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POSITIVE FEEDBACK ONLINE - ISSUE 1
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An Eye for Electricity and an Ear for Mods: Addressing Power and Parts in Amps and Digital Front End
by Greg Maltz

 

I had never enjoyed my system more than I did just prior to sending it away to be modded. Why, then, did I yank the cords and ship it out? One explanation is that I became obsessed with the idea that an aspect of the midrange could improve, particular tones could flow more openly, dynamic nuances could achieve better pacing, and the soundstage could stretch yet deeper. But I fear it had nothing to do with these specifics. Simply, I succumbed to a nagging voice that told me I'd better address every single part in the signal path and in the electric current as comprehensively as possible. So into the original boxes went my Avatar and my SCD-1, all 120 lbs. of them, and I shipped them off, having checked earlier that those doing the mods would be able to handle it in a reasonable time frame. The modders were, for the SCD-1, Richard Kern of Audiomod (www.audiomod.com), and for the amp, the manufacturers themselves, Kevin Hayes and Kevin Carter of VAC (www.vac-amps.com).

SCD-1 Parts Upgrades

With an audio board and chassis highly praised by the press and engineers alike, the SCD-1 uses unexceptional Sony stock parts. Richard Kern began experimenting with Caddock and Vishay resistors and high quality capacitors, including REL, MIT, and Black Gate. He also tried using Hexfred diodes in the power supply. For me, Richard recommended his Caddock-based modification without the high-speed diodes. The parts used for this mod are listed below.

Resistors Caddock MK-132:

Resistors Vishay VSH Bulk Foil:

2x 30 ohm

2x 390 ohm

2x 100 ohm

2x 560 ohm

4x 221 ohm

4x 475 ohm

Black Gate Capacitors:

2x 1.74k ohm

2x 1000 uf 50 volt standard type

2x 2.00k ohm

2x 2.21k ohm

REL Capacitors:

8x 10.0k ohm

2x 0.0015 uf 600 volt

2x 33.2k ohm

8x 0.0022 uf 600 volt

2x 560 pf 600 volt

MIT Capacitors RTX type:

2x 0.1 400 uf volt

Richard and I phoned and e-mailed each other often. The beauty of modding the SCD-1 (or 777ES), he said, is that the parts replaced are used in both CD and SACD circuits. Improve one and you improve the other. This was something Steve Huntley (another modder) of Great Northern Sound quickly discovered and shared with Richard. Both CD and SACD use the same analog low pass filters. Relays are used to switch resistors in or out of the low pass filter, for CD/SACD mode and standard and custom settings. An interesting side note: all the parts in this path are affected by the "custom" switch on the back of the unit. The standard factory setting shunts more treble to ground, effectively rolling it off -3dB at 50kHz, while the custom mode puts a resistor in series with a 560 pico farad capacitor to ground, allowing the response to be flat to 50kHz. (Note: the custom switch only works in SACD mode.)

Richard walked me through much of the work he did and its audible effect on the unit. For example, using Black Gates on the audio board in place of the Sony stock 1000 uf capacitor helped liven the sound and improve the pace and dynamics, particularly of the bass. The Black Gate is a Japanese capacitor with graphite coating, which lowers the ESR and improves dielectric absorption. Compared to the stock parts, the six REL polystyrene capacitors per channel provide better separation, depth and width. Caddock resistors, when used in Richard's SCD-1/777ES mods, provide a smooth, liquid, laid-back quality, while Vishays lend themselves to sparkling treble and rip-roaring pacing.

Richard quickly swapped out the Sony stock parts and soldered in the higher-quality parts. He tested the unit for about two days, allowing the mods to burn in before shipping it back to me. He was so quick that it would be at least a week before the amp (which I had to ship to the other side of the country) had completed its own four-day burn-in process and was on its way back to me. So into my friend's system went the modded SCD-1, upstream of gear which itself was highly modded and tweaked:

  • ARC SP-10 Mk II v6 (heavily Percy/Nunes modified & all Amperex 7308 NOS)

  • Magnepan MG-20R, 1999 Magnepan crossover (to bass only)

