Why Single-Ended?


I’ve long wondered why some manufacturers design their components to be SE only. I work in the industry and know that "balanced" audio lines have been the pro standard (for grounding and noise reduction reasons) and home stereo units started out as single-ended designs.

One reason components are not balanced is due to cost, and it’s good to be able to get high quality sound at an affordable price.
But, with so many balanced HiFi components available these days, why have some companies not offered a fully-balanced amp or preamp in their product line?
I’m referring to fine companies such as Conrad Johnson, Consonance, Coincident, and Bob Carver’s tube amps. CJ builds amps that sell for $20-$39K, so their design is not driven by cost.

The reason I’m asking is because in a system you might have a couple of balanced sources, balanced preamp, and then the final stage might be a tube amp or monoblocks which have SE input. How much of the total signal is lost in this type of setup? IOW, are we missing out on sonic bliss by mixing balanced and unbalanced?

128x128lowrider57
I totally agree Charles. I've been following and enjoying all of these well informed ideas and learning quite a bit in the process. Sounds as if both topologies can offer great sound if properly designed and implemented. Kudo's to all the gents that have contributed their vast knowledge in such a civil fashion. I'm looking at purchasing a new pre and amp that are OTL but don't know if they are single ended or fully balanced.....on one hand this discussion makes me want to find out but on the other hand I guess it doesn't really matter since either approach has its merits. 
Mac,
The OP asked why single ended? He's receiving substantive replies. 
Charles 
Thank you Charles.  While not opposing any topology I think less is more.   As electrical noise is concerned, home environment is in most cases benign.  I argue to learn/understand and I have, especially from Al and Ralph.  This forum is great.
Yes Charles, I'm getting much more info than I expected. And very pleased that a discussion about the different designs has happened.
 Glad that some of brightest minds on the forum have joined in.
Jim
dbphd: "The manual for the Ayre phono stage (I use a JC 3) includes diagrams that seem to suggest converting an RCA plug from a turntable to a balanced input, but I may be misreading that."

Ayre products are zero-feedback, fully-balanced designs.

Ayre provides only XLR connection for the phono input on my phono-stage equipped K-1xe and recommends using balanced-configured cables terminated with XLR connectors into the phono stage, thus they provide a diagram on their website to show how to construct a balanced-configuration XLR-terminated phono cable (pin 2 hot), "This is the preferred solution and offers the highest level of sound quality."

The manual shows the option of using RCA to XLR adapters if the user is determined to use a RCA cable: "...this converts the balanced input into an unbalanced input and causes a slight loss of sound quality."

The stand-alone P-5xe phono stage allows for XLR and RCA connection, but Ayre still recommends the using the balanced XLR inputs and outputs for "the highest level of sound quality."

Dave