2. amps-preamps
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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?

lowrider57
keithr
1,306 posts
 
Honestly you need to audition all kinds of amplifiers (I have). They work best with different speakers as well. I personally don't like SET amps at all (and I've owned 101db and now 91db speakers and tried at least a half dozen of them). I tend to prefer 3rd harmonic over 2nd I guess. But the people who are adamant that only one way is technically correct or sounds right are to be ignored. 

Ironically, the best I've ever heard Avantgarde was Trios w/ basshorns on BAT tubes years ago. The audience gave standing ovations - but darn those complicated balanced amps :)

kijanki's avatar
kijanki
4,477 posts
 
Thank you Ralph for explanation about third harmonics. I understand that advantage of the fully balanced configuration is removal of second harmonic to better hear the third one (that you try to lower?). As for the balanced cable - yes it can run further because of superior noise rejection but still suffers from effects of the capacitance between wires. There is no way of getting rid of it. Capacitance to shield is different story. Reducing it would require usage of low capacitance signal transformers. Otherwise - even if you completely "float" signal ground in preamp and amp it will find return, by substantial capacitance of power transformer, to chassis (that you earth ground) hence to shield attached to it. Am I missing something?

Rane paper shows XLR cable (pattern1) with shield grounded at female end only, while common XLR cables, sold in stores, have shield grounded at both ends.

atmasphere's avatar
atmasphere
12,164 posts
 
It would seem so.

In order to support the balanced line standard:

1) pin 1 is ground, pins 2 and 3 carry the signal
2) the signal occurs between pins 2 and 3.
3) Ground (shield) is ignored
4) the system is low impedance.

Again as I pointed out earlier, most high end audio systems don't do so well with 3) and 4) nor for that matter 2).

If they did though, the capacitance becomes a non-issue in lengths of 200 feet or so (which should be practical in most homes- at my place they are only 30 feet).

So, Again. If the equipment supports the balanced standard, you won't hear the effects of the cable. IOW if you can hear the effects of the cable, its likely that your gear does not support the standard.
controlcentral
4 posts
 
I come from the 'pro audio' side. Looking for a reasonably priced ( OK, cheap) 5 channel amp, I couldn't believe that so many 'hi-fi' amps are unbalanced. I've never used a fully balanced topology (may be, probably is, superior!), but I've come to the conclusion that an XLR connector (with a short cable run)  just introduces yet another circuit into the audio chain ( balanced->unbalanced op-amp) which is to be generally avoided, notwithstanding that companies often choose to shave-off a few cents of quality at this junction.

nugat
38 posts
 
Can somebody give definitions and explain differences  between:
single ended
balanced
truly balanced
fully balanced
differential
differential balanced 
full differential
truly full  balanced
truly full differential balanced



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