  • (2) Genesis 12M subwoofers (run directly from pre-amp) crossed over at 35 Hz

  • Custom Morris Zwerman passive crossover separating: HK Citation II (heavily modified by Charlie Kittleson of VTV) on the T/M section; and NYAL Moscode 300 (heavily modified) on the bass section

  • John Garland Signature 7 interconnects, speaker cables, AC power cords

  • PS Audio Multiwave P300

Before I had any chance to listen to the modded SCD-1 in this system, my friend was reporting to me how smooth, detailed, and laid back the unit sounded. In stock form, the SCD-1 is quite forward. But no early report could have prepared me for what I heard when I had a chance to audition the modded unit in person. Ladies and gentlemen, this was not the same machine anymore. The music was fluid and velvety on CDs that once sounded strident. SACD had all the air and detail that I appreciated before sending away the unit, but now the sound was further back and very smooth.

We listened to a variety of SACDs, from Willie Nelson to Isaac Stern to Louis Armstrong. In each case, the musical smoothness of the SCD-1 was a thing of beauty. But was it too polite? For the grand finale, we listened to "All Blues," from Miles Davis’ Kind of Blue. While highly detailed and velvety smooth, the tenor sax solo by John Coltrane simply lacked balls. My friend said it best: "Not an offensive sound can come out of that thing." Well when it comes to Coltrane solos, some sounds are supposed to be at least somewhat strident, and I was starting to regret having the unit modded with Caddocks. The Vishays may have been a much better choice, I told myself. I had yet to hear the unit in my own system, so I tried to hold off on making a judgement.

As the sound of Coltrane’s sax played in my memory and I toyed with the idea of boxing up the SCD-1 and sending it back to Richard for further modification, I got a call from my friend. While playing an SACD, the left channel output of the SCD-1 went dead. After troubleshooting, this was the only conceivable explanation. As it turned out, this may have been a blessing in disguise. The unit was double-boxed and shipped back to Richard. He immediately identified the problem with the left channel—a shorted REL cap that he promptly replaced in both channels in case they were both from a faulty batch. He also added InfiniCaps in place of a stock feedback capacitor he had previously left unmodified. He swapped Vishays for all the Caddocks and soldered high-speed Hexfred diodes across the power supply. This was the mod I suspected would be perfect for me, as I had been wary of the Caddocks’ laid back sound signature from the start. I wanted to hear the Caddocks in my system, but the nature of the updated mods, judging from Richard's descriptions, more closely approximates my audio preferences and I would just have to sit tight, wait for my gear to arrive, and let my ears judge for themselves.

Meanwhile, Back at VAC

I say that my Avatar integrated amp was modded too, but perhaps this is not accurate. It was "re-voiced." The modifications had been predetermined using a painstaking process that parallels all product development at the company, according to Kevin Hayes, President of VAC. "Once the basic electrical design is completed, in some cases more than 1,000 hours are spent in the process we call ‘voicing,’" Hayes explains. "During this time, small avatar.jpg (16075 bytes)changes in the physical arrangement of the parts are tested, different types of capacitors and wires are auditioned, and even various chassis materials tried. The differences often elude the linear test bench instrumentation but are plainly audible to the human ear. This often frustrating work and attention to detail is required to bring a design to its peak of performance."

So it is no surprise that VAC’s Avatar is itself an exercise in attention to electrical detail. VAC’s Kevin Carter explains that the Avatar is unique in that it was the first time such an amplifier had received special attention to the way all circuits were grounded. "In the Avatar," Carter said, "24 ground wires converge on a single binding post in the rear of the unit. Why? Because we found you lose musical information if you don't carry each wire back from the circuit board individually." This is at the heart of the detailed, crystal-clear sound of the Avatar. Circuits not grounded individually can muddy the sonics, Carter explained. Little did I know, during the two years I owned the Avatar, that the reasons I had selected it over the competition had everything to do with this attention to electrical detail.

