Headroom's Balanced Desktop

[KenW]

Oh, and by the way, my dear Sloth, I got the official go ahead that I can send you a Desktop Balanced w/Home modules to play with. I doubt it'll make it there before Christmas, but please email me you current shipping info (phone# too) to [email protected] so it can asap.

The rest of you can just wait.

Playing favs?? Where's the xmas spirit? Even though I've got a supra xlr, it would be interesting to see how they compare.

[KenW]

I love little boys and the color pink.

Eeewww....an you touched my 701's?? Hope you wipe 'em down and disinfect before you ship 'em back to me.

[TheSloth]

Something very odd is going on in this thread...

[Grand Enigma]

Something very odd is going on in this thread...

Whatever do you mean?

[Tyll Hertsens]

Hey! People are trying to sleep in here! Knock it off!

[TheSloth]

Look what I just found!

And now the bad news - there is a serious buzzing/grounding issue with the left channel irrespective of power supply or input. This is not a shipping unit, only a prototype.

[TheSloth]

And now the bad news - there is a serious buzzing/grounding issue with the left channel irrespective of power supply or input. This is not a shipping unit, only a prototype.

And now it has magically fixed itself. HeadRoom have introduced the self-repairing amplifier.

Listening to an iPod through balanced headphones is just silly-fun.

[n_maher]

Looking forward to your impression of the amp.

[volcomjerk]

Look what I just found!

And now the bad news - there is a serious buzzing/grounding issue with the left channel irrespective of power supply or input. This is not a shipping unit, only a prototype.

Dear god your HR Portable has been breached! What the hell did you do? haha

[TheSloth]

Dear god your HR Portable has been breached! What the hell did you do? haha

That's no Desktop Portable. That's 'The Convertible'! I still intend to make it red some day. If you can bear to go over there, you can read all about it at http://www4.head-fi.org/forums/showthread.php?t=136059

Anyway, I'll post detailed impressions on this when I have some time to put them together. There are however already some obvious differences just in terms of functionality to the Balanced Home I used to own. That case does get quite toasty.

Headphones to use are 650's with Balanced Cardas, sources are MBP optical out - Home Balanced DAC, or iPod (balanced via line driver).

[TheSloth]

First impressions:

Differences from other HeadRoom amps:

No filter switch (treble boost, 3dB from 1.5k or 3k) - no room for one on the board.

Power switch on rear panel.

No dedicated preamp outputs (though as the headphone outputs are XLR, there is no disadvantage to using those as outputs with the required m/f adapters).

No dedicated unbalanced signal path - the unbalanced connectors are fed through the line driver stage which adds some background noise to the signal (more on that later). To get a completely clean signal path for single ended headphones, the balanced inputs need to be used.

General usage notes:

Particularly when placed directly ontop of the DPS which itself can get somewhat toasty, the amps runs hot - it's not hard to see why they felt that Max Modules would be too unreliable as they put out consideraby more heat. Even when standing in free air outside the convertible, the Max's are too hot to touch.

The stepped attenuator has a very different attenuation curve to the pots in the other HR amps. At the low end, the steps are very small, and at the high end the steps are very large. This gives you excellent fine control of the volume, however requires that you optimise the gain setting to keep you in the bottom half of the SA's range. In my use, this means that I tend to have the gain set higher for the same given volume level, relative to what I might think was optimal with a pot.

The silly part:

The balanced iPod test. This was a real shock. Placebo or not, it sounds darn good. I have been using the iPod as a source a lot recently, fed into my convertible running Max Modules. This Desktop has only the Home Modules, but sounds at least as good and in some ways better than that setup. With 650's, the difference immediately strikes you in the bass response, which is more visceral yet at the same time more defined and tuneful - the fundamental tone is somehow more audible, with less general mud. The down side of the unbalanced signal path is that the line driver does add some background hiss to the signal. Combined with the iPod's low 1V output, the unbalanced input isn't really that great if you are using unbalanced cans, as the noise is at the same level but the gain is 6dB lower and therefore the voume setting 6dB higher. The hiss is not loud, but it's clearly there. Used in the context it's designed for, i.e. with balanced cans, the hiss is inaudible at normal listening levels, and you have to turn the volume up a fair way with a silent background to hear a hint of it. Remember this is a worst case scenario due to the low 1V input from the iPod. A source with a standard 2V output would give you another 6dB of S:N.

Would you want to run unbalanced sources through the balanced driver? You are getting a trade-off. You get a small degradation of the original signal, however you also give the amplifier increased control over the headphone, particularly noticeable in the lower frequencies. I'd say in this case it's a wash, and depends on what sonic aspects are most important to you.

