Balanced Amplifier with un-balanced DAC?

You need a DAC with a balanced output . Without a balanced input singal to the amp you won't have a balanced singal out of the amp. .

The pro audio market has cheap and great sounding balanced DACs.

To add to the previous posts, not all headphones benefit from balanced operation. In my experience, it's typically high-impedance, inefficient headphones that benefit most from balanced operation (like the HD650). Almost all of the low-impedance, efficient headphones that I've tried balanced did not benefit from it - the only exception I've heard was the Audio-Technica W5000.

It is very easy to get a balanced signal at the output of an amplifier (or preamp) when the input is single ended. 

Depending how the amp is set up it may cost less (ooh snap!) than doing it wrong.  If your counting pennies, and building on a budget its easy to do for very little additional expense if you plan well. For example every single amplifier that STAX makes (or has ever made for 'stats) will output a balanced signal with a single ended input. 

I dont think the SMACK has provisions for a balanced input. Unless I'm reading the description incorrectly it sounds like a single ended amp with a floated/center tapped transformer.

On that note, Id bet it sounds great! The circuit description makes it sound like something I built a few years ago. It was a very nice little amp and its current owner still enjoys it. 

Quote:

Originally Posted by Twinster 

I read the description of the Smack and was also thinking on sending them an email regarding balanced input.

 

Based on your experienced do you think I can expect good improvement with balanced headphone from a unbalanced input?

 

Also can you please tell me if the Smack architecture consider a hybrid amp?

 

Thanks
 

You could always add input transformers and XLR jacks. Makes balanced inputs to pretty much any amp easy. 

If it floats/center taps the output transformer I doubt there is any real difference. If it uses a balanced active stage, then there are differences compared to SE amps. Try a B52, or a singlepower XLR on the SE and balanced outputs - its a very different sound. Try a Balancing act on the 2 outputs - the same. 

I dont know if the SMACK is a "hybrid" or a "tube" amp. The line between the 2 is blurry, and I haven't even seen a schematic! In reality I gave up on this debate a while ago - its ultimately a very personal choice, and even then is somewhat conditional on the circuit.

In my own definition, it is totally possible to build a "tube amp" that has quite a few SS parts in it, provided their use is limited to certain applications - specifically that the use of SS parts is limited to CCS's and voltage sources. These circuit elements are NOT in the signal path and the tasteful use of a transistor or 2 here does less harm to the signal than a resistor or a resistor and a cap and may work better than an inductor. In the end careful use of SS parts in tube amps offers better performance than "traditional" parts (resistors, inductors, & caps) at a supremely affordable price. The only thing not to love is that there is a rule that says you cant have transistors in a tube amp no matter what problems they solve or what else they do.

I define hybrids as amps where the transistor is used to provide gain or drive a load. It can be a somewhat blurry line, but hybrids regularly perform amazingly well taking the best aspects of various devices and using them together. 

Quick question on "balanced" amps. If my amp has balanced (xlr) inputs on the back of the unit, but it only has a SE output in the front to put in your phones.. what purpose does that serve? Does feeding a balanced dac to the balanced inputs to a SE headphone make any difference in sound quality over the normal RCA setup? Kind of confused, thanks in advance.

Uncle Jessie:

If the amp is set up to accept a balanced input signal there can be some advantages in doing that. Its a problem that comes at you from a few angles. 

If you have noise issues, running a balanced signal into a single ended amp may solve it. After that, its only the lunatic fringe (myself included!) who spends as much time as head-fiers reterminating headphones with XLR plugs to plug into these amps. Ignoring head-fi, you cant really sell a balanced headphone amp. Its simply not convenient! 

Another factor comes from how DAC's and studio equipment runs. Many sources output a SE signal by using only half of the balanced signal - never combining the 2 signals against each other to eliminate certain distortions. It just seems funky to me. Why waste the best operation characteristics of the source like that? If the source isnt guaranteed to do it this way, its not the hardest thing to add to the amp. 

I would try them both and see what you think. If you dont hear a difference, do whichever is more convenient for you.