VAC has been offering its special edition Avatar upgrade for nearly a year, and I was strongly tempted, but could never bring myself to send it away for the mods. But with the SCD-1 gone, it was now or never. The Avatar upgrade often involves the addition of remote control, but I opted for the basic upgrade, not wholly dissimilar from Richard’s mods to the SCD-1. Kevin Carter explained that there are several component families that change to yield overall improvements, specifically a more open sound with bass improvement: "There are several component families that change to make the improvements," Carter said. "All of the audio path resistors are upgraded to Dale RN65D resistors, the audio path capacitors are replaced with InfiniCap SETIs, and the main high voltage caps with Matsushita TSU caps. We also add some additional high voltage bypassing to the line stage and amplifier front end." He emphasized that "The point of the changes is to make improvements in the overall sound of the Avatar, not to replace the components with ‘tony’ brands. We use the parts that work together to make the best sound, rather than using the ‘best’ audiophile parts. This is a very important point. Some manufacturers openly boast about parts quality, but that isn't the solution to the problem of good sound; most of us use excellent quality parts. The solution is the correct combination of parts to give excellent sound. It's hard work and sometimes frustrating, but experience, perseverance, and a good vision of the outcome make it happen."

Carter explained in a phone conversion with Positive Feedback that prior experience using various parts helps, but so does intuition and judgment in engineering. Improving any one part, or group of parts, could be a step backward without addressing the parts’ relationship to the design, because the overall gelling of the parts may not be appropriate. "We don’t know enough to predict all the specifics of how different parts interact ahead of time. We have to go through the empirical process of swapping in various combinations, listening and going through the steps of voicing." After determining which combination is significant enough to offer an improvement, VAC will offer special edition versions/upgrades of their existing products. Subsequent determinations and implementation warrant the development of new products altogether.

A Pair of Fatmans

To reap the full benefits of the improvements within the Avatar and SCD-1, I knew it would be necessary to address the electric current flowing to each of them. I live in a building where the condo association has strict rules about altering the wiring of the individual apartments, but this did not stop me from addressing power once it left my wall. I had already schooled myself on the audible effects of the PS Audio Power Plants, having used a P300 initially and then upgrading to a P600 (after realizing my gear was placing too much of a burden on the lower-powered unit). But the real epiphany about power came when I had a chance to compare several different cords, including the PS Audio Lab Cable, the Mapleshade Double Helix, John Garland’s latest cord, and the Custom Power Cord Company’s Model 11. Incredible differences resulted from swapping these cords in, ranging from slight alterations in imaging and pacing to gross changes in system volume and tone!

Of these cords, the Garland won, providing a liquid quality to the music and improved pacing over the runner up, the Lab Cable cord. This was distressing to me, as I owned the Lab Cable and found the quality of the Garland a significant improvement. Meanwhile, other cords were rumored to be ideal with the SCD-1. I wanted a cord that would not hinder my amp or front end in any way. After a great deal of hand wringing and research, I decided on the Electraglide Fatman, said to go the extra mile in revealing the true sound of components. The cords feature extraordinary attention to detail and hand-assembly by Electraglide owner Scott Hall, who uses "huge silver ribbons" in the design.

As fate would have it, these cords were the first to arrive, as Hall charitably delayed a personal vacation to finish them. The Avatar and SCD-1 were en route via FedEx second day, and all I could do was look at these two Fatmans and wonder if all this attention to electricity would pay off. I desperately wanted to hear nine new SACD acquisitions, which had arrived while my gear was away. But I knew the only chance to hear the new titles would be during burn-in. And before I could even address that, I would need shipment to go off without a hitch, and would also need to set up my system. This presented unique challenges, including floating the 60-lb SCD-1 on MIB Aurios and finding a way to keep the unit floating with the immense Fatman attached. After burn in, it would take many more hours of listening to very familiar material to get a handle on the specific changes to the system.

The next day, the rest of my gear arrived in perfect condition. The Avatar gleamed like new. The parts swapped out from the SCD-1 were neatly returned in a plastic baggie, including the defective REL cap. I painstakingly returned the units to their shelves atop the Aurios and hooked up the Fatmans and interconnects. I switched them on and let them warm up for half an hour before dropping Dai Kimura’s Shunme SACD into the spindle, fixing the brass weight down on top of it, pushing the play button and easing back into my black leather listening chair.

I heard the familiar series of mechanical murmurings and the welcome click after the TOC had been read. My ears perked up. Would I forever wish I had left well enough alone? Would all this attention to parts and power yield no audible difference? A slight improvement? Or would the sound catapult me into bliss? Tune in for a detailed report in the next exciting issue of Positive Feedback Online.

 

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