Okay to use RCA adapter on a fully balanced amp?


Not a XLR is better or RCA is better question BUT if I have an amp (Digital Amplifier Co) that is fully balanced and only has XLR inputs, if you use a converter and go RCA from a Preamp, are you losing out in quality?

 

Here is something from audioholics and their review of one of their amps - 

"The MEGAschino is a true fully balanced differential amplifier from input to output. It is essentially two  amps for each channel, and one amp per phase. This means it really should be used in a fully balanced system.The manufacturer supplies an XLR to RCA adapter, but these should not be used. If a balanced connection cannot be used, note that the amp cannot be driven to full power from a 2-volt single-ended output, the limit of most receivers."

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Here’s the part that concerns me about this amp possibly not having a "true" differential input, despite earlier verbiage:

If a balanced connection cannot be used, note that the amp cannot be driven to full power from a 2-volt single-ended output, the limit of most receivers. You leave half the power on the table.

Maybe it’s a real differential input and the amp simply has a very low sensitivity that requires more than 2 Volts to hit its full rated power output (i.e. use a single ended preamp with some gain, or a DAC with some extra gain, and you’re golden). Or maybe it actually DOESN’T have a differential input, and half of the amp’s 4 phases will be sitting at 0 whenever you use RCA-to-XLR adapters.

We’re trying to derive precise meaning from their verbiage, which could be either partially erroneous or easily misinterpreted. I’d contact the company for clarification.

I just received my Orchard Audio Starkrimson amp today and this is what I purchased with it to convert the balanced to unbalanced and it also supplies an extra 8db of gain

 

Stereo RCA to XLR Converter (orchardaudio.com)

 

Here’s the part that concerns me about this amp possibly not having a "true" differential input, despite earlier verbiage:

If a balanced connection cannot be used, note that the amp cannot be driven to full power from a 2-volt single-ended output, the limit of most receivers. You leave half the power on the table.

@mulveling According to their website, the amp is fully differential and balanced from input to output. Its a bit hard to imagine, but it is possible that the input stage has a really poor CMRR (Common Mode Rejection Ratio) which would cause it to be more distorted and lower power when run with a single-ended source. But its hard to imagine that they would know to do balanced and get the CMRR thing so bad in that light- although I have seen that sort of thing happen.

At any rate it won't hurt to try! If the CMRR is anywhere near what we've been getting with our amps over the last 45 years it won't be any problem at all.

 

 

I have experienced what the OP is talking about. That is why I purchased the active adapter in my previous post

My amps are fully balanced and there is no issue with using them with RCA to XLR adapter. 

The adapter grounds one of the differential inputs to ground and then the amplifier behaves like a single-ended to the differential converter.

The gain of the amplifier does not change and it requires 5V input to get it to full power. This is an issue with standard RCA 2V outputs as 2V will get you less than 1/4 of the amps rated output power.

This is why I recommended to most my customers to get my active RCA to XLR converter that @evank refers to above. With 8dB of gain, it takes 2V up to 5V.