The serious part:

The Home Balanced DAC test. This is really what this amp seems to be designed for - a 1 (or 2) box fully balanced digital source and amp. There's still a big debate about whether there are technically any real benefits from balanced drive, versus for example 3 channel topologies found in some DIY designs. There's no point getting into that debate here, as what is clear is that each situation is unique.

In the case of the HeadRoom Module designs, they do take on a greater level of authority when put together as balanced pairs, and when the signal path is as pure as it would be in a purely single ended design, what's there to lose except cash from your wallet? Whether it's a matter of simply having double the power output, reduction of crosstalk or neither of the above, there is a greater sense of presence. It's slightly smoother but yet less laid back at the same time if that's possible. What's odd about this setup is that it seems to have a greater sonic purity to my convertible setup. If this was a single ended comparison, I wouldn't hesitate to say that the Max Modules have a 'purer' sound than the Home Modules which are relatively euphonic, so it's odd to find that the change in drive scheme can clean up the sound the way it does.

I'm greatly enjoying having a stepped attenuator, which every time I come back to one I always say is the only way to go. Whatever config, whatever amp, if there's a SA option, get it. I think particularly for balanced drive where there are now 4 channels to match, it's a must.

Cosmetic oddities:

The front panel looks ever so slightly strange in that the volume control and switches are lower than they would be on a normal Desktop, leaving a lot of empty space above. This was as far as I can tell necessary, as the main board has to be placed on a lower rung to make room for the secondary board that houses the filter caps and DAC board.

The switches, in being 4 channel switches are nice and chunky, which I rather like. They feel solid when you flip them. Irrelevant but nice.

HeadRoom Desktop w/Max Modules, Max DAC and Stepped Attenuator + DPS: $1895

HeadRoom Balanced Desktop w/Home Modules, Home DAC and Stepped Attenuator + DPS: $2300 est.

That's over a $400 difference, and you are giving up dedicated preamp functionality (which these amps do extremely well), as well as a measure of headphone and input flexiblity. It's a real case where people will just have to listen for themselves to see what this balanced thing is all about. If you are convinced that balance drive is the way to go, then the Balanced Desktop it is, but if you aren't so sure, you can get an amp from HeadRoom that has better electronics throughout for $400 less.

[n_maher]

HeadRoom Desktop w/Max Modules, Max DAC and Stepped Attenuator + DPS: $1895

HeadRoom Balanced Desktop w/Home Modules, Home DAC and Stepped Attenuator + DPS: $2300 est.

Do you have some more recent pricing information? The last I heard it was:

Preliminary pricing for the amp will be $899 with Desktop Modules. $199 Home modules upgrade. $299 Desktop Balanced DAC, $399 Home Balanced DAC. $199 balanced stepped attenuator upgrade.

My math puts the total at: $899 base +$199 module upgrade +$399 Home DAC +$199 SA + $399 DPS = $2095. It'd be a shame if the base price has already gone up $200 more since I'm assuming they have the module and SA upgrades priced accurately.

[TheSloth]

Do you have some more recent pricing information? The last I heard it was:

My math puts the total at: $899 base +$199 module upgrade +$399 Home DAC +$199 SA + $399 DPS = $2095. It'd be a shame if the base price has already gone up $200 more since I'm assuming they have the module and SA upgrades priced accurately.

You're right, I just did it in a hurry and built an amp that has both a Desktop and a Home Balanced DAC in it!

[humanflyz]

Although technically you don't need the DPS right? I would appreciate any comparisons between running with and without DPS.

[TheSloth]

Although technically you don't need the DPS right? I would appreciate any comparisons between running with and without DPS.

I wish I could but I don't have the new high current supply, and the power consumption of the Balanced Desktop goes way over the +/-240mV ceiling of the 'brick' (my guess is it's chewing through somewhere around 500-600mA).

I did do some comparisons between the brick and the Desktop Power Supply in my head-fi module archive thread, and I am guessing that the new wall-wart is closer to the brick than the DPS in performance, but perhaps not. Even if the new supply is no better in quality, simply having much higher current availability should yield more headroom overall, as in my convertible setup I am running the brick at pretty much it's maximum output continuously.

Overall, while I think the DPS is a solid upgrade, the other stuff is more important. I use a combination of the Desktop DAC and Max '06 Modules running off the old 'brick' as my primary headphone setup, and think it works extremely well. You can save the $400 and only sacrifice that last ounce of performance, IMO. I used to own a DPS to use with it, but in the end when I wanted the cash for something else, I didn't feel like I was losing a great deal.

Sorry Tyll, I guess that isn't helping to sell DPS's, but then again, if you consider that by selling less DPS's you are lowering the price of admission by $400, you might sell more other stuff!