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Audio Research Amplifier Balanced Input Question

Hello, I am thinking about upgrading my Audio Research VS55i amplifier to one of the higher Audio Research amplifiers which use balanced connections only... specifically a Reference 110 power amplifier.

Would I be able to run a regular (single ended) linestage such as a Manley or a Herron that uses standard RCA inputs/outputs only into the balanced connection of the Audio Research amplifier and have the amp still operate and amplify correctly given its internally balanced configuration? (They do sell high quality handy RCA to XLR connectors/adapters, so making the jacks compatible is no problem, but I am unsure and not knowledgeable about if the two types of circuits are fundamentally incompatible.)

Or does a balanced amplifier require a balanced input signal to run correctly? What happens when a balanced amp sees a single ended signal (only two of three pins of the balanced connector carries signal)?

Any useful input would be welcome.
troidelover1499
ebm
9,311 posts
 
Call ARC asap.
jjss49's avatar
Ag insider logo xs@2x
jjss49
6,612 posts
 
definitely call or email greg christensen at arc and ask... i suspect the answer is no go... the balanced amp will run, but it won’t run properly, as designed to run
brxl
21 posts
 
The simple Adapter (or DIY) is to connect the inner RCA with (+) Pin2, outer RCA with GND Pin1 and short (-)Pin3 to GND. That sends the "negative" half of the balanced amp on a very long vacation.
You can get yourself two 1to1 transformers...and connect accordingly (that's a challenge with the info given above for you to solve ;-)
Other solution ....2 OpAmps

cheers
brxl
docknow
309 posts
 
I ran into this same problem when I purchased a REF110 to replace my D115mkII when I owned a AI M3a. I was told that adaptors would not work well, leading to higher distortion. I ended up purchasing a LS16mkII and buying balanced cables.
atmasphere's avatar
atmasphere
11,794 posts
 
The Reference 110 is very unhappy with a single-ended source! Essentially its input circuit has a very poor Common Mode Rejection Ratio (CMRR); another way of putting that is that it will have high distortion and low gain if operated by a single-ended signal. The distortion goes to about 10% and the output power to about 1/5th of what it should be. So you need a balanced source!

But you can use your single-ended preamp- you just have to drive a line transformer (Jensen makes some that are excellent) to do the conversion for you.
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