PDA

View Full Version : AMB's γ1 Miniature DAC Project



sponge
17-05-2009, 10:22
I had been thinking about putting together a "portable" headphone system to use in the consevatory in readiness for those warm evenings (Har Har!). This system was (hopefully) going to sound as good as my main system - Squeezebox Classic > TC-7520 (modified) > DIY M3 Headphone Amp > AKG K701 Cans.

Enter the γ1 (gamma 1 http://www.amb.org/audio/gamma1/ ) which I had read about a while back. It seemed to fit the bill - USB, Coax and Optical inputs, compact, USB or wallwart powered.

A quick check on the parts list - Looking good, should cost less the 100GBP complete.

So I went for it.

Well, I have just completed the build and the unit is bedding in (is that necessary?).

I was expecting reasonable performance, but this little DAC is seriously good IMHO - Well above my expectations, and then some!
And what a nice little project - Perfect for any DIY electronics fan.

If any of you guys are interested, I will take and post a few snaps of the DAC, and also my take on how the γ1 compares to the TC-7520.

Cheers - Ken

leo
17-05-2009, 11:57
Course we are interested Ken:) pics, opinions and comparisons are always welcome on here;)

jon1
17-05-2009, 13:26
I had been thinking about putting together a "portable" headphone system to use in the conservatory in readiness for those warm evenings (Har Har!). This system was (hopefully) going to sound as good as my main system - Squeezebox Classic > TC-7520 (modified) > DIY M3 Headphone Amp > AKG K701 Cans.

Enter the γ1 (gamma 1 http://www.amb.org/audio/gamma1/ ) which I had read about a while back. It seemed to fit the bill - USB, Coax and Optical inputs, compact, USB or wall wart powered.

A quick check on the parts list - Looking good, should cost less the 100GBP complete.

So I went for it.

Well, I have just completed the build and the unit is bedding in (is that necessary?).

I was expecting reasonable performance, but this little DAC is seriously good IMHO - Well above my expectations, and then some!
And what a nice little project - Perfect for any DIY electronics fan.

If any of you guys are interested, I will take and post a few snaps of the DAC, and also my take on how the γ1 compares to the TC-7520.

Cheers - Ken



You kept that one quite ken;)some pics please



jon

sponge
17-05-2009, 13:35
You kept that one quite ken;)some pics please



jon

I was always going to do a post about the γ1 - But when the bits started arriving, I got drawn into the build and, well, you know how it is ... ;)

OK, I'll take the γ1 to bits and shoot some pics.

Ken

jon1
17-05-2009, 14:55
I was always going to do a post about the γ1 - But when the bits started arriving, I got drawn into the build and, well, you know how it is ... ;)

OK, I'll take the γ1 to bits and shoot some pics.


Ken




Yes you get addicted ken :)must get it finished...




jon

sponge
17-05-2009, 16:01
Basically, the γ1 can be built several ways - I chose to build the "full" version because I needed USB and Optical inputs. Depending on what you require decides what components or boards are fitted. This also affects the front and rear panel design.
AMB sells pre-cut and etched panels for the full version, but they add $40 to the price - I chose to do my own... If you do this yourself, a vernier caliper is essential

Here is the finished γ1 front and rear:

http://farm3.static.flickr.com/2041/3538804390_86b8f52714.jpg?v=0
http://farm3.static.flickr.com/2218/3538805938_80a4728aa7.jpg?v=0

The USB board can be configured to be a USB-to-S/PDIF and a USB-to-I²S converter if you need it to be, which would require the population of the rest of the board as you can see:

http://farm4.static.flickr.com/3617/3538793438_7cc19bdc56.jpg?v=0

With the full version though, the USB board needs the DAC board:

http://farm4.static.flickr.com/3633/3538795724_6d6d8c2cb7.jpg?v=0

And then the two boards plug together to sorm a DAC butty:

http://farm3.static.flickr.com/2079/3537986029_f194433166.jpg?v=0

Here they are ready to be mated :

http://farm4.static.flickr.com/3364/3538799306_69efab15c7.jpg?v=0

Once they are together and tested, they can be installed in the case :)

http://farm4.static.flickr.com/3337/3538802926_aeb4550a16.jpg?v=0

Front and rear panels are fitted and we are ready to play...

The γ1 is a nice match for AMB's Mini³ portable headphone amplifier which I built some time ago. This is how they look together:

http://farm3.static.flickr.com/2240/3538808626_fac061231f.jpg?v=0

Here is the rig in the conservatory being fed from a Sony CDP via the Optical out - The Mini³ is driving the K701's - Just needs the wallwart:

http://farm3.static.flickr.com/2457/3538811136_2e4c40cc5d.jpg?v=0
http://farm3.static.flickr.com/2123/3538001663_5cd17f43d8.jpg?v=0

And here the kit is attached to the USB hub and using USB power - The selector switch is lit green meaning the γ1 is receiving data - This changes to red on data lost or errors. The Mini³ is driving Senn HD600's (out of shot):

http://farm3.static.flickr.com/2212/3539054214_e41e102c84.jpg?v=0



There you have it :)

This little DAC sounds really nice and VERY close to the TC-7520 - Just how close I will report when I have done some comparison tests.
But for now I'll just enjoy a couple of these :cool: and some quality listening...

