Headroom Module Archive thread

[TheSloth]

Quote:

Originally Posted by jcx At the same power P Balanced Drive amplfiers have to supply the full current I from both amplifiers at the same time to compare we want the same power P into a given load R P = I * V, I = V / R To get a given P a single ended amp is putting out current I amperes and V volts In a Balanced Drive amp there are 2 amplifiers , each putting out ½ V (+ and -) for a total drive voltage difference across the load of ½ V – (- ½ V) = V with V volts across load R the current drawn is V / R = I which is the same current the single ended amplifier has to supply In Balanced Drive each amplifier has to still supply the full I even though they only swing ½ V each Because the operating point of each amplifier side of the Balanced Drive has to supply the full I for only ½ V we say the load on each amplifier looks like the impedance (resistance) is lower by ½ = a 2x “heavier” load Balanced drive doubles the possible voltage swing, but to achieve the potential 2x V the amplifiers on each side would have to supply 2x I

Thank you for the clarification. The relevance here is that in terms of the output stage of the module, it makes no difference to the amount of current supplied whether it is a balanced setup or not, and therefore the improvement from the new output stage will be common to both single ended and balanced drive schemes. In a balanced drive scheme, the imedance is halved, however the current output of each module remains unchanged.

 

[Tyll Hertsens]

I had come to this conclusion myself after thinking about it for a while, but jcx has got it right here. As he said earlier on, I believe, there is a virtual ground half way into the coil of the cans. Each side of a balannced amp is essentially driving half the headphone coil...sort of....

His post also points out that as the impedace of the headphone goes down the amp has to put out more current per volt. If it weren't for the fact that they tend to be far more efficient, low impedance headphones would be harder to drive than high impedance cans.

 

[TheSloth]

Added initial impressions of '06 Max Module to post 22.

 

[TheSloth]

A little tip for those with a Desktop or Home DAC using computer based optical audio out: if your computer is capable of producing a bit accurate stream, and you are using it to feed the Desktop or Home DAC's, upsample it to 24/96 first. There is a reason there is an upsampling section in the Max DAC and it really makes a pretty obvious difference. Of course, I only noticed the deficiency in the first place because of those damn Max '06 Modules, but it's not bad for a free upsampler.

 

[tom2517]

Quote:

Originally Posted by TheSloth A little tip for those with a Desktop or Home DAC using computer based optical audio out: if your computer is capable of producing a bit accurate stream, and you are using it to feed the Desktop or Home DAC's, upsample it to 24/96 first. There is a reason there is an upsampling section in the Max DAC and it really makes a pretty obvious difference. Of course, I only noticed the deficiency in the first place because of those damn Max '06 Modules, but it's not bad for a free upsampler.

Interesting, I will try it.

 

[TheSloth]

Small update to post 22 with some further impressions of the Home and Max Modules.

My favourite module, taking into account factors of price, performance, power consumption and size, from this revision is the Desktop Module. Obviously, the Max Module sounds amazing and sets a new reference standard for HeadRoom, but the surprise to me is just how good the Desktop Module sounds considering it's the 'low end' module. It just loves K701's, is clean yet musical, places no particular strain on the power supply used, and is available without any extra cost in the Micro and Desktop lines.

 

[all2ofme]

Brilliant thread - helped me choose what I went for to go with my HD650s.

Out of interest, though, I'm confused as to which way you're leaning with the following:

----------------------------
A side effect of all of these upgraded modules has been that I have not once found myself reaching for my HD-650's since the headphone comparison. The K701 has, without my noticing until now, completely taken over as my reference headphone.
----------------------------

Update 1: The clarity of this has proved too much for my K701's, and I'm back to 650's. It seems that I prefer my K701's when the system has a bit of extra warmth behind it, and the 650's in a more neutral setup.
----------------------------

Which of these did you write first?

What's your current feeling with your 650s/701s?

