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Old 10th February 2012, 03:24 PM   #2071
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Guys what will in need to add, to drive a small pair of desktop speakers with this amp ?
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Old 10th February 2012, 09:00 PM   #2072
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Quote:
Originally Posted by pjblakey View Post
Thought I would share this.
An O2 and AK4393(with a couple of mods) crammed into a rather nice chinese aluminum enclosure. Need to straighten up the wiring.
Many thanks to RS for a very nice amp.
The input to the DAC is via an HA info spdif device.
This is my first effort at going PC based music system.
I'm very happy with the sound but would consider replacing the DAC with a decent USB input board. Anyone suggest one that would fit and sound as good?

Cheers

Peter
Wow, very nice indeed. I might have to get another O2.
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Old 10th February 2012, 09:32 PM   #2073
jfrana is offline jfrana  United States
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Everything seems to be working.

Volume attenuation works on both channels.

Output voltages are well below 1v. The max voltage with a battery removed was .68 on p4 off U4.

Voltage at Batteries is closer to 11.6 than 11.8, and when I expect 11.8 at any voltage measurement I see 11.6.

I am getting a pretty loud click and thump at turn on and off with volume full down. HD597s and HD518s

Measuring close to
AC, on, no batteries for U2
1=-11.7
2=-8.8
3=-10
4=-11.7
5=-10
6=-11.7
7=8.5

R25 codes are something like (blue body) brown, dark-green, dark-blue/black, light-green, purple

Anything to worry about, or am I ready to sit back and enjoy?
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Old 11th February 2012, 02:05 AM   #2074
MrSlim is offline MrSlim  Canada
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Quote:
Originally Posted by Fivetide View Post
Guys what will in need to add, to drive a small pair of desktop speakers with this amp ?
How about a proper speaker amp...

Sorry, but its a headphone amp.. not a speaker amp.. people need to stop trying to make it into something it's not..
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Old 11th February 2012, 09:36 AM   #2075
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Quote:
Originally Posted by pjblakey View Post
Thought I would share this.
An O2 and AK4393(with a couple of mods) crammed into a rather nice chinese aluminum enclosure. Need to straighten up the wiring.
Many thanks to RS for a very nice amp.
The input to the DAC is via an HA info spdif device.
This is my first effort at going PC based music system.
I'm very happy with the sound but would consider replacing the DAC with a decent USB input board. Anyone suggest one that would fit and sound as good?

Cheers

Peter
Wow! Pretty good job cramming all that in there... Those aluminium enclosures are rather nice... The ODAC should only be a month or so away and if the O2 is used as a yard stick, it should be a nice performer.
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Old 11th February 2012, 11:04 AM   #2076
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It will be interesting to hear the ODAC - will probably build one for fun, if nothing else.
My setup suffers a very small amount of noise and there is a sweetspot on the 25K attenuator where the noise is all but gone. maybe that can be improved. This is my portable system along with a netbook loaded with 200G of FLAC files.
It compares pretty well to my B4 preamp/AK4396 combo.
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Old 11th February 2012, 12:30 PM   #2077
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Can't tell from your photo but is the body of the potentiometer connected to ground... I had a similar issue with my Wire using a near identical case & Alps RK27 pot', grounding the pot was the first recommedation I got and it worked 100%.

Of course if you've already done that then??? Though it does sound like it's a grounding issue.

I need to copy my CD's to HDD, the O2 & Odac should make for a very nice tranportable rig
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Old 11th February 2012, 01:52 PM   #2078
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Thanks for the tip.
I'll check and let you know
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Old 11th February 2012, 02:10 PM   #2079
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Is there a way to tell given an output V for my source and my headphones specs if the O2 will clip at gain level X, Y, etc.? I did some calculations using that spreadsheet that's floating around and it looks like I need a gain of 3.2 for my source (2.16 V) and my headphones (DT880 600 ohm).
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Old 11th February 2012, 02:44 PM   #2080
agdr is offline agdr  United States
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Quote:
Originally Posted by jfrana View Post
Everything seems to be working.
Looks good! The big thing to check is DC offset voltage on the headphone output jack. Can also do it on P2. Just make sure that with the amp power up and nothing plugged into the input jack you only have 3-6mV (0.003Vdc) or so on the left and right channels. If that is OK then enjoy some music!

On the on/off popping, no idea. That is one for RocketScientist.
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