Ken

sponge
17-05-2009, 16:28
If I were making another γ1 I would probably use a black Hammond case rather than the silver, but I had the Mini³ in silver already and wanted a match. Well, nearly, as the Mini³ has black end panels, but you know what I mean :)

Oh, and BTW - It will be interesting to try the original 5V switcher with the γ1 that came with my Squeezebox - I didn't think about it, and bought another 5V wallwart (a linear) which is about 4 times the size and weighs several times the γ1! :doh:

Ken

jon1
17-05-2009, 16:36
Nice one ken..I see that sex had to creep in on your post:lolsign:Pcbs mating..BTW nice pics



jon

sponge
17-05-2009, 16:41
Nice one ken..I see that sex had to creep in on your post:lolsign:Pcbs mating..BTW nice pics



jon

Thanks, I do try to keep it clean Jon - It's just the interlocking procedure that seems to send me off on one :eyebrows:

jon1
17-05-2009, 16:52
Thanks, I do try to keep it clean Jon - It's just the interlocking procedure that seems to send me off on one :eyebrows:


Ken you do not know what members are doing behind the scenes..Like your self quietly building dacs..now enjoy it:smoking:




jon

leo
17-05-2009, 19:02
There you have it :)

This little DAC sounds really nice and VERY close to the TC-7520 - Just how close I will report when I have done some comparison tests.
But for now I'll just enjoy a couple of these :cool: and some quality listening...

Ken

Thats well neat!

I like the options you get and making it available as two parts

If you think its close to your TC-7520 thats a bonus! close is certainly better than no where near.
It looks to be the ideal portable companion:smoking:

sponge
18-05-2009, 08:16
Thats well neat!

I like the options you get and making it available as two parts

If you think its close to your TC-7520 thats a bonus! close is certainly better than no where near.
It looks to be the ideal portable companion:smoking:

Thanks Leo - Yes, it is a nice design and has quite useful options too.

I am guessing it wont need much burn-in as the sound doesn't seem to be changing at all. I will have another good listen tonight - It's always a good sign that a piece of equipment is good when you are looking forward to a listening session - And I am :)

Ken

sponge
18-05-2009, 19:33
OK, I have been doing a few comparison tests with my TC-7520 DAC with the following setup:

Squeezebox Classic Coax out -> 7520 Fixed line out -> M³ amp Input 1 -> AKG K701 cans.
vs
Squeezebox Classic Optical out -> γ1 -> M³ amp Input 2 -> AKG K701 cans.

First impression - 7520 has a higher output than the γ1, so volume has to be adjusted to even things up.
Initially, the 7520 had a deeper bass than the γ1, but that has now changed with a few hours on the γ1's clock, and bass is much tighter and is now very close to the 7520.
The mids and highs; well, I can't name a winner, the γ1 to my ears is a match for the Beresford. Clarity, soundstage and instrument location is spot on - Superb.

I have just been listening to some tracks on the computer via foobar2000 + asio4all and USB out into the γ1 and output to the Mini³ amp, and I have been grinning all the time - This little DAC doesn't put a foot wrong - The whole experience is addictive.

For anyone looking for a portable rig to pack with their laptop, you will do a lot worse than a γ1 and a Mini³ with your choice of phones.

Ken

sponge
03-06-2009, 12:25
I thought I would make an additional entry following the upgrade of my Beresford TC-7520. The upgrade was to swap the stock PCM1716 DAC chip to the Wolfson WM8716 DAC.

The comparison with the γ1 should be quite interesting now as the γ1 also uses a Wolfson DAC - The WM8501.

I will be using the Squeezebox Classic as source playing FLAC files. Coax out to the TC7520, Optical output to the γ1. Both DAC's are sending their output to my M³ headphone amp. so I can switch between the two. The M³ is driving either K701's or HD600's.

On first listen, there appears to be little to choose between the two DACs but I will do a more critical comparison and report back.

Ken

leo
03-06-2009, 14:12
Thats interesting Ken, sounds like the y1 has turned out to be a nice little dac

I've started doing some modifications to a Duet receiver which also uses a WM8501, I'll start a thread soon.

sponge
03-06-2009, 18:57
sounds like the y1 has turned out to be a nice little dac

I've started doing some modifications to a Duet receiver which also uses a WM8501, I'll start a thread soon.

I'll look forward to that Leo. Yes indeed the y1 punches well above it's weight. I have been doing some pretty intensive comparison listening, the upshot of which is:
I'll be damned if I can tell any significant difference between the TC-7520 and the y1.

There does appear to be a "Wolfson sound" which to me is spacious, refined and smooth. The sound will not be to everyones tastes maybe - But it suits me fine.

The y1 as a portable rig coupled to a good quality Cmoy for example, playing off a laptop's USB, is quite a combination.

Ken

leo
03-06-2009, 19:29
But it suits me fine.



Ken


Thats the important thing mate:)

BTW that dac chip should be quite suited to driving headphones no probs.
You can't beat it when a diy project gives you satisfying results , I've built loads of stuff now, not all have been successful:lol:

sponge
03-06-2009, 19:53
Thats the important thing mate:)

BTW that dac chip should be quite suited to driving headphones no probs.
You can't beat it when a diy project gives you satisfying results , I've built loads of stuff now, not all have been successful:lol:

You are spot on there Leo - Nothing quite like the experience of that first listen when you KNOW things are right :). And I've been there myself with the "not so successful" :(

Ken

sponge
15-06-2009, 08:39
Just noticed on AMB's site - An enhanced version of the γ1 has been announced - Called the γ1 "full++", it is the same γ1 but with a USB-to-S/PDIF converter. This requires a new case and some hardwired links to the two boards, but the result is pretty nice. See it here:

http://www.amb.org/audio/gamma1/

Ken