Need advice from the gurus.

@cleeds 

I'm not sure what you mean by 'two channels" and the term "fully balanced" is rather ambiguous.

(Just to stress, I am not an expert.  This is just what my understanding is, which maybe wrong.  So I welcome better clarification and a chance to learn.)

The two channels are the left and right channel.  And what I'm referring to, and on a very basic level, with "fully balanced" being when the circuit maintains the separation of the positive, negative, and ground (i.e. 'balanced') throughout ALL 3 sections of each channel, the input, amplification, and output.  This also requires that the left and right channels can not have a shared or common ground anywhere in the 3 sections.  

That said, what a lot of preamps, amps, etc. will do is have a balanced input connection, to an op-amp which converts the signal to a single ended (i.e. common ground) amplification section, then back through an op-amp to a balanced output connection.  (again, my simplistic understanding). Thus, while the signal is balanced in and balanced out, it is not "fully balanced" thoughout the circuit.

Which leads to the OP quote from 6moons about the Gato:

This is per 6moons regarding the AMP-150, I assume the "AE" version is identical.

"The input PCB sits near the back plate and sports NEC relays and an analog BB PGA2320 resistor-ladder IC. As a single-ended circuit, the XLR i/o ports are convenience items de/symmetrized by a TL07a chip."

- Jeff

jeffbij

... "fully balanced" being when the circuit maintains the separation of the positive, negative, and ground (i.e. ’balanced’) throughout ALL 3 sections of each channel, the input, amplification, and output ...

By your definition, an amplifier using a differentially balanced circuit isn’t "truly balanced."

@jeffbij 

Do you think there is any appreciable difference between a true balanced circuit and Gato’s implementation?  I assume as long as the circuits are well designed it should be good regardless. 

@cleeds - I did some Googling and based on what I read, there is a slight difference between the fully (or truly) balanced and a differentially balanced circuit. Not in the fact that one is balanced and one is not, but rather on how the balanced amplification portion of the circuit is implemented.  I'll be honest, the "explanations" of the difference were not clear cut on what that difference is, but some common threads had to do with the impediance matching between the positive and negative legs of the signal.  I did find a quick video from Paul McGowen at PS Audio where he compares the two, but even after watching that multiple times I was still not sure.

https://www.youtube.com/watch?v=ZiF4sWRlsQw

@tubeguy76 -  

Do you think there is any appreciable difference between a true balanced circuit and Gato’s implementation?  I assume as long as the circuits are well designed it should be good regardless. 

Honestly, at the price point of the Gato, I would think that their design is well done.  Is it "...good regardless", I would say, yes.  Is it as good as a fully (or differential)  balanced design, I think that is a loaded question.  Just like any other piece of audio electronics, there is equipment that is well designed with good parts and crappy designs with cheap parts, balanced or otherwise.  And in this hobby, there is always something better.  

That is why I suggested you try using the Gato as just a preamp with the Cherry's before you change anything else. It may sound fantastic, especially with the LRS+ speakers, which love power and higher current amplification to "sing".

- Jeff