The Sennheiser HD600 headphones are unbelievably good, but be aware that they require at least 200 hours of break in before they start sounding open and uncolored. They also get the most out of very high-quality electronics behind them, such as the Assemblage DACs and Headroom headphone amplifiers. They have enough resolution to show the flaws in mediocre electronics.

The Cardas replacement cable for the high-end dynamic Sennheisers is outstanding! Mine is starting to bloom after breaking in for about a day and it clearly has vastly more resolution and emotional transmission than either of the stock Sennheiser cables. The Cardas is about $200, which seems expensive compared to the headphones, but it represents an excellent value as a hand-crafted, high-end audiophile product compared to the scientifically mass-produced, high-performing headphones. (Sennheiser has two compatible stock cables. The thin Kevlar reinforced one is ok, but breaks at the earpiece plugs easily. The thick one sounded terrible when new and only got slightly better after months of break in. The thick cable does have much larger earpiece plugs which seem comparatively indestructible.) Do not use the stock Sennheiser cables!

To anyone who thinks cables don't make any difference, consider that they are a physically-extended capacitor, inductor and resistor complex network with microphonics, dielectric effects, electromagnetic, electrostatic and mechanical modulation, etc. They need to have a signal running through them for many hours to form the dielectric. The same thing happens in capacitors, but it happens much more quickly there since the power levels are usually so much higher in a typical capacitor application.

My current digital source is a Pioneer Elite DV-58AV bought for $350 from Vann's. It retails for $500. Manufacture date is September 2007 in Thailand. It's gotten rave reviews and has excellent components in its analog chain, such as the superb Burr Brown PCM1796 DACs. Unlike the several years older consumer DV-563A, the 58AV will send unencrypted DVD-Audio to the S/PDIF digital outputs to an external DAC, receiver or surround processor. Neither player will send SACD out their S/PDIF outputs, but the newer player will send both SACD and DVD-Audio out its combined digital video and audio HDMI output. (An HDMI receiver would need to be able to handle encrypted signals for encrypted DVD-Audio and SACD recordings. Such receivers may be uncommon, though Pioneer lists some in the owner's manual.) The earlier player does not have an HDMI output; its only digital audio outputs are S/PDIF over Toslink and RCA. It's main downside is that it doesn't play Blu-ray, and none of Pioneer's Elite Blu-ray players have the same quality of analog electronics. Maybe future models will. Given the specific SACD and DVD-Audio format support and high quality DAC chips, the DV-58AV is clearly specialized as a high-definition audio disc player. As such it's a somewhat unusual product, especially for a mainstream consumer brand like Pioneer. It seems Pioneer has its some audio fans making things happen.

Both used as digital transports, the unmodified Pioneer Elite DV-58AV sounds vastly cleaner and more resolving than my previous unmodified Pioneer DV-563A. Comparing S/PDIF digital outputs from either player fed into the BNC input of the Assemblage digital gear described above, the DV-58AV is quieter (less noisy/hashy/fuzzy), more realistic, and overall much higher quality. Both artificial reverberation and natural spaces are much more clearly rendered. Instrument sounds and harmonics in general are much more apparent and distinctive. I have not looked inside or gotten the DV-58AV service manual yet, but Pioneer presumably spent greater effort at producing a cleaner digital output chain in the Elite electronics. The 563A is low-end consumer electronics. The Elite is more carefully and expensively done, call it upper middle-end consumer electronics. In particular, the choice of DACs in the 58AV is surprising since they're four dollar parts typically found in units costing far more. (Four dollars may not sound like much money, but in consumer electronics selling for less than four hundred dollars, it's notably extravagant. It's a rather incredibly expensive, high-quality part in this market segment.)

Starting with such good-to-great basic parts such as the remarkable DAC, modifiers have turned the DV-58AV into high end players. Naturally they add lots of dedicated, low impedance power supplies, replace capacitors, and especially update or replace the analog output stages. In other words they do the same kinds of mods we've been doing since the early Philips/Magnavox CD players.

Previous digital source was a Pioneer DV-563A, which plays DVD-Video, DVD-Audio, SACD, CD. Manufacture date is September 2003. It was a cheap multi-format player picked up as a demo unit from Circuit City, like my previous multi-format Pioneer disc players having unencrypted, high-resolution digital audio outputs. As a digital source it's ok, but the analog section is expectably mediocre. It was chosen for having 96 kHz x 24-bit digital outputs.

Player before that was an October 1998 manufacture Pioneer DV-414 which was also chosen for having high-bandwidth, PCM digital outputs.

Player before that was a heavily-modified Magnavox 560 which was internally a Philips player. Mods came from the New Jersey Audio Society, Ben Duncan's AMP-01 power supply, plus some of my own. NJAS had a nice DC servo modification with LF411 opamps obsoleting the electrolytic output coupling caps. The AMP-01 had nice, low-impedance, heavily-bypasssed, three-terminal regulator-based power supply. Regulator boards were right next to the circuits they powered. I gave dual-mono, split-rail supplies to the output opamps, plus four more supplies for the digital chips on the output board. Filtered DC for the regulator sections came from a nicely-designed external supply. Ben's AMP-01 preamplifier and its power supply design was very careful and well thought out. I also changed the DAC bit-current capacitors to silver mica, and replaced the good, stock Signetics 5532 output/reconstruction filter opamps with very much nicer Analog Devices AD712s. Internal power wiring was Kimber Teflon wires unwoven from their 8TC speaker cable. Does anyone have copies of my original Usenet postings about these mods?