If Warmth Is a Distortion, Why Do So Many Audiophiles Still Defend It?

Can you explain how you do this:

"You don’t need double the circuitry for a balanced line setup. Our preamps have been fully balanced and differential since their inception in 1989." ?

@kevemaher Sure! We use differential circuits, which seem to require about 50% more parts in round numbers. In places like the phono section where EQ is required, that is done in the differential domain so is the same number of parts that you would see in a single-ended circuit. 

The outputs of our preamps use a circuit called a Circlotron. We obtained two patents regarding its use. Its a fairly simple circuit though that does not take a lot of parts. 

@atmasphere 

Thanks for the explanation.

Am I correct in assuming that you differentially add two input phases from the XLR input jack at or near the input and then use the Circlotron for the output? (I read the Wikipedia article. Clever way to avoid transformers!) In between those is a single ended signal path.

Or am I not thinking clearly?

Some people like catsup on their steak, some like A-1 and some think any sauce is an abomination.  There is no right or wrong taste.

Also, room acoustics and high frequency sensitivity are often factors.

Gary

Too long to read all this over such an easily answered question.  Cause it sounds good bro! 🙄

Am I correct in assuming that you differentially add two input phases from the XLR input jack at or near the input and then use the Circlotron for the output?

@kevemaher I’m not exactly sure what you are asking about here. I wanted to see what would happen if the entire circuit was balanced/differential from input to output. So no single-ended circuits; the signal pins (2 and 3) of the XLR connection drive a differential amplifier in both the phono section and line stage. The Circlotron circuit is the output of the line stage. We use a servo to detect any DC Offsets and correct them. The servo is not responsive anywhere near audio frequencies. In this manner driving low impedance inputs has no effect at all on the preamp’s ability to play low frequencies.  

The advantage of using differential amplifiers is you get noise rejection; if there is noise (perhaps a buzz) to which the interconnect cables are subjected, that noise is common to both the inverting and non-inverting inputs. So the differential amplifier has a property called Common Mode Rejection Ratio (CMRR), which is measured in deciBels. Noise introduced to the interconnect cable tends to not be amplified, unlike a single-ended connection. 

In addition, differential amplifiers also have immunity to power supply noise. 

FWIW a balanced circuit that isn’t differential has no CMRR at all unless the input is transformer coupled.  Circuits like this are simply two single-ended circuit duplicated, one for each phase. They really do require at least double the parts.