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Sigma11 Makes Gamma2 Sing!

post #1 of 19
12/30/09 at 3:01am
Thread Starter 
I was using the wallwart for the Gamma2 until today when I finished the Sigma11 for it. It definitely adds more of that liquid sound and adds a little more sparkle to the top end. There just seems to be a little more effortlessness to the sound. Liquid smooth.

There was a strange phenomenon before with the wallwart, as if the drivers weren't allowed to reach their maximum excursion in some frequency bands, hard to describe, but it's gone now.

Now, to finish the sigma11/M3. Case work is a PITA.
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post #2 of 19
12/30/09 at 3:20am
i've ordered parts for a y-2 and o-11. i also have a wallwart to compare. i hope to get started by this weekend.
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post #3 of 19
12/30/09 at 3:22am
Can the sigma11 fit in the same enclosure model as gamma2?
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post #4 of 19
12/30/09 at 3:28am
The σ11 is roughly 4" x 3.5" x 1.5", so not really... unless you want to go crazy with heatsink choices and flattened capacitors and sanding the board.

Hammond 1455N1201BK is 4.72" x 4.06" x 2.09" and fits the σ11 perfectly (smallest possible size, no internal transformer). Actually maybe the σ24 can fit inside... Ooh the possibilities. Especially since the price of a σ11 isn't too far off a σ25 cased (my σ25 was around $60 with tax and shipping).
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post #5 of 19
12/30/09 at 3:37am
I thought about adding a higher end PS to the y1 or y2 but then I thought about the onboard regs and how, no matter HOW clean you send a signal to them, they'll still be your limiting factor on noise. that's the only issue you have to be concerned with, here, on this kind of circuit. it does not draw much current and it does not draw variable current. its 'easy' and it derives whatever local voltages it needs from the various TPSs.

7805 is fine, 317 is better. beyond that, I think you're throwing money away.
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post #6 of 19
12/30/09 at 3:52am
Interesting... I wonder how the LP2985 (used in the Opus) fares in terms of noise. Peeking at the datasheet, LP2985 (3.3V) has 30μV compared to 32-55μV of the TI 3.3V regulator.

Massive overkill, but we can essentially replace the SMD regulators with something like a TREAD or a Jung super regulator, yes?
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post #7 of 19
12/30/09 at 4:49am
Quote:
Originally Posted by linuxworks View Post
I thought about adding a higher end PS to the y1 or y2 but then I thought about the onboard regs and how, no matter HOW clean you send a signal to them, they'll still be your limiting factor on noise. that's the only issue you have to be concerned with, here, on this kind of circuit. it does not draw much current and it does not draw variable current. its 'easy' and it derives whatever local voltages it needs from the various TPSs.

7805 is fine, 317 is better. beyond that, I think you're throwing money away.
I've contemplated the same, so it seems the sigma25 would work well for the purpose Speaking of which I know the 7805 is a listed part, would the 317 be a drop in replacement on the sigma25? No idea if it's pin-compatible and haven't looked it up so I'm asking here in the off chance you know off the top of your head.
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post #8 of 19
12/30/09 at 5:08am
not at all pin compat.

you'd be thinking of the TREAD which is 317 and also about the same size.
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post #9 of 19
12/30/09 at 7:39am
I tried a TREAD with the Gamma 1 and then the Gamma 2. I couldn't hear any difference to USB power - YMMV.
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post #10 of 19
12/30/09 at 12:29pm
Quote:
Originally Posted by fordgtlover View Post
I tried a TREAD with the Gamma 1 and then the Gamma 2. I couldn't hear any difference to USB power - YMMV.
same here, other than not having drop-outs due to my pc dropping its usb voltage slightly (causing the onboard tps to drop out). only on surges (when plugging in a soldering iron and turning it on, for example).

but on SQ, I've heard zero diff between PSUs on this dac.
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post #11 of 19
12/30/09 at 12:39pm
Quote:
Originally Posted by linuxworks View Post
I thought about adding a higher end PS to the y1 or y2 but then I thought about the onboard regs and how, no matter HOW clean you send a signal to them, they'll still be your limiting factor on noise. that's the only issue you have to be concerned with, here, on this kind of circuit. it does not draw much current and it does not draw variable current. its 'easy' and it derives whatever local voltages it needs from the various TPSs.

7805 is fine, 317 is better. beyond that, I think you're throwing money away.
i understood this before ordering board/parts for a o-11, but i'm still curious. can noise in the uV range add upon one another with the TPS regulator, or does the intrinsic noise of the on-board regulators merely just mask the incoming noise of the PS?
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post #12 of 19
12/30/09 at 12:40pm
the noisier one masks the lower one.

sucks but its true.

you can't 'pre clean' the voltage supply any better than the downstream guys are going to treat it.
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post #13 of 19
12/30/09 at 12:41pm
Quote:
Originally Posted by linuxworks View Post
same here, other than not having drop-outs due to my pc dropping its usb voltage slightly (causing the onboard tps to drop out). only on surges (when plugging in a soldering iron and turning it on, for example).

but on SQ, I've heard zero diff between PSUs on this dac.
how about a separate PS instead of the TPS regulator .

EDIT: "instead"
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post #14 of 19
12/30/09 at 12:44pm
Quote:
Originally Posted by linuxworks View Post
the noisier one masks the lower one.

sucks but its true.

you can't 'pre clean' the voltage supply any better than the downstream guys are going to treat it.
well, if i can't hear a difference, at least i have a PS for my B1 pre/buffer.
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post #15 of 19
12/30/09 at 12:46pm
there are a few tps regs. if you want to have 'high end' regs in place of those, it could work, I guess.

do you really think the sound will improve, though, due to those kinds of tweaks? I have my doubts.

I would work on a discrete output stage and put a separate PS on that, but I'm not sure the digital sections need better PSUs. imho.
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