the things that he does. So I've indulged in a re-itteration of my take on how he does it, and it doesn't seem too inconsistent with what he has said so far.
The overall approach seems to be that contemporary decoders, processors, clocks, DACs and op-amps all perform well in test-bed conditions, when they take the measurements to validate the specs. These conditions are as ideal as possible - the manufacturers will wring every last Hz and dB out of them, and the tests are presumably done with only a signal generator and analyser. The power suppies may be batteries as well; that's what I would do.
A real application in a real player in a real system in a real room is a different matter altogether, and there are lots of sources of noise and interference (mechanical, acoustic, electrostatic, magnetic, conducted, power & ground) that conspire to compromise the performance of a system. The best modern equipment does go some way to minimising the effects of this - for example with vibration damping, soldered cable connections, separate power supplies or compartments for audio and video sections. Even separate boxes for different functions. All this points towards the importance of minimising the interaction between different functions. Its something I've been hearing a lot over the last few years, and TUC seem to be effective in dealing with it.
I couldn't tell you exactly how they do it, though my presumptions were given in the above post, and seem to be along the right lines. The proof was in the eating for me, and although there was no blu-goo, the mods on my Onkyo 885 looked no different to the others posted in this thread. However, in back-to-back comparisons, the effects were to take it from the bottom of the pile in performance, to the top.
Nick
EDIT: sorry for rambling, I forgot about the point I was going to make. One of the things that stuck in my mind about my modded Denon 3800 was how good it sounded on the HDMI output, never mind analogue. PCM audio over HDMI has long had the worst SQ for me, wel behind spdif, i-link and analogue in my system. Playing CDs on my 3800 SE though, was really quite good, and confounded my prejudices. Sure, analogue was better, but not by much. Until that point I had always presumed that PCM over HDMI was compromised by the need to recover the audio clock from the HDMI video pixel clock - so ALL players will sound poor (with CD at least). Well, no, it seems that the source is also to blame, and the HDMI digital audio output from my 3800 was much better better than all other players that I tried. I may not know what the real explanation for that is, but because I only noticed it with CD, and not bitstreamed audio from DVDs adn BDs, I presume it was down to reduced jitter in the player. The data has to be the same - right? The improvements in overall performance must be partly down to the hardware modifications that improve the analogue performance, but there's obviously a significant improvement to digital performance as well. I don't think anything TUC does will change the digital audio (or video) bits, but the clock must be cleaner, and I presume that's down to the screening, damping, filtering, etc.