Ben

 

[Ruppin]

Quote:

Originally Posted by TheSloth '06 Modules My initial impression of this new reference standard is that is by far the most neutral sounding module I've ever heard from HeadRoom. It is NOT forgiving of weaknesses in the signal chain. I am hearing deficiencies in the Desktop DAC that I hadn't heard before - traces of harshness here and there, and a slightly dry sound overall. The sound is right there, without the slightest veil, throwing at your ears whatever you throw at it. It is not inherently harsh or 'forward' however, it just seems to be dangerously transparent. I can hear the difference very easily between the optical output and USB output on my MacBook Pro. The Home Module in comparison is a little warm and fuzzy, especially in the bass, and not the last word in transparency. With lesser sources, the Home Module might be a more pleasing sounding choice to round out the sound a bit, but with a killer source (something I will lack for the forseeable future unfortunately) the Max Module is a markedly more transparent module that will let you hear the most subtle nuances of your recording, as well as cables and all the other junk that sits between the performers and your ears. It's bass response is fantastic, with amazing control over the headphone driver - my K701's produce that wonderful soft visceral feeling of the lowest bass fundamentals when driven by this module. The Max '06 seems to add or subtract practically nothing - that will take a bit of getting used to! Recommended heartily only for people with sources of equivalent quality! Update 1: The clarity of this has proved too much for my K701's, and I'm back to 650's. It seems that I prefer my K701's when the system has a bit of extra warmth behind it, and the 650's in a more neutral setup. Update 2: I've now had the opportunity to spend quite a few hours with the Max Module, and am more and more impressed by the refinement it brings to the performance of HeadRoom's 'cost-no-object' solution. It isn't initially particularly impressive, due to it's neutrality. But the more time I spend with it, the more I appreciate it's sonic honesty. I find the totally controlled, textured and layered bass rather addictive after a while, but it is so well controlled that it takes a while to actually appreciate what it offers - it doesn't jump out at you, it's just there when it's called for and disappears when it's not. It sounds just delicious with the 650's, and when the bass is that clean, it makes me rethink the idea of the 650's having a bass 'hump'. As I said in my earlier update, I find the K701 just too thin sounding in this setup, and find it has bettery synergy with the warmer sounding modules, and perhaps warmer sources in general (I wonder if the K701 really wants a nice tube amp). The 650 OTOH really needs incredibly clean drive to sound its best, and that's exactly what it gets from the '06 Max Module. .

Great information, TheSloth. I have ordered my early 2006 Balanced Home upgraded so that it will have the new Max Modules to go with its original Max Dac and Stepped Attenuator. I intend to use uncompressed or Apple Lossless files (ethernet to airport express to Toslink to Home: or Mac-toslink-home) to feed the beast. Does this qualify as a source of "equivelant quality". If not, what would be? Specifics would be appreciated with respect to CD players or transport and dacs.

I tend to use balanced 650s with Cardas Cables with the Home. Just to pick up on some of your comments on the AKG 701s, they do indeed, in my opinion, sound great with my 2005 Micro (destop module), and they also sound great with a tube amp, as you suggested they might. I look forward to trying them with a new micro with desktop, too. I wonder about obtaining a balanced pair for the new maxxed out Home. Do you think the balancing would help?

Edited to delete pictures thereby shortening thread.

 

[hyamaiata]

Quote:

Originally Posted by TheSloth HeadRoom are working on some exciting things for the future and cannot impliment them with the number of pins currently available on the module. So this is the end of the line for the convertible, and as far as upgrading your existing amp, there is little point waiting for another revision: there isn't going to be one. If you are interested in the upgrade, just do it.

For now, I'll just get a Micro DAC and instead of upgrading my module, I'll wait for those exciting things to come out. When is it going to be?

 

[TheSloth]

Quote:

Originally Posted by all2ofme Brilliant thread - helped me choose what I went for to go with my HD650s. Out of interest, though, I'm confused as to which way you're leaning with the following: ---------------------------- A side effect of all of these upgraded modules has been that I have not once found myself reaching for my HD-650's since the headphone comparison. The K701 has, without my noticing until now, completely taken over as my reference headphone. ---------------------------- Update 1: The clarity of this has proved too much for my K701's, and I'm back to 650's. It seems that I prefer my K701's when the system has a bit of extra warmth behind it, and the 650's in a more neutral setup. ---------------------------- Which of these did you write first? What's your current feeling with your 650s/701s? Ben

Hi there! I wrote the first one first! That was when I had spent most of my time listening to the '06 Desktop Module before the others arrived, and found it just had amazing synergy with the K701.

The second comment was after I bought a DPS and had Home and Max Modules to play with, and found that the clean, neutral presentation of the new Max Modules gave me everything I wanted from my 650's in my current setup, with less than perfect source (the Desktop DAC is good, especially for the price, but it's not the same quality as the Max Modules). The K701 seemed to show up everything that was wrong in the high midrange which I found fatiguing. For the K701's, with my source, I prefer the Home Moules for a slightly more relaxing, tubey (only slightly) sound.

