HeadRoom Balanced Desktop Amp and Benchmark DAC1 USB - Head-Fi: Covering Headphones, Earphones and Portable Audio

dspargo · #1 (**permalink**) 07-27-2008, 06:34 PM

I recently bought the HeadRoom Balanced Desktop Amp to use with my Benchmark DAC1 USB but it looks like I made a mistake:

http://www.head-fi.org/forums/3827917-post1309.html

Any opinions from HeadRoom and the folks in the forum would be greatly appreciated.

elrod-tom · #2 (**permalink**) 07-27-2008, 06:41 PM

If I'm reading and understanding what was discussed in the linked post, I don't see where you have a problem.

You're (again, if I'm understanding) going to use the DAC1 as a source and your HR Balanced Desktop as the headphone amp. That ought to be no different than using any other source. I'm thinking the concern expressed in that post involves using the DAC1 as source and driving balanced headphones off of its XLR jacks - in other words, using the DAC1 as amp and source.

I don't think there's an issue here. Enjoy...

dspargo · #3 (**permalink**) 07-27-2008, 06:47 PM

He says in a recent post:

The DAC1/USB/PRE does, in fact, have true-balanced outputs. These outputs can drive balanced headphones. However, I strongly advise against this configuration using any balanced headphone amplifier.

Also, from the link above:

Balanced headphone amps will double the source impedance of an unbalanced headphone amp. No matter how low the impedance of a balanced headphone amp, it could be half that much if it was unbalanced. This is one reason balanced headphone amps are not a good idea. (It should also be noted that the balanced output of the DAC1 / USB / PRE is 60 ohms or greater, depending on the attenuator settings).

Not only will the source impedance double with balanced headphone amplifiers, but the total distortion and noise of the amplifier will double as well!! Every output device (opamp, transistor, tube) creates some distortion and some noise. If there are two opamps or transistors or tubes driving each headphone speaker, twice as much distortion and noise will be added!!

elrod-tom · #4 (**permalink**) 07-27-2008, 07:34 PM

OK, I think see where you're going with this.

It seems the poster is arguing against balanced headphone amps in general. I'm a fan of balanced headphone amps, and would respectfully disagree that balanced termination for headphones is a "bad idea".

Unless there is something specific about the DAC1 that I'm missing, I'm not sure why it would be any different than any other balanced source used with a balanced amp. My reading of this is that the poster in the linked post simply does not approve of the idea of balanced termination for headphone amps...period.

My suggestion is that you listen to it, and decide for yourself. I'm thinking that you may like it.

dspargo · #5 (**permalink**) 07-28-2008, 02:26 AM

Quote:

Originally Posted by elrod-tom

OK, I think see where you're going with this.

It seems the poster is arguing against balanced headphone amps in general. I'm a fan of balanced headphone amps, and would respectfully disagree that balanced termination for headphones is a "bad idea".

Unless there is something specific about the DAC1 that I'm missing, I'm not sure why it would be any different than any other balanced source used with a balanced amp. My reading of this is that the poster in the linked post simply does not approve of the idea of balanced termination for headphone amps...period.

My suggestion is that you listen to it, and decide for yourself. I'm thinking that you may like it.

Thanks!

dspargo · #6 (**permalink**) 07-29-2008, 01:29 AM

Can someone from HeadRoom please comment on my initial question?

nd4speed · #7 (**permalink**) 07-29-2008, 07:53 PM

Like elrod-tom says, I think it's just a case of differing opinions (take it with a grain of salt). Obviously, Elias subscribes to a radically different view on balanced then does Headroom (read carefully and you'll see he discounts ANY merit of going balanced, which gives me pause).

pirate6955 · #8 (**permalink**) 07-30-2008, 03:03 AM

Quote:

Originally Posted by dspargo

Can someone from HeadRoom please comment on my initial question?

what actually _is_ the original question here?

dspargo · #9 (**permalink**) 07-31-2008, 01:50 AM

Help HeadRoom!

n_maher · #10 (**permalink**) 07-31-2008, 02:18 AM

Quote:

Originally Posted by dspargo

Can someone from HeadRoom please comment on my initial question?

I think elrod_tom addressed it as well as anyone can. But since you're not satisfied I'll have a go. If you're asking a) whether or not balanced is worth it my answer is yes, I've heard the amp in question an it is very nice. If you're asking b) can you use the DAC1 as the source the answer is also yes, the quote you included is (I think) saying that the DAC1 is not suitable for driving headphones directly which is true. It is, however a fine source for any balanced headphone amplifier, even though Benchmark's engineer happens to think that balanced headphone amps in general are not a good idea.

