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Gamma-2 (γ2) DAC Thread - Page 135

post #2011 of 2109
10/23/10 at 10:02pm


 

Quote:
Originally Posted by amb View Post

 

 

OPA2365 and AD8565 are both excellent opamps in this application, I wouldn't necessarily say that the OPA2365 is "better", they're just slightly different and subject to preferences.  The AD8565 has lower output impedance and much more output current capability, so it could drive low-Z loads much more effectively.

 

As far as the anti-clipping switch goes, no, it does not prevent clipping caused by excessive loading at the analog output.  The anti-clipping switch's function is to lower the DAC's volume by 2dB to avoid digital clipping with some recordings.  See the WM8741 datasheet for info.


Oops yeah i read your previous comment about 2365 incorrectly. Thanks for correcting me. 

 

skimmed it..seems like the anticlipping switch doesn't apply to my situation at all. 

 

I saw that the U7 is driving 3.5mm jack in the back but didn't see the front jack. Is the front 3.5mm jack driven by a different(weaker) opamp from the original gamma 1 design???

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post #2012 of 2109
10/23/10 at 10:15pm
Quote:
Originally Posted by flexium View Post

 

I saw that the U7 is driving 3.5mm jack in the back but didn't see the front jack. Is the front 3.5mm jack driven by a different(weaker) opamp from the original gamma 1 design???


U7 drives the 3.5mm and RCA analog output jacks on the rear panel.  The front analog jack is driven by γ1's WM8501 DAC directly.  It's not really "weaker" than the AD8656.  WM8501 has a stout internal output stage and needs no external opamp, and is capable of driving fairly low-Z loads directly (Wolfson datasheet says that it could swing 1Vrms into 16 ohms).  Into an 8 ohm speaker that might be a surprisingly amount of volume, but I don't think the performance would be too good when being so severely loaded.  Since neither γ1 nor γ2 was intended to drive speakers, and I don't expect them to work well as such, I never tested them that way.

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post #2013 of 2109
11/21/10 at 12:50pm

Is anyone selling full kits for a complete γ1/γ2 build?

 

Also, what is needed to omit from the BoM if I only require USB inputs?

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post #2014 of 2109
11/21/10 at 12:55pm

You'd want the "B" configuration. http://www.amb.org/audio/gamma1/

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post #2015 of 2109
11/21/10 at 1:48pm

What is the price difference for the components between a full config and a lighter one? If the difference is only twenty or thirty dollars I think I will just do a full γ1.

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post #2016 of 2109
11/23/10 at 12:00pm

$20, maybe? But you make up for that by requiring an external power supply. It's just simpler to go full++.

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post #2017 of 2109
12/3/10 at 4:18pm

Anyone have a completed/used one they are looking to sell (or full++ y1)? Under $300 or less shipped to N. America as that is a current offer I am trying to beat. I can't post in the classifieds section for some reason..

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post #2018 of 2109
12/9/10 at 3:48am

Do I need a 4 wire or 5 wire cable for this? I've never heard of a 5-wire cable until now...

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post #2019 of 2109
12/9/10 at 9:37am

You need at least 100 posts to be able to use the classifieds.  It keeps the scammers at bay most of the time

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post #2020 of 2109
12/9/10 at 10:47pm
Quote:
Originally Posted by herro View Post

Do I need a 4 wire or 5 wire cable for this? I've never heard of a 5-wire cable until now...


??? confused_face%281%29.gif

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post #2021 of 2109
12/9/10 at 11:25pm

I guess I am not up to date with my USB. It was my understanding that all usb wiring was standard +/-/D+/D-, but when I was looking for cables there are 5 pin ones apparently?
 

Quote:
Originally Posted by amb View Post

Quote:
Originally Posted by herro View Post

Do I need a 4 wire or 5 wire cable for this? I've never heard of a 5-wire cable until now...


??? confused_face%281%29.gif

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post #2022 of 2109
12/9/10 at 11:44pm

http://pinouts.ru/Devices/mini-USB_pinout.shtml

 

USB is a 4-wire system, but the Mini-USB connector has an extra 5th pin (which is unused on the γ1 DAC).  Despite this, you should use a 5-wire cable to ensure that the plug willl mate properly (γ1 has Mini-B connector).  Also, don't confuse Micro-USB connectors with Mini-USB.  They are diffferent.

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post #2023 of 2109
12/10/10 at 12:59am

 

Here is an example image of a 4 pin mini B type USB connector: 

 

ced_usb_minib4pos-m.jpg

 

Here is an example image of a 5 pin mini B type connector:

 

ced_usb_minib5pos-m.jpg

 

(images borrowed from http://www.l-com.com/content/USB-Connector-Chart.html )

 

 

 

 

 

Big thanks the person that fixed my account. :)

 

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post #2024 of 2109
12/12/10 at 12:00pm

I am considering building a sigma11 to power my Gamma2. Right now, I'm using a TREAD with a toroidal. I know a TREAD isn't terrible but I suspect I might hear a difference by using the sigma11, which is much higher quality.

 

Has anyone done a similar upgrade with their Gamma2 - from a TREAD or wallwart up to something more serious, and how much better does it sound?

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post #2025 of 2109
12/12/10 at 11:58pm

 

Quote:
Originally Posted by slowpogo View Post
Has anyone done a similar upgrade with their Gamma2


Lots of people are using the σ11 to power their γ2s, a good number of them are upgrades from other supplies; USB power, linear regulated wallwart, or 3-terminal-regulator based supplies.

 

Quote:
how much better does it sound?

 

42.

 

 

 

 

That's going to be difficult to quantify, don't you think? evil_smiley.gif

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