Cheap balanced amp?
Feb 15, 2014 at 8:29 PM Post #61 of 63
I'm with Chris J on all this. It's more execution than type and common mode rejection is just not a significant issue in home kit. Great for long mic or instrument runs with all kinds of spurious stuff around. For balanced to be as good as single ended it needs the inverse amp to not only measure as well but to be an exact inverted duplicate in the way it behaves dynamically. When you get into top quality designs where transistors are trace matched for top performance, it just gets that much harder unless there's some really cool distortion cancelling going on like feed forward etc.
 
All that said we're not in super high end territory so what your ears tell you is the better amp is the better amp and Ray makes some of those.
 
To the OP. If you've got a cheap stereo amp now, buy another and use them one channel each with the sources' up and down phase positives in separate channels of a single amp and the earth to the common input ground. Output would be the two positives of an amp to the + and - of one channel's leads. Ignore the ground. A bridged amp is a balanced amp. Output impedance will double, voltage swing will double and power quadruple. Check bridging an amp if you want to try.
 
Feb 16, 2014 at 7:03 PM Post #62 of 63
  I'm with Chris J on all this. It's more execution than type and common mode rejection is just not a significant issue in home kit. Great for long mic or instrument runs with all kinds of spurious stuff around. For balanced to be as good as single ended it needs the inverse amp to not only measure as well but to be an exact inverted duplicate in the way it behaves dynamically. When you get into top quality designs where transistors are trace matched for top performance, it just gets that much harder unless there's some really cool distortion cancelling going on like feed forward etc.
 
All that said we're not in super high end territory so what your ears tell you is the better amp is the better amp and Ray makes some of those.
 
To the OP. If you've got a cheap stereo amp now, buy another and use them one channel each with the sources' up and down phase positives in separate channels of a single amp and the earth to the common input ground. Output would be the two positives of an amp to the + and - of one channel's leads. Ignore the ground. A bridged amp is a balanced amp. Output impedance will double, voltage swing will double and power quadruple. Check bridging an amp if you want to try.

 
Sure.
 
Basically, as far as us audiophiles are concerned, balanced transmission lines are really more applicable for rejecting noise in low level audio signals such as:
DAC to pre-amp
pre-amp to power amp
phono cartridge to phono pre-amp
 
I suspect we like balanced output headphone amplifiers because the crosstalk improves.
Each driver in the headphone has it's own dedicated pair of cables.
I've never seen any measurements backing this up, but it seems that most balanced output headphone amp owners talk about an enhanced sense of space, better imaging, etc. 
 
Anybody got any proof?
I'm sure everyone here would like to see some measurements.
 
Oct 8, 2014 at 3:46 PM Post #63 of 63
   
You will need a DAC that offers balanced output (usually using 3-pin XLR) to interface with the Mjolnir. The least expensive balanced DAC I've seen is $300.
 

 
Behringer U-PHORIA UMC204 can be had for $100.  Now, the specs indicates Balanced Outs but these are RCA not XLR.   So not clear if these are truly balanced?  Possible to use adapter to 3-pin XLR?
 
http://www.fullcompass.com/common/files/19797-UMC204_UMC202_UMC22_UM2_WebBrochure.pdf
 
Looks like you could even use as phono pre-amp with XLR inputs + adjustable gain?
 
No idea what the chipset is and seriously doubt much modding potential without serious surface mount soldering skills ...
 

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