2. amps-preamps
  3. 128510-2280

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

Showing 5 responses by pbnaudio

pbnaudio's avatar
pbnaudio
1,613 posts
 
We only do balanced

http://pbnaudio.com/audio-components/audio-preamps/olympia-li-lxi

Our power amplifiers have a fully balanced input stage as well and when used as mono blocks the output stage becomes fully balanced as well.

http://pbnaudio.com/audio-components/audio-amplifiers/olympia-ebsa1

Even in our consumer direct line, Liberty Audio the topology  is similar

http://www.libertyaudio.com/products/b2b-2-line-level-preamp-dac

Same goes for the power amplifier

http://www.libertyaudio.com/products/b2b-100-all-mos-fet-stereo-power-amplifier

And the phono preamplifier, obviously you will need two of them just like the power amplifier

http://www.libertyaudio.com/products/b2b-1-all-fet-phono-preamp

Good Listening

Peter



pbnaudio's avatar
pbnaudio
1,613 posts
 
BD,

Probably not, would there be a way to use the KUBE between your source and the Preamp?  of course with several sources this is a problematic solution. Alternatively could you get a second KUBE ?  would require some fancy wiring but the signal would then be balanced, however probably more effort required than it is worth.


Good Listening

Peter
pbnaudio's avatar
pbnaudio
1,613 posts
 
Ralph,

"Please note that balanced and single-ended are inherently incompatible! You can’t be both at the same time- its either one or the other."  

You can feed a single ended signal into a fully balanced preamplifier, ground the negative (inverting) amplifiers positive input - connect the two negative inputs of both amplifiers (non inverting and inverting) together and a balanced signal will appear at the output of the preamplifier and the signal would be fully balanced from here on.

 Don,

"I have always wondered why "almost nobody" buys (or even tries) inexpensive "pro" balanced cables, on the "true fully balanced" audio equipment, such as Pass Labs and ARC. They sound the same as the expensive ones IMO!"

Me too,  the Canare L-4E6S  wire offered by Bluejeans cable and other makes for a nice set of interconnects.

Good Listening

Peter

pbnaudio's avatar
pbnaudio
1,613 posts
 
Al,

"When the RCA input is used in those cases the unused signal pin on the XLR connector is simply grounded, via either a jumper inserted into the XLR connector"

It is correct that some manufactures use a jumper pin from 1 to 3 when a input are configured with two options - XLR and RCA.  IMO there is several issues with this. First one being that pin 1 of a XLR should have Chassis ground (earth) potential - not signal ground which is what the inverting amplifiers input needs connected to when only feeding the non inverting amplifier to get a balanced output. 

Second one being that the non inverting amplifier is connected to ground via the volume control, which means that a varying resistance ( depending on Volume control setting ) is inserted between signal ground and the inverting amplifiers input.

Our preamps are configured so that when a RCA input is selected the inverting amplifiers positive input is connected to signal ground via a relay AFTER the volume control.  

Good Listening


Peter


pbnaudio's avatar
pbnaudio
1,613 posts
 
Lowrider,

In order to prevent ground hum most have 2 different grounds, one being Chassis Ground (earth, safety ground) which should also be connected to pin 1 of all XLR connectors both in and outputs.   Typically Signal ground is isolated from chassis ground with a dual diode in reverse parallel and a resistor - or something similar.  Signal ground should not be present on pin 1 of the XLRs

I have  referred to this paper before - it contains some very useful information about grounding 

https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf


Good Listening

Peter

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