Gamma-2 (γ2) DAC Thread - Page 67

Someone already has.

74AHC1G08GV,125 NXP Semiconductors Gates (AND / NAND / OR / NOR)

thanks

thanks a ton

fini

Front panels arrived today.

All said and done, these are remarkable units and an incredible value for the performance you get out of them. Hats off to AMB and Mister X - well done. For my non-headphone setup, I use a PS Audio DL-III (a Cullen Stage IV mod) and when we switched between it and the Gamma 2, they were very similar in performance. I have to pick up the parts for a third soon, as the two I've built are already going to friends.

Sweet build pixeljedi, the custom front panels are really sweet!

Itching to get mine going.

Thanks mattcalf, I had a good time with these. Only had a snag with the second one. Had to reflow the oscillator a few times, but then she started singing. Talk about building your smd skills, these are awesome for that. I used to hate it, but now it's almost meditative - haha

I'm listening through it right now and man do I ever love this thing.

Just FYI, if you're planning to build a σ25 PSU with a σ24 transformer mounting board for use with a γ1+γ2, a 2.8VA 9V EI-30 transformer should work well. The σ25 should be configured to output 5V DC.

Part numbers:

Digi-Key: 567-1040-5-ND (115V primary) or 567-1042-5-ND (230V primary)
Farnell: 1689068 (230V primary)

Mouser does not stock any EI-30 transformers with the needed specs . However, if you're going to be powering a γ1 only (no γ2), you can use Mouser 673-030-7151-0

Alternatively, you can use an Amveco TE62011 (Digi-Key TE62011-ND) or TE62021 (TE62021-ND) toroidal transformer, and skip the σ24 PCB. These transformers have two 9V secondary windings which should be wired in parallel. They also have two primary windings which should be wired in parallel for 115V AC mains, or in series for 230V.

You could also use an AC or DC wallwart (unregulated) rated at 9V 300mA or above instead of a transformer.

Just placed my AMB order.

Really excited now, checked off all my parts physically against a BOM and I'm ready to roll.

Can't wait to get building.

Thanks Ti.

Just added to my cart at Farnell.

Has anyone looked into cases suitable for stacking the σ24 and σ25? I came up with 563-CU-791 which I think is spacious enough and maybe allows for a switch as well. Add a 1.3mm cable assembly and something to attach to AC mains and I'm set...

Do not forget a fuse! - course you can just get an IEC that has a switch and fuse builtin for max use of space and also a bit safer since you have less Mains wiring that could be exposed.

I was hoping to keep my adapter small and cute, but I guess it's inevitable eh? I think I have 500mA fuses left over from my Opus... maybe not. I do have a certain metal case 2.75" X 2.1" X 1.60" in mind, and that allows me to put the boards side by side (there is no thickness/strange slots to worry about) but it still won't allow for a fuse/switch unless I leave everything external, which makes me cringe.

You could just wire the fuse with an inline fuse holder and no switch (plug it in and it turns on), and use a strain-relieved AC power cord without IEC -- basically a home-made wallwart that doesn't actually hang on the wall. I would suggest a case with ventilation though, the transformer and the regulator will both get hot.

First of all, hi everybody, while it's been a while following this forum this is kinda my first post, and sadly for a troubleshooting advice.
Actually the trouble is with a gamma1 full, originally to be paired to a gamma2 once working, but the original thread on headwize, as the whole forum, is currently under maintenance and in read only mode.
So, hoping I can still pose my technical question here in the meanwhile (lot of photos for a reward )... I built a gamma1 full, tested voltages and shortcircuits as standard initial testing showed, checked for cold joints with a lens and so on, then I turned it on, connecting to USB for both power and data.
The DAC sounded very well, tested it on a pair of AKG KSC-75, just some little scratches and noise at the maximum iTunes volume, but seemed to dissipate in a few seconds at least for the most. The switch light also lit red to become green when audio was playing to blink red then green again while playing. Then I tried to move the input switch, which of course silenced the headphones, yet, and there it is the problem, when switched back to USB it barely stayed green for a few moments then turned red and no more sound from it from then, like there was no data input. I of course disconnected and reconnected the USB cable, just to be sure restarted the mac, reflowed nearly all SMD components on board, checked again for burned components or toasted smell (both none), cold joints (seems none) and wrong parts (seems none too).
I have to say that I have some experience in SMT soldering and one source of the problem MAY be that I cleaned in isopropolic alcohol spray the boards, which there MAY have been some slight residues under some chip, maybe shortcircuiting it.
I'd hope you can help me at least restrict the possible broken or malfunctioning part with your experience, I followed that schematics and tried to check or reflow anything that may be part, but before replacing al of the components I'd like to have at least a few to try first.
I repeat that voltages where, while powered from USB, perfect from both boards and when mated togheter and sadly I'm not able right now to both try to power the gamma1 from a wall plugged transformer, nor to check for any other input (optical or coaxial), the latter I may be able to try tomorrow.
As this little jewel is surely form a very good pair with my PPAv2 I hope to get it back working again very soon... can't actually wait for it to blossom to a full gamma2 too eh eh...

Thanks anyway for any help, sorry again for not posting in the most right topic, yet can't find or use one more specific.

Ric

The mating pins are probably the most problematic. However if your light switch isn't turning off (just blinking red and green) we can probably rule out a connection problem. The problem is most likely located on the USB board. Is your build the full++ or config A?

What's your operating system? Can you try messing with the buffer length in foobar2000 (press stop and then play after every buffer length change), and maybe try ASIO or WASAPI?

I tought mating pins too, I tried to bend the males a little to force a little more contact while pushing them in yet no change.
Also the switch light isn't turning red and green, it stay solid red always, just blinked, actually like a faulty jumping connection for a few moments before just turning solid red, no matter what.
My build is the A profile, full one, not full++.
I tried it on MacOSX and linux (so Core Audio and PulseAudio over ALSA respectively), haven't tried changing the buffer sizes, but on both systems are dinamically set based on latency and system load, also I'm not so sure it is a software problem... kinda fear is a faulty hardware one... :/

Some more informations: after a very engaging saturday morning with me, a multimeter and the gamma1 I found that U5D middle gnd pin was lifted and I reflowed it, checking for correct connection.
Yet same results, no sound and red light only. But I've noticed another strange behaviour, the DAC is always powered by USB, when the switch is in the middle position is always a bright, firm red, when I select the coaxial setting it becomes nearly visible, only to become redder and redder in a three-four seconds, like some capacitor charging or something like that...