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Old 11th June 2011, 03:46 AM   #121
wlowes is offline wlowes  Canada
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Default Great power!!

Simon
The mega power supply looks great. I doubt there ever has been a CD that has had more attention to good power than yours. I am willing to bet that it is truely reference grade. I can't imagine any stock CD at any price beating your sound quality.

You have me reading about super regulators. I can imagine that this is the one biggy that I have yet to experience.
Walter
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Old 11th June 2011, 03:56 AM   #122
wlowes is offline wlowes  Canada
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Default More on Power

I made a simple change tonight that may not apply to others, but in my rig it was significant.

I ran a ground wire from the center tap of the audio board transformer to the earth ground on the IEC plug.

I had been reading about power supply design for my amp. I kept seeing references to grounding the center tap to create a balanced power source for the +/- dual supply in audio. And it hit me that since I replaced the DAC transformer there was no reference to earth ground on the center tap. It is supposed to drain eddy currents in the transformer before they can create noise that pollutes the supply and the circuit it supplies.

Well in my case it was pretty important. Like so many other changes before it just increased dynamics, sound stage, air around everything. Lots easy natural extension at both ends.

Again, I don't run the full CD, so I don't know if this will somehow have a negative impact on grounding in the alpha that still looks like an alpha.

I am literally rediscovering all the music yet again. What a great machine this ARCAM is.
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Old 11th June 2011, 08:58 AM   #123
SimontY is offline SimontY  United Kingdom
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It is a fine machine. I'll think about that mod.

There are others with equal and even better supplies than mine, though they are few and far between. I don't know how my player would now stack up vs a top dollar machine. It would do ok I think but I doubt it would surpass the very finest, but should be close.
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Old 12th June 2011, 03:41 PM   #124
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Thx to all contributors to this experience, i'm actually modding slitly an alpha 5+ , less space to fit any F&T or Bhc on the psu, but with somes nice nichiconzz and panazz Fc all is nice, + mmk for the sound board this arcam gear takes another dimension , next stage i plan to swap 317 337 combozz with linear tech quieter regs + somes heat sink to cooling the dac and Sa bugs!

Bravo to Simon to share your "extrem" experience


P,

Last edited by Gonethesame; 12th June 2011 at 03:45 PM.
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Old 13th June 2011, 10:05 PM   #125
SimontY is offline SimontY  United Kingdom
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The Alpha 5+ looks like a fairly decent player from what I've read. Probably better than the original Alpha I would guess but not had a really detailed look.

I've had another play this evening.. I just can't help myself, I keep wanting more! First, as per Walter's advice, I decided to try connecting the signal ground (from the centre of the DAC PSU transformer) to the safety ground. I did it via a 2.2uF film cap so as to not cause an earth loop. I didn't listen to this mod in isolation as it was just a bonus whilst I had the player on the operating table.
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Old 13th June 2011, 10:19 PM   #126
SimontY is offline SimontY  United Kingdom
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After that little tweak I went to work adding more filtering to my output stage (Pass D1 class A thing) supplies, which are off-board so there's plenty of room to play in. The PSU consisted of a 100VA 25-0 25-0 toroid into a big bridge and 2x 10,000uF F&T caps.

I made this CRLC by adding 2 x 33R 1/2W resistors in series and then an 8mH (or thereabouts) coil. This was followed by some more used Silmics: 1000u/50V, 470u/50V & 47u/63V in parallel per rail. I initially just connected the coil but they only have 1R of DC resistance, which was barely dropping the voltage. I wanted more voltage drop to give the S Power regulators an easier time as they were working with +-37-38V going into them. I tried various resistors till I got the rails down to +-34~35V. I calculated they were only dissipating something like 0.1W each, so quite safe and cool-running.

It's too late to play at test levels but it does sound very smooth, pleasant and with more tonal information than I usually notice.

I want to upload a couple more pics but it's not working right now!
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Last edited by SimontY; 13th June 2011 at 10:25 PM.
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Old 13th June 2011, 10:39 PM   #127
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One more... this Internet connection is bad tonight, it keeps dropping out
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Old 16th June 2011, 10:20 AM   #128
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thx Simon,

just tested op627 to the place of the NE in ouput, pants!

this remove all the analogic raw sound, don't like it!

fitted the Linear Technology 4 regs, and it gets more air between instruments, this regs are really less noisy!
yellojackets have recovered their wings!

next stage? don't know yet, i would stay tuned on Pundits endevouring adavntures!

have a great week!
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Old 16th June 2011, 10:24 AM   #129
SimontY is offline SimontY  United Kingdom
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There are better op-amps than OPA627 these days, though I would say I find that quite an "analogue" sounding op-amp personally, just a bit shut-in and restrained next to better, modern ones.
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Old 16th June 2011, 10:41 AM   #130
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the 5534 gets me full satisfaction, a friend gets me op27 to test, i'll try! but at least i think Arcam was right on this analyse!

don't like analytic tones ..

Last edited by Gonethesame; 16th June 2011 at 10:43 AM.
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