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Massdrop O2 + SDAC DAC/Amp

Massdrop O2 + SDAC DAC/Amp

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Hello Everyone,

Sorry it took a while, we did hear you.

There have been 6,647 requests for another drop of the Massdrop O2+ODAC DAC/Amp Combo:
https://www.massdrop.com/buy/massdrop-o2-odac

We were not able to continue offering that version at the price point that made the product accessible, so we reached out to Grace Design for a new DAC that meets or exceeds all of the ODAC specifications (at a reasonable price).

Please meet the new Massdrop Objective 2 + Grace Design Standard DAC (SDAC) combo.

Designed to measure well, sound transparent, and be affordable.

Michael Grace does a great job of explaining some details about the SDAC here:
https://www.massdrop.com/buy/massdrop-x-grace-design-standard-dac/talk/1806625

In addition:
Since we have several DAC & Amp products available right now, here’s an overview to help with your options…

DAC & Amp Family UPDATE 9/18/2017:
https://www.massdrop.com/talk/2363/audiophile-custom-products-dac-amp-update-9-18-2017

Thank you so much for all of the requests and support!
Load 8 more comments
CEE_TEE
Hi when is the next drop ? I miss the first one cause i didn't know they is this drop happening on oct.
CEE_TEE
Alot of us waiting for the second drop please make it happen asap. Thks.
price ??????
saudregion
It was $149.99 on the latest drop (late 2017).
Can we expect this drop again or soon ?
It took me awhile to notice that something is wrong with my O2+SDAC. My particular unit came with wrong gain configuration (2.5X and 6.5X* instead of 1X and 3.3X listed on the product page) and other units might be affected by this as well (at least from what I've noticed on a teardown from Reddit).

*O2's input stage will overload when set to high gain of 6.5X with SDAC's output at max, which may cause the sound to become distorted but it won't harm the O2.


THE DISASSEMBLY

*Before disassembly "...wait at least 15 seconds with the power turned ON(in) after the power is removed to let the capacitors discharge."-NwAvGuy

FRONT PANEL:
*turn CCW to unscrew any of the screw or nut
-Remove the volume knob by removing the hex screw securing it to the pot's shaft.
-Remove the nut securing the potentiometer to the front panel.
-Remove 4 Phillips screws on the front.
by now the front panel should be able to be come off with the jack attached and you should be able to see if the resistors are of right values (R19, R23) and left out(R17, R21) if they aren't contact MD's support.

*the nut is on the jack assembly 1K resistors removed from R17, R21 on the side
-Remove the 1/4" HP jack by turning the black plastic nut CCW (it may help to grip both sides of the jack while turning and use a wide elastic band or piece of cloth to help grip and prevent an scratches on the nut).

BACK PANEL:
-Unscrew 4 Phillips screws and 1 Torx screw on the back.
The back panel should come right off.

THE PCB:
-Slide PCB out the back of the enclosure (it will get stuck if you slide it out through the front because of how the SDAC is mounted)


THE GAIN RESISTORS

"Resistor Values – The O2’s gain (for one channel) is: Low Gain Ratio = 1 + R16/R17 High Gain Ratio = 1 + R16/R19 Voltage Gain in dB = 20 * Log(Gain Ratio)
…For 1X gain just leave out the gain resistors"-NwAvGuy

Switch out: R17and R21 needs to be left out for 1X gain (gain switch pushed out) but 1K ohms resistors are installed.
So the gain is 1+1500/1000 = 2.5

Switch in: R19 and R23 needs to be 665 ohms or 649 ohms (closest standard resistor values) but 274 ohms resistors are installed.
665 ohms: 1+(1500/665) = 3.26 (~3.3X)
649 ohms: 1+(1500/649) = 3.31 (~3.3X)

274 ohms: 1+(1500/274) = 6.47 (~6.5X)


THE "FIX"
*this is done at your own risk

Method 1(no soldering required): Clip off or desolder the "high gain resistors" (R19, R23) and leave the "low gain" resistors intact(R17, R21).

Now the gain switch be the following:
SWITCH IN = LOW GAIN (1X)
SWITCH OUT = HIGH GAIN (2.5X)

Method 2 (soldering required): Do the same as the first method so while you get the resistors you still have high and low gain(1X and 2.5X). Clip out R17, R21 and solder in the "high gain" resistors in R19 and R23.


Links
O2's gain resistors:
http://nwavguy.blogspot.com/2011/08/o2-details.html#circuitboardconstruction
in "THE GAIN RESISTORS" section

O2's maximum input:
http://nwavguy.blogspot.com/2011/08/o2-details.html#maximuminput

The teardown post on Reddit:
https://www.reddit.com/r/Massdrop/comments/7ny0vj/massdrop_o2_sdac_dacamp_teardown/

SDAC measurements on ASR:
https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-massdrop-x-grace-design-sdac.2495/
Load 36 more comments
I do agree to some extent, though a valid outcome of the resolution of warranties is a full refund which they offered. I think as a company, it doesn't look good not standing behind your products.

They should also be sending warranty cards with what they cover for each product, for example in this case they didn't state they would refund if there are issues. I'm not sure if this is against FTC regulations, but I snipped my resistors at this point
Yes, that was a mistake I made initially so the original picture on that post is a "how to not" and not a "how to do".

"...the other pair was clipped off just for me to figure out a second later; that I should've clipped of the "high gain" resistors(6.5X) and leave the "low gain" resistors(2.5X) intact so I had switchable gain of 1X and 2.5X while I waited for my parts to arrive."

Regarding Massdrop's warranty, I'm unable to find any info of it on their terms and conditions page (except for their RETURN POLICY).
Alot of us waiting for the second drop please make it happen asap. Thks.
when is the next drop i been waiting since last year?
I need an adapter for 110V, what is compatible specs?
Mine has 220V but now I need 110...
escknx
You can get one from JDS labs (link: https://www.jdslabs.com/products/147/15vac-power-adapter/ make sure you select the US one) or Triad Magnetics WAU120-1000 should work as well.
Hi when we going to have another drop it's been too long since last drop. Any hiccup?
When will this drop be live again? Since i need a better amp to power the HD6XX I bought.
I hope this drop will be live soon after the HD6XX drop closes I bet they will sell like hot potato's since a lot of folks will have to buy a good amp/dac combo to drive their new headsets!
How does this compare to the sound blaster X7? I'm looking for a different yet still lively sound
Anyone any idea around when this will drop? My O2 amp on the way, hd6xx in march, i need a dac now... Hmmmm
KrisBali
this is a combo dac+amp..you are waiting for this I think: https://www.massdrop.com/buy/massdrop-x-grace-design-standard-dac
GonzoNakamura
Thanks!
When the both headphones and RCA are connected via USB, it seems that audio isn't muted for the RCA.