 

[TheSloth]

Quote:

Originally Posted by hyamaiata For now, I'll just get a Micro DAC and instead of upgrading my module, I'll wait for those exciting things to come out. When is it going to be?

In about 4 years time...

 

[TheSloth]

Quote:

Originally Posted by Ruppin Great information, TheSloth. I have ordered my early 2006 Balanced Home upgraded so that it will have the new Max Modules to go with its original Max Dac and Stepped Attenuator. I intend to use uncompressed or Apple Lossless files (ethernet to airport express to Toslink to Home: or Mac-toslink-home) to feed the beast. Does this qualify as a source of "equivelant quality". If not, what would be? Specifics would be appreciated with respect to CD players or transport and dacs. I tend to use balanced 650s with Cardas Cables with the Home. Just to pick up on some of your comments on the AKG 701s, they do indeed, in my opinion, sound great with my 2005 Micro (destop module), and they also sound great with a tube amp, as you suggested they might. I look forward to trying them with a new micro with desktop, too. I wonder about obtaining a balanced pair for the new maxxed out Home. Do you think the balancing would help? Edited to delete pictures thereby shortening thread.

I think you'll be amazed by balanced Max '06 Modules. Quite a few people were at the National Meet, though I've actually not heard such a combination.

Regarding sources, I think APX is an excellent transport, with surprisingly low jitter. When I had Max DAC's in both Desktops and Balanced Home's I used APX in exactly that manner and found the sound quality to be excellent, and considering what you pay as an add-on for the Max DAC, unbeatable in the VFM department. You may want to try optical output directly from your Mac, and use AudioMidi setup to upsample to 24/96. I find with my Desktop DAC that the upsampling in this way results in a significant improvement in sound, and possibly a reduction in jitter. Of course the Max DAC does already have upsampling, but that is to 192k, so is not redundant, and I believe the 96k stream from the computer may have less intrinsic jitter in the first place, making the later upsampling and reclocking even more effective. To cut all of that short, yes I do think the Max DAC is a source worthy of the Max Modules, and may be getting HeadRoom to shoehorn a Max DAC into the convertible (paid for of course) in the near future. You could get better sources, but a fully balanced DAC that would sound better than the Max DAC in the Balanced Home is going to set you back more than $2k.

Apple Lossless --> APX --> Balanced Home [Max DAC -> Max Modules] --> Balanced HD-650 was once something you would find in my signature. Unfortunately, duty called and it was reluctantly sold to help fund my beautiful piano.

 

[Ruppin]

Sorry TheSloth, but now I am a bit confused. When you say "APX" are you referring to Apple?

I just used spotlight to find a utility called Audio Midi, but haven't a clue how to set the output and input controls to achieve upsampling. Also, will the utility work through an airport express?

Thanks for introducing me to a new utility.

 

[TheSloth]

Quote:

Originally Posted by Ruppin Sorry TheSloth, but now I am a bit confused. When you say "APX" are you referring to Apple? I just used spotlight to find a utility called Audio Midi, but haven't a clue how to set the output and input controls to achieve upsampling. Also, will the utility work through an airport express? Thanks for introducing me to a new utility.

APX refers to AirPort eXpress! I don't like APE, the other acronym. When you open Audio MIDI setup, you will see a screen that in the right bottom section has settings for Audio Output. When no output device is connected, the source will read 'internal speakers'. When you plug in your optical cable, it will add the option to select 'digital output'. Next to the format, it will by default be set to 44100hz 2ch-24 bit. To upsample, simple click on the drop down menu and set 96000hz (the highest sampling frequency the HeadRoom DAC's can handle). The only irritation with this is that whenever you plug in or unplug the output device, the sampling frequency resets to either 44100hz if you aren't doing anything, and 48000hz if you are playing a DVD. When you get your amp back, play around with it and see if you hear any differences when fliping between the various sampling rate settings.

Airport Express always outputs at 44100hz, 16bit, irrespective of what sampling rate the original file is. That is not such a bad thing, as it's output is very reliable and relatively low jitter because of that.

 

[Ruppin]

Thanks, I'll give audio midi a try.

So, the Apple using the APX or an optical out with a good external DAC (max DAC, Benchmark(?)) as good as a dedicated redbook CD player? Or is there a point where the external transport is better? Cary 303/300? Meridian?