If you want Headroom's counter argument (they are, afterall pretty much the pioneer of the idea of balanced headphones) I suggest reading all of this.

wavoman · #11 (**permalink**) 07-31-2008, 02:37 AM

Quote:

Originally Posted by dspargo

I recently bought the HeadRoom Balanced Desktop Amp to use with my Benchmark DAC1 USB but it looks like I made a mistake ...

You didn't make a mistake, you did perfect research, I would have bought the exact pair for the given dollars. You are dead optimal. I have actually heard this pair with Senn 600's using a balanced cable (don't recall which one). You will connect the balanced XLR outs of the Benchmark to the balanced XLR ins on the HeadRoom, and then plug your balanced HPs into the front of the HeadRoom. And you will love what you hear.

Relax and enjoy. Benchmark does not provide balanced HO, only SE HO, so of course they don't recommend it. Their comments re noise may be true for their units, but not for HeadRoom's or Ray Samuels RSA Apache (which I have heard) or (I assume, have only really heard those two, and one SinglePower balanced) any other dedicated balanced HP amp suggested by the members here. These implement true dual paths; there is no doubling of the noise.

HeadphoneAddict · #12 (**permalink**) 07-31-2008, 03:52 AM

When Elias was speaking out against balanced headphone amps due to doubling the noise and distortion is when I tuned him out and stopped following the DAC1 thread.

The Headroom Desktop balanced has a THD at 1V output: <.002 which is pretty darn low. And if I am guessing that if a normal signal to noise ratio is 110db then doubling the noise will drop the signal noise ratio to 107db, which is still pretty darn good. The benefits of controlling the driver better with push pull amplification, and keeping the right and left driver electrically isolated from each other to eliminate crosstalk outweigh any increase in distortion or noise as discussed above.

dspargo · #13 (**permalink**) 07-31-2008, 05:25 AM

Quote:

Originally Posted by n_maher

I think elrod_tom addressed it as well as anyone can. But since you're not satisfied I'll have a go. If you're asking a) whether or not balanced is worth it my answer is yes, I've heard the amp in question an it is very nice. If you're asking b) can you use the DAC1 as the source the answer is also yes, the quote you included is (I think) saying that the DAC1 is not suitable for driving headphones directly which is true. It is, however a fine source for any balanced headphone amplifier, even though Benchmark's engineer happens to think that balanced headphone amps in general are not a good idea.

If you want Headroom's counter argument (they are, afterall pretty much the pioneer of the idea of balanced headphones) I suggest reading all of this.

Your post is what I was looking for...thank you!!!

dspargo · #14 (**permalink**) 07-31-2008, 05:29 AM

Quote:

Originally Posted by wavoman

You didn't make a mistake, you did perfect research, I would have bought the exact pair for the given dollars. You are dead optimal. I have actually heard this pair with Senn 600's using a balanced cable (don't recall which one). You will connect the balanced XLR outs of the Benchmark to the balanced XLR ins on the HeadRoom, and then plug your balanced HPs into the front of the HeadRoom. And you will love what you hear.

Relax and enjoy. Benchmark does not provide balanced HO, only SE HO, so of course they don't recommend it. Their comments re noise may be true for their units, but not for HeadRoom's or Ray Samuels RSA Apache (which I have heard) or (I assume, have only really heard those two, and one SinglePower balanced) any other dedicated balanced HP amp suggested by the members here. These implement true dual paths; there is no doubling of the noise.

Thank you too!!! It concerned me how Elias was so against balanced...and not just running balanced headphones directly from the DAC1...I get that.

dspargo · #15 (**permalink**) 07-31-2008, 05:32 AM

Quote:

Originally Posted by HeadphoneAddict

When Elias was speaking out against balanced headphone amps due to doubling the noise and distortion is when I tuned him out and stopped following the DAC1 thread.

The Headroom Desktop balanced has a THD at 1V output: <.002 which is pretty darn low. And if I am guessing that if a normal signal to noise ratio is 110db then doubling the noise will drop the signal noise ratio to 107db, which is still pretty darn good. The benefits of controlling the driver better with push pull amplification, and keeping the right and left driver electrically isolated from each other to eliminate crosstalk outweigh any increase in distortion or noise as discussed above.

I will tune him out on the balanced piece too because he is definitely part of a small minority. Thank you!