Modding my ARC Ref Anniversary
- Thread starter ayreman
- Start date
Thanks ayreman for sharing your journey!
Few are likely to undertake your trip, but if they want a little more magic from their REF40, REF10 Pre, or REF10 Phono with just a few parts changes, they might try swapping in the the Vishay Z-foil/TX 2575s for some of the stock resistors.
Start with the 402 ohm output resistors behind the output coupling caps. What you should get is more immediacy and presence with the lower noise floor. Also, you should hear a more defined spatial presentation with clearer placement of images in it.
Like it? Replace the 1K resistors between the 6H30 gain stage tubes and the output buffer tubes. That should result in more of the above by removing even more of the slight stock veiling and it will improve musical timing, especially the decay of notes. Retaining the stock resistors before the gain stage preserves the overall "flavor" of the stock unit. It also allows easier reversal of the mods if you want to sell it or to service it.
Replacing the 10uF output caps may not even be necessary. The ARC parts are pretty neutral sounding. You could try bypassing them with Duelund JDM .01uF parts. The silver ones with the stock 10uF caps would be a little dry sounding in this application. The Sn/Cu's are intoxicatingly realistic with vocals, but the highs are just too rolled off for my tastes. Go with the Cu Foil types if you need just a little more warmth than the ARC caps alone provide.
Remember YMMV. I'm not advocating this unless you really know what you're doing.
Few are likely to undertake your trip, but if they want a little more magic from their REF40, REF10 Pre, or REF10 Phono with just a few parts changes, they might try swapping in the the Vishay Z-foil/TX 2575s for some of the stock resistors.
Start with the 402 ohm output resistors behind the output coupling caps. What you should get is more immediacy and presence with the lower noise floor. Also, you should hear a more defined spatial presentation with clearer placement of images in it.
Like it? Replace the 1K resistors between the 6H30 gain stage tubes and the output buffer tubes. That should result in more of the above by removing even more of the slight stock veiling and it will improve musical timing, especially the decay of notes. Retaining the stock resistors before the gain stage preserves the overall "flavor" of the stock unit. It also allows easier reversal of the mods if you want to sell it or to service it.
Replacing the 10uF output caps may not even be necessary. The ARC parts are pretty neutral sounding. You could try bypassing them with Duelund JDM .01uF parts. The silver ones with the stock 10uF caps would be a little dry sounding in this application. The Sn/Cu's are intoxicatingly realistic with vocals, but the highs are just too rolled off for my tastes. Go with the Cu Foil types if you need just a little more warmth than the ARC caps alone provide.
Remember YMMV. I'm not advocating this unless you really know what you're doing.
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I know this is an old(er) thread, but pinging it because I have an LS-5 mkiii I'm thinking of having serviced.
I would like to update the preamp without "ruining" what makes ARC ARC.
I think the most obvious upgrade that wouldn't do any harm would be to upgrade the 6 output caps to Stealthcaps (or at least as many as will fit...the Stealthcaps might be larger than stock).
Other than that, I'm not sure what would be the next steps (if any). Not sure if this is a lifetime keeper preamp, but it's pretty good. I think I'd be safe (resale value wise) with the Stealthcaps, but other than that, it seems any other mod would hurt resale value.
Here's a schematic of the LS-5 mkiii
I would like to update the preamp without "ruining" what makes ARC ARC.
I think the most obvious upgrade that wouldn't do any harm would be to upgrade the 6 output caps to Stealthcaps (or at least as many as will fit...the Stealthcaps might be larger than stock).
Other than that, I'm not sure what would be the next steps (if any). Not sure if this is a lifetime keeper preamp, but it's pretty good. I think I'd be safe (resale value wise) with the Stealthcaps, but other than that, it seems any other mod would hurt resale value.
Here's a schematic of the LS-5 mkiii
Why Stealthcaps? You should use copper foil caps instead. That alone will produce much better results.
I'm inclined to use Stealthcaps because that's what AR uses in their reference amps/preamps and I am not sure if the LS-5 is a "keep for life" preamp (meaning, I don't know if I'm going to sell it in the future, and if I did go full cray-cray, then the ARC purists wouldn't like that one bit). Also, the tech I'd use (Pyramid Audio in Austin) is reticent to mod things, but I think I could "sell" them on Stealthcaps since that's what ARC uses.
Now, I AM willing to go full crazy copper foils on my Sonic Frontiers SFL-2. It already has V-Caps, so I'd be interested in taking it to the extreme like the ARC Ref in this thread (which also serves as motivation).